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1 인사말 2010년한국의학물리학회춘계학술대회가공기맑고학문적기운이충만한대덕단지내표준연구원에서개최하게되었습니다. 본학술대회를위하여훌륭하게준비해주신표준연구원전국진박사님을비롯한많은분들에게다시한번감사를드립니다. 대덕단지는우리나라연구의요람지로서과학기술의메카이며나라발전의구심적인역할을하는곳입니다. 특히, 표준연구원에서수행하고있는방사선절대선량계측및보정방법등은의학물리분야의핵심적기본요소로서매우필요한분야입니다. 이번학술대회를통해서활발한학문적교류의장이펼쳐지고, 이러한아름다운단지내봄의기운이감도는대덕단지의향취를한껏누리시기를바랍니다. 이번학술대회에서는방사선선량측정을주도하고계시는국내외선도연구자 4분의초청강연을준비했습니다. 표준연구원기반표준본부장이신우삼용박사님의측정표준에관한특강을비롯하여, 전국진박사, 오영기박사, 김광표박사님의선량측정기술에대한현황과앞으로의전망에대한심포지엄은우리회원들에게유익한정보를제공하리라믿습니다. 1990년한국의학물리학회가창립된이래지금까지많은회원님들의노력으로비약적인발전을해오고있습니다. 창립당시의어려웠던태동기를지나그동안많은노력으로국내외적으로탄탄한위상을마련하였고이제한국의학물리학회의비상을기대하고있습니다. 특히, 2010년은한국의학물리학회가창립된지 20년이되는해로서, 지난역사를다시한번되돌아보고, 미래의의학물리발전을위하여새로운비전을제시할때라생각합니다. 우리학회에서도창립 20 주년을기념하기위하여, 기념학술대회및기념집발간, 의학물리제도및정책에대한발전계획등을수립하여미래의초석을다지고자합니다. 지금까지학회에보내주신성원에다시한번감사드리며, 학회의발전을위해열심히동참해주시고, 많은격려부탁드립니다. 마지막으로오늘학술대회에참석하신모든분들이즐겁고유익한시간을갖기를기대합니다. 감사합니다. ( 사 ) 한국의학물리학회장서태석

2 제 40 회한국의학물리학회춘계학술대회일정표 일시 : 2010 년 4 월 9 일 ( 금 ) 11:30 18:00 장소 : 한국표준과학연구원 (KRISS) 기술지원동 11:30-12:40 학술대회등록 & 접수 12:40-13:00 개회사서태석회장 (KSMP) 환영사 박용기선임부장 (KRISS) 13:00-13:40 Plenary Session Invited Talk 물리단위를중심으로하는측정표준여행 KRISS 기반표준본부우삼용 13:40-15:10 Professional Symposium: Advanced Dosimetry Issues in Medical Physics Field 좌장 : 김성훈 ( 한양대학교 ), 신교철 ( 단국대학교 ) 1. 국가표준기관에서의물흡수선량절대측정 KRISS 전국진 2. 방사선치료에서정도관리와선량측정계명대학교오영기 3. CT 에의한환자의방사선피폭이슈와그에따른국제연구및대응동향경희대학교김광표 Poster Session 15:10-15:40 Poster Session & Coffee Break 15:40-17:00 Scientific Sessions 1. 방사선치료분야 (8 연제 ) 2. 진단 / 핵의학 / 기타 (5 연제 ) 좌장 : 이동준 ( 인제대학교 ), 지영훈 ( 한국원자력의원 ) 좌장 : 최보영 ( 가톨릭대학교 ), 김경민 ( 한국원자력의원 ) 17:00-17:10 Coffee Break Industrial Presentation 좌장 : 이 석 ( 고려대학교 ) 17:10-17:40 INFINITT RTIS 및 Tomo Viewer 소개 인피니트헬스케어 최석우 17:40-18:10 임시총회 (2009년도재무발표 ), 논문 ( 구연, 전시 ) 발표상시상 18:00- 만찬행사 - ii -

3 제 40 회한국의학물리학회춘계학술대회목차 Plenary Session 1. 물리단위를중심으로하는측정표준여행 우삼용 ( 3 ) Professional Symposium 1. 국가표준기관에서의물흡수선량절대측정 전국진ㆍ하석호ㆍ이철영ㆍ김현문 (7 ) 2. 방사선치료에서정도관리와선량측정 오영기 ( 9 ) 3. Public Concern about Radiation Exposure from Computed Tomography and Relevant International Studies and Actions Kwang Pyo Kim ( 12 ) Scientific Session I - 방사선치료분야 O-T-01. Gated therapy에서환자의호흡양상유지방법이환자선량분포에미치는영향 안소현ㆍ백지혜ㆍ오윤진나원경ㆍ여인환ㆍ정재원ㆍ이레나 ( 15 ) O-T-02. Performance Evaluation of the In-house Software for Radiochromic Film Dosimetry Ji-Yeon Park, Jeong-Woo Lee Kyoung-Sik Choi, Won-Gyun Jung, Tae-Suk Suh (16 ) O-T-03. Effect of Multi-leaf Collimator and Set-up Error on Intensity Modulated Radiation Therapy: Bio-physical Perspective Jeong-Woo Lee, Ji-Yeon Park, Jeong-Hoon Park Kyoung-Sik Choi, Jin-Beom Chung, Semie Hong Jae-Sung Kim, Tae-Suk Suh (17 ) O-T-04. Depth Dose Measurement of Proton Therapy Beam by Using Scintillating Fiber Optic Dosimetry Ui-Jung Hwang, Hojin Jeong, Jeong-Eun Rah Sung Hwan Ahn, Sang-Yeob Lee, Myonggeun Yoon Dong Ho Shin, Se Byeong Lee, Sung Yong Park Kyong Won Jang, DongHyun Cho, Bongsoo Lee ( 19 ) - iii -

4 O-T-05. 투과선량측정법을이용한 IMPAC 시스템업그레이드전후빔변수의무결성검증기법의제안및활용 Siyong Kimㆍ오승종ㆍ서태석 ( 21 ) O-T-06. 팬텀을이용한 3차원초음파의부피측정정확성평가 백지혜ㆍ정광주ㆍ김명수김동영ㆍ안소현ㆍ오윤진나원경ㆍ조성호ㆍ이레나 ( 22 ) O-T-07. KRISS 137 Cs 감마선조사장치의공기커마절대측정 이철영ㆍ하석호 ( 23 ) O-T-08. KRISS 60 Co 감마선조사장치의공기커마절대측정 이철영ㆍ전국진ㆍ정재필 ( 25 ) Scientific Session II - 진단 / 핵의학 / 기타 O-D-01. Optimization of Radiation Dose and Image Quality for Various Phantom Sizes in MDCT Seung-Wan Lee, Do-Young Kim Dae-Hong Kim, Hee-Joung Kim ( 29 ) O-D-02. Shielding Effect of Lead Free Material for Diagnostic X Rays Energy Tae Jin Cho Young Gi Oh, Jin Hee Kim, Ok Bae Kim ( 30 ) O-D-03. TW3법을이용한한국인소아의골성숙도분포양상 오윤진ㆍ김혜순ㆍ안소현백지혜ㆍ나원경ㆍ조성호ㆍ이레나 ( 31 ) O-D-04. 콘빔 CT의산란선제거를위한 Multiple-slit 콜리메이터시스템 장지나ㆍ서태석장도윤ㆍ김시용 ( 33 ) O-D-05. 치과방사선의이용현황과치과방사선검사별유효선량측정 신기순ㆍ김유현ㆍ이보람한수철ㆍ이유경ㆍ이귀원박창서ㆍ박혁ㆍ장계용 ( 34 ) Industrial Presentation INFINITT RT Solution 소개 - RT PACS, RTIS - 최석우 ( 37 ) Poster - 치료 P-T-01. The Study of the Accuracy of Different Combination of Automatic Registration Factors in 2 nd Generation Tomotherapy Suk Lee, Jang Bo Shim, Kyung Hwan Chang Yuanjie Cao, Sam Ju Cho, Sang Hoon Lee Dae Sik Yang, Young Je Park, Won Seob Yoon, Chul Yong Kim ( 43 ) - iv -

5 P-T-02. The Study of Optimized Radiotherapy Plan in Intensity-Modulated Radiation Therapy of Lung Cancer Kyung Hwan Chang, Suk Lee, Jang Bo Shim Yuanjie Cao, Yoo Hyun Kim, Chul Kee Min Kwang Hwan Cho, Hyun Do Huh, Dae Sik Yang Young Je Park, Won Seob Yoon, Chul Yong Kim ( 44 ) P-T-03. Comparison of Target Coverage and Organs at Risk Dose between whole Field Intensity Modulated Radiation Therapy and a Junctioned Intensity Modulated Radiation Therapy with Conventional Radiotherapy Field in Treatment of Nasopharyngeal Carcinoma Jin Beom Chung, Woo Lee Jeong, Sung Joon Ye Jae Sung Kim, In Ah Kim, Tae Suk Suh ( 46 ) P-T-04. Isocenter Verification using Polymer Gel for Stereotactic Radiosurgery Kyung-Nam Lee Dong-Joon Lee, Dae-Hong Kim, Tae-Suk Suh (48 ) P-T-05. Beam Modeling Technique to Optimize Beam Spectrum and Dose Profile for Treatment Planning System Woong Cho, Jeong-Hoon Park Won-Gyun Jung, Jeong-Woo Lee, Lei Xing, Tae-Suk Suh (49 ) P-T-06. Feasibility Study of Radiophotoluminescent Glass Dosimeter for High-Energy Electron Beams Kihong Son, Chang Yeol Lee, Sang Hun Shin Seungwoo Park, Haijo Jung, Dong-Han Lee Mi-Sook Kim, Young Hoon Ji, Kum Bae Kim ( 50 ) P-T-07. Estimation of Diagnostic Imaging Dose irradiated for Patient Positioning Hojin Jeong, Ui-Jung Hwang, Jeong-Eun Rah Sung Hwan Ahn, Myonggeun Yoon, Dong Ho Shin Sung Yong Park, Se Byeong Lee ( 51 ) P-T-08. The Feasibility of Dose Delivery Error Prediction of IMRT Fields Using Support Vector Machine: Preliminary Results Hosang Jeon, Dahl Park, Ji Ho Nam Won Taek Kim, Yong Ho Kim Dong Hyun Kim, Dong Won Kim ( 52 ) P-T-09. PTW31014 Pinpoint 이온함의줄기가기준선량측정에미치는영향에대한예비분석 김성훈ㆍ조성구ㆍ허현도ㆍ최상현ㆍ최진호ㆍ신동오 ( 54 ) P-T-10. The Influence of Inserted Location of Inhomogeneities on Penetration Path of Proton So-Hyun Park, Won-Gyun Jung Jeong-Eun Rah, Sungyong Park, Tae-Suk Suh ( 55 ) - v -

6 P-T-11. 유리선량계와 Gafchromic 필름을이용한 Co-60 방사선의좁은직사각형조사면에대한방사선량분포측정 신상훈ㆍ박승우ㆍ이창열손기홍ㆍ최문식ㆍ이동한김금배ㆍ오원용ㆍ지영훈ㆍ정해조 ( 56 ) P-T-12. 최적의 CT 영상획득인자를이용한 TENOMAG 겔의선량분석 조광환ㆍ조삼주ㆍ이석이상훈ㆍ임상욱ㆍ허현도ㆍ민철기심장보ㆍ조유라ㆍ김용호문성권ㆍ김은석ㆍ권수일 ( 57 ) P-T-13. Cone Beam CT의 Virtual Simulator 개발 이정민ㆍ문선미ㆍ김가을심주희ㆍ금오연ㆍ한영이 ( 58 ) P-T-14. 간암치료의 4차원치료계획을위한변형가능영상정합기반의선량평가 정상훈ㆍ박성호ㆍ조병철박재원ㆍ윤상민ㆍ김종훈ㆍ안승도 ( 60 ) P-T-15. GEANT4를이용한강자기장의인가방향에따른비균질물질내광자선의깊이선량률변화평가 이세형ㆍ박성호ㆍ곽정원ㆍ정상훈 ( 61 ) P-T-16. 폐암치료시움직이는종양의체적결정을위한 Slow CT 효용성평가 안우상ㆍ박성호ㆍ곽정원ㆍ최은경송시열ㆍ김수산ㆍ안승도 ( 62 ) Poster - 진단 P-D-01. Age-Related Differences in Cerebral Glucose Metabolism Using PET-CT Hyun-Ju Ryu, Su-Jin Park, A-Ram Yu In-Soo Hong, Hee-Joung Kim ( 65 ) P-D-02. 잘못된반응순서가컴프턴카메라의영상해상도에미치는영향 서희ㆍ박진형김찬형ㆍ이주한ㆍ이춘식ㆍ이재성 ( 67 ) P-D-03. Neurochemical Profile Quantification of Normal Adult Mice Brain by ex vivo 1 H Magic Angle Spinning Solid-State NMR Spectroscopy Do Wan Lee, Dong Cheol Woo Sung Ho Lee, Sang Young Kim, Goo Young Kim, Hyang Shuk Rhim Chi Bong Choi, Hwi Yool Kim, Chang Wook Lee, Bo Young Choe ( 69 ) P-D-04. Neurochemical Dysfunction and Morphological Abnormalities on the Mouse Brain in Parkinson's Disease Moon-Hyun Yoon, Hyun-Jin Kim Jin-Yeung Chung, Bo-Young Choe ( 70 ) - vi -

7 P-D-05. 3차원자기공명담췌관조영술에서Prospective Acquisition Correction (PACE) Technique과 Respiratory Triggered (RESP) Technique의비교 : 정상인을중심으로 구은회ㆍ김문집이재승ㆍ이선엽ㆍ박철수ㆍ권대철동경래ㆍ류영환ㆍ최성현ㆍ조재환 ( 72 ) P-D-06. 기능적자기공명영상기법과자기공명확산텐서기법을이용한방사관에서손과발운동에관련된뇌척수로의부위별대응구조에관한연구 이동훈ㆍ홍철표ㆍ강진구ㆍ장성호ㆍ한봉수 ( 73 ) P-D-07. Evaluation of Fractional Anisotropy and Apparent Diffusion Coefficient of Broca's Area in Parkinson's Disease Using Diffusion Tensor Imaging Jung-Hun Lee, Kyung-Bae Lee Yun-Bong Choe, Bo-Young Choe ( 75 ) P-D-08. Metabolic Changes of Zebrafish Brain by Acute Alcohol Treatment Using NMR Spectroscopy Dong-Cheol Woo, Goo-Young Kim, Hyun-Joo Kim Eunjung Bang, Hyang-Shuk Rhim, Sang-Young Kim Do-Wan Lee, Chi-Bong Choi, Youl-Hun Seoung, Bo-Young Choe ( 77 ) P-D-09. Evaluation of Reducing Head Radiation Dose Using Automatic Exposure Control Technique Youl-Hun Seoung Yong-Ok Kim, Bo-Young Choe ( 79 ) P-D-10. Development of Radiation Dosimetry Methods to Establish Diagnostic Reference Levels in Radiographic Examination Kwang Pyo Kim, Haijo Jung Geon-Ho Jahng, Hyuk Joo Kim, Dong-Wook Sung ( 80 ) P-D-11. Radiation Dose in Cephalography by Monte-Calro Simulation: Collimation Effect Boram Lee, Gwisoon Shin, Kyunghwan Chang Wonho Lee, Jonghak Choi, Youhyun Kim ( 81 ) P-D-12. 진료용 X 선방어용품의납당량측정 이철영ㆍ김은주 ( 82 ) P-D-13. 스텐트의구조와기계적인반응의최적인자도출과유한요소해석법을통한검증 전동민ㆍ정원균ㆍ김한기ㆍ김상호ㆍ장홍석ㆍ서태석 ( 84 ) P-D-14. 미세석회화병변검출을위한 3차원 Digital Tomosynthesis 기법연구 황지명ㆍ김효정오지은ㆍ조효성 ( 85 ) P-D-15. Assessment of Utility for SMART Image Using Phantom Kyung-Bae Lee, Jung-Hun Lee Yun-Bong Choe, Bo-Young Choe ( 87 ) P-D-16. 진단 X- 선에너지스펙트럼측정 이철영ㆍ김현문ㆍ김용호ㆍ임천ㆍ이병영ㆍ이현구 ( 89 ) - vii -

8 제 40 회한국의학물리학회춘계학술대회 Plenary Session

9 제 40 회한국의학물리학회춘계학술대회 물리단위를중심으로하는측정표준여행 한국표준과학연구원 우삼용 미터체계에대한발상은프랑스혁명때인 1799년백금으로미터와킬로그램원기를제작하여프랑스파리에있는국립문서보관소에보관한데서출발한다. 후일이들문서보관소원기들은프랑스과학원에의해세계적으로사용될수있는새로운단위체계의기준으로사용되게되었다. 1946년미터, 킬로그램, 초, 암페어를나타내는 MKSA체계가미터협약국가들의승인을받아전세계적으로사용되게되었고 1954년온도 ( 켈빈 ) 와광도 ( 칸델라 ) 가단위계에합류하였다. 1971년물질량의기본단위로몰을추가하여오늘날의 7개기본단위가구성되게되었다. 이들은유도단위들과함께일관성있는단위체계를이루고있으며그에더하여국제단위체계이외의어떤단위들은국제단위계와함께사용되도록허용되었다. 이들중기본단위는주어진양의체계에속한기본량의측정단위이다. 각기본단위의정의및구현은측정학이발달함에따라수정된다. 본측정표준여행에서는가장기본적인물리량인시간, 길이, 질량을중심으로단위의과거와오늘그리고미래에대한여행을출발하고자한다. 시간단위의정의는 세슘-133 원자의바닥상태에있는두초미세준위간의전이에대응하는복사선의 주기의지속시간이다. 최초로세슘을이용한원자시계가개발된것은 1955년영국표준연구소이며이로써시간의정의가바뀌게되었다. 최초지구운동을기준으로하던초가어떻게진화해오늘날의정확도 에이르고있는지를설명한다. 길이단위의정의는 1983년 빛이진공중에서 1/ 초동안진행한경로의길이이다. 로정의되었으며이로써빛의속도가상수로고정되게되었다. 최초미터단위는파리를지나는지구자오선길이의 4천만분의 1로 1791년에정의되었으며그측정정확도는오늘날지속적으로향상되어 0.02 nm 수준의정확도를갖게되었다. 오늘날많이사용되는길이표준기는요드안정화헬륨네온레이저이며보다높은정확도를위해요드분자대신이터븀원자등을이용한연구가진행중이다. 질량단위의정의는 국제킬로그램원기의질량과같다. 이며오늘날남아있는유일한인공구조물을이용한표준이다. 킬로그램원기는백금 90%, 이리듐 10% 로이루어진합금이며파리에있는국제도량형국 (BIPM) 에보관되어있다. 킬로그램원기는조금씩이나마계속변하고있어자연의기본적인자연상수를이용한정의로의변경하려는노력이국제수준에서진행되고있다. 측정표준, 국제단위계, 기본단위 3

10 제 40 회한국의학물리학회춘계학술대회 Professional Symposium 좌장 : 김성훈 ( 한양대 ), 신교철 ( 단국대 )

11 제 40 회한국의학물리학회춘계학술대회 국가표준기관에서의물흡수선량절대측정 한국표준과학연구원삶의질표준부방사선표준센터 전국진ㆍ하석호ㆍ이철영ㆍ김현문 서론 : 흡수선량이라는물리량은 1954 년 ICRU (International Commission on Radiation Units and Measurements: 국제방사선단위및측정위원회 ) 에의해서방사선조사에의하여매질에흡수되는방사선량을평가하기위하여도입된개념으로서, 전리방사선이조사되는매질내임의의측정지점을포함하고있는미소질량에방사선에의하여부여되는에너지로서정의된다. 흡수선량측정대상매질중가장중요한매질은물이다. 인체의 70 % 이상이물로되어있고물이방사선을흡수하는특성이인체조직과유사하다고판명되어서 1969년 ICRU에의하여방사선조사시인체에흡수되는선량은물에흡수되는선량값으로대치될수있다고권고되었다. 방사선을이용한체외치료과정에서가장중요한일은환자의조직속으로흡수되는방사선의양, 즉흡수선량과치료용방사선장비에서방출되는선량을정확하게평가하는것이다. 인체에흡수되는흡수선량에대한보다정확한측정및평가는국제적으로도그중요성이인정되어서기준방사선인 60 Co 감마선에대한물흡수선량의표준화가국제도량형국 (BIPM) 의전리방사선분야 (CCRI(I)) 국제비교의한분야로채택되어있다. 또한암치료에사용되는선량범위는치사선량의십여배까지해당되는대단위선량으로치료정밀도여부에따라인체에주는부작용이매우크기때문에국제방사선단위측정위원회 (ICRU) 에서는방사선에의한치료선량을 5% 내로권고하였고미국의학물리학협회 (AAPM) 에서도이러한치료선량을유지하기위해서는흡수선량의측정불확도가 3% 미만으로주어져야한다고보고하고있다. 국제도량형국에서도이러한상황의중요성을인식하고 2007년 CCRI 총회에서일선병원에서치료에사용되는방사선인고에너지 X-선및전자선에대한물흡수선량의국제표준을확립하기위하여치료방사선에대한물흡수선량의국제비교필요성이강력하게제안이되었고, 2009년 CCRI 총회에서도이분야의국제비교추가및 CCRI의치료방사선물흡수선량측정기술구축및국제비교추가안건이매우심도있게토의되고있는실정이다. 따라서선진국수준의기준방사선및치료방사선물흡수선량의확보및보급은매우중요하며시급하게이루어져야할사안이다. 물흡수선량절대측정및절대측정용원기급장비 : 물흡수선량을측정하는전통적인방법은이온전리함을이용한절대측정에의하여정확하게결정된 air kerma의값을기준으로물흡수선량을구하는방법과원기급이온전리함과물팬텀에의한물흡수선량절대측정법, 열량계및흡수선량측정시스템을이용한절대측정법이있다. 첫번째방법은 air kerma의절대측정값을이용하는간접측정법이고두번째와세번째방법은원기급장비를이용한직접측정법이다. 여기서절대측정이라함은방사선선원으로부터일정한거리의기준점에서선량을측정할때측정값에영향을주는모든요인들을측정또는이론적인계산에의하여그영향을모두보상하여최종측정값과그측정불확도를결정하는측정법이다. 물흡수선량절대측정에사용되는원기급수준의이온전리함은국제도량형국에서자체제작한전리함으로서현재 7

12 Professional Symposium : Advanced Dosimetry Issues in Medical Physics Field 이온전리함을이용한물흡수선량절대측정및국제비교를원하는국가가있으면동일한이온전리함을제작하도록제작도면을제공하고국제도량형국에서절대측정을수행한절차에따라얻은측정결과를비교하고있다. 또한, 물흡수선량절대측정용원기급열량계는흑연열량계와물열량계로나뉘는데흑연열량계는방사선조사시열량계핵심부인 core에흡수되는감마선에너지를 core의온도변화, 물열량계는물속의기준점에서의온도변화로부터각각흡수된에너지를측정하며이에각종관련보정인자를평가하여흡수선량을결정한다. 다만흑연열량계의경우에는우선흑연흡수선량을결정한후이에물과흑연의환산인자를적용하여물흡수선량을결정하며물흡수선량은바로물흡수선량을결정한다. 현재흑연열량계를자체개발하여물흡수선량국가표준을확립한국가는프랑스를비롯한 4 5 개국, 물열량계를개발한국가는미국, 영국을비롯한 6 7 개국정도만이있는실정이다. 한편이온전리함과물팬텀을이용한절대측정법은국제도량형국에서만수행하고있으나국제도량형국에서도물흡수선량값에대한국제적신뢰성을더욱향상시키기위하여열량계를이용한물흡수선량측정법으로전환하기로결정하고흑연열량계를제작하였고현재시험가동중이다. 따라서향후국제도량형국에서도열량계법 (calorimetric method) 에의하여결정된물흡수선량값으로대체하고국제비교를주관하리라예상한다. 본발표에서는앞에기술한세가지물흡수선량절대측정법과측정에사용되는원기급장비를소개하고절대측정에포함되는보정인자 (correction factor) 에대한물리적의미를구체적으로살펴봄으로써국가표준기관에서수행하는절대측정에대한이해를돕고자한다. 결론 : 방사선치료 / 수술에서가장기본적이며중요한물리량은물흡수선량이란것은이미앞에서수차례언급하였다. 국가표준기관에서가장우수한절대측정법으로물흡수선량국가표준을확립하고국제적동등성을확보한후일선기관에보급하는것은국가표준기관의기본미션이며이것이방사선치료의최적화를이루고환자의건강을보호하는데크게기여를할것이라는점은믿어의심치않는다. 다만첨단방사선의료장비와치료기법의급격한발전과함께등장한기준조건과전혀다른치료조건에서의물흡수선량에대한평가는또다른과제를던져주고있다. 소조사야를이용하는첨단장비및기법이수십 Gy의고선량을사용하고있기에보다이러한조사야에서의정확한물흡수선량평가는더욱시급하게해결이되어야할사안이다. 본연구실에서는첨단장비유형에맞는현장용물흡수선량측정장비및측정기술을개발하여각장비별치료조건에맞는물흡수선량값을보급하기위하여최선을다할것이다. 치료방사선, 물흡수선량, Air kerma, 절대측정, 열량계, 흡수선량측정시스템 8

13 제 40 회한국의학물리학회춘계학술대회 방사선치료에서정도관리와선량측정 계명대학교동산의료원방사선종양학과 오영기 Introduction: 방사선치료의성적은환자에조사된방사선량의정확도에직접적으로연관되어있다. 또한조사된방사선량의정확성은치료계획시스템에서사용되는빔데이터의정확성과연결되어있으며이러한빔데이터를확인하고그변화정도를파악하여보정하는일련의과정을정도관리라한다. 따라서방사선치료물리학의근간은초기에정확한빕데이터수집에서부터이를유지관리보정하는 QA일것이다. 최근에 tomotherapy, Cyberknife, micro-mlc 등과같은다양한방사선치료기기의개발과 IMRT, IGRT, VMAT 등의복잡하고어려운치료기술의발전으로인해기존의빔데이터수집및 QA과정에많은변화가있었다. 본연구에서는이러한변화에대한 TG 등과같은 AAPM 의최근의연구들을조사하여빠르게발전하고있는국내방사선치료의실정에맞는 QA 프로토콜개발에기초자료로활용코자한다. beam data commissioning of medical accelerator: 대부분의빔데이터측정과정이상대적으로단순한것처럼보이지만그결과는그림 1에서보여주는것처럼사용한팬텀과측정시스템에따라다소의차이를보인다. 측정기의부적절한사용으로인해수집된빔데이터의신뢰성이낮아질수있다. 따라서팬텀및측정기의적절한선택과정확한사용및빔데이터수집을위한팬텀의셋업등에대한가이드라인을제시하고자 AAPM TG-106이 2008년에발간되었다. 또한이보고서에는광자선과전자선에대한여러가지인자들을수집하는과정과측정오차를줄이기위한방법, 수집된빔데이터의프로세싱및정확한빔프로파일을위해측정기크기에관련문제등을포함하고있다. 이보고서에대한내용을파악하고이론적인토의와실제적인경험을기반으로최신방사선치료기기에대한빔데이터수집의표준절차서확립을이루고자한다. 9

14 Professional Symposium : Advanced Dosimetry Issues in Medical Physics Field Quality assurance of medical accelerator: 1994년에발간된 AAPM TG-40은의료용선형가속기의일반적인 QA에대한가이드로서폭넓게사용되고있다. 그러나, 최근에 MLC, asymmetric jaws, dynamic and virtual wedges, EPID 및 CBCT 나 kv imagimg을이용한영상유도치료장치등다양한기기들이소개되고치료에적용되고있으며, SRS. SBRT 및 IMRT 등과같이보다정밀하고복잡한기술이개발됨에따라 TG-40에서제시한가이드라인및허용수준과는그사용정도에따라많은차이가있으므로인해이들에의해 QA 과정에서의차이점과달라져야할내용들을포함한 TG-142를 2009년에발표하였다. 이보고서에는 SRS나 IMRT를위한장비들이요구하는시험법과허용수준의정도, IMRT용 MLC QA를위한가이드라인제시등의내용들이상세히기술되어있다. 예로서 Table II에월간 QA 점검항목및허용수준을나타내었다. 이보고서의내용을정리하고분석하여다양한치료기기를위한일일, 주간, 월간및연간 QA 내용과절차에대한국내의기준마련에토대를마련하고자한다. 10

15 제 40 회한국의학물리학회춘계학술대회 Summary: TG-106에서는정확한빔데이터수집을위해치료기의종류, TPS의요구사항, 치료기의사용환경등과같은기본적인정보를토대로가능한한감응도가좋고, 크기가작으며, 선량율및에너지의존성이적은측정기를사용하고, 기계적정확도가높은 3D 물팬텀을이용하여스캔속도와데이터수집시간, 측정기의방향등을적절히정하여측정하여야하는등의가이드라인을제안하였고, TG-142에서는 QA의주기, acceptance test 및 commissioning의허용치에대한가이드라인및최신개발된치료기기등에대한 QA 내용등을제안하였다. References 1. TG-106, Accelerator beam data commissioning equipment and procedure: Report of the TG-106 of the Therapy Physics Committee of the AAPM. Med. Phys. 35: (2008) 2. TG-40, Comprehensive QA for radiation oncology: Report of AAPM Radiation Therapy Committee Task Group 40. Med. Phys. 21: (1994) 3. TG-53, Quality assurance for clinical radiotherapy treatment planning: Report of AAPM Radiation Therapy Committee Task Group 53. Med. Phys. 25: (1998) 4. TG-142, Quality assurance of medical accelerators: Report of AAPM Radiation Therapy Committee Task Group 142. Med. Phys. 36: (2009) 11

16 Professional Symposium : Advanced Dosimetry Issues in Medical Physics Field Public Concern about Radiation Exposure from Computed Tomography and Relevant International Studies and Actions Kyung Hee University Kwang Pyo Kim PURPOSE: CT is a valuable imaging tool and provides great medical benefits in modern medicine. However, rapid increase of CT examinations and high radiation dose from CT scan have given rise to concerns. The objective of this study is to introduce international studies and actions associated with the issue. MATERIAL AND METHOD: Recently, many studies and actions have been performed on this issue. Here, I introduce risk projection studies, epidemiology studies, dosimetry studies, and actions to reduce medical exposure. RESULTS: Risk projection study is to estimate future cancer risks associated with radiation exposure from CT examinations. The main objective of the studies is to balance the benefits and risks from CT scan. Many studies have been performed about CT screenings. A recent study on cancer risk from CT scans in the US has attracted worldwide attention. However, there is no direct epidemiological studies on cancer risk due to CT scan. Therefore, epidemiologic studies are under performance or preparation. A leading United Kingdom (UK) and US NIH (US National Institutes of Health) study is being performed in the UK. Similar studies are also being performed in many other countries. One big study including 9 European countries is currently under preparation. Radiation dosimetry is important for this issue. Although there are several CT dosimetry programs, they have many limitations especially for patient anatomy and bone marrow dosimetry. A study to generate CT organ dose database based on advance human phantoms and to develop a CT dosimetry program is being performed. International and national agencies initiated actions to reduce unnecessary radiation exposure from medical imaging. CONCLUSIONS: Radiation exposure to patients can be minimized without detriment to the clinical purpose. Radiation protection of patients can be achieved by alliance of many parties. Role of medical physicists is essential for the radiation protection. Computed tomography, Patient exposure, Cancer risk, Radiation protection 12

17 제 40 회한국의학물리학회춘계학술대회 Scientific Session I 방사선치료분야 좌장 : 이동준 ( 인제대 ), 지영훈 ( 한국원자력의원 )

18 제 40 회한국의학물리학회춘계학술대회 O-T-01 Gated Therapy 에서환자의호흡양상유지방법이환자선량분포에미치는영향 이화여자대학교의과학과 *, Cooper University Hospital, 이대목동병원방사선종양학과 안소현 * ㆍ백지혜 * ㆍ오윤진 * ㆍ나원경 * ㆍ여인환 ㆍ정재원 ㆍ이레나 목적 : Gating technique을이용한방사선치료는종양주변의정상조직에대한선량을효과적으로감소시킬수있는방법이다. 하지만 4D CT 촬영시와치료시의환자호흡의재현성이이루어져야만 gated therapy에서의치료효과를극대화할수있다. 그러므로호흡의재현성을위해 audio-instruction 또는 audio-visual biofeedback 등의호흡양상유지방법이사용되고있다. 본연구에서는, gated therapy에서호흡양상유지방법에따른호흡재현성이환자선량분포에미치는영향을실제환자호흡데이터를이용하여정량적으로평가한다. 재료및방법 : 본연구에서는 19명의폐암환자에게서일주일간격으로얻은 5 세션의호흡정보를이용하여선량분포변화를평가하였다. 각각의호흡세션들은 free-breathing (FB), audio-instruction (A), audio-visual biofeedback (AV) 의세가지호흡형태에대한정보로이루어져있다. 각환자의첫번째호흡세션을이용하여 ITV 영역을설정하고, 나머지 4번의호흡정보는반복되는치료시환자의호흡으로가정하였다. Matlab을이용하여 phase/amplitude gating에대한선량계산모델을구현하여선량분포를평가하였다. 이때, CTV와 ITV 영역내의정상조직에서처방선량의 90% 이상을피폭한부피 (V 90) 으로비교평가하였다. 결과 : ITV 영역을결정하기위해첫번째호흡세션에서해당 gating window 내의전체잔류움직임 (residual motion) 을고려하였기때문에, CTV 영역의선량분포는의미있는차이를보이지않았다. 그러나 ITV 내의정상조직에서는 phase와 amplitude gating에서 V 90 이각각 21.6% 와 2.51% 의차이를보였다. 특히 phase gating에서는 AV에비해 FB에서의 V 90 이큰차이를보였으나, amplitude gating에서는호흡형태에따른의미있는차이는관찰되지않았다. 또한 amplitude gating은 phase gating에비하여모든호흡형태에서정상조직피폭을감소시키는것을알수있었고, 특히 FB에서그영향이큼을알수있었다. 결론 : 본연구에서는실제환자의호흡정보를이용하여호흡양상유지방법에따른환자의호흡재현성이환자선량분포에미치는영향에대하여평가하였다. 그결과, 특히 phase gating에서 AV가 FB에비해종양주변의정상조직피폭감소율이큰차이를보임을알수있었다. 하지만실제치료에서는종양의모든잔류움직임을 ITV에고려하기어렵기때문에 CTV coverage에대한연구도진행되어야할것이다. 감사의글 : 이발표는정부 ( 교육과학기술부 ) 의재원으로한국과학재단의지원을받아수행된연구임 ( 원자력연구개발사업고유강점기술육성분야, M M ). Gated therapy, 호흡양상유지, 호흡재현성 15

19 Scientific Session O-T-02 Performance Evaluation of the In-house Software for Radiochromic Film Dosimetry Department of Biomedical Engineering, The Catholic University of Korea*, Research Institute of Biomedical Engineering, The Catholic University of Korea, Department of Radiation Oncology, Konkuk University Medical Center, Department of Radiation Oncology, SAM Anyang Medical Center Ji-Yeon Park*, Jeong-Woo Lee, Kyoung-Sik Choi, Won-Gyun Jung*, Tae-Suk Suh* PURPOSE: Software of radiochromic film dosimetry was developed to analyze dosimetric characteristics and to be applied for dose verification. MATERIAL AND METHOD: The software provides film calibration functions depending on color channels, red, green, blue, and gray. Evaluations of the correction effects for light scattering on a flat-bed scanner and thickness differences of the active layers are available. Dosimetric results using radiochromic films can be compared with those from the treatment planning system or the two-dimensional ionization chamber array. After two different types of dose matrixes are aligned, isodose curves and profiles are compared. In addition, the gamma index and gamma histogram are analyzed according to the determined criteria of distance-to-agreement and dose difference. The performance evaluations were achieved by dose verification in the 60 -enhanced dynamic wedged field and intensity modulated beams for prostate cancer using GafChromic EBT2 films. RESULTS: Absolute dose discrepancies of 3 6% and pass ratio difference of 1 9% were generated by the effect of the applied sensitometric curve. Dose discrepancies were lower than 1% according to the correction methods of background or active layer correction. All pass ratios for the two types of tests showed more than 99% in the evaluation, as 3 mm and 3% criteria was applied. CONCLUSIONS: The software was developed for use in routine periodic quality assurance and verification of complex intensity modulated beam verification. It can also be used as a dedicated radiochromic film software tool for analyzing dose distribution and characteristics. ACKNOWLEDGEMENT: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST). (No ) Radiochromic film, Calibration, Background correction, Dose verification 16

20 제 40 회한국의학물리학회춘계학술대회 O-T-03 Effect of Multi-leaf Collimator and Set-up Error on Intensity Modulated Radiation Therapy: Bio-physical Perspective Department of Radiation Oncology, Konkuk University Medical Center*, Department of Biomedical Engineering, The Catholic University of Korea, Research Institute of Biomedical Engineering, The Catholic University of Korea, Department of Radiation Oncology, SAM Anyang Medical Center, Department of Radiation Oncology, Seoul National University Bundang Hospital Jeong-Woo Lee*, Ji-Yeon Park*, Jeong-Hoon Park*, Kyoung-Sik Choi*, Jin-Beom Chung*, Semie Hong, Jae-Sung Kim, Tae-Suk Suh* PURPOSE: The aim of the present study is to apply bio-physical parameters for IMRT QA using MLC dynalog files, and to verify the feasibility of this method as compared to conventional gamma evaluation. MATERIAL AND METHOD: For this study, two prostate cancer patients were selected for evaluation of bio-physical analyzing method combined by the reconstructed IMRT dose distributions using MLC log files as compared to conventional gamma method. Five-field IMRT plan was established for the patient who underwent a prostatectomy, while Seven-field IMRT plan was adopted for the intact prostate cancer patient. A linear accelerator with a Millennium 120 leaf-mlc (CL21EX, Varian, Palo Alto, USA) and an Eclipse system (v. 6.5, Varian, Palo Alto, USA) for inverse planning were used for the study. IMRT dose distributions were reconstructed by in-house program to convert DLG files from an MLC controller to MLC field files, which were used to generate actual fluence data for recalculating IMRT dose distribution. In addition, to similate the erroneousdelivery induced by MLC position and set-up position, MLC field files were modified by moving toward or backward 1 mm in the every segments and moving isocenter ±1 mm according to the X and the Y coordinate orthogonally four directions, respectively. For bio-physical quantitative analysis, equivalent uniform dose (EUD)-based normal tissue complication probability (NTCP) and tumor control probability (TCP) mathematical models were introduced. RESULTS: The physical dose discrepancies from the MLC erroneousplans were found to be more severe than those from DLG with set-up erroneous plans in the DVH analysis. In the DVH analysis of PTVs in the IMRT (A), the mean dose differences were between 6.8% and +6.6% for the MLC erroneous plans and between 0.1% and 0.2% for the DLG with set-up erroneous plans as compared to the reference plan. On the other side, in the IMRT(B), the mean dose differences were between 2.7% and +2.7% for the MLC erroneous plans and between 0.2% and 0.2% for the DLG with set-up erroneous plans. The other physical indices of HI and CI showed much difffereces in the MLC erroneous plans from the both patients. In the bio-physical analyses, the IMRT (A) also showed much differences of TCP and NTCP results, while in the IMRT (B), there were not prominent differences among the both erroneous plans. 17

21 Scientific Session CONCLUSIONS: Our study involving both physical analysis, eg., conventional gamma-index, DVH comparison, andthe bio-physical EUD based analysis showed that the MLC erroneous IMRT was much more sensitive than set-up erroneous IMRT in the prostate bed treatment. Both analyses showed relatively good agreements in aspect of quantitative evaluation. It is our belief that such analyses will be mutally supportive tools for a reliable evaluation of complex IMRT dose discrepancy. ACKNOWLEDGEMENT: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST). (No ) Gamma-index, Bio-physical anaysis, dynalog files, IMRT QA 18

22 제 40 회한국의학물리학회춘계학술대회 O-T-04 Depth Dose Measurement of Proton Therapy Beam by Using Scintillating Fiber Optic Dosimetry National Cancer Center*, Konkuk University Ui-Jung Hwang*, Hojin Jeong*, Jeong-Eun Rah*, Sung Hwan Ahn*, Sang-Yeob Lee*, Myonggeun Yoon*, Dong Ho Shin*, Se Byeong Lee*, Sung Yong Park*, Kyong Won Jang, DongHyun Cho, Bongsoo Lee PURPOSE: Scintillating fiber type dosimeter was investigated to determine the proton beam range in a short time for the purpose of quality assurance of patient in the proton therapy. Degradation of output signal in scintillator has to be overcome for applying the scintillating fiber dosimeter on clinical use. This effect was investigated for a fiber type scintillator. One dimensional dosimeter array was tried to measure the range at a time and required characteristics for this application were evaluated. MATERIAL AND METHOD: Our previously developed scintillating fiber Dosimetry system was used for investigating depth dose distribution of proton beam. The dosimetry system was composed of scintillating fiber of BCF series optically coupled with organic based optical fiber. Scintillating light was amplified by photo multiplier tube before being gathered by commercial data acquisition system. Firstly, Bragg peak and spread out Bragg peak (SOBP) was measured with scintillating fiber dosimetry system. Secondly, the variation of the output signal was measured to evaluate the effect of noise originated by adjacent scintillator when there was another scintillating fiber around the scintillating fiber. One dimensional scintillating fiber array dosimeter was prepared and Bragg peak and SOBP of proton beam were measured and analyzed. RESULTS: The Bragg peak measured by scintillating fiber dosimetry showed degradation of the output signal in high dose region when comparing with the results of the ionization chamber, which is known to quenching effect of scintillator. Quenching effect could corrected well by fitting the measured data to quenching equation. However, the difference between the peaks of scintillator and ionization chamber decreased as the diameter of scintillating fiber decreased and it didn t show significant degradation of the signal enough to miss the range within sub-millimeter for the scintillator smaller than the diameter of 0.5 mm. The SOBP curve measured by scintillating fiber also showed good agreement with the ionization chamber results after being modified by considering the quenching effect. It was revealed that the scintillator output signal was not affected by the other scintillating fiber located vicinity of it. It can be applied to construct the scintillator array to measure the depth dose distribution at a time. CONCLUSIONS: Scintillating fiber optic dosimetry was suitable for measuring depth dose distribution of proton therapy beam and determining its range. Quenching effect of scintillator was dealt with well within our tolerable range by fitting method. One dimensional scintillating fiber array provided more applicable and faster way for applying it to clinical field. 19

23 Scientific Session ACKNOWLEDGEMENT: This study was supported by the National Cancer Center Grant (NCC ) Proton therapy, Scintillating fiber, Dosimetry 20

24 제 40 회한국의학물리학회춘계학술대회 O-T-05 투과선량측정법을이용한 IMPAC 시스템업그레이드전후빔변수의무결성검증기법의제안및활용 Department of Radiation Oncology, Mayo Clinic, Jacksonville, FL, USA*, 가톨릭대학교의공학교실 Siyong Kim* ㆍ오승종 ㆍ서태석 목적 : 방사선치료기술의발달로인해환자에게조사되는방사선을정교하게조절할수있게되었으며, 이를위한많은빔변수들의효율적전달을위해 Record and Verification (R&V) 시스템의중요성이증가하고있다. 그러나 R&V 시스템업그레이드과정중데이터베이스에저장된빔변수들이구조적으로동일하게읽혀지는지에대한보증이이루어지지않고있다. 본연구에서는 R&V 시스템인 IMPAC 시스템의업그레이드전후빔변수들의무결성을평가하기위한투과선량측정기법을제안ㆍ활용하였다. 재료및방법 : 빔변수무결성을검증하기위하여 IMPAC 시스템업그레이드전, 모든 IMRT 수행환자에대하여환자치료중기준누적플루언스패턴을획득하였다. IMPAC 시스템업그레이드후다음치료가이루어지기전 QA 모드에서동일한측정을반복하여기준플루언스패턴과비교하였다. 플루언스측정을위해, radiochromic 필름을중앙에고정할수있는홀더를제작하였다. 고안된필름홀더는액세서리코드를방해하지않고, 액세서리슬롯에단단하게고정될수있도록하였으며, 방사선질에미치는영향을최소화하고, 갠트리클리어런스가손상되지않도록하였다. 홀더와필름에의한감쇠효과와표면선량을 5 5, 10 10, 필드에대해측정하였다. 또한, 본측정법을수행함으로증가된업무부담과치료시간에대해여섯명의방사선사에게설문조사를수행하였다. 결과 : 필름과필름홀더에의한감쇠정도는측정된모든필드에서 0.4% 이하였으며, 표면선량의경우 5 5, 10 10, 필드에대해서최대선량의 0.0, 0.1, 0.6% 증가하였다. 설문조사결과여섯명중네명의방사선사들은추가적인업무부담을느끼지않았다고대답하였으며, 두명의방사선사들은아주약간의업무부담을추가적으로느꼈다고답했다. 기준누적플루언스측정을위해총 2분의시간이필요하였으나, 이중대부분은문서기록을위한것으로환자치료시간의증가는 30초이하였다. 검증을위한플루언스측정을위해서는필드수에따라환자당 10분에서 20분정도의시간이소요되었다. 결론 : 본연구에서제안된방법을이용하여 IMPAC 시스템의업그레이드전후의빔데이타무결성을손쉽게보증할수있었다. 제안된방법을치료중수행할때업무부담의증가는없었으며, 전체환자치료시간에별다른차이가없었다. 향후투과선량측정을통한빔플루언스측정방법을이용함으로 IMRT 치료시 MLC 시퀀싱이잘이루어졌음을확인할수있을것이다. 감사의글 : 본연구는차세대지능형방사선치료계획시스템개발 ( ) 과차세대의학물리핵심기술개발센터 (K E ) 사업의연구비지원으로이루어졌습니다. 투과선량측정, 빔변수무결성, Record and Verification, IMPAC 21

25 Scientific Session O-T-06 팬텀을이용한 3 차원초음파의부피측정정확성평가 이화여자대학교의과학과 *, 이대목동병원방사선종양학과 백지혜 * ㆍ정광주 ㆍ김명수 ㆍ김동영 ㆍ안소현 * ㆍ오윤진 * ㆍ나원경 * ㆍ조성호 ㆍ이레나 목적 : 본연구의목적은 3차원초음파장비의부피측정정확성평가를통하여전립선암환자의치료성적을개선하는것이다. 부피측정의정확성을평가하기위하여, 3차원초음파뿐아니라 CT, MRI를사용하여팬텀의부피를측정하여비교하였다. 재료및방법 : 연조직으로구성된전립선및방광의부피측정정확성평가를위하여초음파팬텀을제작하였다. 이팬텀은아가로스젤 (2% by weight, BNC) 로구성된백그라운드물질과물이채워진탄성재질의타겟으로구성되었다. 타겟은구형 10, 20, 300, 500 cc, 타원체형 150, 350 cc, 불규칙형 330 cc의모양과부피로제작되었다. 팬텀의 3차원초음파 (Prestige, MEDISON), CT (Somaton sensation 16, Siemens), 그리고 MRI (Achieva, 3T, Philips) 영상을획득하였다. 초음파영상의팬텀부피는 SonoView 사용하여영상의타겟컨투어를통해측정되었으며, CT, MRI 영상은같은방법으로 Pinnacle을사용하여부피를측정하였다. 결과 : 3차원초음파장비는구형과타원체형팬텀에서 % 오차로부피가측정되었고, CT와 MRI의경우 %, % 의오차로부피가측정되었다. 이것은 % 의오차로부피를측정했던 2차원초음파장비보다정확한부피측정을나타낸다. 불규칙형팬텀의부피측정결과초음파에서 6.34%, CT 1.57%, MRI 4.09% 의오차가발생하였다. 구형과타원체형팬텀에서는 CT나 MRI 만큼정확하게부피가측정되었고, 불규칙형팬텀에서는 CT와 MRI 보다정확하지는않지만큰차이없는오차로부피가측정되었다. 결론 : 3차원영상에서타겟컨투어를통해측정한부피가정확함은영상의질이좋기때문에보다정확한컨투어가가능하였음을입증한다. 따라서 3차원초음파영상은연조직인방광과전립선을정확하게컨투어하여전립선암환자의치료마진을정확하게제시하는데도움을줄것으로기대할수있다. 감사의글 : 이발표는정부 ( 교육과학기술부 ) 의재원으로한국과학재단의지원을받아수행된연구임 ( 원자력연구개발사업고유강점기술육성분야, M M ). 3 차원초음파, 부피측정 22

26 제 40 회한국의학물리학회춘계학술대회 O-T-07 KRISS 137 Cs 감마선조사장치의공기커마절대측정 한국표준과학연구원 이철영ㆍ하석호 목적 : 137 Cs은대표적인인공방사성핵종으로산학연에서널리이용되는선원이다. 137 Cs 감마선은방사선안전관리장비의교정및시험을위한가장기본적인감마선질이다. 국제도량형총회 (Conférence Générale des Poids et Mesures, CGPM) 산하의방사선자문위원회 (Comité Consultatif des Rayonnements Ionisants, CCRI) 는 137 Cs 감마선공기커마를표준기관간의국제비교를위한중요방사선질로규정하고있다. 본연구에서는한국표준과학연구원에서자체제작한국가표준 137 Cs 감마선조사장치의기준면에서공기커마를절대측정하고그불확도를평가하였다. 재료및방법 : 한국표준과학연구원에서신규로자체제작한국가표준 137 Cs 감마선조사장치는 2007년 2월 8일현재 78.1 TBq (2,110 Ci) 인 137 Cs 선원이내장되어있다. 조사장치전면에는정밀정반을기초로한측정스테이지가위치하고있다. 스테이지는 x, y, z 방향으로각각 1 μm의분해능으로표준기를이동시킬수있다. 기준면은선원의중심으로부터 1.0 m 거리에정의되어있다. 기준면에서빔크기는 115 mm 로평가되었다. 절대측정에사용한그래파이트재질의공기커마표준기는한국표준과학연구원에서설계, 제작한것으로 ø19 19 mm 규격의원통형태이다. 전리함벽의두께는 3.0 mm 였고부도체는 PTFE (polytetrafluoroethylene, Teflon) 를이용하였다. 전리함제작에사용한그래파이트의순도는 5 PPM 미만으로평가되었고밀도는 (1.836 ± 0.001) g/cm 3 로측정되었다. 절연체로사용한 PTFE의밀도는 (2.142±0.003) g/cm 3 로측정되었다. 전리전류측정은 electrometer (Keithley model 6517A) 를이용하여외부축전기방식으로수행하였다. 각종보정인자를평가하여절대측정을수행하였는데이들중습도, 이온재결합, 전리함지지대보정인자는실험적으로결정되며나머지는 PENELOPE 2006[1] 을이용한 Monte Carlo 전산모사방식 [2] 으로결정하였다. 결과 : KRISS 공기커마표준기의 mean cord length는 cm 이고전자의비정대에너지관계 [3] 로부터차단에너지는 17.9 kev 로결정되었다. 차단에너지 17.9 kev를입력항으로계산한일차표준기의저지능비 [4] 는 137 Cs 고준위조사장치의기준면에대해 이었다. 질량에너지흡수계수는이조사장치의기준면에서 로평가되었다. 전리함지지대보정인자는 로측정되었다. 제동광자선손실보정인자는 로평가되었다. 이온재결합보정인자는 이었다 TBq 137 Cs 고준위조사장치기준면에서절대측정한공기커마의상대합성불확도는 0.18% 로평가되었다. 결론 : KRISS 78.1 TBq 137 Cs 고준위감마선조사장치의기준면에서공기커마를절대측정하고그불확도를평가하였다. 절대측정에요구되는각종보정인자를실험및이론적방법으로평가하고그결과를제시하였다. 측정한공기커마의상대합성불확도는 0.18% 로평가되었는데이는선진국과대등한수준이다. 국제도량형국 (Bureau International des Poids et Mesures, BIPM) 과의양자비교와다자간국제비교가앞으로의과제이다. 23

27 Scientific Session 감사의글 : 본연구는교육과학기술부가지원한기관고유사업과원자력중장기사업의연구비로수행되었다. 참고문헌 1. F. Salvat et al., PENELOPE - A Code System for Monte Carlo simulation of Electron and Photon Transport, Workshop Proceedings Issy-Ies-Moulineaux, France (2006). 2. Chul-Young Yi, Suck-Ho Hah and Min Sun Yeom, Monte Carlo calculation of the ionization chamber response to 60Co beam using PENELOPE, Med. Phys., 33(5), 1213 (2006) 3. M. J. Berger, J. S. Coursey, M. A. Zucker, and J. Chang, ESTAR, PSTAR, and ASTAR: Computer Programs for Calculating Stopping-Power and Range Tables for Electrons, Protons, and Helium Ions (2005) (version 1.2.3). [Online] Available at National Institute of Standards and Technology, Gaithersburg, MD. 4. Chul-Young YI, Suck-Ho HAH, Kook Jin CHUN and Hyun-Moon KIM, "Monte Carlo Calculation of the Spencer-Attix Graphite-to-Air Stopping Power Ratios for Photon Beams," J. Kor. Phys. Soc., 56: (2010). 137 Cs 감마선, 공기커마, 공동전리함, 절대측정 24

28 제 40 회한국의학물리학회춘계학술대회 O-T-08 KRISS 60 Co 감마선조사장치의공기커마절대측정 한국표준과학연구원 이철영ㆍ전국진ㆍ정재필 목적 : 60 Co 감마선공기커마는치료용물흡수선량환산에이용되는중요물리량인동시에방사선방호를위한기본물리량이다. 이러한중요성을고려하여국제도량형총회 (Conférence Générale des Poids et Mesures, CGPM) 산하의방사선자문위원회 (Comité Consultatif des Rayonnements Ionisants, CCRI) 는 60 Co 감마선공기커마를표준기관간의국제비교를위한첫번째방사선질로규정하고있다. 본연구에서는한국표준과학연구원에설치한국가표준 60 Co 감마선조사장치의기준면에서공기커마를절대측정하고그불확도를평가하였다. 재료및방법 : 한국표준과학연구원의국가표준 60 Co 감마선조사장치는 Eldorado 8이며방사능은 2006년 6월 21일현재 145 TBq (3,923 Ci) 이다. 공기커마절대측정이수행된기준면은선원의중심으로부터 1.0 m 거리에정의되어있다. 기준면에서빔크기는 115 mm 로평가되었다. 공기커마절대측정을위해한국표준과학연구원에서설계, 제작한 ø19 19 mm 규격의원통형그래파이트공동전리함을사용하였다. 전리전류측정은전기계 (Keithley 모델 6517A) 를이용하여외부축전기방식으로수행하였다. 아래의식을이용하여측정된전리전류로부터공기커마를결정하였다 : (1) 여기서 는전리전하, 는전리함의내부체적, 는공기밀도, 는공기중에이온쌍한개를생성시키는데 소요되는에너지, 전리함벽 ( 그래파이트 ) 에대한공기의질량저지능비, 는공기에대한그래파이 트의질량에너지흡수계수의비이고각종보정인자의곱 는다음과같이주어진다 : (2) 여기서 는습도보정인자, 는이온재결합보정인자, 는전리함지지대보정인자, 전리함벽에의한감쇄보 정인자, 는전리함벽에의한산란보정인자, 는전리함에사용된절연체보정인자, 는제동광자 (bremsstrahlung) 재흡수보정인자, 는축방향비균질보정인자, 방사방향보정인자이다. 이들보정인자중습 도, 이온재결합, 전리함지지대보정인자는실험적으로결정되며나머지는이론적으로결정해야한다. 본연구에서는보정인자의이론적결정에 PENELOPE 2006[2] 을이용한 Monte Carlo 전산모사방식을도입하였다. 결과 : KRISS 공기커마표준기의 mean cord length는 cm 이고전자의비정대에너지관계 [3] 로부터차단에너지는 17.9 kev 로결정되었다. 차단에너지 17.9 kev를입력항으로계산한일차표준기의저지능비 [4] 는 137 Cs 고준위조사장치의기준면에대해 이었다. 질량에너지흡수계수는이조사장치의기준면에서 로평가되었다. 25

29 Scientific Session 전리함지지대보정인자는 로측정되었다. 제동광자선손실보정인자는 로평가되었다. 이온재결합보정인자는 이었다. 145 TBq 60 Co 고준위조사장치기준면에서절대측정한공기커마의상대합성불확도는 0.18% 로평가되었다. 결론 : KRISS 145 TBq 60 Co 감마선조사장치의기준면에서공기커마를절대측정하고그불확도를평가하였다. 절대측정에요구되는각종인자들을실험적방법과이론적방업을통해획득하였다. 절대측정을통해결정된공기커마값을국제비교를통하여동등도를확인하고국가표준으로확립하는문제가당면한과제이다. 감사의글 : 본연구는교육과학기술부가지원한기관고유사업과원자력중장기사업의연구비로수행되었다. 참고문헌 1. F. Salvat et al., PENELOPE - A Code System for Monte Carlo simulation of Electron and Photon Transport, Workshop Proceedings Issy-Ies-Moulineaux, France (2006). 2. Chul-Young Yi, Suck-Ho Hah and Min Sun Yeom, Monte Carlo calculation of the ionization chamber response to 60 Co beam using PENELOPE, Med. Phys., 33(5), 1213 (2006) 3. M. J. Berger, J. S. Coursey, M. A. Zucker, and J. Chang, ESTAR, PSTAR, and ASTAR: Computer Programs for Calculating Stopping-Power and Range Tables for Electrons, Protons, and Helium Ions (2005) (version 1.2.3). [Online] Available at National Institute of Standards and Technology, Gaithersburg, MD. 4. Chul-Young YI, Suck-Ho HAH, Kook Jin CHUN and Hyun-Moon KIM, "Monte Carlo Calculation of the Spencer-Attix Graphite-to-Air Stopping Power Ratios for Photon Beams," J. Kor. Phys. Soc., 56: (2010). 60Co 감마선, 공기커마, 공동전리함, 절대측정 26

30 제 40 회한국의학물리학회춘계학술대회 Scientific Session II 진단 / 핵의학 / 기타 좌장 : 최보영 ( 가톨릭대 ), 김경민 ( 한국원자력의원 )

31 제 40 회한국의학물리학회춘계학술대회 O-D-01 Optimization of Radiation Dose and Image Quality for Various Phantom Sizes in MDCT Department of Radiological Science, College of Health Science, Yonsei University*, Research Institute of Health Science, Yonsei University Seung-Wan Lee*, Do-Young Kim*, Dae-Hong Kim*, Hee-Joung Kim* PURPOSE: The use of CT (Computed Tomography) in the diagnosic imaging has been greatly increased, and the percentage of CT examinations has been rapidly increasing in children. The purpose of this study was to estimate the effects of various tube voltage on radiation dose, image noise and image contrast in different phantom sizes corresponding to abdominal size, and to provide possible ways of dose reduction on the basis of patient size. MATERIALS AND METHODS: MDCT (SIEMENS SOMATOM Sensation 4, Germany) and PMMA (Polymethylmethacrylate) phantoms were used in all experiments. PMMA phantom diameters are 10 cm, 16 cm, and 32 cm, and these correspond to a newborn, 5 age, and adult abdominal size, respectively. To estimate radiation dose, CTDI w (weighted CT dose index) was calculated from the measured CTDI using ion chamber, and to evaluate image quality, image noise and image contrast were measured using scanned images. Finally, the CNRD (dose-weighted contrast-to-noise ratio) was calculated based on the radiation dose, image noise, and image contrast. RESULTS: The radiation dose decreased as a function of phantom diameter and increased as a function of kvp. Especially, for the increase in tube voltage from 80 to 140 kvp, there were 395.2% and % increase in radiation dose for 10 cm and 32 cm phantoms, respectively. The image noise increased as a function of phantom diameter and decreased as a function of kvp. The image contrast decreased as a function of phantom diameter and kvp. And, the values of CNRD were maximum at 80 kvp for all three phantoms. CONCLUSIONS: The results of this study demonstrated that it is possible to reduce radiation dose and maintain same image quality by using a lower tube voltage on CT examination. Moreover, this study suggested that optimal tube voltage for various patient size could be achieved. Computed Tomography, Radiation dose, Image noise, Image contrast 29

32 Scientific Session O-D-02 Shielding Effect of Lead Free Material for Diagnostic X Rays Energy Department of Medical Bio-Physics Engineering*, Radiation Oncology, School of Medicine, Keimyung University Tae Jin Choi*, Young Gi Oh, Jin Hee Kim, Ok Bae Kim PURPOSE: The shielding materials designed for replacement of lead equivalent materials of apron in diagnostic photon beams. MATERIAL AND METHOD: The absorption characteristics of elements was applied to investigate the lead free material for design the shielding materials through the 50 KVp to 110 KVp x-ray spectrum in energy interval of 20KVp respectively. The idea focused to the effect of K-edge absorption of variable elements excluding the lead material for weight reduction. The alloy material is consist of Tin, Antimon and Iodine elements for shielding material. RESULTS: The equivalent of lead 0.5mm thickness generally used for shielding apron of diagnostic X rays which is transmitted 0.01% for 50 KVp, 0.36% for 70 KVp and 7.72% for 100 KVp in computation with energy spectrum. The designed shielding material is alloyed of Tin 34.1%, Antimon 33.8% and Iodine 26.8% gram weight for 90 percent of lead equivalent thickness which transmitted less than lead equivalent apron. The experiment of transmittance has showed 0.4% for 50 KVp, 0.2% for 70 KVp, 0.7% for 90 KVp and 1.8% for 110 KVp in 2.7 mm thickness of shielding alloy, respectively. CONCLUSIONS: The designed shielding alloy (density 3.29 g/cc) of 2.7 mm thickness showed less transmittance of lead equivalent material. ACKNOWLEDGEMENT: Following are results of a study on the Human Resource Development Center for Economic Region Leading Industry Project, supported by the Ministry of Education, Science &Tehnology (MEST) and the National Research Foundation of Korea (NRF). Lead rree shielding material, Apron, Lead equivalent 30

33 제 40 회한국의학물리학회춘계학술대회 O-D-03 TW3 법을이용한한국인소아의골성숙도분포양상 이화여자대학교의과학과 *, 이화여자대학교의과대학이대목동병원소아청소년과, 이화여자대학교의과대학이대목동병원방사선종양학과 오윤진 * ㆍ김혜순 ㆍ안소현 * ㆍ백지혜 * ㆍ나원경 * ㆍ조성호 ㆍ이레나 목적 : 소아성장을평가하기위해서골연령을이용하고있으며, 골연령을측정방법으로는주로연령에해당하는손뼈사진과대조하여측정하는 Greulich-Pyle (GP) 법과손을구성하는뼈의성숙도기준에따라점수화하여측정하는 Tanner-Whitehouse (TW3) 법이있다. TW3법은각구성뼈를비교하여점수화함으로서보다객관적이고정확한결과를얻을수있으나, 유럽계미국인소아를대상으로개발되어한국소아에게적용하는데오차를가지며오랜검사시간을요구한다. 본연구에서는한국인정상소아를대상으로골성숙도의표준치를제시하고, 나아가검사시간의절감과정확한측정을위한성장측정소프트웨어의개발에있다. 재료및방법 : 년, 이화여자대학교부속목동병원소아청소년과에내원한아동을대상으로선천적, 내분비적질환및성조숙증과같은특이질환자를제외하고, 키와몸무게가표준성장도표의 5% 미만, 95% 초과된자들은제외하였다. 각소아들은왼손과손목의 X-선사진을 1년단위로구분하여, 요골과척골, 1, 3, 5번째중수골, 1, 3, 5번째기절골, 3, 5번째중절골, 1, 3, 5번째말절골의 13개뼈들의모양에따라골성숙등급을지정하였다. 각등급에따라가중된점수를합산하여얻어진골성숙도를아시아권국가와미국의산출치와비교하였고, 얻어진골성숙도를 TW3 표를통하여구한골연령과정상소아의역연령 ( 달력나이 ) 의차이를분석하였다. 결과 : 나라별골성숙도를비교한결과, 남아의경우골성숙도가 250이전까지는큰차이가없으나그이후에는급격히성숙됨을보여주었고, 400이후부터는미국에비해 1년정도성숙이앞서며, 에서는중국에비해 0.8년정도성숙이앞섰다. 여아의경우골성숙도가 400이전까지는외국과비슷한양상으로분포되고, 그이후에는인도와일본소아에비해급격히진행되나중국과미국소아는큰차이가없었다 에서는미국에비해 0.7년정도성숙이빠르게진행되나, 에서는중국에비해 0.5년정도지연되었다. 산출된국내소아의골성숙도를 TW3 골연령표에대입하여골연령을얻고역연령과차이를비교하였다. 남아의경우 27% 는골연령과역연령의차이가 2년이상나고, 52% 는 1년, 차이가없는소아는 21% 에불과했으며, 여아의경우 24% 가 2년이상의차이를보이고, 38% 는 1 년, 나머지 38% 만차이가없었다. 결론 : 나라별골성숙도의증가양상을비교하였고정상소아의역연령과 TW3법의골연령의차이를분석하였다. 인종과측정시기에따라소아의골성숙도분포에영향을미쳤으며, 2000년대측정된중국인소아와가장비슷함을알수있었다. TW3법은 90년대미국인소아를대상으로개발되어국내소아의성장진행과차이를보였으며, 이로인해산출된골연령은정상소아의역연령과 20 30% 정도만일치하는결과를얻었다. 소아성장의평가를위하여국내정상소아를대상으로표준치제정이필요하며, 더욱신속하고정확한평가를위한 SW개발이필요하다. 31

34 Scientific Session 감사의글 : 이발표는정부 ( 교육과학기술부 ) 의재원으로한국과학재단의지원을받아수행된연구임 ( 원자력연구개발사업교육강점기술육성분야, M M ). 소아성장평가, 골연령, 성인예측키 32

35 제 40 회한국의학물리학회춘계학술대회 O-D-04 콘빔 CT 의산란선제거를위한 Multiple-slit 콜리메이터시스템 가톨릭대학교의과대학의공학교실 *, 한양대학교원자력공학과, Mayo Clinic Florida 장지나 * ㆍ서태석 * ㆍ장도윤 ㆍ김시용 목적 : 본연구에서는콘빔 CT에서산란선제거를위한 multiple-slit 콜리메이터시스템을설계하고이시스템의효율성을검증하기위하여 MC 시뮬레이션을수행하였다. 재료및방법 : 설계된 multiple-slit 콜리메이터는 x-ray의발산성을고려한각이동일한아크형태이고, 길이방향에서의산란선을막는구조이다. 콜리메이터의위치는 x-ray 소스의 40 cm 아래에위치하고콜리메이터의열린부분과닫친부분에서획득된영상을이용하여특정부분에서의산란선의양을추정하고이를바탕으로하여산란선을제거한다. 2D projection 영상을얻기위해전체의콜리메이터는한번의갠트리회전후콜리메이터에의해가려진부분의영상획득을위해다시한번회전하는구조이다. 효용성의평가는콜리메이터를사용하지않았을때의일차선과산란선을비교함으로수행되었다. 결과 : 획득된영상의길이방향프로파일을얻어일차선과상대오차를계산한결과콜리메이터의모든폭 (1 cm, 2 cm, 3 cm) 에서 2 % 이내의일치율을보여주었다. 대조도향상지수는 2D projection에서 1.165, 재구성된콘빔 CT의중심슬라이스와끝슬라이스에서 1.005와 1.026이었다. 결론 : 본 multiple-slit 콜리메이터시스템의 MC 시뮬레이션을이용한효용성평가결과, 상당한산란선제거효과를확인할수있었다. 차후 MC 시뮬레이션에서검출기의크기를줄이고공간해상도평가를위한다양한구조와밀도물질을삽입하여본콜리메이터시스템의검증을수행할예정이다. 감사의글 : 본연구는한국연구재단의차세대지능형방사선치료계획시스템개발과제 ( ) 와차세대의학물리핵심기술개발센터과제 (K E ) 의지원을받아수행되었음. Multiple-slit, 산란선제거, 콘빔 CT 33

36 Scientific Session O-D-05 치과방사선의이용현황과치과방사선검사별유효선량측정 동남보건대학방사선과 *, 고려대학교보건과학대학방사선학과, 연세대학교치과대학병원 신기순 * ㆍ김유현 ㆍ이보람 ㆍ한수철 ㆍ이유경 ㆍ이귀원 * ㆍ박창서 ㆍ박혁 ㆍ장계용 목적 : 의학기술의발전으로치과방사선의장치및관련기기는빠르게변화되어가고있으며, 치과방사선검사또한증가되고있는추세이다. 본연구에서는치과방사선의이용현황분석및치과방사선검사별환자선량을측정하였다. 재료및방법 : 국내치과병ㆍ의원에서이용되는치과방사선의현황을파악하기위해서전국치과병 의원을대상으로설문지를발송하여 77곳으로부터회송되었다. 회송된설문지의자료를바탕으로각그룹별로우리나라치과방사선의이용실태에대하여비교분석하였다. 그리고 Male ART and Neck Phantom (Fluke Biomedical Co., USA) 와 TLD (Thermo Co., USA)Thermoluminescent dosimeter chip (LiF : Mg,Ti) 을사용하여치과방사선검사별로조직선량을측정한후유효선량 (μsv) 산출하였다. 결과 : 치과병 의원한곳당평균 unit chairs수는 A그룹 140.2개, B그룹 15.3개, C그룹 5.8개, 평균치과의사수는 A 그룹 112.6명,B그룹 7.3명 C그룹 1.7명, 평균방사선사수는 A그룹 3.1명, B그룹 12.5명 C그룹 3.3명이었다. 설치된치과용 X선장치의평균보유수는 A그룹 14.64대 B그룹 3.21대, C그룹 2.19대로나타났다. 이중에서구내촬영장치가가장많았고, 다음은파노라마장치, 세팔로장치, CBCT 장치순이었으며, 장치시스템의비율은세그룹모두 DR 시스템이 50% 이상으로가장많았다. 필름시스템인경우, 사용된구내필름은감광도가높은 Insight 필름 (Kodak, USA) 이대부분이었으며, 자동현상기는사용하는곳이적었으나, 필름유지기구는사용하는곳이약간많았다. PACS 이용률은 A 그룹 90.9%, B 그룹 83.8%, C 그룹 16.7% 이었다. 치과병ㆍ의원한곳당 2008년도의연간평균촬영건수는 A그룹이 B그룹보다 6.8배, C그룹보다 21.2배더많았으며, 구내치근단촬영과파노라마촬영이대부분이었다. 구내치근단촬영시관전압과관전류는세그룹모두비슷하였으나, 노출시간은 C그룹이 A그룹의 12배, B그룹의 3.5배정도길었다. 다음은치과방사선검사별로입사피부선량 (μsv) 및유효선량 (μsv) 을 ICRP 103 통해산출해낸값이다. Intraoral검사에서입사피부선량은 611μSv이고세팔로검사에서의유효선량은 14.4μSv, 파노라마검사에서는 29.5μSv, 이고, CBCT 검사중상악촬영은 209.6μSv, 하악촬영은 391.5μSv, 상 하악촬영은 756.5μSv로측정되었다. CT검사에서는상악은 158.6μSv, 하악은 291.6μSv로산출하였다. 결론 : 설문지를통해국내치과방사선의이용실태를파악하였다. 치과방사선촬영에있어서촬영조건은경험적지식을따르기보다는권장되는값을이용해야하며, 필름시스템에서는자동현상기와필름유지기구를사용하면방사선노출량을줄여줄수있다. 또한환자나의료종사자의피폭선량의감소와더불어 X선영상의질향상을위해서치과방사선장치및관련기기에대한체계적인정도관리가반드시필요하다. 치과방사선촬영시유효선량은 CBCT, CT, 파노라마촬영, 세팔로촬영순으로나타났다. 치과방사선촬영, 의료인력현황, 촬영조건, 유효선량, ICRP

37 제 40 회한국의학물리학회춘계학술대회 Industrial Presentation 좌장 : 이석 ( 고려대 )

38 제 40 회한국의학물리학회춘계학술대회 INFINITT RT Solution 소개 - RT PACS, RTIS - 인피니트헬스케어 최석우 INFINITT RT PACS 일반적으로방사선치료는먼저 CT 영상을취득하여영상위에신체장기및종양에대한 ROI 등을그리고, DRR을구성하고치료계획에따른선량분포를계산하게된다. 치료계획이끝나면 QA를거쳐실제치료를진행하게된다. 이모든과정에서치료계획에대한다량의영상및정보들이발생한다. 보통방사선치료를위한시스템은, RTP ( 치료계획장치 ), RNV (Record and Verify System), 그리고방사선치료기 (Linac, Tomo 등 ) 로구성된다. 그런데이러한통합시스템은타사의 RTP를사용하는경우, 호환이제대로이루어지지않으며, 그내용을조회하거나병원정보시스템혹은병원의료기록시스템으로저장이불가능하다. 이때문에병원에서는이러한 RTP의데이터를캡처하거나종이로출력하여스캔을하는방식을선택적으로사용한다. 인피니트헬스케어에서는이러한문제를해결하고자 RT PACS를개발하였다. RT PACS에서는 RTP에서 DICOM RT 데이터를받아실제 RTP와동일한방식으로영상을조회할수있으며, 일반영상의학과 PACS와같이간편한마우스조작으로 Window Width Level 조정, Zoom, Pan 고같은기본적인기능을 DICOM 기반에서제공한다. 이러한영상은선택적으로캡처를통하여바로지정된폴더로이동하거나, 병원정보시스템이나병원의료기록시스템으로전송할수있도록하여번거로운작업을줄일수있게하였다. 37

39 Industrial Presentation 결과적으로는필름없는, 종이없는환경으로전환되며, 모든정보들은간편히병원정보시스템이나병원의료기록시스템으로연동이가능하게된다. 본시스템의구성은기본적으로 Server-Client로구성되어있다. Server에서는여러 RTP에서 DICOM RT형식으로데이터를획득하고이를분석하여영상은 Storage에저장하고, 정보는 DB에기록한다. 이러한데이터는 RT PACS Viewer를통하여조회가가능하며, Broker를통하여병원정보시스템이나병원의료기록시스템으로연동이가능하다. INFINITT RT PACS Viewer는여러가지모드로되어있는데이중 Axial 모드는 CT영상위에 ROI정보를색깔별로표시하고, 여기에 Dose의분포도를나타내어 RTP와동일한형태의조회가가능하다. 또한모든항목은선택적으로 On/Off가가능하여원하는항목만조회를할수있고, Dose 분포값의경우에는원하는퍼센트의값을변경하여조회할수있다. 원본데이터가 DICOM 이므로 Window Width Level 조정, Zoom, Pan 고같은기본적인기능을모두지원하고덧붙여 Sagittal, Coronal 영상도동시에확인할수있다. DRR 모드에서는 DRR 영상들조회할수있으며, 현재 MLC 에대한부분도동영상처럼조회하여실제차폐가어떤식으로이루어지는지직관적으로나타낸다. SIM 모드에서는 Simulation 시에생성되는영상을조회할수있으며, QA 모드에서는치료직전환자의위치를정확히확인할수있도록하는 Portal 영상을조회할수있다. Beam 모드에서는실제계획된치료빔의정보를조회할수있으며정보의내용으로는 Field Order Type, Machine Name, Energy, SAD (cm), ISO Center, SSD, Gantry Angle, Couch Angle, Collimator Angle, Width/Height, Wedge, Bolus, Block, MLC, Accessories, MU value 등의값들이있다. DVH 모드에서는각 ROI 에대응하는 DVH (Dose Volume Histogram) 정보를조회할수있다. 각그래프는선택적으로조회할수있으며, 각각 Min, Max cgy 값들을조회할수있다. 각모드에서조회되는모든내용은간단한버튼클릭을통하여캡처가가능하며캡처된영상은간단한방식으로병원정보시스템및병원의료기록시스템으로전송이가능하다. 최근 Tomotherapy 의치료계획을분석하여연동이가능하도록지원하고있다. 38

40 제 40 회한국의학물리학회춘계학술대회 현재연동가능한 RTP의종류는 Varian사의 Eclipse 모든버전, Philips 사의 Pinnacle 모든버전, Elekta (CMS) 사의 XiO, Helax, Tomotherapy 등이있으며, 현재 DICOM RT를지원하는모든장비의연동을계획하고있다. INFINITT RT PACS의주요장점은방사선종양학과의필름과종이가없는환경을제공할수있다는점이다. 또한 DICOM RT를지원하는모든 RTP와연동이가능하며, 모든치료계획데이터를저장하여예전데이터와비교를용이하게한다. 그리고이러한모든데이터를간편하게병원정보시스템이나병원의료기록시스템으로연동할수있다. 현재 Reference Site는 4곳으로, 서울대학교병원, 삼성서울병원, 아주대학교병원, 제주대학교병원에서진료에적용하여사용을하고있다. INFINITT RTIS (RT Information System) 39

41 Industrial Presentation 방사선종양학과에서는환자가처음접수되면방사선치료에대한전반적인치료 Outline을만들고, Outline에따른 Simulation을수행하며, 이때발생되는환자의 Setup 정보들을기록한다. 이러한정보들은치료계획에사용되며, 치료계획이완료되면치료를실시하게된다. 이모든과정을종이차트를사용하여기록하고조회하게되는데이러한종이차트는분실의위험도따르게되며수기로입력하는데에따르는오류, 보관및관리의어려움을갖고있다. 이러한이유로병원정보시스템을통한전자차트화를구현하여해결하려고하지만, 방사선종양학과의특성과방대한정보를관리하는데는많은제약이따르게된다. INFINITT RTIS는이러한모든 Workflow에서발생되는데이터를기록할수있고관리할수있는방사선종양학과에특화된정보시스템으로각종정보들과발생되는영상을모두관리할수있다. 기본적인 UI는실제종이차트와흡사하게구성하여한눈에모든정보를쉽고빠르게찾을수있다. 각환자별로진행되었던기록을 Order Tree로서쉽게조회할수있으며, 기능별로상하 Tab을지정하여필요한정보를적절히비교하여사용할수있다. 각 Worklist는 Simulation Room, Plan Room, Treatment Room에서편리하게사용할수있는전용 View로 Simulation Worklist는 Simulation 에대한정보를기록하고, setup 사진과같은정보를저장할수있다. Plan Worklist 는 Normal Contouring, Target Contouring, Planning, Confirming 의단계로진행되는치료계획의상황을한눈에확인할수있으며, 실제각단계의상황을체크할수있도록지원하고있다. Tx. Worklist는치료실에서치료에필요한데이터를조회하고치료기록을남길수있는기능을지원하며, 치료시특이사항을기록할수있다. 기능 Tab 중 Patient Manager Tab은환자의 Outline에따른 Dose Schedule, Treatment Schedule을조회할수있으며, Tx. Parameter Tab은 Simulation Parameter 또는 Setup 사진을조회할수있다. Tx. Record Tab은현재까지의치료기록을조회할수있고, Plan Data Tab에서는실제치료계획에따른정보와영상을조회할수있다. INFINITT RT Solution 인피니트헬스케어에서는현재방사선종양학과에서필요한기능들을추가개발하고있으며, 통합영상및정보시스템으로거듭나고있다. 최근 EMR ( 전자의료의무기록 ) 에대한관심이증대되고있고병원의필수요소로자리잡고있는이때에, 방사선종양학과의효율적인전자차트및영상시스템으로발전하기위해노력하고있다. 최근, INFINITT RT Solution을도입한병원에서실제로사용하던 RNV 시스템이오류가생겨치료가불가능하게되었을때, INFINITT RT Solution에저장된치료계획정보를사용하여진료및치료에적용한사례도보고되고있다. 이는치료기와의데이터연동을통하여 RNV 시스템을대체할수있는가능성에대한부분도고려하고있다. 현재방사선치료계획장비및치료기는전량수입에의존하고있고한글이지원되지않는불편함도있다. 또한한국의진료실정에맞지않는 Workflow로이중작업이많이진행되고있다. INFINITT RT Solution은한글이지원되는순수국내기술로개발된솔루션으로국내시장에서수입대체효과를창출하고있고, 나아가국내기술을수출할수있는발판을만들어나가고있다. 40

42 제 40 회한국의학물리학회춘계학술대회 Poster 치료

43 제 40 회한국의학물리학회춘계학술대회 P-T-01 The Study of the Accuracy of Different Combination of Automatic Registration Factors in 2 nd Generation Tomotherapy Department of Radiation Oncology, College of Medicine, Korea University*, Department of Radiation Oncology, College of Medicine, Eulji University, Department of Radiation Oncology, Cheil General Hospital & Women's Healthcare Center, Kwandong University College of Medicine Suk Lee*, Jang Bo Shim*, Kyung Hwan Chang*, Yuanjie Cao*, Sam Ju Cho, Sang Hoon Lee, Dae Sik Yang*, Young Je Park*, Won Seob Yoon*, Chul Yong Kim* PURPOSE: To evaluate the accuracy based in different selective factors of both automatic registration control and scan image control when performing pre 2 nd generation tomotherapy mega-voltage computed tomography, MVCT. MATERIAL AND METHOD: Total 10 patients (5 of cranial, 5 of extra-cranial) were scheduled to tomotherapy (2 nd Generation HI-ART Tomotherapy, Madison, WI). High density tissues like skull and spinal cord are used as anatomic marking in cranial, while spinal cord and treatment organs are used as anatomic marking in extra-cranial. There are 3 factors when performing pre treatment MVCT automatic registration control. They are technique (A; bone, B; bone and tissue, C; full image) and resolution (D; standard, E; fine, F; superfine) in automatic registration control and tomoimage filter (none, low, medium, high) in scan image control. For comparing and analyzing MVCT images, translational adjustments (lateral, longitudinal, vertical) and rotation adjustments (pitch, roll, yaw) are performed separately after auto registration KVCT images and MVCT images using 3 selective factors. RESULTS: Registration results of root mean square translation and rotation in phantom study are A, 15.35, 0.1, B, 15,47, 0, C, 15.7, 0,41. When based in A, the differentiating values of translational and rotational adjustments in cranial patients are A-D, , , A-E, , , A-F, , , and when based in D, the values are D-A, , , D-B, , , D-C, , In extra-cranial patients, when based in B, B-D, , , B-E, , , B-F, , , and when based in D, D-A, , , , D-B, , , D-C, , Tomoimage filter may affect smoothing of image, but exert no influence on automatic registration control. CONCLUSIONS: Our findings confirmed the mechanical difference according to different selective factors in treatment regions is identified, and we believe that more imaging studies which is based in visual comparison between KVCT images and MVCT images are needed in further research. Tomotherapy, MVCT, Automatic registration control, Scan image control 43

44 Poster P-T-02 The Study of Optimized Radiotherapy Plan in Intensity-Modulated Radiation Therapy of Lung Cancer Department of Radiation Oncology, College of Medicine, Korea University*, Department of Radiation Oncology, College of Medicine, Kunyang University, Department of Radiation Oncology, Sooncheonhayng Hospital, Department of Radiation Oncology, Inha Hospital Kyung Hwan Chang*, Suk Lee*, Jang Bo Shim*, Yuanjie, Cao*, Yoo Hyun Kim*, Chul Kee Min, Kwang Hwan Cho*, Hyun Do Huh, Dae Sik Yang*, Young Je Park*, Won Seob Yoon*, Chul Yong Kim* PURPOSE: The present study suggests the feasibility of the proposed Intensity-Modulated Radiotherapy (IMRT) techniques for minimizing doses of lung and critical organs according to the variations of the number of beams, beam orientations, virtual organ delineation position, VOD size and dose constraints in order to develop the optimized radiotherapy plan. MATERIAL AND METHOD: Three patients with stage Ⅲ non-small-cell lung cancer (NSCLC) were planned using IMRT techniques. Beam orientations were used equiangular spaced 5, 7, 9, and 14 beams and non-equiangular spaced 7 and 9 beams. We evaluated the volume of the lungs receiving at least 20 and 25 Gy (V20 and V25) according to the variations of beam orientations for tumor lung and contra-lateral lung. VOD was configured close to the critical organ in order to evaluate V20 according to the variation of VOD position, size and dose constraints for tumor lung and contra-lateral lung. RESULTS: The V20 and V25 values of equiangular spaced 14 ports were slightly lower compared to other equiangular spaced beam orientations for tumor lung and contra-lateral lung. In the light of non-equiangular spaced beam orientations, the V20 and V25 values of 9 ports were lower in tumor lung, while the values of 7 ports were lower in contra-lateral lung. On average, the values of non-equiangular spaced 7 ports were smaller than equiangular spaced 14 ports for tumor lung. The V20 and V25 values of non-equiangular spaced 9 ports were lower when compared to equiangular spaced beams for contra-lateral lung. When VOD dose constraint was applied 10 Gy, the V20 value was approximately lower 16 and 12% than 30 Gy dose constraint was applied in patient 1 and 2 for tumor lung, respectively. But, it was increased about 10 % for patient 3. In patient 1 and 2 for contra-lateral lung, when VOD dose constraint was 10 Gy, the V20 value was decreased about 84 and 24 %, respectively. For patient 3, the V20 value has zero volume in all dose constraints. We evaluated the V20 values according to the variations of VOD position and size when VOD dose constraints were applied 10 Gy in all patients. In patient 1 for tumor lung, the V20 value was increased about 6 % according to the variation of the VOD position. For patient 2 and 3, the V20 value was decreased about 68 and 100%, respectively. However, the V20 value was seriously increased in all pa- 44

45 제 40 회한국의학물리학회춘계학술대회 tients for contra-lateral lung. In three patients tumor lung, the V20 value was decreased about 1, 57 and 100 % according to the variations of VOS size, respectively. But, for contra lateral lung, the V20 value was largely increased in three patients. CONCLUSIONS: The VOD and beam orientations techniques developed in this study reduces radiation dose to normal tissue and the incidence of radiation induced pneumonitis for patients with NSCLC. The IMRT techniques with VOD and beam orientations were used as an important factor in treatment plan. The results of our work point to several promising applications for future research. IMRT, VOD, Optimization, Lung cancer 45

46 Poster P-T-03 Comparison of Target Coverage and Organs at Risk Dose between whole Field Intensity Modulated Radiation Therapy and a Junctioned Intensity Modulated Radiation Therapy with Conventional Radiotherapy Field in Treatment of Nasopharyngeal Carcinoma Department of Radiation Oncology, Seoul National University Bundang Hospital*, Department of Biomedical Engineering, Research Institute of Biomedical Engineering, The Catholic University of Korea, Department of Radiation Oncology, Konkuk University Hospital, Department of Radiation Oncolgy, Seoul National University Hospital Jin Beom Chung*, Woo Lee Jeong, Sung Joon Ye, Jae Sung Kim*, In Ah Kim*, Tae Suk Suh PURPOSE: To compare the effect on target coverage and sparing of organs at risk (OARs), including laryngeal sparing in the optimal simultaneous integrated boost whole field intensity modulated radiation therapy (SIB WF-IMRT) plan with that achieved using a ounctioned intensity modulated radiotherapy (J- IMRT) technique for nasopharyngeal carcinoma (NPC). MATERIAL AND METHOD: We have retrospectively investigated 20 nasopharyngeal carcinoma patients treated in our institution between March 2007 and August 2009 was reviewed. We used SIB WF-IMRT to treat the entire planning target volume in the head and neck cancer. For comparison with the J-IMRT technique, treatment plans were each replanned using J-IMRT technique at 6 MV. The effect on target coverage and sparing of organs at risk, including laryngeal sparing in the optimal SIB WF-IMRT plan was compared with that achieved using a J-IMRT technique. RESULTS: In the SIB WF-IMRT, the median dose to the PTV1 was 68.1 cgy; in all patients 95% PTV1 received at least 63.1 cgy. In the J-IMRT, the median dose to the PTV1 was 67.9 cgy; in all patients 95% PTV1 receive at least 63.8 cgy. The mean dose and standard deviation to the larynx was 25.2±5.8 Gy in the WF-IMRT and 19.8±16.8 Gy in the J-IMRT. The mean dose to the larynx was relatively consistent in 20 patients planned with SIB WF-IMRT with a range Gy. However, for the patients planned with J-IMRT, the mean dose to the larynx varied widely, because it was dependent on the proximity of the PTV to the larynx. In other OAR such as left and right parotid, brainstem, and spinal cord, no significant effect was found on the maximum and mean dose. CONCLUSIONS: Our study demonstrates that it is possible to reduce the larynx dose to clinically acceptable levels using a SIB WF-IMRT technique that incorporates larynx sparing into the optimization without significantly compromising target coverage or other normal tissue constraints. Also, the SIB WF-IMRT does not have the problem of the machine setup at the math line, as well as an excellent coverage in the lower neck. Therefore, in our cur- 46

47 제 40 회한국의학물리학회춘계학술대회 rent practice we use the SIB WF-IMRT technique in treatment of nasopharyngeal carcinoma. ACKNOWLEDGEMENT: This work was supported by nuclear research & development program of the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korean government (MEST). (Grant code, ) Intensity modulated radiation therapy, Nasopharyngeal carcinoma, Simultaneous integrated boost whole field IMRT, Junctioned IMRT 47

48 Poster P-T-04 Isocenter Verification Using Polymer Gel for Stereotactic Radiosurgery Department of Biomedical Engineering, The Catholic University of Korea*, Research Institute of Biomedical Engineering, The Catholic University of Korea, Department of Neurosurgery, College of Medicine, Inje University, Department of Radiological Science, College of Health Science, Yonsei University Kyung-Nam Lee*, Dong-Joon Lee, Dae-Hong Kim, Tae-Suk Suh* PURPOSE: To evaluate 3-dimensional deviation of radiation isocenter position at various brain regions by using gel dosimeter with SRS treatment based on non-coplanar arcs plan. MATERIAL AND METHOD: To begin with, we designed and made anatomical head phantom for imitating major brain tumor sites and using gel dosimeter. Determining tumor position & volume was performed by help of radiosurgery expert. In addition, we simulated virtual patient by using head frame and made radiation treatment plan for SRS treatment. we used spherical target with having prescribed isocenter at geometric center of target and 6 non-coplanar arcs plan using 4 mm cone. After imaginary treatment, MR T2 image (TE=100 ms, TR=3300) was used for detection of radiation isocenter. Finally, we evaluated position deviation between prescribed isocenter in treatment plan and radiation isocenter in MR T2 image at various brain regions. Image fusion and measurement function included in treatment planning system (Novalis Treatment Planning 5.31, BrainLAB) were used for quantitative and alternative analysis. RESULTS: Total deviation is not over 1.6 mm. Directional deviation is less than 1.2 mm for A-P direction, 1.0 mm for Lateral direction and 1.4 mm for vertical direction. Most of total deviation is existed between 1.0 mm and 1.2 mm and between 1.4 mm and 1.5 mm for 10 targets. At various brain regions, average total deviation is 1.07 mm and standard deviation is 0.2 mm. Deviation due to tumor position is below 0.5 mm for total deviation. CONCLUSIONS: In conclusion, we can find out that deviation of radiation isocenter can be existed above 1mm after mechanical quality assurance for isocenter. We need to check more about deviation of isocenter at often used combination of gantry and couch angles for clinical treatment. Isocenter verification, Gel dosimeter, T2 image, Combination of gantry and couch angles 48

49 제 40 회한국의학물리학회춘계학술대회 P-T-05 Beam Modeling Technique to Optimize Beam Spectrum and Dose Profile for Treatment Planning System Department of Biomedical Engineering, The Catholic University of Korea*, Research Institute of Biomedical Engineering, The Catholic University of Korea, Department of Neurosurgery, Seoul National University Bundang Hospital, Department of Radiation Oncology, School of Medicine, Konkuk University, Department of Radiation Oncology, Stanford University Woong Cho*, Jeong-Hoon Park, Won-Gyun Jung*, Jeong-Woo Lee, Lei Xing, Tae-Suk Suh* PURPOSE: Auto-optimization method was implemented to make calculated dose distribution approximate measured dose distribution for treatment planning system. MATERIAL AND METHOD: Approximate formular with 2 variables (μ, σ) was used to express the distribution of photon with its energy. Kernels considering photon spectrum were constructed using the TERMA weighted photon energy spectrum and published mono-energy kernel data. Percent depth dose and dose profile at specific depth were calculated using collapsed cone convolution algorithm. Beam hardening effect with penetrated depth, kernel tilting effect, beam softening effect with off axis distance, off axis ratio, and blurring effect by finite beam source size were considered. Auto-optimization method based on steepest decent method was used to minimize objective function which was defined with the sums of differences between measured PDDs (or profile) and calculated PDDs (or profile). Final optimized PDDs and profiles were compared with measured data. RESULTS: Determined energy spectrums were not similar to rear photon spectrums, but calculated PDDs with each field size showed good agreements with measured data. The dose error beyond build-up depth was less than 2% at any depth. Under-dose (> 5%) were observed at the build-up regions (<2 cm depth) at large field (>30 30 cm 2 ) because we didn't consider the dose of electron contamination. Calculated dose profiles were also well agreed with measured dose profiles (<3% errors) up to cm 2, but some discrepancies at penumbra region were appeared at large field. CONCLUSIONS: Determined energy spectrums at various field sizes could simulate the trend of increasing PDDs according to increased field size. The modeling method to have individual spectrum with each field size was good to simulate measured dose distribution, and it seemed to compensate the limitation of classical convolution/superposition algorithm using finite radius of kernel. ACKNOWLEDGEMENT: Research was sponsored by the National Research Foundation of Korea (NRFK) grant funded by the Korea government (MEST) (No. K E ). Optimization, Beam spectrum, RTP 49

50 Poster P-T-06 Feasibility Study of Radiophotoluminescent Glass Dosimeter for High-Energy Electron Beams University of Science & Technology (UST)*, Department of Radiation Oncology, Research Institute of Radiological and Medical Sciences, Cyberknife Center, Korea Institute of Radiological & Medical Sciences, Korea Kihong Son*, Chang Yeol Lee, Sang Hun Shin, Seungwoo Park, Haijo Jung*, Dong-Han Lee, Mi-Sook Kim*, Young Hoon Ji*, Kum Bae Kim* PURPOSE: The purpose of this study is to examine the dosimetric properties of glass dosimeter including uniformity, dose linearity of response and energy dependency in high-energy electron beams for clinical and physical use. MATERIAL AND METHOD: The model GD-302M (Asahi Techno Glass Corporation, Shizuoka, Japan) glass dosimeter was irradiated in water phantom using the stick holder designed for glass dosimetry study with therapeutic electron beam at Korea Cancer Center Hospital and γ-ray from 60 Co teletherapy unit (Teratron 780, AECL, Canada) for dose calibration factor. FGD-1000 reader (Chiyoda Technol, Tokyo, Japan) was used for dose reading. RESULTS: The uniformity of the response from high-energy electron beams was measured with the acceptable range (±1.1% (1SD)) considering the uniformity of high-energy photon beams (±1.1% (1SD)). The dose linearity represented the lower level (within 4%) in comparison with ideal linear points. The energy dependency also showed the lower level (within 2%) in comparison with 60 Co photon's response at calibrated point from ionization chamber. CONCLUSIONS: This study investigated the feasibility study of RPL glass dosimeter in high-energy electron beams, such as uniformity, dose linearity and energy dependency. The results represent that the glass dosimeter system should be used for quantitative dose evaluation of electron beam considerably. ACKNOWLEDGEMENT: This work was supported by Nuclear Research Development Program of the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korean government (MEST). Electron beam, Glass dosimeter, Uniformity, Linearity 50

51 제 40 회한국의학물리학회춘계학술대회 P-T-07 Estimation of Diagnostic Imaging Dose irradiated for Patient Positioning National Cancer Center, Proton Therapy Center Hojin Jeong, Ui-Jung Hwang, Jeong-Eun Rah, Sung Hwan Ahn, Myonggeun Yoon, Dong Ho Shin, Sung Yong Park, Se Byeong Lee PURPOSE: In the proton therapy, due to the large variation in the spatial dose distribution, particularly near the Bragg Peak, the verification of target location is highly important. Therefore, in order to accurately verify the target location, many proton therapy centers including our institution routinely take anatomic images at every daily treatment. This procedure obviously reduces the potential set-up error in the patient positioning, but simultaneously increases the radiation-induced secondary cancer risk due to the extra dose in image taking procedure. Our aim in the present work is to provide the basic information of the secondary cancer risk induced by the diagnostic imaging dose for patient positioning. MATERIAL AND METHOD: Our institution uses the digital imaging positioning system (DIPS) as an imaging modality in the proton therapy. We first measured the basic beam data of the DIPS, and then incorporated the measured beam data into commercial planning system to simulate the dose distributions in patient. And finally we calculated the risk factors by using the calculated dose-volume histograms. RESULTS: Several patient cases with treatment sites in brain, thorax, abdomen, and pelvis are chosen for this analysis. The results show thatthe imaging doses could exceed the recommended guideline for extra dose management (lesser than 0.2% of prescribed dose) particularly at skins and bones and are substantially delivered even into deep lying organs depending on the numbers of treatment fields and fractions. CONCLUSIONS: As the daily image taking become a routine process in the proton therapy, patients may receive a considerable amount of extra imaging dose exceeding the extra-dose guideline, which increase radiation-induced secondary cancer risk. 51

52 Poster P-T-08 The Feasibility of Dose Delivery Error Prediction of IMRT Fields Using Support Vector Machine: Preliminary Results Pusan National University Yangsan Hospital*, Pusan National University Hospital Hosang Jeon*, Dahl Park, Ji Ho Nam*, Won Taek Kim, Yong Ho Kim, Dong Hyun Kim, Dong Won Kim PURPOSE: It is reported that approximately 30 60% of cancer patients in the United States are currently being treated with IMRT. In 2008, however, the Radiological Physics Center (RPC) reported that of the 250 irradiations of a head and neck phantom as part of an IMRT credentialing process, 71 (28%) had failed to meet accuracy criteria of 7% for dose in a low gradient region and/or 4mm distance to agreement in a high gradient. Our purpose is verifying the feasibility of dose delivery error prediction of intensity modulated radiation therapy (IMRT) fields for the support of optimized IMRT planning. MATERIAL AND METHOD: Though dynamic MLC system is accurate and effective, there is still difference between IMRT planned dose and actually measured dose. Differences may be caused by measurement uncertainty, limitations in the accuracy of dose calculations, and limitations in the dose delivery mechanisms. We supposed that dose delivery errors were mainly caused by limitations in the dose delivery mechanisms, especially using sliding window method. To verify the feasibility of dose delivery prediction of IMRT using support vector machine (SVM), which is a newest algorithm of artificial neural network to assign an object to one of several categories. The optimal hyper-plane is given by SVM to classify groups. We designed experiments as below four steps. Step 1: Measurement of actual dose delivery of IMRT fields using electronic portal imaging device (EPID) in a linear accelerator Step 2: Gamma criteria analysis of beam fluences for verification of dose delivery difference between prediction and measurement Step 3: Acquisition of support vectors using planned MLC dynamics data and calculated gamma criteria data of several IMRT fields Step 4: Evaluation of acquired support vectors by comparing predicted gamma criteria and measured gamma criteria of an IMRT field The 2-D predicted images of IMRT dose delivery were calculated by portal dose image prediction (PDIP) algorithm, which was the integrated IMRT QA solution of Varian medical systems. For gamma criteria analysis, the 2-D actual dose delivery images were measured by using EPID and were compared with predicted images. The SVM was 52

53 제 40 회한국의학물리학회춘계학술대회 trained with our database which is composed of dynamic properties of MLCs and gamma criteria of each pixel. 11 IMRT fields for prostate cancer treatment were used to make a SVM training database, and we found some meaningful hyper planes to classify pixels into two groups according to gamma criteria. The MLC dynamic properties of 1 IMRT fields were extracted by our program and were analyzed by trained SVM. RESULTS: figure 1 shows a dose delivery prediction image of an IMRT field in prostate cancer, and figure 2 shows a gamma criteria distribution of that field. The red pixel means that a gamma criterion is over 1. As the preliminary result, we obtained 2-D gamma criteria prediction images of IMRT dose delivery as shown in figure 4, which were similar to actually measured gamma criteria in figure 3. The error prediction results show high specificity (0.945) and accuracy (0.837), and relatively low sensitivity (0.452). CONCLUSIONS: We made a system for IMRT dose delivery evaluation and prediction, and acquired a preliminary result with IMRT field data of prostate cancer. Our results present high accuracy and specificity, but relatively low sensitivity. It may be caused by insufficient γ>1 data (only 10.8% of all data). Out further study will be focused to obtain a training model with high statistical reliability. IMRT, SVM, DMLC 53

54 Poster P-T-09 PTW31014 Pinpoint 이온함의줄기가기준선량측정에미치는영향에대한예비분석 한양대학교병원 *, 한양대원자력공학과, 인하대학교병원, 가천의과학대학교, 경희의료원 김성훈 * ㆍ조성구 ㆍ허현도 ㆍ최상현 ㆍ최진호 ㆍ신동오 목적 : IMRT를구현하는체계 (Tomotherapy, VMAT, RapidArc 등 ) 및방사선수술장비 (Gammaknife, Cyberknife, Nobalis, BrainLab 등 ) 의급속한발전에따라소조사면의기준선량측정에대한관심이높아져가고있다. 소조사면의선량측정을향상시키기위한소체적검출기들또한다양하게개발되어오고있다. PTW31014 Pinpoint 이온함은체적이 cc로서소조사면측정에다양하게사용되고있다. 이러한 Pinpoint 이온함같이측정부피가작은소체적이온함검출기의경우에줄기효과 (stem effect) 가측정에상당부분영향을미칠수있다. Cobalt-60 빔과광자빔 6 MV의두경우에 PTW31014 Pinpoint 이온함의줄기효과가어떠한차이를보이는지조사하고자하였다. 재료및방법 : EGSnrcC++ Monte Carlo 코드를사용하여 PTW31014 Pinpoint 이온함을줄기 (stem) 를포함하여전산모사하였다. Cobalt-60 빔과광자빔 6 MV를이온함줄기 (stem) 가있을때와없을때두경우에대해조사하여이온함공기체적에퇴적된흡수선량을계산하였다. 이온함줄기 (stem) 가있을때와없을때이온함공기체적에퇴적된흡수선량의비를줄기효과보정인자라고정의하고, Cobalt-60 빔과광자빔 6 MV 두경우에대해상호비교하였다. 결과 : Cobalt-60 빔과광자빔 6 MV 두경우모두 5 억개히스토리를사용하였다. 조사면크기 cm 2 에서, Cobalt-60 빔의경우에줄기 (stem) 가있을때와없을때이온함공기체적에퇴적된흡수선량의비는 이었으며, 광자빔 6 MV의경우에는 이었다. 결론 : PTW31014 Pinpoint 이온함의경우에 Cobalt-60 빔과광자빔 6 MV에서줄기효과보정인자값이다르다. 이는소체적이온함의경우에선질에따라줄기효과가다를수있다는것을보여준다. 따라서, 빔선질 coblat-60에서교정받아온소체적이온함을고에너지광자빔에서사용할경우에선질에따른줄기효과의차이를고려해야할것으로사료된다. 감사의글 : 본연구는 2010년도식품의약품안전청용역연구개발과제의연구개발비지원 (10172방사선454) 에의해수행되었으며이에감사드립니다. 소체적이온함, 이온함줄기 (stem), 줄기효과 54

55 제 40 회한국의학물리학회춘계학술대회 P-T-10 The Influence of Inserted Location of Inhomogeneities on Penetration Path of Proton The Catholic University of Korea*, National Cancer Center So-Hyun Park*, Won-Gyun Jung*, Jeong-Eun Rah, Sungyong Park, Tae-Suk Suh* PURPOSE: To describe the effect on the Bragg peak curve by inhomogeneous materials located in entrance region of Plateau and Bragg peak. MATERIAL AND METHOD: The Geant4 simulation toolkit, version was used. The bone and adipose tissue were inserted in the entrance to the Plateau and Bragg peak region. The position of inhomogeneities was selected at the proximal 36% (entrance region of the Plateau) and 50% (entrance region of the Bragg peak) points of the maximum dose. At first, the thickness of each material was varied from 0.1 to 1.0 cm in each region and the initial energy of proton was fixed with MeV. Second, the initial energy of proton beam was changed from 108 MeV to 220 MeV with an order of 30 MeV and thickness of material was fixed with 1.0 cm. RESULTS: The dose perturbation was shown in the region of Bragg peak and inhomogeneous material concerning the location of inhomogeneities. There were great differences of the dose when the material of high density was inserted within homogeneous structure. However, there were no significant variations of other evaluated parameters concerned with inserted location of each material. CONCLUSIONS: Although there were no effects on material location except for dose perturbations, this study shows that the Bragg peak curve is sensitive to the location of material when material of high density is inserted in the penetration path of proton beams. ACKNOWLEDGEMENT: This work was supported by Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST; N ) and National Cancer Center of Korea. Bragg peak curve, Inhomogeneities, Proton 55

56 Poster P-T-11 유리선량계와 Gafchromic 필름을이용한 Co-60 방사선의좁은직사각형조사면에대한방사선량분포측정 한국원자력의학원방사선의학연구소 *, 국립의료원 신상훈 * ㆍ박승우 * ㆍ이창열 * ㆍ손기홍 * ㆍ최문식 * 이동한 * ㆍ김금배 * ㆍ오원용 ㆍ지영훈 * ㆍ정해조 * 목적 : Co-60 방사선원으로부터발생되는고에너지감마선은표면선량이낮고, 최대선량지점인 5 mm 까지의선량이급격하게증가하는축적 (build-up) 구간을형성하며, 이러한선량분포의특징은방사선치료시피부보호효과 (skin sparing effect) 의장점을가진다. 그러나표면과가깝고조사면적이작은경우불충분한선량분포를형성하여치료또는실험시에장애가될수있으므로정확한선량정보가요구된다. 본연구에서는 Co-60 방사선을이용한실험시정확한선량정보전달을위해좁은직사각형조사면에대한방사선량분포를유리선량계와 Gafchromic (EBT2) 필름을이용하여계측하였고, 결과를비교분석하였다. 재료및방법 : 실험에사용된유리선량계 (GD-301, Asahi Techno Glass Corporation, Shizuoka, Japan) 는직경이 1.5 mm, 길이가 8.5 mm인원통형이고, 선량측정범위는 10 ugy Gy까지로넓은선량영역에서의측정이가능하다. 실험에사용된 EBT2 필름 (GAFCHROMIC R EBT2 film, International Specialty Products) 은방사선치료시흡수선량을측정하기위하여개발된필름으로선량측정범위는 1 cgy에서 10 Gy 이다. Co-60 원격치료장치로는한국원자력의학원의 Theratron 780 (AECL, Canada) 을사용하였고, 방사선원-표면간거리 (SSD: source-surface distance) 는 80 cm, 조사면적은 2 30, 3 30, 5 30 cm 2 에서각각의방사선량분포를측정하였다. 인체조직과등가인볼루스및고체형물팬텀을이용하여최대선량지점인 5 mm 깊이의방사선량분포를측정하였다. 결과 : 실험결과는필름의경우조사면적 2 30, 3 30, 5 30 cm 2 에서치료시유효한 % 조사선량에해당되는면적은 , , cm 2 로측정되었고, 유리선량계의경우 , , cm 2 로측정되었다. 세가지조사면적에대한방사선량분포를측정한결과유리선량계와 EBT2 필름모두조사면적이작아질수록불충분한선량분포를형성하는것을확인할수있다. 결론 : 본연구에서는유리선량계와 EBT2 필름을사용하여조사면적의크기에따른 Co-60 방사선원의고에너지감마선에대한방사선량분포를계측하였다. 유리선량계는실시간방사선량측정이불가능하고, 측정할수있는개수에한계가있으며, 필름에비해방사선량공간분포분해능이낮은단점이있다. 하지만 EBT2 필름에비해값이저렴하고측정오차율이적으며열처리후반복적인사용이가능하기때문에필름과선량분포결과에대한오차의비교를통하여선량을보정한다면더정확한선량분포에대한정보를제공할수있을것이다. 앞으로연구는불특정한조사면에서의방사선량분포를계측하여실제동물실험시유용한선량정보제공을위한지표를제시할것이다. 감사의글 : 이논문은교육과학기술부의재원으로시행하는한국과학재단의방사선기술개발사업으로지원받았습니다. 유리선량계, Gafchromic 필름, Co-60, 방사선량분포 56

57 제 40 회한국의학물리학회춘계학술대회 P-T-12 최적의 CT 영상획득인자를이용한 TENOMAG 겔의선량분석 순천향대학교 *, 경기대학교, 을지대학교, 고려대학교, 관동대학교, 고신대학교, 인하대학교 #, 건양대학교 ** 조광환 *, ㆍ조삼주 ㆍ이석 ㆍ이상훈 ㆍ임상욱 ㆍ허현도 # ㆍ민철기 ** 심장보 ㆍ조유라 ㆍ김용호 * ㆍ문성권 * ㆍ김은석 * ㆍ권수일 목적 : 본연구에서는 TENOMAG (Tetrakis hydroxymethyl phosphonium chloride - normoxic methacrylic acidgelatin) 겔의선량평가시노이즈를줄이기위한최적의 CT 영상획득인자를찾아선량평가시불확도를줄이고분해능을향상시키고자하였다. 재료및방법 : 6% Gelatin, 8% methacrylic acid (MAA), 10 mm의 hydroquinone (HQ), 0.05 mm의 tetrakis hydroxymethyl phosphonium (THP) 을이용하여 TENOMAG 겔을합성하였다. 겔에방사선을조사하고 CT 영상을획득하기위한 phantom를제작하였다. TENOMAG 겔을분석하기위하여 CT (GE Bright Speed) 를사용하였고, 노이즈를줄이기위한최적의 CT 영상획득인자를찾기위해서 tube voltage, tube current, scan time, slice thickness, field of view (FOV), reconstruction algorithm에대하여실험한후, 기존의물을이용하여얻은값과비교하였다. TENOMAG 겔에적합한 CT 영상획득인자를이용하여선량특성을평가하였다. 선량특성은선량반응도, 재현성, 정확도, CT 영상획득시간에따른변화, 선량율의존성에대하여수행하였다. 결과 : TENOMAG 겔의최적의 CT 영상획득인자는물과전체적으로유사한결과를얻었다. tube voltage, tube current, scan time, slice thickness를증가시킴에따라서노이즈가감소하였고, FOV를크게할수록노이지는감소하였으나그차이는아주작았다. Reconstruction algorithm은다른어떤인자보다도노이즈에가장큰영향을주는것을알수있었다. 18 Gy까지방사선을조사한 TENOMAG 겔의 dose response curve에서선형상관계수 r 2 =0.992였다. 2 Gy 와 4 Gy에대한재현성은각각 1.84%, 2.13% 이었고, 정확도는 3.0%, 2.6% 였다. CT 영상획득시간의변화따라서 dose response curve의기울기가계속증가하였다. 결론 : TENOMAG 겔의선량분석을위해서최적의 CT 영상획득인자를찾아노이즈를최소화하였다. 이러한 CT 영상획득인자를이용하여 TENOMAG 겔의선량특성을분석한결과재현성, 정확도등에서우수한결과를얻을수있었다. 감사의글 : 본연구는 2009년교육과학기술부의재원으로한국연구재단의지원을받아수행되었음 ( ). TENOMAG, 정상산소중합체겔, CT 57

58 Poster P-T-13 Cone Beam CT 의 Virtual Simulator 개발 경북대학교 IT 대학전기공학과 *, 전자공학부, 성균관대학교의과대학삼성병원방사선종양학교실 이정민 * ㆍ문선미 ㆍ김가을 * ㆍ심주희 * ㆍ금오연 ㆍ한영이 목적 : 콘빔형전산화단층영상진단 (Cone Beam Computed Tomography; CBCT) 은방사선치료기와결합하여환자의해부영상을 3차원영상으로재구성하고치료의정확성을증진시킬수있는첨단영상장치이다. 그러나, 실제 CBCT 는연구나교육목적으로이용하기엔경제적부담이크고방사선을이용하는장치의특수성으로인해접근이용이하지못하다. 따라서본연구는 CBCT의 virtual simulator를개발함으로서, 교육이나연구활동에유용하게활용하여, 차세대 CBCT를위한연구를용이하게하고자하였다. 또한실제장비를통해서는알수없는복합적인상황들을 simulation기법으로쉽게이해할수있고, 외부에서필요한변수를임으로조절할수있기때문에더욱다양한현상을연구 / 교육할수있는장점이있다. 본연구에서는 virtual human과결부하여 4D CBCT 개발및영상유도방사선치료 (IGRT) 등의문제를 simulation 하는기반을제공하고자한다. 재료및방법 : Ray-tracing method는그림 1에서보는바와같이 에서시작하여 로가는 ray가물체의각 voxel을지나는길이를계산하는방법이다. 여러가지 algorithm이알려져있지만본연구에서는 Siddon algorithm을이용하여 ray가지나는 voxel의수와각좌표및코드길이를계산하는프로그램을 C언어를통해구현하였다. 한점에서시작한 ray가물체를통과할때해당 voxel의물질고유감쇄계수 에따라 signal의감도는아래의식과같이감소하게된다 (Fig. 2a). Fig. 1. Ray-tracing method. 즉, detector는 I 값에비례하는전류나전압을유발함으로서 signal의감도를측정값으로변환한다. 이측정값을모은자료가 raw파일이며이를이용하여 reconstruction을수행한다 (Fig. 2b). Reconstruction은각 voxel의물질계수 ( ) 를찾아내어피사체를 slice마다볼수있도록하는과정이다. Ray-tracing 으로계산한 raw파일은 Fourier slice theorem에따라 CBCT reconstruction algorithm 을이용하여 dicom파일로변환된다. Cone beam CT reconstruction에서는직각좌표계를이용하는것보다 ray source를기준으로경사진면에따른좌표계를이용하는것이계산이편리하므로본연구에서는경사좌표계를사용하였다. 시각화 simulator는 open source library 인 VTK(visualization toolkit) 를이용하여수행하였다. 58

59 제 40 회한국의학물리학회춘계학술대회 Fig. 2. Cone beam CT simulator; (a) X-ray decay phenomena; (b) CBCT simulator의 beam source, phantom and detector with sensors. 결과 : Fig. 3. (a) Cylinder object as target; (b) Top view object; (c) Reconstruction image slice #26. 본연구에서는피사체를 cube속에들어있는실린더로 simulation했다 (Fig. 3a). 실린더를둘러싸고있는 cube는각각의 voxel로나누고실린더를포함한곳은물질계수상수값을주고 cube만있는곳은물질계수 0으로하여 ray-tracing을수행했다 (Fig. 3b). Detector sensor의숫자는 이고 (Fig. 2b), 재구성한이미지의픽셀수는 이고 slice 수는 64개이다. 재구성결과는위의 Fig. 3c와같다. 이그림은 slice 64개중 26번째 slice이다. Ray-tracing은 0.5도간격으로 720개의 raw파일을생성했다. 계산하는시간이오래걸리기때문에 linux 기반의클러스터를이용하여 parallel computing을하여시간을단축시켰다. Reconstruction하는과정에서필터의역할이중요한데본연구에서는 Fourier transform filter를이용하였고현재 Logan-shepp filter를이용한 reconstruction을연구중에있다. Reconstruction도 CUDA 언어를이용하여실시간계산이가능하도록연구하고있다. 본연구는이론적인 simulation 이므로 CT의회전각을정확하게통제할수있고, 다양한외부변수를직접통제할수있는장점이있다. 결론 : 본연구에서는 CBCT의 algorithm을분석하여 virtual simulator를제작, 가시화함으로서 CBCT 에대한이해를높이고, 쉽게연구용이나교육용으로조작할수있도록하였다. 속도개선을위하여 ray-tracing은 linux 기반의클러스터를이용한 parallel computing으로계산하였고 reconstruction은 CUDA 언어를이용한 parallel computing을연구중이다. 본 simulator는 ray-tracing을통해투사하고싶은물체를마음대로조정할수있도록하였으며, 또임의로 noise를조작함으로서 noise의영향을구체적으로연구할수있고, 실제상황에서의복잡한변수들을개별적으로통제하여그결과를살펴볼수있도록하였다. 본연구에서개발한 virtual simulator는 Monte Carlo code와결부시켜 CBCT 질향상연구에이용될수있으며, virtual human과결부하여 simulation을통한영상유도방사선치료 (IGRT) 의연구기반을제공할수있다. 감사의글 : 경북대학교 IT대학 IT 융복합글로벌인재양성센터의지원에감사한다. CBCT Ray-tracing, Reconstruction, VTK, 4DCT, IGRT 59

60 Poster P-T-14 간암치료의 4 차원치료계획을위한변형가능영상정합기반의선량평가 서울아산병원방사선종양학과 정상훈ㆍ박성호ㆍ조병철ㆍ박재원ㆍ윤상민ㆍ김종훈ㆍ안승도 목적 : 최근방사선을이용한간암치료에있어각장기의움직임을확인하여정상장기에전달되는선량을확인할수있는 4DCT (4 Dimensional Computed Tomography) 를이용한치료계획이널리사용되고있다. 하지만, 완전한 4D 기반의치료가아닌한호흡주기에서의영상을이용하여치료계획을수립하는것이일반적이다. 본연구에서간암치료에있어 4D CT 영상및변형가능영상정합을이용하여 4차원치료계획을위한선량평가연구를수행하였다. 재료및방법 : 간암치료를위해본원에서치료받은환자의 4DCT 영상을 16 Slice CT scanner (GE healthcare, USA) 와 RPM(Rea-time position management, Varian, USA) 을이용하여획득하였다. 최대호기때의영상을이용하여각장기및치료표적을정의하고치료계획을수립하였다. Eclipse Ver. 7.5 (Varian, USA) 를이용하여최대호기때의환자의각장기및치료표적의선량을계산하였다. 각각의호흡영상을 Horn-Schunck Optical Flow Algorithms을이용하여최대호기때의영상에변형가능영상접합을수행하였다. 영상접합에서얻어진각각의화소들에대한방향량분포를이용하여최대호기때의선량을각각의호흡주기때의선량분포로변형접합하여각주요장기및치료표적의 4차원선량분포를계산하였다. 결과 : Horn-Schunck Optical Flow Algorithms을이용한최대호기와최대흡기때의영상에대한변형가능영상정합에대한분석결과는방향량분포에대해 Jacobian Analysis는평균 (±0.064) 로나타났으며, 최대호기때의영상을이용한변형가능영상접합의결과는최대흡기때의영상과비교하여변형접합이전에 MI (Mutual Information) 와 MSE (Mean Square Error) 가각각 2.93에서 0.59, 에서 로감소된결과를확인할수있었고, 최대호기때의영상을이용하여최대흡기때의영상과잘정합된영상을획득할수있었다. 이때획득한방향량분포를이용하여최대호기때의선량분포를최대흡기때의분포로정합할수있었다. 결론 : 본연구를통해 HS Optical Flow Algorithms을이용한변형가능영상접합을수행하고간암치료환자의각장기및치료표적의 4차원선량분포를계산할수있었다. 본연구에서구현한선량계산절차및방법은 4차원치료계획의선량분포를계산하는데직접활용될수있을것이다. 변형가능영상접합, 4 차원방사선치료, 간암치료 60

61 제 40 회한국의학물리학회춘계학술대회 P-T-15 GEANT4 를이용한강자기장의인가방향에따른비균질물질내광자선의깊이선량률변화평가 울산대학교의과대학서울아산병원방사선종양학교실 이세형ㆍ박성호ㆍ곽정원ㆍ정상훈 목적 : 최근자기공명영상장치를이용하여연조직기반영상유도방사선치료에관한연구가활발히진행중에있다. 이에따라, 본연구는자기공명영상장치와선형가속기결합시발생할수있는강자기장에의한광자선의깊이선량률변화를평가하였다. 재료및방법 : 본연구에서는깊이선량률계산을위하여 GEANT4 몬테칼로전산모사툴키트를이용하여 cm 3 크기의물팬텀을모델링하였고, 연조직과공동이혼합된인체를고려하기위하여팬텀의중앙 2 cm, 즉표면에서 9 11 cm 깊이의물질은공기로구성하였다. 모델링된팬텀에 6 MV 광자선을 5 5 cm 2 크기의표면선원으로조사하였다. 팬텀에인가되는자기장의방향에의한깊이선량률변화를평가하기위하여 0 T, 1.5 T의세기의자기장을각각빔축과동일방향및수직방향으로인가하였다. 결과 : 자기장이인가되지않은조건에서 6 MV 광자선을조사하였을때팬텀내최대선량이분포하는지점은 1.9 mm 에나타났으며, 빔방향에서나타나는물-공기의표면에서선량이감소하여, 10 cm 깊이지점에서는최대선량의 25% 가전달됨을볼수있었다. 또한, 공기-물표면에서는선량보강이재발생하게되고, 경계면에서 9 mm지점에최대선량지점이다시나타남을볼수있었다. 빔축과동일방향으로 1.5 T의자기장을인가하였을경우, 자기장이인가되지않은경우와비교하여물-공기경계면이나타나는 9 cm 깊이까지의깊이선량률변화는미세하였지만, 10 cm 깊이지점에전달되는선량은최대선량의 45% 로증가되고, 공기-물경계면을지나나타나는최대선량지점이경계면에서보다가까운곳에나타남을볼수있었다. 반면, 1.5 T의자기장이빔축과수직한방향으로인가되는경우최대선량지점은팬텀의표면에서가까워지며, 물-공기경계면에서최대선량의 110 % 로급격히증가되고, 10 cm 깊이지점에서최대선량의 10% 로보다적은선량이전달되었다. 또한공기-물에서의표면선량은감소하고, 재발생되는최대선량지점은경계면에서더욱깊은지점에서발생됨을볼수있었다. 결론 : 본연구에서는서로다른방향에서인가되는자기장에의한비균질한팬텀에서의깊이선량률변화에대하여비교 분석하였다. 그결과, 동일한세기의자기장이인가되더라도, 인가되는방향에따라전자들이편향되는방향이다름으로깊이선량률변화의경향이상이하게차이가나타남을볼수있었다. 깊이선량률, 강자기장, GEANT4 61

62 Poster P-T-16 폐암치료시움직이는종양의체적결정을위한 Slow CT 효용성평가 울산대학교의과대학서울아산병원방사선종양학교실 안우상ㆍ박성호ㆍ곽정원ㆍ최은경ㆍ송시열ㆍ김수산ㆍ안승도 목적 : 폐암치료시움직이는종양의체적을정확하게반영하기위하여 SSCT (slow scan computed tomography) 이용의효용성을평가하였다. 재료및방법 : 일차원 (superior-inferior 방향 ) 으로움직이는자체제작팬텀과 16 slice CT 스캐너 (GE healthcare, USA) 를이용하여영상을획득하였다. 촬영은 4.0초의회전시간 (gantry rotation time), axial의스캔타입, 영상두께 2.5 mm, 관전압 120 kv, 관전류 100 ma의조건하에서시행되었다. 움직이는팬텀위에반지름이 1.5 cm인구 (sphere) 와한변의길이가 3 cm인정육면체형태의아크릴을배치하였고팬텀의운동주기는총 6가지 (1회/4초, 2회 / 4초, 3회 /4초, 4회 /4초, 5회 /4초, 그리고 6회 /4초) 로실험하여각각의부피 (V1회, V2회, V3회, V4회, V5회, 그리고 V6 회 ) 를획득하였고각각의부피는기준영상 (V6회) 과포함되는부피 (V1-5회 V6회), 포함되지않는부피 (V6회 V1-5회c), 그리고기준영상밖에나타난영역 (V1-5회 V6회c) 을정량적으로평가하였다. 결과 : 각각의운동주기 (1회/4초, 2회 /4초, 3회 /4초, 4회 /4초, 5회 /4초) 에서얻어진종양의부피가기준영상에나타난종양의부피비에포함되는비율은구에서각각 97.7%, 95.7%, 99.6%, 98.9%, 그리고 99.8% 이고, 정육면체에서각각 92.1%, 92.8%, 94.8%, 94.3%, 그리고 94.6% 이였다. 또한기준영상에종양이위치하는부분에종양이없는것으로평가되는부피는구의경우각각 2.3%, 4.3%, 0.4%, 1.1%, 그리고 0.2% 이고, 정육면체의경우각각 7.9%, 7.2%, 5.2%, 5.7%, 그리고 5.4% 이였다. 마지막으로기준영상부피밖에나타난종양으로표시된영역의비율은구의경우각각 27.9%, 46.4%, 1.7%, 4.8%, 그리고 0.4% 이고, 정육면체의경우각각 13.3%, 47.0%, 2.8%, 6.0%, 그리고 2.9% 이었다. 결론 : SSCT를이용하여종양의움직임을충분히포함할수있는종양의운동주기를평가한결과, 종양의움직임을충분히반영하기위해적어도 3회이상의운동주기를포함할필요가있었으며그경우에구와정육면체에서얻어진종양의체적은기준영상과비교하여각각 99% 와 95% 를포함할수있었다. 4SSCT (Slow scan CT), 움직이는종양체적 (ITV), 팬텀 (phantom) 62

63 제 40 회한국의학물리학회춘계학술대회 Poster 진단

64 제 40 회한국의학물리학회춘계학술대회 P-D-01 Age-Related Differences in Cerebral Glucose Metabolism Using PET-CT Department of Radiological Science, College of Health Science*, Research Institute of Health Science, Yonsei University, Department of Radiology, Wonju College of Medicine, Yonsei University Hyun-Ju Ryu*, Su-Jin Park*, A-Ram Yu*, In-Soo Hong, Hee-Joung Kim* PURPOSE: Fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) scan on brain was performed to visualize cerebral glucose metabolism. The cerebral aging process can be represented by the value of glucose metabolism. Therefore, differences of FDG metabolism among the people from in their 30s to the 70s were analyzed by Statistical Parametric Mapping(SPM) to visualize the degree of cerebral aging. A voxel-wise comparison of spatially normalized images characterizes and quantifies age-related changes in the human brain. The results showed the degree of diminishment of brain function from aging process, and it was visualized on the image of standardized brain. MATERIAL AND METHOD: Twenty-five healthy adult subjects with no neurological, medical, psychiatric condition underwent PET-CT scanning. Twenty-five subjects were selected for this study, and the subjects comprised 5 age-groups (aged 30 39, median 36.4; aged 40 49, median 44.5; aged 50 59, median 54.3; aged 60 69, median 65; aged 70 79, median 72). The subjects of each group consisted of 2 men and 3 women. PET brain images were spatially normalized to standardize each age group using the PET-template which provided by SPM. After spatial normalization, the images were smoothed convoluting 12 mm FWHM Gaussian kernel. Comparison of glucose metabolism between 30s and other groups were analyzed with two-sample t test after normalization and smoothing on MATLAB 7.1 (MathWorks, Natick, MA) and SPM 2.0. Significance level for the two-sample t test was set at the threshold P<0.001, with a minimum cluster size k=100. The values of glucose metabolism among all groups were compared with the group of age 30's. This process denotes the degree of cerebral glucose metabolism of each group measured against 30's. Metabolism decrement of each group in comparison to the group 30's was counted on a voxel level, with the result of the two-sample t test. RESULTS: The declines of FDG uptake values among the age groups were compared with the group 30's. Then, the number of voxels which presents lower glucose metabolism values than the group of 30's were counted. The degree of glucose metabolism was calculated with the voxels which had lower signals. Total number of voxels with decreased metabolism was increased as aging. Decreased glucose metabolism in the frontal cortex was indicated from all age groups. Group 40's had decreased metabolism in the right mid frontal area (BA 46) and frontal cortex. Group 50's indicates decrement of metabolism in the frontal cortex and parietal lobe (BA 7). The cerebral glucose metabo- 65

65 Poster lism of anterior cingulated cortex started to decrease from the group 60's. This tendency was also observed in the group 70's. Among group 70's, diminution of glucose metabolism on the parietal lobe was presented as well. CONCLUSIONS: In this study, the process of aging brain was observed by counting the signal loss of each voxels. The age-related decrement of glucose metabolism tended to be linear. It showed the result of voxel-wise negative correlations with age. We found lower glycometabolism in the frontal cortex among normal aging brain. Elder groups had significantly lower glucose metabolism bilaterally in the superior frontal and medial frontal. The decreased glycometabolism on anterior cingulated gyrus was observed from the age group 60's. Though, the study was processed with a small number of subjects, the data provided negative patterns of glucose metabolism correlated to age. PET, SPM, Glucose metabolism 66

66 제 40 회한국의학물리학회춘계학술대회 P-D-02 잘못된반응순서가컴프턴카메라의영상해상도에미치는영향 한양대학교 *, 중앙대학교, 서울대학교 서희 * ㆍ박진형 * ㆍ김찬형 * ㆍ이주한 ㆍ이춘식 ㆍ이재성 목적 : 현재개발중인프로토타입이중산란형컴프턴카메라는 2대의산란부검출기와하나의흡수부검출기로구성되어있다. 선원에서방출된감마선이각각의산란부에서한번씩컴프턴산란을일으킨후흡수부에서완전히흡수되었을때유효반응으로인정하고동시계수회로를통하여데이터를획득한다. 그러나감마선은빛의속도로이동을하기때문에수 cm 떨어진거리에위치하고있는검출기사이에서발생한신호의시간차로검출기반응순서를결정하기는매우어렵다. 따라서동시계수를통해기록된반응은모두제대로된반응순서 ( 산란부1-산란부2-흡수부의순서 ) 를가지고있다고가정을하고있다. 그러나 3대의검출기로구성되어있으므로총 6가지의서로다른반응순서를가질수있고이들중하나를제외하고는모두잘못된반응순서를가지고있으므로제거의대상이된다 (Fig. 1). 따라서본연구에서는몬테칼로전산모사를통해잘못된반응순서를갖는이벤트들의발생분포를확인해보고, 이러한이벤트들이컴프턴카메라의영상해상도에미치는영향을정량적으로평가하였다. Fig. 1. 유효반응들중에서발생가능한반응순서. 1번순서를제외하고는모두잘못된반응순서를가지고있음. 재료및방법 : 몬테칼로전산모사에서발생할수있는통계적오차를고려하기위하여시드넘버 (seed number) 를달리하여총 8번의전산모사를수행하였으며, 전체유효반응들중에서각각의순서를갖는이벤트들이발생할확률의평균과표준오차를구하였다. 전산모사는 Geant4 툴킷을사용하였으며, 기댓값최대화알고리듬을사용하여컴프턴영 67

67 Poster 상을재구성하였다. 두산란부는 10 cm 거리를두었으며, 두번째산란부와흡수부는 1 cm 거리를두었다. 선원은점선원의형태로컴프턴카메라로부터 4 cm 거리를두고중심축상에위치시켰다. 결과 : 제대로된유효반응인 1번순서의경우에는전체이벤트들중에서 94.8% 의확률을가지고있는것으로나타났고, 그외의잘못된반응순서를갖는이벤트들은 5.2% 에불과하였다 (Table 1). 기록된에너지정보를통해잘못된반응순서의이벤트들을제거하려고시도하였으나유효한반응순서를갖는이벤트들의에너지범위와중복되어서가능하지않았다. 이에잘못된반응순서가영상에미치는영향을확인하기위하여모든이벤트를사용하였을경우의영상과제대로된반응순서를갖는이벤트들만을사용한영상을서로비교하여보았다. 이두가지의경우에있어서영상해상도는각각 5.72 mm와 5.64 mm로나타나서큰차이를보이지않음을확인하였다. Table 1. 각각의반응순서를갖는이벤트들의발생확률 반응순서 ( 검출기반응순서 ) 전체이벤트중발생확률 Good 순서 1 (1-2-3) 94.8±0.25% Bad 순서 2 (1-3-2) 순서 3 (2-3-1) 순서 4 (2-1-3) 순서 5 (3-2-1) 순서 6 (3-1-2) 4.7±0.22% 0.12±0.03% 0.21±0.04% 0.13±0.03% 0.05±0.01% 결론 : 본연구에서는이중산란형컴프턴카메라에대하여잘못된반응순서를갖는이벤트들의발생확률분포및이들이영상해상도에미치는영향을 Geant4 몬테칼로전산모사를통해확인하였다. 삼중동시계수로획득한유효반응들중에서잘못된반응순서를갖는이벤트의비율은 5% 정도임을확인하였고, 이들이영상해상도에미치는영향은미미하다고평가되었다. 따라서이중산란형컴프턴카메라의경우유효반응에포함되어있는잘못된반응순서를갖는이벤트들에의한영향은작다고볼수있다. 감사의글 : 본연구는원자력연구개발사업 (BAERI, 핵심기초 ) 및지식경제부 (2008-P-EP-HM-E )/ 선광원자력 ( 주 ) 의연구비지원으로수행되었습니다. 컴프턴카메라, 반응순서, 영상해상도 68

68 제 40 회한국의학물리학회춘계학술대회 P-D-03 Neurochemical Profile Quantification of Normal Adult Mice Brain by ex vivo 1 H Magic Angle Spinning Solid-State NMR Spectroscopy Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea*, Department of Veterinary Surgery, Kon-Kuk University, Department of Molecular Biology, College of Medicine, The Catholic University of Korea, Department of Radiology, Kyung-Hee University, Department of Psychiatry, College of Medicine, The Catholic University of Korea Do Wan Lee*, Dong Cheol Woo*,Sung Ho Lee, Sang Young Kim*, Goo Young Kim, Hyang Shuk Rhim, Chi Bong Choi, Hwi Yool Kim, Chang Wook Lee, Bo Young Choe* PURPOSE: The purpose of this study is to quantitate regional neurochemical profile of regional normal adult mice brain and assess regional metabolic differences by using ex vivo 1 H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy ( 1 H HR-MAS NMRS). MATERIALS AND METHODS: The animals were matched in sex and age. The collected brain tissue included frontal cortex, temporal cortex, thalamus, and hippocampus. Quantitative 1D spectra were acquired on 40 samples with the CPMG pulse sequence (8 khz spectral window, TR/TE = 5500/2.2 ms, NEX = 128, scan time: 17 min 20 sec). The mass of brain tissue and D2O+TSP solvent were 8 14 mg and 7 13 mg. A total of 16 metabolites were quantified as follow: Acet, NAA, NAAG, tcr, Cr, tcho, Cho, GPC + PC, mins, Lac, GABA, Glu, Gln, Tau and Ala. RESULTS: As a results, Acet, Cho, NAA, NAAG and mins were showed significantly different aspects on frontal cortex, hippocampus, temporal cortex and thalamus respectively. CONCLUSIONS: The present study demonstrated that absolute metabolite concentrations were significantly different among four brain regions of adult mice. Our finding might be helpful to investigate brain metabolism of neuro-disease in animal model. ACKNOWLEDGEMENT: This study was supported by a grant of the Seoul R&BD Program (10550), the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (A081057), a grant (R ) from the Purpose Basic Research Grant of the KOSEF, the Korea Research Foundation Grant funded by the Korean Government (KRF D01324), the program of Basic Atomic Energy Research Institute (BAERI) which is a part of the Nuclear R&D Programs funded by the Ministry of Education, Science & Technology (MEST) of Korea. The authors are grateful for a technical assistance from Hae-Chung Shin, Yoon-Ki Nam, and Jun-Sung Han, NMR&MRI Systems, Varian Technologies Korea, Ltd. 1 H HR-MAS NMRS, Metabolites, Normal mice, Neurochemical profile. 69

69 Poster P-D-04 Neurochemical Dysfunction and Morphological Abnormalities on the Mouse Brain in Parkinson's Disease Department of Biomedical Engineering, Research Institute of Biomedical Engineering College of Medicine, The Catholic University of Korea*, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, Korea Moon-Hyun Yoon*, Hyun-Jin Kim, Jin-Yeung Chung, Bo-Young Choe* PURPOSE: The purpose of the present study was to investigate whether magnetization transfer ratio (MTR) histogram changes were related to the specific Parkinson's disease (PD) characteristics and whether MTR histogram parameters were related to the neurochemical dysfunction by proton magnetic resonance spectroscopy (1H- MRS). MATERIALS AND METHODS: The C57BL/6 mouse strain (n=12) was used in this MTR and 1H-MRS studies. All MTR and 1H-MRS studies were performed on a 9.4 T/20cm magnet using a standard head coil. Proton-density fast spin echo (FSE) images (TR/TE/excitations 6000/11.6 ms/8, echo train length 8, acquisition matrix ) and T2-weighted spin echo (SE) images (TR/TE/excitations 6000/11.6/46.5 ms/8) were acquired with 1.0 mm slice thickness and no gap. Outer volume suppression (OVS) combined with the ultra-short echo-time STEAM (TE=2.2 ms, TM=20 ms, TR=5 sec, spectral width=5,000 Hz, number of acquired complex points=2,048) was used for localized 1H-MRS. RESULTS: The highest peak height value of the MTR histogram in the group of PD models was significantly higher than that in the group of healthy controls (P<0.05 for both the striatum and the SN). The MTR values corresponding to the peak heights were significantly differed between two groups (P<0.05). In the midbrain, MTR values in volume were lower in PD models compared with controls in the striatum and the SN (p<0.05) 1H-MRS cerebral metabolite concentrations before and after MPTP intoxication were compared. All six subjects demonstrated the increase of the Glx/Cr ratio (mean change 21%) in the right striatum concurrent with a reduction in PD symptom. CONCLUSIONS: The present study demonstrated that highest peak height value of MTR histogram and the increase of the Glx/CR ratio were observed in the striatum in the PD models. This result could be the early phase of the influence of specific neurotransmitters on the mean MTR values and MPTP intoxication suggesting neuronal dysfunction. ACKNOWLEDGEMENT: This study was supported by a grant of the Seoul R&BD Program (10550), the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (A081057), a grant (R ) from the Purpose Basic Research Grant of the KOSEF, the Korea Research Foundation Grant funded by 70

70 제 40 회한국의학물리학회춘계학술대회 the Korean Government (KRF D01324), the program of Basic Atomic Energy Research Institute (BAERI) which is a part of the Nuclear R&D Programs funded by the Ministry of Education, Science & Technology (MEST) of Korea. Magnetization transfer ratio (MTR) histogram, Proton magnetic resonance spectroscopy, MPTP intoxication 71

71 Poster P-D-05 3 차원자기공명담췌관조영술에서 Prospective Acquisition Correction (PACE) Technique 과 Respiratory Triggered (RESP) Technique 의비교 : 정상인을중심으로 순천향대학교 *, 서울대학교병원, 한동대학교선린병원, 한림성심대학, 신흥대학, 광주보건대학, 서울의료원 #, 한서대학교 **, 순천향대학교부천병원 구은회 * ㆍ김문집 * ㆍ이재승 * ㆍ이선엽 ㆍ박철수 권대철 ㆍ동경래 ㆍ류영환 # ** ㆍ최성현 ** ㆍ조재환 목적 : Navigator를이용한 prospective acquisition correction (PACE) 기법과 respiratory belt를이용한 respiratory triggered (RESP) 기법을비교하여영상의질을평가하고자한다. 재료및방법 : 정상인을대상으로 PACE기법과 RESP기법을이용한 3차원호흡유발기법의자기공명담췌관조영술를시행한 20명을대상으로하였다. 정량적분석방법으로는신호대잡음비와대조도대잡음비, 해부학구조의관찰, 호흡에의한인공물, 담췌관의선명도을 paired t-test로유용성을평가하였다. 정성적분석은 5등급을기준으로평가불가 (unacceptable, 1), 불량 (poor, 2), 보통 (fair, 3), 양호 (good, 4) 나우수 (excellent, 5) 이었으며 Wilcoxon signed-rank test을이용하여 2명의복부방사선과의사와방사선사가독립적으로점수를주었다. 결과 : 담췌관의해부학적구조물과선예도영상에서모두 PACE기법이 RESP기법보다높은점수를보였으나 (p< 0.05), 호흡에의한인공물만이통계적으로유의한차이를보이지않았다 (p>0.05). 신호대잡음비와대조도대잡음비는총간관을제외하고 (p>0.05), 유의성있는결과를얻었다 (p<0.05). 결론 : 정상인을대상으로호흡유발 3차원담췌관자기공명조영술에서 RESP기법과비교했을때 PACE기법이영상의질에서우위로평가했다. Prospective acquisition correction (PACE), Respiratory triggered (RESP), 신호대잡음비, 대조도대잡음비 72

72 제 40 회한국의학물리학회춘계학술대회 P-D-06 기능적자기공명영상기법과자기공명확산텐서기법을이용한방사관에서손과발운동에관련된뇌척수로의부위별대응구조에관한연구 연세대학교보건과학대학방사선학과 *, 영남대학교의과대학재활의학교실 이동훈 * ㆍ홍철표 * ㆍ강진구 * ㆍ장성호 ㆍ한봉수 * 목적 : 뇌척수로는신체의수의운동에관여하는신경다발의경로로서손, 발, 얼굴등과같은신체각부위의운동에관여하는뇌척수로를분리하여그정확한경로를아는것은환자의병을정확히진단하고예후를예측하는데대단히중요하다. 이를위해자기공명확산텐서영상트렉토그래피를기능적자기공명영상기법을이용하여뇌척수로를신체부위별로분리하는연구가진행되고있다. 한편결정론적방법 (deterministic method) 의자기공명확산텐서기법을통해얻어진뇌척수로는일반적으로예측되는것보다뇌의중심부로치우쳐져서기능적자기공명영상에서손운동에의해활성화되는부위와뇌척수로사이의연관성을찾기가어려운경우가많다. 따라서손운동과관련된뇌척수로를분리하기위해서는결정론적방법의확산텐서기법을사용하기가어려운것으로알려져있다. 따라서본연구에서는확률론적방법의자기공명확산텐서기법을이용하여정상성인 13인에대해손과발운동과관련된뇌척수로를분리하여방사관 (corona radiata) 에서확률맵을구하고자한다. 재료및방법 : 건강한 13인의자원자 ( 오른손잡이, 20 50세, 평규나이 35세 ) 를대상으로기능적자기공명영상과자기공명확산텐서영상을획득하였다. 기능적자기공명영상에서는손과발을구부렸다펴기를 1 Hz로반복하여 30초안지속하게하였으며 30초의휴식기를갖고 3회반복하도록하였다. 또한영상획득을위해다음과같은영상화파라미터를사용하였다. TR/TE=2,000/60 ms, FOV=210 mm, matrix=64 64, 단면의두께 =5 mm. 기능적자기공명영상데이터는 SPM2를이용하여분석하였다. 확산텐서데이터는다음과같은영상화파라미터를사용하여획득하였다. 영상단면수 =67, TR/TE=10,726/75 ms, FOV=221 mm, matrix= , 단면두께 =2.3 mm, b=1,000 mm 2 s 1, 확산강조경사자장수 =32. 뇌척수로는 FMRIB에서제공되는확률론적트렉토그래피 (probabilistic tractography) 기법을이용하여얻었다. 손과발운동에관련된뇌척수로를추출하기위해손과발운동에대한기능적자기공명영상으로확인된활성화부위와 pons내뇌척수로경로에각각관심영역을설정하였다. 대상자들의손과발운동관련뇌척수로의확률맵은개인의뇌척수로를 MNI EPI templetes에규격화 (normalization) 하여구하였다. 결과 : 대상자모두에서손과발운동에관련된뇌척수로를분리할수있었다. 또한방사관에서손과발운동에관련된뇌척수로에대한확률맵은손과발운동에관련된뇌척수로의부위별대응구조 (somatotopic structure) 를명확히보여주고있다. 결론 : 뇌척수로손상환자의다수가방사관에그환부가있어이들에대한치료를위해서는방사관에서뇌척수로의정확한위치에대한정보는대단히중요하지만이에대한연구결과는거의없다. 따라서방사관에서손과발운동에관 73

73 Poster 련된뇌척수로의위치와부위별대응구조를보여주는본연구는중요한의미를가진다고생각된다. 그러나연구결과에서알수있는바와같이뇌척수로의위치는사람마다차이가있어서방사관에서뇌척수로의부위별대응구조를밝히기위해서는더많은대상자들에대한보강연구가필요하다. Diffusion tensor tractography, Functional magnetic resonance imaging, Corticospinal tract 74

74 제 40 회한국의학물리학회춘계학술대회 P-D-07 Evaluation of Fractional Anisotropy and Apparent Diffusion Coefficient of Broca's Area in Parkinson's Disease Using Diffusion Tensor Imaging Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea*, Department of Radiology, Kyung-Hee University Medical Center, Seoul, Korea Jung-Hun Lee*, Kyung-Bae Lee*, Yun-Bong Choe, Bo-Young Choe* PURPOSE: The purpose of this study was to evaluate the changes of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of Broca's area in patients with Parkinson's disease using magnetic resonance image and diffusion tensor image (DTI). MATERIALS AND METHODS: The study included total 10 patients who were more than 60 years old with Parkinson s disease (PD) group and control group. All MR imaging data were acquired by using 3.0T scanner (Philips archiva 3.0T MRI system, Netherlands). A single-shot spin echo EPI sequence was used for DTI acquisition (TR/TE: 8,962 ms/67 ms, slice thickness: 2.0 mm, FOV: mm 2 ). Diffusion properties were measured along 32 diffusion directions with a b-value of 8,00 s/mm 2. As for statistics, SPSS was used, and Mann-Whitney U-test, Spearman correlation coefficient, Kendall's tau-b correlation coefficient, and scatter plot were obtained. RESULTS: FA value was measured as an average of 0.266±0.036 in PD group and 0.384±0.076 in control group with an significant difference as p=0.009 by Mann-Whitney U-test. Also, as p=0.038 at Spearman correlation coefficient of FA and ADC values and p=0.025 at Kendall's tau-b correlation coefficient, it indicated significant correlation between FA and ADC values. CONCLUSIONS: The present study showed a significant decrease in FA value in the Broca's areas with PD group compared with control group. Also, in FA and ADC values, its correlation was significant. The result shows that more lack language ability of patients with PD than normal persons due to the degeneration in nerve fiber of Broca's area is indicated. ACKNOWLEDGEMENT: This study was supported by a grant of the Seoul R&BD Program (10550), the Korea Health 21 R&D Project, Ministry of Health & Welfare, Republic of Korea (A081057), a grant (R ) from the Purpose Basic Research Grant of the KOSEF, the Korea Research Foundation Grant funded by the Korean Government (KRF D01324), the program of Basic Atomic Energy Research Institute (BAERI) 75

75 Poster which is a part of the Nuclear R&D Programs funded by the Ministry of Education, Science & Technology (MEST) of Korea. Diffusion Tensor Imaging (DTI), Parkinson disease (PD), Fractional anisotrophy (FA), Apparent diffusion coefficient (ADC) 76

76 제 40 회한국의학물리학회춘계학술대회 P-D-08 Metabolic Changes of Zebrafish Brain by Acute Alcohol Treatment Using NMR Spectroscopy The Catholic University of Korea*, Korea Basic Science Institute, Kyung-Hee University Dong-Cheol Woo*, Goo-Young Kim*, Hyun-Joo Kim, Eunjung Bang, Hyang-Shuk Rhim*, Sang-Young Kim*, Do-Wan Lee*, Chi-Bong Choi, Youl-Hun Seoung*, Bo-Young Choe* PURPOSE: The purpose of this study was to investigate the metabolic alteration in acute alcohol induced zebrafish brain using NMRS in this study. MATERIAL AND METHOD: Adult zebrafish (Danio rerio) of the AB strain were used. In order to investigate the acute alcohol effect by the variation of alcohol concentration, zebrafish were treated in the four alcohol dissolved tanks in the presence of the 0.00% (control n=11), 0.25% (n=11), 0.50% (n=11) and 1.00% (n=11) (v/v). For 1h, fish were exposed acute alcohol in the four tanks. As soon as fish were removed from the alcohol dosing tanks, their whole brains removed from the skull and frozen in liquid nitrogen. The metabolite powders were obtained from fish brains using methanol-chloroform (M/C)water extraction. Spectroscopy was performed at 25 o C with a Varian 500 MHz FT-NMR spectrometer. Metabolite concentrations were calculated using internal referencing quantification (TSP peak reference). RESULTS: NOVA (LSD analysis) showed a significant time effect for all neurochemicals tested: glutamate (Glu) F (3,43)=4.367, p<0.01; scyllo-inositol (sins) F (3, 43) = 4.619, p<0.01 myo-inositol (mins) F (3,43= 5.010, p <0.01; [Glu]/[tCr] F (3,43)=2.750, p<0.05; [sins]/[tcr] F (3, 43)=5.656, p<0.01; [mins]/[tcr] F (3, 43)= 2.873, p<0.05. The concentrations relative to tcr of sins, mins and Glu also were significantly different among four groups. The concentration of Glu ([Glu]) and [Glu]/[tCr] was reduced by acute alcohol exposure. [sins] and [sins]/[tcr] increased while [mins] and [mins]/[tcr] decreased. CONCLUSIONS: In this work, the metabolite concentrations of zebrafish brain as our result were good agreement with previous article. [4]As well as this study demonstrated that sins is an excellent biomarker of brain metabolism in acute/chronic alcohol effect of zebrafish as the published report. In this study, NAA, Tau and Cho were not significantly altered because of the use of whole brain. However, we demonstrated that acute alcohol exposure decreases Glu and mins, and increases sins in zebrafish brain. These results support that the induced alcohol in a brain reduces Glu level for detoxification of blood and works a disturbance the pathway from sins to mins. We revealed in this study that the combination of zebrafish and NMRS was suitable to research the alcohol effect forbrain system such as alcohol withdrawal effect, alcohol addiction. 77

77 Poster ACKNOWLEDGEMENT: is study was supported by a grant of the Seoul R&BD Program (10550), a grant (R ) from the Purpose Basic Research Grant of the KOSEF, the program of Basic Atomic Energy Research Institute (BAERI) which is a part of the Nuclear R&D Programs funded by the Ministry of Education, Science & Technology (MEST) of Korea. Zebrafish, Acute alcohol treatment, Nuclear magnetic resonance spectroscopy 78

78 제 40 회한국의학물리학회춘계학술대회 P-D-09 Evaluation of Reducing Head Radiation Dose Using Automatic Exposure Control Technique Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea*, Seoul, Department of Radiological Science, Daewon University Science College, Chechon, Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Korea Youl-Hun Seoung*, Yong-Ok Kim, Bo-Young Choe* PURPOSE: The purpose of this study was to evaluate the usefulness of reducing of head radiation dose using automatic exposure control (AEC) technique in the 64 multi-detector computed tomography (MDCT). MATERIAL AND METHOD: We used SOMATOM Definition 64 MDCT, and head of whole body phantom (KUPBU-50, Kyoto Kagaku CO. Ltd). The protocol were helical scan method with 120 kvp, 1 sec of rotation time, 5 mm of slice thickness and increment, 250 mm of field of view (FOV), of matrix size, mm of collimation, and 1 of pitch. The evaluation of dose reducing effect was compared the fixed tube current of 350 with AEC technique. The image quality was measured the noise using standard deviation of CT number. The range of craniofacial bone was to mentum end from calvaria apex, which devided three regions: calvaria~superciliary ridge (1 segment), superciliary ridge~acanthion (2 segment), and acanthion~mentum (3 segment). RESULTS: In the fixed tube current technique, CTDIvol was 57.7 mgy, DLP was mgy cm in the all regions. The AEC technique was showed that 1 segment were 30.7 mgy of CTDIvol, mgy cm of DLP, 2 segment were 46.5 mgy of CTDIvol, mgy cm of DLP, and 3 segment were 30.3 mgy of CTDIvol, mgy cm of DLP. CONCLUSIONS: The head radiation dose using AEC technique in the 64 MDCT was reduced that 1 segment was 46.8%, 2 segment was 19.6%, and 3 segment was 47.4%. ACKNOWLEDGEMENT: This study was supported by a grant of the Seoul R&BD Program (10550), the Korea Health 21 R&D Project, Ministry of Health & Welfare (A081057), a grant (R ) from the Purpose Basic Research Grant of the KOSEF (KRF D01324), the program of Basic Atomic Energy Research Institute (BAERI) which is a part of the Nuclear R&D Programs funded by the Ministry of Education, Science & Technology (MEST) of republic of Korea. Multi-detector computed tomography (MDCT), Reducing dose, Automatic exposure control (AEC) 79

79 Poster P-D-10 Development of Radiation Dosimetry Methods to Establish Diagnostic Reference Levels in Radiographic Examination Kyung Hee University*, Korea Institute of Radiological and Medical Sciences, National Institute of Food and Drug Safety Evaluation Kwang Pyo Kim*, Haijo Jung, Geon-Ho Jahng*, Hyuk Joo Kim, Dong-Wook Sung* PURPOSE: A nationwide survey is being performed to establish diagnostic reference levels (DRL) in radiographic examinations in Korea. The objective of this study, as part of national patient dose investigation, is to develop radiation dosimetry methods for the DRL establishment. MATERIAL AND METHOD: Number of hospitals involved in this study is more than 300. Examination types include 22 conventional radiographic images and 11 fluoroscopic procedures. Therefore, it is necessary to develop dosimetry methods to efficiently measure patient doses and to fully obtain information associated with patient doses. We reviewed literature on nationwide patient dose survey and DRL establishments. Based on the various approaches, we developed dosimetry methods which are best suitable for this study design. RESULTS: For radiographic examinations, radiation doses are measured using phantoms under typical x-ray equipment settings (e.g., kvp, mas, etc.) of the various examinations at each hospital. Entrance surface dose (ESD) is measured using glass dosimeters placed on phantom surface. For fluoroscopic examinations, dose rates of fluoroscopic equipments are measured. Cumulative patient doses varied with fluoroscopy time, number of spot images, and others. Such information is collected by interview with operators at each hospital. Such condition is simulated with phantom and cumulative dose area product and ESD from fluoroscopic examinations are measured. Checklists were developed to collet information associated with patient dose. The collected data include information on x-ray equipment, technical parameter settings, dose reduction technique, and patient dose. Once patient dose database are established, DRL values are selected on the basis of 75 percentile point on the observed distribution of patient doses. CONCLUSIONS: To establish DRLs in radiographic examinations in Korea, dosimetry methods for radiographic images and fluoroscopic procedures were developed. The developed methods are being used to measure patient doses and to collect associated information at hospitals in Korea. Once the databases on patient dose and other information is established, DRL values for each examiation will be selected. The developed DRLs will effectively contribute to minimize radiation exposure to patients without detriment to the clinical purpose. ACKNOWLEDGEMENT: This research was supported by a grant (10172KFDA451) from Korea Food & Drug Administration in Diagnostic reference level, DRL, Radiographic examination, Patient exposure 80

80 제 40 회한국의학물리학회춘계학술대회 P-D-11 Radiation Dose in Cephalography by Monte-Calro Simulation: Collimation Effect Department of Radiologic Science, College of Health Sciences, Korea University Boram Lee, Gwisoon Shin, Kyunghwan Chang, Wonho Lee, Jonghak Choi, Youhyun Kim PURPOSE: Recently, the simulation based on monte-calro code has been increasingly used for physics phenomenon, patient dose and QA of radiation system. This study was to verify the effective dose and dose reduction in cephalograpy using monte-calro simulation. MATERIAL AND METHOD: The collimator was made of 3-mm thick lead plate and attached to tube head to remove the region of uninterest organ for radiation field. In order to evaluate patient dose, voxel patient phantom was used. And, detector of pixel size 1 1 cm 2 and cm 2 be made to check location of collimator. The low resolution detector was used to check location of collimation because it has fast simulation time. The high resolution detector was used to confirm for location as image after check of low resolution detector. The measurement data of detector converted to image by matlab. The energy spectrum entered by SRS-78 as beam energy was calibrated as normalization factor of between measurement data and simulation data. we used local network structure by calculation of monte-calro. Because simulation time was very slow, it is importance that networking method can to reduce computing time. The simulation time of network to be used 18-cores for parllel processing was fell 15 times compared single-core computing time. The effective dose according to the ICRP 103 was calculated for with collimation and without collimation. RESULTS: The effective dose for without collimation was 11.4 usv and effective dose of collimation was 5.5 usv. The results of the calculated effective dose are shown 61.7% reduction of field area and 52% of effective dose. CONCLUSIONS: The study was implemented to evaluate patient dose in cephalography by monte-calro simulation. Study on monte-calro simulation for complex struture of patient phantom should continue. Monte-calro simulation can contribute to evaluation of study for patient dose. It was verfies that monte-calro simulation is a good tool evalution of study for patient dose. Monte-calro simulation, Cephalography, ICRP103 81

81 Poster P-D-12 진료용 X 선방어용품의납당량측정 한국표준과학연구원 *, 식품의약품안전평가원 이철영 * ㆍ김은주 목적 : 납유리, 방어장갑, 방어앞치마, 방어칸막이등진료용 X선방어용품은진단 X선종사자나핵의학종사자의방사선방호에필수적인물품이다. 이들진료용 X선방어용품의차폐성능은납당량으로평가할수있다. 특히, 진료용 X 선방어용품의차폐성능은일정규격이상의납당량을갖추도록법으로규정되어있다 [1,2]. 본연구에서는국내에서이용되고있는진료용 X선방어용품의납당량을측정하였다. 재료및방법 : 국내에서유통되고있는진료용 X선방어용투명판, 방어장갑, 방어앞치마, 방어칸막이등방어용품의납당량을한국산업규격 KS A 4025(X선방호용품류의납당량시험방법 ) 의규정에따라평가하였다. ISO4037[3] 에서제시한 100 kv 고준위공기커마계열의 X선질 (HK100) 을사용하였고차폐율측정은구형전리함 (Exradin 모델 A3 및 A6) 을이용하였다. 전리전류측정은 Keithley 모델 6517A 전기계와표준정전용량기를이용하였다. 전리전류측정에수반된표준불확도 (type A) 는 0.05% 미만이었다. KS A 4025 요건을만족하는기준거리에서순도 99.9% 이상의납판의두께를변화시키면서납판두께에따른 X선투과곡선을먼저획득하였고이곡선을바탕으로시료의납당량을측정하였다. 결과 : 진료용 X선방어용투명판두개에대한납당량은각각 0.6 및 1.9 mm로평가되었다, 이들의명목두께는각각 8.9 mm와 12 mm이었다. 진료용 X선방어앞치마의납당량은 7개의샘플에대해 mm의범위에있었다. 진료용 X선방어용칸막이의납당량은 3개의샘플에대해 mm의범위에있었다. 진료용 X선방어장갑의납당량은 4개의샘플에대해 mm의범위에있었다. 납당량측정의상대불확도는신뢰수준 95.45% 에서 3.0% 이하로평가되었다. 결론 : 진료용 X선방어용품에대한납당량을측정하였다. 같은종류유사한규격의시료에대해서도납당량은상당한편차가있음을확인하였다. 납당량측정에수반되는기술기반을교정기관에보급함으로써국내진료용 X선방어용품의차폐능향상과품질관리에일조하고관련시장을활성화하는데기여할수있길기대한다. 감사의글 : 본연구는교육과학기술부의기관고유사업과원자력중장기사업및식약청의연구비 (09141의료기454) 로수행되었다. 참고문헌 1. 진단용방사선발생장치의안전관리에관한규칙 ( 보건복지가족부령제156호, , 일부개정 ). 2. 전자의료기기기준규격 ( 식품의약품안전청고시제 호, , 개정 ). 3. International Organization for Standardization (ISO), X and Gamma Reference Radiation for Calibrating Dosemeters and Doserate Meters and for Determining Their Response as a Function of Photon Energy Part 1: Radiation Character- 82

82 제 40 회한국의학물리학회춘계학술대회 istics and Production Methods, ISO , Geneva (1996). 납당량, 진료용 X 선, 방어장갑, 방어앞치마, 방어칸막이, 납유리 83

83 Poster P-D-13 스텐트의구조와기계적인반응의최적인자도출과유한요소해석법을통한검증 가톨릭대학교의과대학의공학교실 *, 가톨릭대학교생체의공학연구소, ( 주 ) 엠아이텍중재의학연구소, 가톨릭대학교서울성모병원방사선종양학과 전동민 * ㆍ정원균 * ㆍ김한기 ㆍ김상호 ㆍ장홍석 ㆍ서태석 * 목적 : 최근내시경기술발전과더불어수술의편의성, 회복시간의단축, 환자고통감소등의효과를위하여스텐트가개발되고있다. 이를위해스텐트구조와기계적인반응에최적의인자를찾고유한요소해석법을통해최적조건임을검증하였다. 재료및방법 : 현재상용화된제품들중선호도가높은 Zilver (Cook, Bloomington, Indiana, USA) 와 S.M.A.R.T (Cordis, Bridgewater Towsnhip, New Jersey, USA) 모델을분석하였고, 스텐트의기계적영향을미치는중요인자를도출하기위해다구치요인분석으로배열하고유한요소해석법으로유연성과팽창성을찾아보았다. 또한반응표면분석의중심합성법을이용하여최적조건에알맞는중요인자를찾고이를고려한최적설계를하였다. 결과 : 본연구의결과, 다구치요인분석을통한유연성평가와는다르게팽창력평가에서는최적조건을만족시키는인자를찾을수없었다. 반응표면분석법의중심합성법으로수행결과스텐트의유연성에대한중요인자는스텐트의두께 (T), 단위넓이 (W) 이고, 팽창력에대한중요인자는스텐트의두께 (T) 로도출되었다. 반응면을통한중요인자는유연성에대한것은두께 (T), 단위두께 (W) 로도출되나, 팽창력의경우에는다른중요인자가있는것으로나타났다. 최적형상을도출한인자는 T=0.17, W=0.09이다. 결론 : 본연구기관에서유한요소해석으로최적조건을검증하여스텐트로제작하였으며제작된스텐트의유연성과팽창성능이최적조건에좀더부합됨을알수있었다. 유한요소해석에서발생되는환경적인오차로인해실제구조데이터와다소차이가있으므로이러한환경적인오차를줄이고검증한다면보다최적화된중요인자를구할수있다. 감사의글 : 본연구는중기청산학연협력기업부설연구소업그레이드자원사업 ( 협력번호 : 산기업 ) 의지원으로수행되었습니다. 스텐트, 중심합성법, 유한요소해석법, 중요인자 84

84 제 40 회한국의학물리학회춘계학술대회 P-D-14 미세석회화병변검출을위한 3 차원 Digital Tomosynthesis 기법연구 연세대학교방사선학과 황지명ㆍ김효정ㆍ오지은ㆍ조효성 목적 : 최근의산업제품군은소형경량화및다기능화가이루어지고있어전자회로기판의집적율이높아짐에따라일반 X-선영상촬영법에의한결함검사의정확도가떨어지고또한유방촬영이나흉부촬영과같은의료진단시 X선의투과성질을이용한일반 X선검사시미세석회화병변등과같은대상물체가작거나그구조가복잡할경우정확한정보를파악하기어려운경우가있다. 또한유방암촬영시유방조직의미세한 X-선감약차로인해영상대조도가극히열악함으로인해오진율이높기때문에보다정확한검사및진단의필요성이강조되고있다. 본연구에서는낮은선량으로비교적간단하게단층영상을재구성할수있는디지털단층합성법 (DTS, digital tomosynthesis) 기법을바탕으로 CT촬영과같은정밀검사에활용될수있는 3차원단층영상재구성방법에대해모색하였다. 재료및방법 : 1. 단층합성법모의실험환경 : 본연구에서는스캔구동에따른재구성단층영상의화질에관한상관관계를정량적으로분석하기위해선량이동일한조건에서모의실험을수행하였다. 모의실험은 MATLAB R 7.7 프로그램을사용하여구현하였으며, 이때사용한테스트팬텀은 Fig. 1에나타낸바와같이크기가 mm인 5개의평면에폭이서로다른 bar 패턴을갖도록구성하였다. Fig. 1. 모의실험에사용된실험구성도및테스트팬텀. Fig. 2. X 선관의이동궤적. 2. 단층촬영방식에따른이동궤적비교 : DTS는기하학적구조를고려하여단층영상을합성하므로 Fig. 2와같은다양한스캔구조가존재할수있으며, 스캔구조에따라 central slice theorem에의한 Radon 및 Fourier space 매핑구조가달라진다. 따라서스캔구조에따라변화하는매핑구조의일반화된수식도출을위해스캔구조에따른 Radon 및 85

85 Poster Fourier space의데이터분포분석과부족한데이터의범위에따라발생하는 blur artifact의영향을분석하였다. 결과 : Fig. 2는다양한형태의구조물들에대해단층촬영방식에따른 blurring 패턴을알아본결과이다. 각구조물들의형태는 impulse 함수를측정하기위한점팬텀, blurring 형태의균일성을보기위한 ring 구조, 방향성을테스트하기위한 star 팬텀을사용하였다. 이때 star 팬텀은 6개의 wire, 즉 0 o, 30 o, 60 o, 90 o, 120 o 과 150 o 로구성되어있다. 전체스캔각도가 ±40 o 이고, 스캔각도간격이 1 o 인조건에서촬영하였으며, 초점면으로부터 0.4 mm 떨어진위치에서 blur 단층영상을획득하였다. 따라서균등한흐림을얻기위해선 X선관의이동궤적이복잡할수록좋다는것을확인할수있다. 또한보다정량적으로평가하기위해 SDNR 인자를사용하여비교해보았다. Linear motion의경우 31.92로가장낮고, circular motion과 hypocycloidal motion의경우, 및 로상대적으로높은 SDNR값을나타내는것을알수있었다. (a) (b) (c) (d) 결론 : 기존연구와같은보편화된단층합성기법은적은선량으로도인체의내부기관을가시화하는데좋은화질의영상을제공했지만, 2차원영상이라는한계를가지고있어, CT와같이대상물체의단면을보다정확하게볼수있으면서도낮은선량으로검사법에대한연구가절실하다. 따라서본연구에서여러가지스캔구동방법에따라 blur artifact의영향이다르게나타나며, 검사물체의형태에의해서도구동방법에따라서다른영향을미치기때문에재구성된단층영상이달라지는것을확인할수있었다. 따라서단층합성법을이용할때는이러한스캔구동의영향을이해하고, 검사에적절히이용한다면단층영상획득시영상의질이향상될것으로예상된다. 디지털토모신스시스, 3D reconstruction, 비파괴검사 86