• Radiation Oncology Journal
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• v.30 no.1
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• pp.43-48
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• 2012

Purpose: To develop the dose volume histogram (DVH) management software which guides the evaluation of radiotherapy (RT) plan of a new case according to the biological consequences of the DVHs from the previously treated patients. Materials and Methods: We determined the radiation pneumonitis (RP) as an biological response parameter in order to develop DVH management software. We retrospectively reviewed the medical records of lung cancer patients treated with curative 3-dimensional conformal radiation therapy (3D-CRT). The biological event was defined as RP of the Radiation Therapy Oncology Group (RTOG) grade III or more. Results: The DVH management software consisted of three parts (pre-existing DVH database, graphical tool, and $Pinnacle^3$ script). The pre-existing DVH data were retrieved from 128 patients. RP events were tagged to the specific DVH data through retrospective review of patients' medical records. The graphical tool was developed to present the complication histogram derived from the preexisting database (DVH and RP) and was implemented into the radiation treatment planning (RTP) system, $Pinnacle^3$ v8.0 (Phillips Healthcare). The software was designed for the pre-existing database to be updated easily by tagging the specific DVH data with the new incidence of RP events at the time of patients' follow-up. Conclusion: We developed the DVH management software as an effective tool to incorporate the phenomenological consequences derived from the pre-existing database in the evaluation of a new RT plan. It can be used not only for lung cancer patients but also for the other disease site with different toxicity parameters.

• Progress in Medical Physics
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• v.26 no.4
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• pp.201-207
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• 2015

The new function of 3DVH software for dose calculation inside the patient undergoing TomoTherapy treatment by applying the measured data obtained by ArcCHECK was recently released. In this study, the dosimetric accuracy of 3DVH for the TomoTherapy DQA process was evaluated by the comparison of measured dose distribution with the dose calculated using 3DVH. The 2D diode detector array MapCHECK phantom was used for the TomoTherapy planning of virtual patient and for the measurement of the compared dose. The average pass rate of gamma evaluation between the measured dose in the MapCHECK phantom and the recalculated dose in 3DVH was $92.6{\pm}3.5%$, and the error was greater than the average pass rate, $99.0{\pm}1.2%$, in the gamma evaluation results with the dose calculated in TomoTherapy planning system. The error was also greater than that in the gamma evaluation results in the RapidArc analysis, which showed the average pass rate of $99.3{\pm}0.9%$. The evaluated accuracy of 3DVH software for TomoTherapy DQA process in this study seemed to have some uncertainty for the clinical use. It is recommended to perform a proper analysis before using the 3DVH software for dose recalculation of the patient in the TomoTherapy DQA process considering the initial application stage in clinical use.

• Progress in Medical Physics
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• v.28 no.4
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• pp.181-189
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• 2017

The conventional delivery quality assurance (DQA) process for RapidArc (Varian Medical Systems, Palo Alto, USA), has the limitation that it measures and analyzes the dose in a phantom material and cannot analyze the dosimetric changes under the motional organ condition. In this study, a DQA method was designed to overcome the limitations of the conventional DQA process for internal target volume (ITV) based RapidArc. The dynamic DQA measurement device was designed with a moving phantom that can simulate variable target motions. The dose distribution in the real volume of the target and organ-at-risk (OAR)s were reconstructed using 3DVH with the ArcCHECK (SunNuclear, Melbourne, USA) measurement data under the dynamic condition. A total of 10 ITV-based RapidArc plans for liver-cancer patients were analyzed with the designed dynamic DQA process. The average pass rate of gamma evaluation was $81.55{\pm}9.48%$ when the DQA dose was measured in the respiratory moving condition of the patient. Appropriate method was applied to correct the effect of moving phantom structures in the dose calculation, and DVH data of the real volume of target and OARs were created with the recalculated dose by the 3DVH program. We confirmed the valid dose coverage of a real target volume in the ITV-based RapidArc. The variable difference of the DVH of the OARs showed that dose variation can occur differently according to the location, shape, size and motion range of the target. The DQA process devised in this study can effectively evaluate the DVH of the real volume of the target and OARs in a respiratory moving condition in addition to the simple verification of the accuracy of the treatment machine. This can be helpful to predict the prognosis of treatment by the accurate dose analysis in the real target and OARs.

• Radiation Oncology Journal
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• v.17 no.3
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• pp.261-267
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• 1999

Purpose : In FSRT (Fractionated stereotactic radiotherapy) planning, we studied the usefulness between multiple arc FSRT and conformal FSRT by comparing tumor shape and DVH (dose volume histogram). Materials and Methods In Chungnam Univ. hospital, we had treated the sixteen patients with FSRT from Aug. 1997 to Dec. 1998. In choosing multiple arc FSRT or conformal FSRT, we had considered If (irregular factor) after calculating tumor volume and surface area. We had considered multiple arc FSRT if tumor shape was similar to sphere or the value of If was less than 1.25, conformal FSRT if tumor shape was very irregular or If was more than 1.3. For evaluation of treatment planning, we had considered the appropriate DVH for tumor volume and for critical organs. Results : The errors between reference point and the coordinates point on AP, Lat radiography were less than 1 mm before treatment. We had planned $3\~$5 arcs for multiple arc FSRT, $5\~6$ports for conformal FSRT. The mean dose distribution of tumor volume of cumulative DVH between multiple arc FSRT and conformal FSRT was 90.6, 85%, respectively. The dose of critical organs irradiated was less than $5\%$ maximum dose of cumulative DVH. Conclusion : We had obtained the similar value between multiple arc FSRT and conformal FSRT, so that we had appropriate treatment planning of FSRT for multiple arc FSRT and conformal FSRT according to tumor shape and size.

• Progress in Medical Physics
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• v.17 no.1
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• pp.6-16
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• 2006

The goal of this study was to develop new indices for effectively evaluating the dose coverage and homogeneity based on the target-volume dose-volume histogram (TV-DVH) of intensity-modulated radio-therapy treatment plans. A new coverage Index and a new homogeneity index were developed by integrating a modified TV-DVH and by fitting a TV-DVH with a modified step function, respectively. The coverage index, named the l-index, indicates whether the dose coverage for the target volume is adequate based on user-defined criteria. A lower l-index indicates higher dose coverage of the tumor volume. The index for assessing dose homogeneity in a target volume, named the n-index, is more accurate than the conventional method in evaluating the dose homogeneity in a tumor volume. The baseline treatment plan for a target volume coverage and homogeneity is discussed. The proposed simple indices have been demonstrated to be effective in evaluating the dose coverage and homogeneity for TV-DVHs.

• The Journal of Korean Society for Radiation Therapy
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• v.14 no.1
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• pp.1-5
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• 2002

I. 목적 : 방사선 치료 시 최적화된 체내 선량분포를 얻는 것은 정상조직의 장애를 줄이고 종양선량을 높여 치료 효율을 극대화하는데 매우 중요하다. 본원에서는 병변 부위가 한쪽으로 치우친 head&neck 환자 치료 시 정상조직(tongue)을 보호하기 위해 tongue displacer를 만들어 사용한다. 이에 본 저자는 tongue displacer사용의 치료 유용성을 평가 하고자 한다. II. 대상 및 방법 : head & neck 치료 환자 중 병변 부위가 인체의 정중선(MSP)을 기준으로 한쪽으로 치우친 환자를 대상으로 하였다. 사용된 실험재료로는 C-T (high speed advantage, GE,US), RTP System (3D RTP system, prowess, US), 치과용 인상제 주입기(caulk system, quixx, japan), tongue displacer 등이 있다. 실험 방법은 모의 치료나 planning C-T를 시행하기 전에 치료 환자에게 사용할 개인용 tongue displacer를 치과용 인상제로 자체 제작하였다. 제작 후 모의 치료를 시행하고 3D plan을 하기 위해 planning C-T를 촬영하게 되는데 이때 tongue displacer사용 유. 무에 따라 각각 촬영을 하였다. 촬영된 두 가지의 CT영상을 prowess를 이용하여 3D plan을 하게 되는데 이때의 plan parameter나 beam direction등 plan에서의 모든 조건은 모두 동일시하고 선량 분포 및 DVH(dose volume histogram)값을 비교하였다. III. 결과 : tongue displace의 사용 유. 무에 따른 3D plan상의 DVH 비교 결과 tumor volume 주위의 다른 organ들은 모두 비슷한 양상의 DVH를 보였으나 tongue에 있어서 큰 변화를 보였다. tongue displacer를 사용 시, 미 사용시 보다 tongue의 위치를 변화시켜 치료 부위 외의 tongue에 받는 방사선 피폭 면적을 줄일 수 있었고 그 결과 DVH상의 $50\%$ volume이 $16\%$ 정도 줄어드는 것이 확인되었다. IV. 결론 : tongue에 방사선을 조사하면 방사선 부작용으로 mucositis, ulcer, hemorrhage등의 pain(동통)이 수반되므로 치료환자의 음식물 섭취불량으로 체증감소 등 전신 쇠약으로 이어질 수 있다. head & neck 환자 중에서 병소 위치가 한쪽으로 치우쳐서 있을 경우 인상제를 이용하여 tongue displacer를 만들어서 사용하면 tongue 의 위치를 변화시켜 방사선 조사 야에서 제외시켜준다. 그러므로 방사선 치료 시 tongue의 부작용을 최소화 할 수 있고 환자의 방사선 치료 만족도를 높일 수 있다고 사료된다.

• Radiation Oncology Journal
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• v.27 no.4
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• pp.240-248
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• 2009

Purpose: To provide a simple research tool that may be used to analyze a dose volume histogram from different radiation therapy planning systems for NTCP (Normal Tissue Complication Probability), OED (Organ Equivalent Dose) and so on. Materials and Metohds: A high-level computing language was chosen to implement Niemierko's EUD, Lyman-Kutcher-Burman model's NTCP, and OED. The requirements for treatment planning analysis were defined and the procedure, using a developed GUI based program, was described with figures. The calculated data, including volume at a dose, dose at a volume, EUD, and NTCP were evaluated by a commercial radiation therapy planning system, Pinnacle (Philips, Madison, WI, USA) for comparison. Results: The volume at a special dose and a dose absorbed in a volume on a dose volume histogram were successfully extracted using DVH data of several radiation planning systems. EUD, NTCP and OED were successfully calculated using DVH data and some required parameters in the literature. Conclusion: A simple DVH analyzer program was developed and has proven to be a useful research tool for radiation therapy.

• Progress in Medical Physics
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• v.13 no.3
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• pp.129-134
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• 2002

The radiosurgery is planned that prescribed dose was irradiated to tumor for obtaining expected remedial value in stereotactic radiosurgery. The planning for many irregular tumor shape requires long computation time and skilled planners. Due to the rapid development in computer power recently, many optimization methods using computer has been proposed, although the practical method is still trial and error type of plan. In this study, many beam variables were considered and many tumor shapes were assumed cylinderical ideal models. Then, beam variables that covered the target within 50％ isodose curve were searched, the result was compared and analysed. The beam variables considered were isocenter separation distance, number of isocenters and collimator size. Dose distributions obtained with these variables were analysed by dose volume histogram(DVH) and dose profile at orthogonal plane. According to the results compared, the use of more isocenters than specified isocenter dosen't improve DVH and dose profile but only increases complexity of plan. The best result of DVH and dose profile are obtainedwhen isocenter separation was 1.0-1.2 in using same number of isocenter.

• Radiation Oncology Journal
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• v.38 no.1
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• pp.60-67
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• 2020

Purpose: We performed three-dimensional (3D) dose reconstruction-based pretreatment verification to evaluate gamma analysis acceptance criteria in volumetric modulated arc therapy (VMAT) for prostate cancer. Materials and Methods: Pretreatment verification for 28 VMAT plans for prostate cancer was performed using the COMPASS system with a dolphin detector. The 3D reconstructed dose distribution of the treatment planning system calculation (TC) was compared with that of COMPASS independent calculation (CC) and COMPASS reconstruction from the dolphin detector measurement (CR). Gamma results (gamma failure rate and average gamma value [GFR and γAvg]) and dose-volume histogram (DVH) deviations, 98%, 2% and mean dose-volume difference (DD_98%, DD_2% and DD_mean), were evaluated. Gamma analyses were performed with two acceptance criteria, 2%/2 mm and 3%/3 mm. Results: The GFR in 2%/2 mm criteria were less than 8%, and those in 3%/3 mm criteria were less than 1% for all structures in comparisons between TC, CC, and CR. In the comparison between TC and CR, GFR and γAvg in 2%/2 mm criteria were significantly higher than those in 3%/3 mm criteria. The DVH deviations were within 2%, except for DD_mean (%) for rectum and bladder. Conclusions: The 3%/3 mm criteria were not strict enough to identify any discrepancies between planned and measured doses, and DVH deviations were less than 2% in most parameters. Therefore, gamma criteria of 2%/2 mm and DVH related parameters could be a useful tool for pretreatment verification for VMAT in prostate cancer.

• Progress in Medical Physics
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• v.34 no.2
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• pp.15-22
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• 2023

This study compared the dose calculated using the electron Monte Carlo (eMC) dose calculation algorithm employing the old version (eMC V13.7) of the Varian Eclipse treatment-planning system (TPS) and its newer version (eMC V16.1). The eMC V16.1 was configured using the same beam data as the eMC V13.7. Beam data measured using the VitalBeam linear accelerator were implemented. A box-shaped water phantom (30×30×30 cm³) was generated in the TPS. Consequently, the TPS with eMC V13.7 and eMC V16.1 calculated the dose to the water phantom delivered by electron beams of various energies with a field size of 10×10 cm². The calculations were repeated while changing the dose-smoothing levels and normalization method. Subsequently, the percentage depth dose and lateral profile of the dose distributions acquired by eMC V13.7 and eMC V16.1 were analyzed. In addition, the dose-volume histogram (DVH) differences between the two versions for the heterogeneous phantom with bone and lung inserted were compared. The doses calculated using eMC V16.1 were similar to those calculated using eMC V13.7 for the homogenous phantoms. However, a DVH difference was observed in the heterogeneous phantom, particularly in the bone material. The dose distribution calculated using eMC V16.1 was comparable to that of eMC V13.7 in the case of homogenous phantoms. The version changes resulted in a different DVH for the heterogeneous phantoms. However, further investigations to assess the DVH differences in patients and experimental validations for eMC V16.1, particularly for heterogeneous geometry, are required.