정위적체부방사선치료시 ExacTrac과 CBCT를 이용한 Combine IGRT의 유용성 평가

안민우,강효석,최병준,박상준,정다이,이건호,이두상,전명수,Ahn, Min Woo,Kang, Hyo Seok,Choi, Byoung Joon,Park, Sang Jun,Jung, Da Ee,Lee, Geon Ho,Lee, Doo Sang,Jeon, Myeong Soo 대한방사선치료학회 2018 대한방사선치료학회지 Vol.30 No.1

목 적 : 본 연구에서는 정위적체부방사선치료시 ExacTrac과 CBCT를 단계적으로 적용한 Combine IGRT를 사용하여 Set-up 오차를 비교 및 분석하여 Combine IGRT의 유용성을 평가하고자 한다. 대상 및 방법 : 2014년 5월에서 2017년 11월까지 본원에 내원하여 trueBEAM Stx(Varian medical System, USA)에서 정위적체부방사선치료를 받은 환자 중 부위별로 뇌(Brain) 3명, 척추(Spine) 9명, 골반(Pelvis) 3명으로 분류하였다. 치료전 ExacTrac을 사용하여 Lateral(Lat), Longitudinal(Lng), Vertical(Vrt) 방향과 Roll, Pitch, Yaw 방향으로 Set-up 오차를 보정하였고, ExacTrac 이동 값을 적용 후 CBCT를 추가적으로 수행하여 Lat, Lng, Vrt, Rotation(Rtn) 방향으로 보정하였다. 결 과 : ExacTrac 사용시 뇌 부위의 오차는 Lat $0.18{\pm}0.25cm$, Lng $0.23{\pm}0.04cm$, Vrt $0.30{\pm}0.36cm$, Roll $0.36{\pm}0.21^{\circ}$, Pitch $1.72{\pm}0.62^{\circ}$, Yaw $1.80{\pm}1.21^{\circ}$, 척추 부위는 Lat $0.21{\pm}0.24cm$, Lng $0.27{\pm}0.36cm$, Vrt $0.26{\pm}0.42cm$, Roll $1.01{\pm}1.17^{\circ}$, Pitch $0.66{\pm}0.45^{\circ}$, Yaw $0.71{\pm}0.58^{\circ}$, 골반 부위는 Lat $0.20{\pm}0.16cm$, Lng $0.24{\pm}0.29cm$, Vrt $0.28{\pm}0.29cm$, Roll $0.83{\pm}0.21^{\circ}$, Pitch $0.57{\pm}0.45^{\circ}$, Yaw $0.52{\pm}0.27^{\circ}$로 나타났다. Couch 이동 후 CBCT를 하였을 때, 뇌 부위는 Lat $0.06{\pm}0.05cm$, Lng $0.07{\pm}0.06cm$, Vrt $0.00{\pm}0.00cm$, Rtn $0.0{\pm}0.0^{\circ}$, 척추 부위는 Lat $0.06{\pm}0.04cm$, Lng $0.16{\pm}0.30cm$, Vrt $0.08{\pm}0.08cm$, Rtn $0.00{\pm}0.00^{\circ}$, 골반 부위는 Lat $0.06{\pm}0.07cm$, Lng $0.04{\pm}0.05cm$, Vrt $0.06{\pm}0.04cm$, Rtn $0.0{\pm}0.0^{\circ}$ 오차가 발생하였다. 결 론 : 정위적체부방사선치료시 ExacTrac에 추가적으로 CBCT를 사용한 Combine IGRT의 경우는 ExacTrac만 사용한 경우보다 환자의 Set-up 오차를 줄일 수 있게 나타났다. 그러나 Combine IGRT를 적용함으로 환자 Set-up 확인시간, 영상획득을 위한 체내 흡수선량이 증가한다. 그러므로 환자 상황에 따라 Combine IGRT를 사용하여 환자의 Set-up 오차를 적게 함으로써 방사선치료 효과비를 증가시킬 수 있을 것으로 사료된다. Purpose : The purpose of this study is to compare and analyze the set-up errors using the Combine IGRT with ExacTrac and CBCT phased in the treatment of Stereotatic Body Radiotherapy. Methods and materials : Patient who were treated Stereotatic Body Radiotherapy in the ulsan university hospital from May 2014 to november 2017 were classified as treatment area three brain, nine spine, three pelvis. First using ExacTrac Set-up error calibrated direction of Lateral(Lat), Longitudinal(Lng), Vertical(Vrt), Roll, Pitch, Yaw, after applied ExacTrac moving data in addition to use CBCT and set-up error calibrated direction of Lat, Lng, Vrt, Rotation(Rtn). Results : When using ExacTrac, the error in the brain region is Lat $0.18{\pm}0.25cm$, Lng $0.23{\pm}0.04cm$, Vrt $0.30{\pm}0.36cm$, Roll $0.36{\pm}0.21^{\circ}$, Pitch $1.72{\pm}0.62^{\circ}$, Yaw $1.80{\pm}1.21^{\circ}$, spine Lat $0.21{\pm}0.24cm$, Lng $0.27{\pm}0.36cm$, Vrt $0.26{\pm}0.42cm$, Roll $1.01{\pm}1.17^{\circ}$, Pitch $0.66{\pm}0.45^{\circ}$, Yaw $0.71{\pm}0.58^{\circ}$, pelvis Lat $0.20{\pm}0.16cm$, Lng $0.24{\pm}0.29cm$, Vrt $0.28{\pm}0.29cm$, Roll $0.83{\pm}0.21^{\circ}$, Pitch $0.57{\pm}0.45^{\circ}$, Yaw $0.52{\pm}0.27^{\circ}$ When CBCT is performed after the couch movement, the error in brain region is Lat $0.06{\pm}0.05cm$, Lng $0.07{\pm}0.06cm$, Vrt $0.00{\pm}0.00cm$, Rtn $0.0{\pm}0.0^{\circ}$, spine Lat $0.06{\pm}0.04cm$, Lng $0.16{\pm}0.30cm$, Vrt $0.08{\pm}0.08cm$, Rtn $0.00{\pm}0.00^{\circ}$, pelvis Lat $0.06{\pm}0.07cm$, Lng $0.04{\pm}0.05cm$, Vrt $0.06{\pm}0.04cm$, Rtn $0.0{\pm}0.0^{\circ}$. Conclusion : Combine IGRT with ExacTrac in addition to CBCT during Stereotatic Body Radiotherapy showed that it was possible to reduce the set-up error of patients compared to single ExacTrac. However, the application of Combine IGRT increases patient set-up verification time and absorption dose in the body for image acquisition. Therefore, depending on the patient's situation that using Combine IGRT to reduce the patient's set-up error can increase the radiation treatment effectiveness.

IGRT를 위한 비침습적인 호흡에 의한 장기 움직임 실시간 추적시스템

김윤종,윤의중,Kim, Yoon-Jong,Yoon, Uei-Joong 대한의용생체공학회 2007 의공학회지 Vol.28 No.5

A non-invasive respiratory gated radiotherapy system like those based on external anatomic motion gives better comfortableness to patients than invasive system on treatment. However, higher correlation between the external and internal anatomic motion is required to increase the effectiveness of non-invasive respiratory gated radiotherapy. Both of invasive and non-invasive methods need to track the internal anatomy with the higher precision and rapid response. Especially, the non-invasive method has more difficulty to track the target position successively because of using only image processing. So we developed the system to track the motion for a non-invasive respiratory gated system to accurately find the dynamic position of internal structures such as the diaphragm and tumor. The respiratory organ motion tracking apparatus consists of an image capture board, a fluoroscopy system and a processing computer. After the image board grabs the motion of internal anatomy through the fluoroscopy system, the computer acquires the organ motion tracking data by image processing without any additional physical markers. The patients breathe freely without any forced breath control and coaching, when this experiment was performed. The developed pattern-recognition software could extract the target motion signal in real-time from the acquired fluoroscopic images. The range of mean deviations between the real and acquired target positions was measured for some sample structures in an anatomical model phantom. The mean and max deviation between the real and acquired positions were less than 1mm and 2mm respectively with the standardized movement using a moving stage and an anatomical model phantom. Under the real human body, the mean and maximum distance of the peak to trough was measured 23.5mm and 55.1mm respectively for 13 patients' diaphragm motion. The acquired respiration profile showed that human expiration period was longer than the inspiration period. The above results could be applied to respiratory-gated radiotherapy.

Optimization of treatment planning workflow and tumor coverage during daily adaptive magnetic resonance image guided radiation therapy (MR-IGRT) of pancreatic cancer

Olberg, Sven,Green, Olga,Cai, Bin,Yang, Deshan,Rodriguez, Vivian,Zhang, Hao,Kim, Jin Sung,Parikh, Parag J.,Mutic, Sasa,Park, Justin C. BioMed Central 2018 Radiation oncology Vol.13 No.-

<P><B>Background</B></P><P>To simplify the adaptive treatment planning workflow while achieving the optimal tumor-dose coverage in pancreatic cancer patients undergoing daily adaptive magnetic resonance image guided radiation therapy (MR-IGRT).</P><P><B>Methods</B></P><P>In daily adaptive MR-IGRT, the plan objective function constructed during simulation is used for plan re-optimization throughout the course of treatment. In this study, we have constructed the initial objective functions using two methods for 16 pancreatic cancer patients treated with the ViewRay™ MR-IGRT system: 1) the conventional method that handles the stomach, duodenum, small bowel, and large bowel as separate organs at risk (OARs) and 2) the OAR grouping method. Using OAR grouping, a combined OAR structure that encompasses the portions of these four primary OARs within 3 cm of the planning target volume (PTV) is created. OAR grouping simulation plans were optimized such that the target coverage was comparable to the clinical simulation plan constructed in the conventional manner. In both cases, the initial objective function was then applied to each successive treatment fraction and the plan was re-optimized based on the patient’s daily anatomy. OAR grouping plans were compared to conventional plans at each fraction in terms of coverage of the PTV and the optimized PTV (PTV OPT), which is the result of the subtraction of overlapping OAR volumes with an additional margin from the PTV.</P><P><B>Results</B></P><P>Plan performance was enhanced across a majority of fractions using OAR grouping. The percentage of the volume of the PTV covered by 95% of the prescribed dose (D<SUB>95</SUB>) was improved by an average of 3.87 ± 4.29% while D<SUB>95</SUB> coverage of the PTV OPT increased by 3.98 ± 4.97%. Finally, D<SUB>100</SUB> coverage of the PTV demonstrated an average increase of 6.47 ± 7.16% and a maximum improvement of 20.19%.</P><P><B>Conclusions</B></P><P>In this study, our proposed OAR grouping plans generally outperformed conventional plans, especially when the conventional simulation plan favored or disregarded an OAR through the assignment of distinct weighting parameters relative to the other critical structures. OAR grouping simplifies the MR-IGRT adaptive treatment planning workflow at simulation while demonstrating improved coverage compared to delivered pancreatic cancer treatment plans in daily adaptive radiation therapy.</P>

온보드 영상장치(On-Board Imager) 및 콘빔CT (CBCT)를 이용한 환자 자세 검증의 유용성에 대한 연구

박진호(Jino Bak),박성호(Sung Ho Park),박석원(Suk Won Park) 대한방사선종양학회 2008 Radiation Oncology Journal Vol.26 No.2

목 적: 온보드 영상장치(On-Board Imager, OBI) 및 콘빔CT (Cone Beam Computerized Tomography, CBCT)를 이 용하면 치료실에 위치한 환자의 자세 및 위치와 모의치료 시점의 환자의 자세 및 위치를 비교할 수 있다. 온라인 영상유도방사선치료(on-line Image Guided Radiation Therapy, on-line IGRT)에서는 이러한 정보를 이용하여 방사 선 치료 직전에 환자의 위치를 확인하고 보정한다. 이때 모의치료 시 획득한 영상과 치료실에서 실시간 얻은 kV X선 영상 또는 콘빔CT 영상을 이용하여 2차원/2차원 맞춤(2D/2D Match) 또는 3차원/3차원 맞춤(3D/3D Match)의 이미지 퓨젼 프로그램을 사용하여 그 편차를 산출한다. 이 과정에서 주어지는 편차가 환자 자세에 대한 오차를 정 확히 반영하고 있는지에 대해 알아보고자 한다. 대상 및 방법: 신체 내부 구조가 모사된 팬톰(The RANDOⓇ Phantom, Alderson Research Laboratories Inc., Stamford, CT, USA)을 사용하여 실제 방사선 치료와 동일한 과정을 따라 모의치료 및 치료계획을 시행한 후 치료테이블 위에 팬톰을 셋업한다. 그리고 모의치료 시 표시된 팬톰의 표면 지점에 치료실의 레이저에 일치시킨다. 이때, CT 모의치료실과 가속기가 있는 치료실의 벽면 고정 레이저에 대한 정렬의 일치만 확인하면, 치료테이블에 놓여진 팬톰의 위치는 모의치료 시 위치와 정확히 일치한다. 실제로는 팬톰 표면에 나타나는 레이저 선의 두께 정도되는 오차를 무시한다면, 두 시점에서 팬톰의 위치가 정확히 같다고 말할 수 있다. 정확히 위치가 재현되었다고 가정되는 팬톰에 대해 평행이동 또는 회전이동의 변화를 만들어 준 후, 위치가 옮겨지고 틀어진 팬톰에 대해 온보드 영상장치로부터 kV X선 영상을 그리고 콘빔CT로부터 CT 영상을 얻는다. kV X선 영상과 모의치료 시 획득한 CT영상을 이용하여 OBI 프로그램에서 제공되는 2차원/2차원 맞춤의 결과를 얻는다. 그리고 콘빔CT 영상과 모의치료 시 획득한 CT영상을 가지고 이미지 퓨젼 과정을 거쳐 3차원/3차원 맞춤의 결과를 얻는다. 이렇게 얻은 2차원/2차 원 맞춤 및 3차원/3차원 맞춤의 결과와 처음에 팬톰에 인위적으로 만들어준 위치 변화를 비교한다. 결 과: 온보드 영상장치로 획득한 kV X선 영상과 모의치료 시 영상을 비교하는 2차원/2차원 맞춤에서는 팬톰의 위치에 회전이동만 존재한다고 가정했을 때에는 평균 0.06o의 오차 내에서 모의치료 시 팬톰의 위치에 대한 편차를 찾을 수 있었다. 또한 평행이동만 존재한다고 가정했을 때에는 편차 벡터의 크기가 평균 1.8 mm였다. 그리고 회전이동과 평행이동이 동시에 존재하는 일반적인 경우에는 편차 벡터의 크기는 평균 2.1 mm, 테이블 회전 방향으로 평균 0.3o의 오차 내에서 모의치료 시 팬톰의 위치를 찾을 수 있었다. 콘빔CT로 획득한 영상을 이용하는 3차원/3차원 맞춤의 과정에서 팬톰의 위치가 회전이동만 존재할 때에는 평균 0.03o의 오차 내에서, 평행이동만 있는 경우는 편차 벡터의 크기의 평균이 0.16 mm 내에서, 틀어지고 이동된 팬톰의 위치를 찾을 수 있었다. 그리고 회전이동과 평행이동이 동시에 존재하는 일반적인 경우에는 편차 벡터의 크기는 1.5 mm, 테이블 회전 방향으로 평균0o의 오차 내에서, 모의치료 시 팬톰의 위치와 맞출 수 있었다. 결 론: 온보드 영상장치와 콘빔CT를 이용한 영상유도방사선치료(on-line IGRT)에서 모의치료 시 팬톰의 위치는 가속기의 치료테이블 위에서 매우 정확히 재현되어졌다. 온보드 영상장치는 kV X선 영상을 이용하여 간단하게 위치의 검증과 보정을 할 수 있었고, 콘빔CT를 이용하는 경우에는 2차원적인 정면 또는 측면 영상이 아니라, 3차원 영상을 비교함으로서 더욱 정확한 위치보정이 가능하였다. Purpose: On-line image guided radiation therapy (on-line IGRT) and (kV X-ray images or cone beam CT images) were obtained by an on-board imager (OBI) and cone beam CT (CBCT), respectively. The images were then compared with simulated images to evaluate the patient’s setup and correct for deviations. The setup deviations between the simulated images (kV or CBCT images), were computed from 2D/2D match or 3D/3D match programs, respectively. We then investigated the correctness of the calculated deviations. Materials and Methods: After the simulation and treatment planning for the RANDO phantom, the phantom was positioned on the treatment table. The phantom setup process was performed with side wall lasers which standardized treatment setup of the phantom with the simulated images, after the establishment of tolerance limits for laser line thickness. After a known translation or rotation angle was applied to the phantom, the kV X-ray images and CBCT images were obtained. Next, 2D/2D match and 3D/3D match with simulation CT images were taken. Lastly, the results were analyzed for accuracy of positional correction. Results: In the case of the 2D/2D match using kV X-ray and simulation images, a setup correction within 0.06o for rotation only, 1.8 mm for translation only, and 2.1 mm and 0.3o for both rotation and translation, respectively, was possible. As for the 3D/3D match using CBCT images, a correction within 0.03o for rotation only, 0.16 mm for translation only, and 1.5 mm for translation and 0.0o for rotation, respectively, was possible. Conclusion: The use of OBI or CBCT for the on-line IGRT provides the ability to exactly reproduce the simulated images in the setup of a patient in the treatment room. The fast detection and correction of a patient’s positional error is possible in two dimensions via kV X-ray images from OBI and in three dimensions via CBCT with a higher accuracy. Consequently, the on-line IGRT represents a promising and reliable treatment procedure.

영상유도 방사선 치료(IGRT)에 따른 정상 조직의 추가 피폭에 대한 연구

김가중(Gha-Jung Kim),류준민(Jun-Min Ryu),최준구(Jun-Gu Choi),홍동희(Dong-Hee Hong) 한국콘텐츠학회 2016 한국콘텐츠학회논문지 Vol.16 No.1

최근 방사선 치료 분야에서는 다양한 영상유도 방사선 치료(IGRT) 장치들을 이용한 환자 셋업으로 고도의 정밀성이 보장된 치료가 가능해 졌다. 그러나 환자의 정상 조직에 받는 추가 선량 또한 더불어 증가되고 있다. 이에 본 연구에서는 영상유도 방사선 치료 장치 중 OBI, CBCT, ExacTrac를 이용한 환자 셋업에 주변 정상 조직에 받는 피폭선량을 측정하였다. 결과 팬텀 중심부의 선량이 CBCT의 경우 두부 12.57 mGy, 흉부 20.82 mGy, 복부 82.93 mGy, 골반부위 52.70 mGy로 측정되었으며 OBI는 0.76 ~ 8.58 mGy, ExacTrac의 경우 0.14 ~ 0.63 mGy로 CBCT의 피폭선량이 다른 장비에 비해 월등히 높게 나타나는 것을 알 수 있었다. 표면 선량의 경우에서도 CBCT가 다른 장비에 비해 높게 나타났으나 입사 피부표면 선량(Enterance skin dose)의 경우 OBI도 CBCT의 피폭선량과 거의 비슷한 흡수선량이 측정 되었다. The recent radiation therapy field can provide treatment which guarantees a high degree of accuracy, due to patient set-up using various image guided radiation therapy(IGRT) instruments. But the additional absorbed dose to patient’s normal tissues is increasing. Therefore, this study measured the absorbed dose to surrounding normal tissues which is caused by patient set-up using OBI, CBCT, ExacTrac, among various IGRT instruments. The absorbed dose to the head, the chest, the abdomen, and the pelvis from CBCT was 12.57 mGy, 20.82 mGy, 82.93 mGy, and 52.70 mGy, respectively. Also, the absorbed dose from OBI and ExacTrac ranged from 0.76 to 8.58 mGy and from 0.14 to 0.63 mGy, respectively. As a result, CBCT’s absorbed dose was far higher than other instruments. CBCT’s surface dose was far higher than others, too, but OBI’s entrance skin dose was almost the same as CBCT’s

ViewRay MRIdian System을 이용한 MRI only based plan의 유용성 고찰

전창우,이호진,안범석,김찬용,이제희,Jeon, Chang Woo,Lee, Ho Jin,An, Beom Seok,Kim, Chan young,Lee, Je hee 대한방사선치료학회 2015 대한방사선치료학회지 Vol.27 No.2

목 적 : MRI를 기반으로 한 CT fusion plan과 MRI only based plan을 비교함으로써 MRI only plan의 유용성을 평가하고, 나아가 Simulation과 치료계획을 포함한 방사선치료의 전 과정을 CT 촬영 없이 MRI 영상으로 구성하여 실시간 MR-IGRT를 구현하고자 한다. 대상 및 방법 : 본원에서 사용중인 BBB CT (Brilliance Big Bore CT, 16slice, Philips)와 Viewray MRIdian System (Viewray, USA)으로 환자 11명(Head and Neck 1명, Breast 5명, Lung 1명, Liver 3명, Prostate 1명)을 대상으로 CT & MR simulation 및 치료계획을 세웠다. Head and Neck, Breast, Prostate환자는 자유호흡(Free Breathing) 상태로, Lung과 Liver 환자는 흡기 호흡중지(Inhalation Breathing Holdng)상태로 Simulation을 진행하였다. Viewray의 Bore 크기 및 Coil 위치를 고려하여 환자 자세 및 고정기구를 동일한 조건을 유지하여 CT simulation을 시행하였다. Viewray MRIdian 시스템을 이용하여 MR 영상을 기반으로 한 CT fusion plan과 CT fusion 없이 [ICRU 46]에서 권고하는 폐, 공기, 뼈의 전자밀도를 입력한 동일한 조건의 MR only plan을 세웠다. Head and Neck, Breast, Prostate는 IMRT, Lung과 Liver 는 Gating치료계획을 세웠고, 치료계획의 평가는 PTV의 균질성 지표 (Homogeneity Index, HI)와 일치성 지표 (Conformity Index, CI), 그리고 각 PTV와 OAR의 DVH와 선량차이를 각각 비교하였다. 결 과 : 두 치료계획간 치료부위별 PTV에 대한 HI 값의 차이는 Head and Neck, Breast, Lung, Liver, Prostate 부위별로 각각 0.089, 0.26, 0.67, 0.2, 0.4%로 나타났으며, CI 값의 차이는 부위별로 각각 0.043, 0.84, 0.68, 0.46, 0.3%로 두가지 평가 값 모두 Head and Neck 부위가 가장 작은 차이를 나타냈다. PTV에 대한 평균선량 차이는 치료부위별로 각각 0.07, 0.29, 0.18, 0.3, 0.18 Gy로 나타났다. 이를 백분율로 나타냈을 때 0.06, 0.7, 0.29, 0.69, 0.44%으로 모두 1% 이하의 차이를 보였다. 두경부암의 각 OAR은 전체적으로 0.01~0.12 Gy의 평균선량 차이를 보였으며, 유방암은 0.04~0.06 Gy, 폐암에서는 0.01~0.21 Gy, 간암은 0.06~0.27 Gy, 전립선암은 0.02~0.23 Gy의 평균선량 차이를 나타냈다. 결 론 : MR 영상을 이용한 치료계획은 연부조직에서 탁월한 대조도를 나타낼 뿐만 아니라 CT fusion한 MR 치료계획과 비교했을 때 PTV의 HI, CI, 선량차이 모두 1%미만의 차이를 보였으며, OAR의 경우 비균질한 조직이 많은 부위일수록 최대 0.89 Gy 선량차이를 보였다. 이결과를 토대로 두경부암, 부분적 유방암이나 전립선암등 비균질도 차이가 적은 부위에는 CT촬영 없이 MR 영상만을 이용한 방사선치료의 가능성을 확인 할 수 있었다. Purpose : By comparing a CT fusion plan based on MRI with a plan based on only MRI without CT, we intended to study usefulness of a plan based on only MRI. And furthermore, we intended to realize a realtime MR-IGRT by MRI image without CT scan during the course of simulation, treatment planning, and radiation treatment. Materials and Methods : BBB CT (Brilliance Big Bore CT, 16slice, Philips), Viewray MRIdian system (Viewray, USA) were used for CT & MR simulation and Treatment plan of 11 patients (1 Head and Neck, 5 Breast, 1 Lung, 3 Liver, 1 Prostate). When scanning for treatment, Free Breathing was enacted for Head&Neck, Breast, Prostate and Inhalation Breathing Holding for Lung and Liver. Considering the difference of size between CT and Viewray, the patient's position and devices were in the same condition. Using Viewray MRIdian system, two treatment plans were established. The one was CT fusion treatment plan based on MR image. Another was MR treatment plan including electron density that [ICRU 46] recommend for Lung, Air and Bone. For Head&Neck, Breast and Prostate, IMRT was established and for Lung and Liver, Gating treatment plan was established. PTV's Homogeneity Index(HI) and Conformity Index(CI) were use to estimate the treatment plan. And DVH and dose difference of each PTV and OAR were compared to estimate the treatment plan. Results : Between the two treatment plan, each difference of PTV's HI value is 0.089% (Head&Neck), 0.26% (Breast), 0.67% (Lung), 0.2% (Liver), 0.4% (Prostate) and in case of CI, 0.043% (Head&Neck), 0.84% (Breast), 0.68% (Lung), 0.46% (Liver), 0.3% (Prostate). As showed above, it is on Head&Neck that HI and CI's difference value is smallest. Each difference of average dose on PTV is 0.07 Gy (Head&Neck), 0.29 Gy (Breast), 0.18 Gy (Lung), 0.3 Gy (Liver), 0.18 Gy (Prostate). And by percentage, it is 0.06% (Head&Neck), 0.7% (Breast), 0.29% (Lung), 0.69% (Liver), 0.44% (Prostate). Likewise, All is under 1%. In Head&Neck, average dose difference of each OAR is 0.01~0.12 Gy, 0.04~0.06 Gy in Breast, 0.01~0.21 Gy in Lung, 0.06~0.27 Gy in Liver and 0.02~0.23 Gy in Prostate. Conclusion : PTV's HI, CI dose difference on the Treatment plan using MR image is under 1% and OAR's dose difference is maximum 0.89 Gy as heterogeneous tissue increases when comparing with that fused CT image. Besides, It characterizes excellent contrast in soft tissue. So, radiation therapy using only MR image without CT scan is useful in the part like Head&Neck, partial breast and prostate cancer which has a little difference of heterogeneity.

Evaluation of the Elekta SymmetryTM 4D IGRT System by Using a Moving Lung Phantom

신헌주,김신욱,계철승,서재혁,이기웅,강기문,장홍석,강영남 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.1

Purpose: 4D cone-beam computed tomography (CBCT) is a beneficial tool for the treatment of movable tumors because it can help us to understand where the tumors are actually located and it has a precise treatment plan. However, general CBCT images have a limitation in that they cannot perfectly perform a sophisticated registration. On the other hand, the SymmetryTM 4D image-guided radiation therapy (IGRT) system of Elekta offers a 4D CBCT registration option. In this study, we evaluated the usefulness of SymmetryTM. Method and Materials: Planning CT images of the CIRS moving lung phantom were acquired 4D multi-detector CT (MDCT), and the images were sorted as 10 phases from 0% phase to 90% phase. The thickness of the CT images was 1 mm. Acquired MDCT images were transferred to the contouring software, and a virtual target was generated. A one-arc volumetric-modulated arc therapy (VMAT) plan was performed by using the treatment planning system on the virtual target. Finally, the movement of the phantom was verified by using the XVI SymmetryTM system. Results: The physical movement of the CIRS moving lung phantom was ±10.0 mm in the superiorinferior direction, ±1.0 mm in the lateral direction, and ±2.5 mm in the anterior-posterior direction. The movement of the phantom was measured from the 4D MDCT registration as ±10.2 mm in the superior-inferior direction, ±0.9 mm in the lateral direction, and ±2.45 mm in the anterior-posterior direction. The movement of the phantom was measured from the SymmetryTM registration as ±10.1 mm in the superior-inferior direction, ±0.9 mm in the lateral direction, and ±2.4 mm in the anterior-posterior direction. Conclusion: We confirmed that 4D CBCT is a beneficial tool for the treatment of movable tumors, and that the 4D registration of SymmetryTM can increase the precision of the registration when a movable tumor is the target of radiation treatment.

A comparative planning study for lung SABR between tri-Co-60 magnetic resonance image guided radiation therapy system and volumetric modulated arc therapy

Park, J.M.,Park, S.Y.,Kim, H.J.,Wu, H.G.,Carlson, J.,Kim, J.i. Elsevier Science Publishers 2016 Radiotherapy and oncology Vol.120 No.2

<P>Background and purpose: To compare the plan quality of tri-Co-60 magnetic-resonance image-guided radiation therapy (IGRT) to that of volumetric modulated arc therapy (VMAT) for lung stereotactic ablative radiotherapy (SABR). Materials and methods: A total of 22 patients with lung tumors located in the lower lobe were selected retrospectively. For each patient, VMAT plans with linac and intensity-modulated radiation therapy (IMRT) plans with the tri-Co-60 system were generated with prescription doses of 60 Gy (daily dose =15 Gy). For both plan types, identical CT image sets and structures were used, with the exception of planning target volumes (PTV). The PTV for VMAT was generated from the internal target volume (ITV) while the PTV for the tri-Co-60 system was generated from the gross tumor volume (GTV). Clinically relevant dose-volumetric parameters were calculated and analyzed. Results: The average PTV volumes of tri-Co-60 plans and VMAT plans were 10.5 +/- 12.3 cc vs. 27.2 +/- 23.5 cc, respectively (p < 0.001). The maximum and mean doses to PTVs were 64.0 +/- 2.6 Gy vs. 62.5 +/- 0.9 Gy (p = 0.005) and 61.4 +/- 1.7 Gy vs. 60.0 +/- 0.5 Gy (p < 0.001), respectively. The conformity and homogeneity indices were 1.89 +/- 0.38 vs. 1.01 +/- 0.40 (p < 0.001) and 0.06 +/- 0.02 vs. 0.04 +/- 0.00 (p < 0.001), respectively. No considerable differences for organs at risk (OARs) were observed between tri-Co-60 plans and VMAT plans. In terms of target conformity, integral dose and lung mean dose, the plan quality of tri-Co-60 plans was inferior to that of VMAT plans when the PTV volumes of tri-Co-60 plans were less than 10 cc. However, all treatment plans of tri-Co-60 system were clinically acceptable. Conclusion: For lung SABR, the quality of ITV-based VMAT plans was better than that of GTV-based tri-Co-60 plans especially when the PTV volumes of the tri-Co-60 plans were less than 10 cc. If the breathing pattern of a patient is reproducible, VMAT is considered the optimal option for lung SABR, otherwise the tri-Co-60 IGRT should be considered due to the ability to monitor tumor motion during treatment. (C) 2016 Elsevier Ireland Ltd. All rights reserved.</P>

IGRT (Image Guided Radiation Therapy) 시스템 교육 및 검증용 팬톰 개발

김정호,박지훈,박소현,김태규,박병도 대한방사선방어학회 2022 대한방사선방어학회 학술발표회 논문요약집 Vol.2022 No.11

무선 CCTV 시스템을 이용한 환자 고정 보조기술의 개발

박양균(Yang Kyun Park),하성환(Sung Whan Ha),예성준(Sung Joan Ye),조웅(Woong Cho),박종민(Jong Min Park),박석원(Suk Won Park),허순녕(Soon Nyung Huh) 대한방사선종양학회 2006 Radiation Oncology Journal Vol.24 No.4

목 적 본 연구에서는 선헝가속기 캔트리 헤드에 부착된 우선 CCTV 카메라를 이용한 영상처리들 동하여 환자 고 정과 지료에 있어서의 정확성과 재현성 향상 방안률 개발하고자 하였다. 대상 및 방법 선형가속기의 유사-빔 방항상 (semi-beams eye view, semi-BEV)을 얻기 위하여 무선 CCTV 모률을 자체 제작된 아크링 이흘리케이터를 이용하여 겐트리 헤드에 부착하였다 CC 미 카메라의 영상온 2.4 GHz의 고주파를 동해 치료실 벅언의 수신기로 전송된다 선헝가속기 작동시 발생하는 무선 주파수에 의한 간섭현싱 (RFinterterence) 과 누설 방사선으로 영상에 잡음이 발생하는데, 구리 호일로 카메라를 차폐하고 미디얀 필터링과 같은 영상처리 기업를 이용하여 이러한 잡음를 최소화할 수 있었다 스테레오 정합 기법과 Gauss-Newton 최적화 방법 돈툴 기반으묻 자체 제작펀 소프트웨어들 동해, 환자의 고정 상태들 나타내는 3차원적 위치, 이동, 회전 정도들 정량적으로 평가하였다 시스템의 정획도를 평가하기 위하여 팬톰 실힘을 수행하였다 또, 환자 호흥에 대한 실시간영상분석을 통해 호흠 동기 시스템 (respiratory gating system)을 구현하기 위한 방법론을 개발하였다. 결 과: 구리 호일 차페와 영상처리를 통해 잡음을 80% 이상 줄일 수 있었다 3차원 위치정보의 오차는 팬돔 실험을 통해 1.5±0.7 mm로 나타났고, 이동 및 회전랑에 대한 오자는 각각, 1 mm, 1。미만으로 나타났다 환자 호홉에 따른 호흥 동기 시스템툴 구현한 결과, 0.2초의 오차 범위 내에서 실시간 모나터링 01 가능한 것으로 나타났다. 결 론 선형가속기에 부착펀 CCTV틀 이용한 환자 고정 보조기술은 기존의 높은 비용을 필요여 하는 바 IGRT 기엄에 비하여 설치와 이용이 간펀하다 시스템이 선형가속기와 근접해 있기 때문에 야기되는 문제점은 온 연구에서 제시된 방법를 통해 해결될 수 있었다 시스템의 정확도를 평가해 볼 때 임상적으로 적용이 가능할 것으로 판단된다. Purpose: To develop a wireless CCTV system in semi-beam’'s eye view (BEV) to monitor daily patient setup in radiation therapy. Materials and Methods: In order to get patient images in semi-BEV, CCTV cameras are installed in a custom-made acrylic applicator below the treatment head of a linear accelerator. The images from the cameras are transmitted via radio frequency signal (-2.4 8Hz and 10 mW RF output). An expected problem with this system β radio frequency interference, which is solved utilizing RF shielding with Cu foils and median filtering software. The images are analyzed by our custom-made software. In the software, three anatomical landmarks In the patient surface are indicated by a user, then automaticalψ the 3 dimensional structures are obtained and registered by utilizing a localization procedure consisting mainly of stereo matching algorithm and Gauss Newton optimization. This algorithm is applied to phantom images to investigate the setup accuracy Respiratory gating system is also researched with real-time image processing. A line-laser marker projected on a patient's surface is extracted by binary image processing and the breath pattern is calculated and displayed in real-time. .Results: More than 80% of the camera noises from the linear accelerator are eliminated by wrapping the camera with copper foils. The accuracy of the localization procedure is found to be on the order of 1.5 上0 .7 mm with a point phantom and sub-millimeters and degrees with a custom-made head/neck phantom. With line-laser marker, real-time respiratory monitoring is possible in the delay time of - O. t7 sec Conclusion: The wireless CCTV camera system IS the novel tool which can monitor daily patient setups. The feasibility of respiratory gating system with the wireless CCTV is hopeful.