• 한국의학물리학회지:의학물리
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• 제31권4호
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• pp.172-178
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• 2020

Purpose: Radiation oncology information systems (ROIS) have evolved toward connecting and integrating information between radiation treatment procedures. ROIS can play an important role in utilizing modern radiotherapy techniques that have high complexity and require a large amount of information. Methods: Using Access^TM software, we have developed a relational database that is highly optimized for a radiotherapeutic workflow. Results: The prescription table was chosen as the core table to which the other tables were connected, and three types of forms-charts, worklists, and calendars- were suggested. A fast and reliable channel for delivering orders and remarks according to changes in the situation was also designed. Conclusions: We expect our ROIS design to inspire those who need to develop and manage an individual ROIS suitable for their radiation oncology departments at a low cost.

• Radiation Oncology Journal
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• 제34권2호
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• pp.81-87
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• 2016

Hypofractionated whole breast irradiation (HF-WBI) has been proved effective and safe and even better for late or acute radiation toxicity for early breast cancer. Moreover, it improves patient convenience, quality of life and is expected to be advantageous in the medical care system by reducing overall cost. In this review, we examined key randomized trials of HF-WBI, focusing on adequate patient selection as suggested by the American Society of Therapeutic Radiology and Oncology (ASTRO) guideline and the radiobiologic aspects of HF-WBI in relation to its adoption into clinical settings. Further investigation to identify the current practice pattern or cost effectiveness is warranted under the national health insurance service system in Korea.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.65-67
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• 2002

A PC based software, the RTP Research Tool Box (RTB), was developed for IMRT optimization research. The software was consisted of an image module, a beam registration module, a dose calculation module, a dose optimization module and a dose display module. The modules and the Graphical User Interface (GUI) were designed to easily amendable by negotiating the speed of performing tasks. Each module can be easily replaced to new functions for research purpose. IDL 5.5 (RSI, USA) language was used for this software. Five major modules enable one to perform the research on the dose calculation, on the dose optimization and on the objective function. The comparison of three cost functions, such as the uncomplicated tumor control probability (UTCP), the physical objective function and the pseudo-biological objective function, which was designed in this study, were performed with the RTB. The optimizations were compared to the simulated annealing and the gradient search optimization technique for all of the optimization objective functions. No significant differences were found among the objective functions with the dose gradient search technique. But the DVH analysis showed that the pseudo-biological objective function is superior to the physical objective function when with the simulated annealing for the optimization.

• 한국의학물리학회지:의학물리
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• 제27권4호
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• pp.258-266
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• 2016

We have treated various disease sites using wobbling and scanning proton therapy techniques since December 2015 at the Samsung Medical Center. In this study, we analyze the treatment time for each disease site in 65 wobbling and 50 scanning patient treatments. Treatment times are longest for liver and lung patients using the respiratory gating technique in the wobbling treatment and for cranio-spinal irradiation in pediatric patients with anesthesia in the scanning treatment. Moreover, we analyze the number of incidents causing treatment delays and the corresponding treatment delay time. The X-ray panel was the main reason for delays in the wobbling treatment; this decreased continually from January to June 2016, related closely to the proficiency of the human operators involved. The main reason for delays in the scanning treatment was interlocks during scanning pattern delivery; this was resolved by proton machine engineers. Through this work, we hope to provide other institutes with useful insight for initial operation of their proton therapy machines.

• Radiation Oncology Journal
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• 제37권2호
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• pp.67-72
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• 2019

Concurrent chemoradiation therapy (CCRT) has played the most important and central role in the definitive therapy for the patients with locoregionally advanced stage nasopharynx cancer. The addition of induction chemotherapy (IC) or adjuvant chemotherapy (AC) to CCRT have been widely accepted with the rationale of improving distant control in the clinical practices. This review article investigated the role of IC and AC based on 11 recent meta-analysis publications, and found that the clinical benefits obtained by the additional IC or AC to CCRT, at the cost of the increased risks of more frequent and more severe side effects, seemed not big enough. More intervention is not always better, however, less seems frequently good enough. The author would speculate that 'less is more' and would advocate CCRT alone as the current standard.

• 대한방사선치료학회지
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• 제33권
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• pp.15-24
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• 2021

본 연구는 악성두피종양 환자를 대상으로 자체 개발한 보루스헬멧(bolus-helmet)의 제작방법에 관한 소개 및 유용성 평가에 관한 연구이다. 두피종양환자의 치료를 위한 헬멧제작(helmet-production)에 있어 매우 창의적이고 다양한 방법의 연구들이 시도되어 왔고, 앞으로도 지속되어져 나갈 것이지만, 보고된 대부부분에 연구자료에서 헬멧(helmet)의 제작에 소요되는 시간적 경제적인 비용이나 제작의 편의성과 과정의 복잡성으로 인해 환자가 부담해야 하는 심리적인 부담감과 신체적 물리적 불편함은 크게 감소되지 않았으며, 치료효과를 높이기 위한 방안으로 최근 연구되고 있는 3D-프린터(printer) 기술과 같이 보다 첨단화된 기술과 장비를 사용하는 등에 연구들이 소개되고 있는데 이러한 방안들 또한 시간적 경제적인 소요비용과 심리적 물리적 부담을 오롯이 환자의 몫으로 보다 가중되고 있는 것은 아닌가? 하는 우려의 생각 또한 지울 수 없는 것이 현실이다. 이에 본원에서는 보루스(bolus)가 가진 물리적 성질을 그대로 유지하고 사용함으로 별도의 추가비용의 발생이 없이, 보루스(bolus)를 이용해 헬멧(helmet)을 제작함으로 환자에게 발생된 물리적 신체적인 불편함을 감소시키고자 하였으며, 헬멧의 제작에 요구되는 절차와 시간을 줄이고자 안내서(guide-line)를 제작하여 공유함으로 약 3~40분의 시간이면 누구나 쉽게 제작이 가능한 시스템을 마련하도록 했다. 헬멧(helmet)의 제작에 소요되는 시간과 환자가 부담해야 하는 경제적 비용 및 물리적인 불편함을 감소시킴으로 보이지 않게 발생되는 환자의 심리적 부담 또한 최소화할 수 있었다고 사료되며, 추가적으로 헬멧의 유용성 평가에 있어서도 공기층(air-gap)의 발생간격을 줄이는 방안을 지속적으로 모색하고 발전시켜 나감으로 결과적으로 2.0mm이내로 유지하는 방안을 본 연구를 통해 제작방법과 함께 소개할 수 있게 되어 매우 반갑게 생각된다. 본원에서 제공한 헬멧의 제작에 관한 안내서(guide-line)을 통해 방사선종양학과에 종사하는 누구나 보루스(bolus)를 이용하여 방사선 치료에 요구되는 헬멧(helmet)을 쉽게 제작할 수 있게 되기를 바라며, 제작과정에서 생기는 궁금한 사항이나 문의가 있다면 언제든지 본 연구자의 메일과 휴대폰을 통해 문의해 주시기를 적극적으로 바라고 소망합니다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권5호
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• pp.1743-1745
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• 2015

Objective: To evaluate the efficacy and adverse effects of three dimensional conformal radiotherapy (3D-CRT) with tamoxifen in treating patients with postoperative malignant glioma. Patients and Methods: 60 patients of postoperative malignant glioma were randomly assigned into two groups, 30 patients were treated with 3D-CRT plus tamoxifen (treatment group), and the other 30 patients with 3D-CRT plus temozolomide (control group). All patients were radiated by 6MV X-ray, 2.0Gy per fraction, once daily, with a total dose (DT) of 56~60Gy. Tamoxifen was delivered at $60mg/m^2/d$, temozolomide was given at $75mg/m^2/d$. All patients were treated with concurrent radiotherapy. Results: One, 2, 3 year survival rates of treatment and control group were 63.3%, 30.0%, 23.0% and 70.0%, 33.3%, 26.7%, respectively (${\chi}^2=0.01$, 0.23, 0.09, P>0.05). The rate of thromboembolism in treatment group was 6.7%. Conclusion: Therapeutic efficacy of two groups was similar, but it was more cost-effective in treatment group, and toxicity did not increase.

• Radiation Oncology Journal
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• 제29권3호
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• pp.199-205
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• 2011

Purpose: The present study compared the difference between intraoperative transrectal ultrasound (iTRUS)-based prostate volume and preplan computed tomography (CT), preplan magnetic resonance imaging (MRI)-based prostate volume to estimate the number of seeds needed for appropriate dose coverage in permanent brachytherapy for prostate cancer. Materials and Methods: Between March 2007 and March 2011, among 112 patients who underwent permanent brachytherapy with $^{125}I$, 60 image scans of 56 patients who underwent preplan CT (pCT) or preplan MRI (pMRI) within 2 months before brachytherapy were retrospectively reviewed. Twenty-four cases among 30 cases with pCT and 26 cases among 30 cases with pMRI received neoadjuvant hormone therapy (NHT). In 34 cases, NHT started after acquisition of preplan image. The median duration of NHT after preplan image acquisition was 17 and 21 days for cases with pCT and pMRI, respectively. The prostate volume calculated by different modalities was compared. And retrospective planning with iTRUS image was performed to estimate the number of $^{125}I$ seed required to obtain recommended dose distribution according to prostate volume. Results: The mean difference in prostate volume was 9.05 mL between the pCT and iTRUS and 6.84 mL between the pMRI and iTRUS. The prostate volume was roughly overestimated by 1.36 times with pCT and by 1.33 times with pMRI. For 34 cases which received NHT after image acquisition, the prostate volume was roughly overestimated by 1.45 times with pCT and by 1.37 times with pMRI. A statistically significant difference was found between preplan image-based volume and iTRUS-based volume (p<0.001). The median number of wasted seeds is approximately 13, when the pCT or pMRI volume was accepted without modification to assess the required number of seeds for brachytherapy. Conclusion: pCT-based volume and pMRI-based volume tended to overestimate prostate volume in comparison to iTRUS-based volume. To reduce wasted seeds and cost of the brachytherapy, we should take the volume discrepancy into account when we estimate the number of $^{125}I$ seeds for permanent brachytherapy.

• 대한방사선치료학회지
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• 제10권1호
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• pp.97-101
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• 1998

In recent days, although many kinds of beam modifiers are developing and using for clinical purposes in accordance with progressing medical engineering, physical wedges are preferred to use as a beam modifier by a lot of institutions until now because of cost, complexities of dosimetry and mechanical uncertainties. According to progressing technology, available field size of wedge is more enlarger than that of old model LINAC. Because field size dependence of wedged fields increases in new model LINAC, we was trying to know that how much different PSFs are in enlarged wedged fields compared with open fields. In small or middle size of fields($4{\times}4{\sim}15{\times}15cm$), there are only a few percents of PSF variation between open and wedged fields. But there are $2{\sim}8\%\;variations\;in\;relatively\;large\;fields(20{\times}20{\sim}30{\times}40cm)$.

• 한국의학물리학회지:의학물리
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• 제31권3호
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• pp.99-110
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• 2020

With hope and concern, the first Korean proton therapy facility was introduced to the National Cancer Center (NCC) in 2007. It added a new chapter to the history of Korean radiation therapy. There have been challenging clinical trials using proton beam therapy, which has seen many impressive results in cancer treatment. Compared to the rapidly increasing number of proton therapy facilities in the world, only one more proton therapy center has been added since 2007 in Korea. The Samsung Medical Center installed a proton therapy facility in 2015. Most radiation oncology practitioners would agree that the physical properties of the proton beam provide a clear advantage in radiation treatment. But the expensive cost of proton therapy facilities is still one of the main reasons that hospitals are reluctant to introduce them in Korea. I herein introduce the history of proton therapy and the cutting edge technology used in proton therapy. In addition, I will cover the role of a medical physicist in proton therapy and the future prospects of proton therapy, based on personal experience in participating in proton therapy programs from the beginning at the NCC.