• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.95-99
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• 2002

I. 목적 : 결막 림프종 환자의 전자선 치료를 위해 Lens shielding block의 제작시 외부 의뢰 제작과 SMC 자체 제작의 장${\cdot}$단점을 비교해보고 제작 과정에 있어 업무의 효율성을 평가하고자 한다. II. 대상 및 방법: Lens shielding block의 제작시 외부의뢰제작과정과 자체 제작 과정을 비교하여 업무의 효율성, 인력의 변화 및 두방법의 장?단점을 분석하였다. 모의치료후 두 방법의 제작 시간을 비교하였으며, 재료의 차이점과 이용방법을 비교하여 개선된 사항을 알아보았다. III. 결과 : Lens shielding block의 자체 제작시 치료 시작시기는 모의치료 실시 후 7일에서 3일로 단축되어 업무의 효율성과 그에 따른 환자의 불편함이 줄어들게 되었다. 또한, 외부의뢰 제작 과정에서 실시되었던 치과와 치과 기공실에 의뢰하던 과정이 없어지고 과내 모의치료실과 공작실에서 작업하게 되어 모든 작업을 과내에서 일률적으로 실시할 수 있게 되었다. 또한, 모의치료를 실시하면서 실시간으로 shielding block을 수정 할 수 있어 정확성이 재고되었고, 반복되는 제작 작업으로 인해 제작 공정이 보편화되고, 손쉬어졌으며, 재료 활용의 효율성이 증대되었다. IV. 결론 : Lens shieiding block의 자체 제작으로 시간이 단축되어 업무의 효율성이 증대되었고 그에 따른 인력소모와 환자의 불편함이 줄어들게 되었으며, 제작자가 모의치료를 통해 바로 block의 오차를 수정할 수 있어 치료의 안정성 및 정확성이 높아졌으므로 결론적으로 의료의 질 개선과 서비스 향상이 이루어졌다.

• Progress in Medical Physics
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• v.13 no.2
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• pp.90-97
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• 2002

The simulator which has a identical geometry with radiotherapy equipments, is a essential equipment to accomplish optimized radiotherapy plan through simulation by using diagnostic low energy X-ray. A Radiotherapy simulator has a combined technology from the therapeutic and diagnostic radiology and needs a periodical test for mechanical and optical properties, X-ray generator, image intensifier of simulator to keep the proper maintenance and radiation safety. Hence, tests were done and classified as i) mechanical and optical parameter for the gantry, collimator, and couch ii) key performance of the X-ray generator such as a kVp, mAs, and timer iii) performance of the image intensifier such as a resolution and contrast for three kinds of simulator, common use in clinic. The above result of tests will be applied to the acceptance test and periodical quality assurance procedure.

• Radiation Oncology Journal
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• v.25 no.1
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• pp.26-33
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• 2007

[ $\underline{Purpose}$ ]: The aim of this study is to evaluate and compare the incidence and aspects of myocardial perfusion defects in patients who were subjected to either two-dimensional or three-dimensional simulation techniques for early left-sided breast cancer. The myocardial perfusion defects were determined from using single photon emitted computerized tomography (SPECT) myocardial perfusion images. $\underline{Materials\;and\;Methods}$: Between January 2002 and August 2003, 32 patients were enrolled in this study. The patients were diagnosed as having early (AJCC stage T1-T2N0M0) left-sided breast cancer and were treated with tangential irradiation after breast-conserving surgery and systemic chemotherapy. The patients were divided into two groups according to the type of simulation received: two-dimensional simulation using an X-ray fluoroscope simulator or three-dimensional simulation with a CT simulator. All patients underwent technetium-99m-sestamibi gated perfusion SPECT at least 3 years after radiotherapy. The incidence and area of myocardial perfusion defects were evaluated and were compared in the two groups, and at the same time left ventricular ejection fraction and cardiac wall motion were also analyzed. The cardiac volume included in the radiation fields was calculated and evaluated to check for a correlation between the amount of irradiated cardiac volume and aspects of myocardial perfusion defects. $\underline{Results}$: A myocardial perfusion defect was detected in 11 of 32 patients (34.4%). There were 7 (46.7%) perfusion defect cases in 15 patients who underwent the two-dimensional simulation technique and 4 (23.5%) patients with perfusion defects in the three-dimensional simulation group (p=0.0312). In 10 of 11 patients who had myocardial perfusion changes, the perfusion defects were observed in the cardiac apex. The left ventricular ejection fraction was within the normal range and cardiac wall motion was normal in all patients. The irradiated cardiac volume of patients in the three-dimensional simulation group was less than that of patients who received the two-dimensional simulation technique, but there was no statistical significance as compared to the incidence of perfusion defects. $\underline{Conclusion}$: Radiotherapy with a CT simulator (three-dimensional simulation technique) for early left-sided breast cancer may reduce the size of the irradiated cardiac volume and the incidence of myocardial perfusion defects. Further investigation and a longer follow-up duration are needed to analyze the relationship between myocardial perfusion defects and clinical ischemic heart disease.

• 대한방사선치료학회:학술대회논문집
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• 1998.03a
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• pp.20-21
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• 1998

• Radiation Oncology Journal
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• v.26 no.2
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• pp.118-125
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• 2008

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 $0.06^{\circ}$ for rotation only, 1.8 mm for translation only, and 2.1 mm and $0.3^{\circ}$ for both rotation and translation, respectively, was possible. As for the 3D/3D match using CBCT images, a correction within $0.03^{\circ}$ for rotation only, 0.16 mm for translation only, and 1.5 mm for translation and $0.0^{\circ}$ 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.

• The Journal of Korean Society for Radiation Therapy
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• v.13 no.1
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• pp.104-108
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• 2001

• Radiation Oncology Journal
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• v.20 no.2
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• pp.165-171
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• 2002

Purpose : In order to perform craniospinal irradiation (CSI) in the supine position on patients who are unable to lie in the prone position, a new simulation technique using a CT simulator was developed and its availability was evaluated. Materials and Method : A CT simulator and a 3-D conformal treatment planning system were used to develop CSI in the supine position. The head and neck were immobilized with a thermoplastic mask in the supine position and the entire body was immobilized with a Vac-Loc. A volumetrie image was then obtained using the CT simulator. In order to improve the reproducibility of the patients' setup, datum lines and points were marked on the head and the body. Virtual fluoroscopy was peformed with the removal of visual obstacles such as the treatment table or the immobilization devices. After the virtual simulation, the treatment isocenters of each field were marked on the body and the immobilization devices at the conventional simulation room. Each treatment field was confirmed by comparing the fluoroscopy images with the digitally reconstructed radiography (DRR)/digitally composite radiography (DCR) images from the virtual simulation. The port verification films from the first treatment were also compared with the DRR/DCR images for a geometrical verification. Results : CSI in the supine position was successfully peformed in 9 patients. It required less than 20 minutes to construct the immobilization device and to obtain the whole body volumetric images. This made it possible to not only reduce the patients' inconvenience, but also to eliminate the position change variables during the long conventional simulation process. In addition, by obtaining the CT volumetric image, critical organs, such as the eyeballs and spinal cord, were better defined, and the accuracy of the port designs and shielding was improved. The differences between the DRRs and the portal films were less than 3 mm in the vertebral contour. Conclusion : CSI in the supine position is feasible in patients who cannot lie on prone position, such as pediatric patienta under the age of 4 years, patients with a poor general condition, or patients with a tracheostomy.

• 대한방사선치료학회:학술대회논문집
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• 1999.05a
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• pp.18-19
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• 1999

• The Journal of Korean Society for Radiation Therapy
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• v.10 no.1
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• pp.53-59
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• 1998

• Progress in Medical Physics
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• v.14 no.3
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• pp.189-195
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• 2003

The comparative analysis of a portal image and a simulation image is a very important process in radiotherapy for verifying the accuracy of an actual treatment field. In this study, we applied a chamfer-matching algorithm to compare a portal image with a simulation image and verified the accuracy of the algorithm to analyze the field matching error in the portal image. We also developed an analysis program that could analyze the two images more effectively with a chamfer-matching method and demonstrated its efficacy through a feasibility study. With virtual portal images, the accuracy of the analysis algorithm were acceptable considering the average error of shift (0.64 mm), rotation (0.32$^{\circ}$), and scale (1.61%). When the portal images of a head and neck phantom were analyzed, the accuracy and suitability of the developed analysis program was proven considering the acceptable average error of shift (1.55 mm), rotation (0.80$^{\circ}$), and scale (1.72%). We verified the applicability of a chamfer-matching algorithm to the comparative analysis of a portal image with a simulation image. The analysis program developed in this study was a practical tool to calculate the quantitative error of the treatment field in a portal image.