• Progress in Medical Physics
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• v.24 no.2
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• pp.127-132
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• 2013

The position of the internal organs can change continually and periodically inside the body due to the respiration. To reduce the respiration induced uncertainty of dose localization, one can use a respiratory gated radiotherapy where a radiation beam is exposed during the specific time of period. The main disadvantage of this method is that it usually requests a long treatment time, the massive effort during the treatment and the limitation of the patient selection. In this sense, the combination of the real-time position management (RPM) system and the volumetric intensity modulated radiotherapy (RapidArc) is promising since it provides a short treatment time compared with the conventional respiratory gated treatments. In this study, we evaluated the accuracy of the respiratory gated RapidArc treatment. Total sic patient cases were used for this study and each case was planned by RapidArc technique using varian ECLIPSE v8.6 planning machine. For the Quality Assurance (QA), a MatriXX detector and I'mRT software were used. The results show that more than 97% of area gives the gamma value less than one with 3% dose and 3 mm distance to agreement condition, which indicates the measured dose is well matched with the treatment plan's dose distribution for the gated RapidArc treatment cases.

• Progress in Medical Physics
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• v.21 no.2
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• pp.165-173
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• 2010

In this paper, we evaluated the performance of 3D CRT, IMRT and three kind of RA plannings to investigate the clinical effect of RA with liver cancer case. The patient undergoing liver cancer of small volume and somewhat constant motion were selected. We performed 3D CRT, IMRT and RA plannings such as 2RA, limited triple arcs (3RA) and 3MRA with Eclipse version 8.6.15. The same dose volume objectives were defined for only CTV, PTV and body except heart, liver and partial body in IMRT and RA plannings. The steepness of dose gradient around tumor was determined by the Normal Tissue Objective function with the same parameters in place of respective definitions of dose volume objectives for the normal organs. The approach between the defined dose constraints and the practical DVH of CTV, PTV and Body was the best in 3MRA and the worst in IMRT. The DVHs were almost the same among RAs. Plans were evaluated using Conformity Index (CI), Homogeneity Index (HI) and Quality of coverage (QoC) by RTOG after prescription with dose level surrounding 98% of PTV in the respective plans. As a result, 3MRA planning showed the better favorable indices than that of the others and achieved the lowest MUs. In this study, RA planning is a technique that is possible to obtain the faster and better dose distribution than 3D CRT or IMRT techniques. Our result suggest that 3MRA planning is able to reduce the MUs further, keeping a similar or better targer dose homogeneity, conformity and sparing normal tissue than 2RA or 3RA.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.405-410
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• 2022

In brachytherapy, a radiation source is inserted into the body to kill tumor tissue. Therefore, it is important to accurately measure the location of the source and the dose distribution. In this study, a dosimeter that can be used for brachytherapy was developed using CsPbBr₃ which is cheaper than the existing detector materials and has a simpler manufacturing process. The CsPbBr₃ dosimeter performance was evaluated by analyzing reproducibility, linearity, and distance dependence in ¹⁹²Ir source. As a result of reproducibility evaluation, the RSD was 1.36%, which satisfies the standard value of 1.5%. As a result of the linearity evaluation, the R² value was 0.9993, which satisfies the standard R² of 0.9990. The distance dependence evaluation showed a signal value that decreased exponentially as the distance increased. The evaluation results show that the CsPbBr₃ dosimeter satisfies the evaluation criteria and can be used as a brachytherapy quality assurance dosimeter.

• Radiation Oncology Journal
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• v.23 no.2
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• pp.106-110
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• 2005

Purpose : Repetitive bleeding into the joint space is the cause of debilitative hemophilic arthropathy. To interrupt this process, we treated the hemophilic patients suffering from repetitive joint bleeding with radiation therapy. Materials and Methods : From 1997 to 2001, a total of 41 joints from 37 hemophilic arthropathy patients were treated with radiation therapy at Kyung Hee University Hospital. The treated joints were 35 ankles, 3 knees and 3 elbows, respectively. The age of the patients ranged from 4 to 27 years (median age: 11 years). The radiation dose ranged from 900 cGy to 2360 cGy (median dose: 900cGy). The fraction size was 150 cGy, 180 cGy or 200 cGy. The number of bleeding in one year before and after radiotherapy was compared. Results : There was a tendency of frequent bleeding for the Patients younger than 11 (p=0.051) but there was also a tendency for more improvement in this group (p=0.057). The number of joint bleedings was related with joint pain (p=0.012) and joint swelling (p=0.033) but not with the Arbold-Hilgartner stage (p=0.739), cartilage destruction (p=0.718) and synovial hypertrophy (p=0.079). The number of bleeding was reduced in thirty-three cases, and eight cases showed no improvement after radiation therapy. The average number of bleeding in a month was 2.52 before radiotherapy, but this was reduced to 1.4 after radiotherapy (p=0.017). Conclusion : Radiation therapy was effective for the hemophilia patients with repetitive joint bleeding to decrease the bleeding frequency and to prevent hemophilic arthropathy.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.915-918
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• 2010

본 연구는 대장암환자 치료와 신체기능과의 관련요인을 규명하고자 시도되었다. 2009년 12월 15일부터 2010년 1월 30일까지 한 종합병원 외과에 내원한 대장암환자 110명을 대상으로 설문조사를 하였다. 자료분석은 치료시점과 신체기능과의 관련요인은 ANOVA를 이용하여 분석하였으며 방사선치료 시기 및 장루유무 등과 신체기능과의 요인은 t-test로 하였다. 연구결과 첫째, 치료시점은 성기능에서 유의한 차이를 보였다(F=3.482, p<0.05), 둘째, 오심구토, 식욕저하, 치료부작용은 복원수술 전, 성기능은 복원수술 후에 유의하게 높게 나타났다(p<0.05). 셋째, 장루유무의 경우 성적만족은 장루가 없는 경우가 63.40점으로 장루가 있는 경우의 45.69점 보다 높은 반면 배뇨문제에서는 장루가 있는 경우가 28.17점으로 장루가 없는 경우의 14.69점보다 유의하게 높은 불편감을 가진 것으로 나타났다.(t=1.548, p<0.05). 결론적으로 대장암 환자 치료의 신체기능을 향상하기 위해서는 기능상태와 증상불편감을 개선시킬 수 있는 중재프로그램의 개발과 적용에 관한 연구가 필요하다.

• Journal of the Korean Arthroscopy Society
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• v.15 no.1
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• pp.13-18
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• 2011

Purpose: The purpose of this study is to evaluate the radiologic and clinical results of the arthroscopic coracoclavicular fixation of the acute acromioclavicular dislocation using $TightRope^{(R)}$ (Arthrex, Inc, Naples, FL). Materials and Methods: We performed the arthroscopic coracoclavicular fixation using $TightRope^{(R)}$ in twenty patients with the Rockwood type III or V acute acromioclavicular dislocation between February, 2009, and February, 2010. Mean follow-up was 13.4(range 8~22) months. Radiologic results were evaluated by comparing the distances between the clavicle and the coracoid process with those in the contralateral sides using the acromioclavicular stress radiographs. Clinical results were made according to the KSS(Korean Shoulder Scoring System), and the cosmetic satisfaction of the patient was assessed. Results: Radiologically, 18 cases showed excellent, 1 case showed good and 1 case showed fair results. Clinically, KSS was mean 98.5 (range 92~100) points and all cases revealed satisfactory cosmetic results. Because one case complained of skin tenderness and discomfort of palpation, we closed the knot with surrounding muscle & fascia. Then local wound infection occurred, so we treated it by incision and drainage under local anesthesia and antibiotic therapy for 2 weeks. Conclusion: Arthroscopic coracoclavicular fixation using $TightRope^{(R)}$ for treating the Rockwood type III or V acute acromioclavicular dislocation showed satisfactory radiologic and clinical results. It seems to be a good treatment method that has little postoperative complication, provides an early rehabilitation and an excellent cosmetic result, and does not require secondary operation for removal of metal implant.

• Journal of the Korean Society of Radiology
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• v.16 no.6
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• pp.735-740
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• 2022

In order to reduce side effects such as rectal bleeding in the Brachytherapy, the rectal retractor and wet gauze have been used to increase the distance between the rectum and the tandem. However, there were disadvantages that it was difficult to insert through a narrow entrance into the vagina and poor reproducibility. Also, based on the CT image of the selected catheter, the distance from the tandem to the rectum with or without the balloon catheter was checked and the reduction of the dose to the rectum was confirmed. As a result of the experiment, catheter No. 7 was selected considering the maximum balloon size at a level that does not affect the distance between the start point of the balloon and the end of the catheter, and the ovoid applicator. Based on the CT image of the selected catheter, the degree of expansion according to the presence or absence of the balloon catheter was compared, and it was found that the distance difference was 0.3 - 1 cm. In addition, it was confirmed that a decrease of about 32% was observed due to this distance difference. Therefore, the actual clinical application of the selected catheter can be used as a substitute for the existing rectal retractor and wet gauze.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.153-156
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• 2004

Korea Food and Drug Administration(KFDA) has peformed the calibration of therapy level dosimeters for Co-60 radiation since 1979. The reference standard ionization chamber has been calibrated at BIPM in France. The uncertainty on the KFDA calibration coefficients is 0.9 %(k=2) for air kerma and absorbed dose to water. Since 1999 a national quality audit program for ensuring dosimetry accuracy in Korea radiotherapy centers has been performed by the KFDA. The uncertainty associated with the determination of the absorbed dose to water from the TLD readings for high energy x-ray is 1.6 %(k=1). The correction factors for energy, non-linearity dose response, and TLD holder are used in the dose determination. Agreement between the user stated dose and KFDA measured dose within ${\pm}$ 5 % is considered acceptable. KFDA TLD postal dose quality audit program was peformed for 71 beam qualities of 53 domestic radiotherapy centers in 2003. The results for quality assurance showed that 63 out of 71 beam qualifies (89 %) satisfied the acceptance limit. The second audit was carried out for the centers outside the limit and ail of them have been corrected.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.325-332
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• 2019

This study analyzed the movement of tumors using 4DCT. Appropriate uniform IM were identified using TC, II and CI depending on ITV margins. DVH and NTCP were also compared in each case. Dose analysis on tumors with uniform IM showed that the optimal treatment plan for satisfying all TC, CI, II was evaluated as 2 mm in phase 20 and 3 mm in 40%. That was compared to the dose from the normal tissues of $PTV_{20}$, $PTV_{40}$. In the 20% radiation field, V5, V10, and V20 for the lungs increased 1.49, 1.26, and 0.65%, while 40% increased by 1.9, 2.41 and 1.23%. NTCP had a dose increase of 0.57 to 0.029% from 20% and 40%. There was a dose increase in the spinal cord and heart at uniform IM, but there was no significant difference. These data suggest that the ITV setting of 20%, phase for Respiratory Gated Radiotherapy using Novalis ExacTrac system can be applied with a uniform IM 2 mm and 40% with 3 mm for optimal treatment plan.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.207-216
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• 2014

Purpose : We present a method to reduce this gap and complete the treatment plan, to be made by the re-optimization is performed in the same conditions as the initial treatment plan different from Monaco treatment planning system. Materials and Methods : The optimization is carried in two steps when performing the inverse calculation for volumetric modulated radiation therapy or intensity modulated radiation therapy in Monaco treatment planning system. This study was the first plan with a complete optimization in two steps by performing all of the treatment plan, without changing the optimized condition from Step 1 to Step 2, a typical sequential optimization performed. At this time, the experiment was carried out with a pencil beam and Monte Carlo algorithm is applied In step 2. We compared initial plan and re-optimized plan with the same optimized conditions. And then evaluated the planning dose by measurement. When performing a re-optimization for the initial treatment plan, the second plan applied the step optimization. Results : When the common optimization again carried out in the same conditions in the initial treatment plan was completed, the result is not the same. From a comparison of the treatment planning system, similar to the dose-volume the histogram showed a similar trend, but exhibit different values that do not satisfy the conditions best optimized dose, dose homogeneity and dose limits. Also showed more than 20% different in comparison dosimetry. If different dose algorithms, this measure is not the same out. Conclusion : The process of performing a number of trial and error, and you get to the ultimate goal of treatment planning optimization process. If carried out to optimize the completion of the initial trust only the treatment plan, we could be made of another treatment plan. The similar treatment plan could not satisfy to optimization results. When you perform re-optimization process, you will need to apply the step optimized conditions, making sure the dose distribution through the optimization process.