• Radiation Oncology Journal
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• 제34권2호
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• pp.145-155
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• 2016

Purpose: Radiation therapy targeting axilla and groin lymph nodes improves regional disease control in locally advanced and high-risk skin cancers. However, trials generally used conventional two-dimensional radiotherapy (2D-RT), contributing towards relatively high rates of side effects from treatment. The goal of this study is to determine if three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or volumetric-modulated arc therapy (VMAT) may improve radiation delivery to the target while avoiding organs at risk in the clinical context of skin cancer regional nodal irradiation. Materials and Methods: Twenty patients with locally advanced/high-risk skin cancers underwent computed tomography simulation. The relevant axilla or groin planning target volumes and organs at risk were delineated using standard definitions. Paired t-tests were used to compare the mean values of several dose-volumetric parameters for each of the 4 techniques. Results: In the axilla, the largest improvement for 3D-CRT compared to 2D-RT was for homogeneity index (13.9 vs. 54.3), at the expense of higher lung $V_{20}$ (28.0% vs. 12.6%). In the groin, the largest improvements for 3D-CRT compared to 2D-RT were for anorectum $D_{max}$ (13.6 vs. 38.9 Gy), bowel $D_{200cc}$ (7.3 vs. 23.1 Gy), femur $D_{50}$ (34.6 vs. 57.2 Gy), and genitalia $D_{max}$ (37.6 vs. 51.1 Gy). IMRT had further improvements compared to 3D-CRT for humerus $D_{mean}$ (16.9 vs. 22.4 Gy), brachial plexus $D_5$ (57.4 vs. 61.3 Gy), bladder $D_5$ (26.8 vs. 36.5 Gy), and femur $D_{50}$ (18.7 vs. 34.6 Gy). Fewer differences were observed between IMRT and VMAT. Conclusion: Compared to 2D-RT and 3D-CRT, IMRT and VMAT had dosimetric advantages in the treatment of nodal regions of skin cancer patients.

• Radiation Oncology Journal
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• 제28권4호
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• pp.238-248
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• 2010

목적: 폐암환자의 종양추적 정위방사선치료에서 삼차원 및 사차원치료계획의 선량분포 차이를 비교하였고 선량계산 알고리즘에 따른 폐의 비균질성 보정 결과에 커다란 차이가 있음을 확인하고자 하였다. 대상 및 방법: 7명의 폐암환자를 대상으로 전향적 호흡동조된 사차원 컴퓨터단층촬영 영상을 얻었다. 획득한 영상은 환자의 호흡에 대응하는 10개의 삼차원단층촬영 영상이며 이를 바탕으로 사차원치료계획이 수립되었다. 사차원 치료계획에서는 종양과 주변장기의 움직임을 고려하여 X선의 방향과 선량분포를 최적화한다. 사차원치료계획에서 최적화된 빔을 호흡의 50% 위상에 해당하는 한 개의 삼차원단층촬영 영상에 동일하게 적용하여 삼차원치료계획을 만들었다. 삼차원 및 사차원 치료계획에서 선량계산을 위하여 각각 Ray-tracing과 몬테칼로 알고리즘을 사용하였다. 수립된 4개의 치료계획에서 처방선량의 종양체적 포함률 종양체적의 95%를 포함하는 선량인 D95, 종양의 최대선량, 그리고 척수의 최대선량을 비교하였고 종양의 위치에 대한 연관성도 함께 고찰하였다. 결론: 몬테칼로 알고리즘을 사용한 삼차원 및 사차원 치료계획에서 종양이 폐의 하엽에 위치해 있는 경우에는 사차원치료계획에서 종양 포함률이 평균 4.4% 높았던 반면에 종양이 폐의 중엽이나 상엽에 위치해 있는 경우에는 반대로 평균 4.6% 낮았다 또한 D95도 종양이 폐의 하엽에 위치해 있는 경우에는 사차원치료계획에서 평균 4.8% 높았던 반면에 종양이 폐의 중엽이나 상엽에 위치해 있는 경우에는 반대로 평균 1.7% 낮았다. 척수의 최대선량에 대한 비교에서도 종양과 유사한 경향이 나타났다. 치료계획의 차원과 무관하게 Ray-tracing과 몬테칼로 알고리즘 사이의 선량계산 차이는 평균 30% 정도로 몬테칼로 알고리즘을 사용하였을 때 처방선량이 포함하는 종양의 부피는 크게 줄어들었다. 결론: 폐 종양의 삼차원 및 사차원 치료계획 사이의 차이를 종양과 척수의 선량분포를 통해 비교하였다. 두 치료계획 사이에서 planning target volume (PTV) 포함률이나 D95와 같이 종양과 관련된 선량학적 인자들의 차이 또는 척수의 최대선량 차이는 종양의 이동크기와 형태변화의 정도에 밀접하게 연관되어 있는 것으로 나타났다. 또한, 치료계획의 차원과 무관하게 몬테칼로 알고리즘을 사용하면 처방선량이 포함하는 PTV 포함률이나 D95가 크게 줄어드는 것을 확인하였다.

• Radiation Oncology Journal
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• 제36권1호
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• pp.63-70
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• 2018

Purpose: The objective of this study was to compare dosimetric characteristics of three-dimensional conformal radiotherapy (3D-CRT) and two types of intensity-modulated radiotherapy (IMRT) which are step-and-shoot intensity modulated radiotherapy (s-IMRT) and modulated arc therapy (mARC) for thoracic esophageal cancer and analyze whether IMRT could reduce organ-at-risk (OAR) dose. Materials and Methods: We performed 3D-CRT, s-IMRT, and mARC planning for ten patients with thoracic esophageal cancer. The dose-volume histogram for each plan was extracted and the mean dose and clinically significant parameters were analyzed. Results: Analysis of target coverage showed that the conformity index (CI) and conformation number (CN) in mARC were superior to the other two plans (CI, p = 0.050; CN, p = 0.042). For the comparison of OAR, lung V5 was lowest in s-IMRT, followed by 3D-CRT, and mARC (p = 0.033). s-IMRT and mARC had lower values than 3D-CRT for heart $V_{30}$ (p = 0.039), $V_{40}$ (p = 0.040), and $V_{50}$ (p = 0.032). Conclusion: Effective conservation of the lung and heart in thoracic esophageal cancer could be expected when using s-IMRT. The mARC was lower in lung $V_{10}$, $V_{20}$, and $V_{30}$ than in 3D-CRT, but could not be proven superior in lung $V_5$. In conclusion, low-dose exposure to the lung and heart were expected to be lower in s-IMRT, reducing complications such as radiation pneumonitis or heart-related toxicities.

• 대한방사선기술학회지:방사선기술과학
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• 제20권2호
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• pp.79-82
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• 1997

Image-based three dimensional radiation treatment planning(3D RTP) has a potential of generating superior treatment plans. Advances in computer technology and software developments quickly make 3D RTP a feasible choice for routine clinical use. However, it has become clear that an evaluation of a 3D plan is more difficult than a 2D plan. A number of tools have been developed to facilitate the evaluation of 3D RTP both qualitatively and quantitatively. For example, beam's eye view(BEV) is one of the most powerful and time-saving method as a qualitative tools. Dose-volume histogram(DVH) has been proven to be one of the most valuable methods for a quantitative tools. But it has a limitation to evaluate several different plans for biological effects of the tissue and critical organ. Therefore, there is a strong interest in developing quantitative models which would predict the likely biological response of irradiated organs and tissues, such as tumor control probability(TCP) and normal tissue complication probability(NTCP). DVH and NTCP of hepatoma were evaluated for three dimensional conformal radiotherapy(3D CRT). Also, 3D RTP was analysed as a dose optimization based on beam arrangement and beam modulation.

• Asian Pacific Journal of Cancer Prevention
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• 제14권4호
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• pp.2243-2248
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• 2013

Background: To compare the dosimetric coverage of target volumes and organs at risk in the radical treatment of nasopharyngeal carcinoma (NPC) between intensity-modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3DCRT). Materials and Methods: Data from 10 consecutive patients treated with IMRT from June-October 2011 in Penang General Hospital were collected retrospectively for analysis. For each patient, dose volume histograms were generated for both the IMRT and 3DCRT plans using a total dose of 70Gy. Comparison of the plans was accomplished by comparing the target volume coverage (5 measures) and sparing of organs at risk (17 organs) for each patient using both IMRT and 3DCRT. The means of each comparison target volume coverage measures and organs at risk measures were obtained and tested for statistical significance using the paired Student t-test. Results: All 5 measures for target volume coverage showed marked dosimetric superiority of IMRT over 3DCRT. V70 and V66.5 for PTV70 showed an absolute improvement of 39.3% and 24.1% respectively. V59.4 and V56.4 for PTV59.4 showed advantages of 18.4% and 16.4%. Moreover, the mean PTV70 dose revealed a 5.1 Gy higher dose with IMRT. Only 4 out of 17 organs at risk showed statistically significant difference in their means which were clinically meaningful between the IMRT and 3DCRT techniques. IMRT was superior in sparing the spinal cord (less 5.8Gy), V30 of right parotid (less 14.3%) and V30 of the left parotid (less 13.1%). The V55 of the left cochlea was lower with 3DCRT (less 44.3%). Conclusions: IMRT is superior to 3DCRT due to its dosimetric advantage in target volume coverage while delivering acceptable doses to organs at risk. A total dose of 70Gy with IMRT should be considered as a standard of care for radical treatment of NPC.

• Asian Pacific Journal of Cancer Prevention
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• 제14권10호
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• pp.5989-5993
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• 2013

Background: Radiation therapy is the mainstay of treatment for nasopharyngeal carcinoma. Importance of tumor coverage and challenges posed by its unique and critical location are well evident. Therefore we aimed to evaluate our radiation treatment plan through dose volume histograms (DVHs) to find planning target volume (PTV) dose coverage and factors affecting it. Materials and Methods: This retrospective study covered 45 histologically proven nasopharyngeal cancer patients who were treated with definitive 3D-CRT and chemotherapy between Feb 2006 to March 2013 at the Department of Oncology, Section Radiation Oncology, Aga Khan University Hospital, Karachi, Pakistan. DVH was evaluated to find numbers of shrinking field (phases), PTV volume in different phases and its coverage by the 95% isodose lines, along with influencing factors. Results: There were 36 males (80%) and 9 females (20%) in the age range of 12-84 years. Stage IVA (46.7%) was the most common stage followed by stage III (31.1). Eighty six point six-percent received induction, 95.5% received concurrent and 22.2% received adjuvant chemotherapy. The prescribed median radiation dose was 70Gy to primary, 60Gy to clinically positive neck nodes and 50Gy to clinically negative neck regions. Mean dose to spinal cord was 44.2Gy and to optic chiasma was 52Gy. Thirty seven point eight-percent patients completed their treatment in three phases while 62.2% required four to five phases. Mean volume for PTV3 was $247.8cm^3$ (50-644.3), PTV4 $173.8cm^3$ (26.5-345.1) and PTV5 $119.6cm^3$ (18.9-246.1) and PTV volume coverage by 95% isodose lines were 74.4%, 85.7% and 100% respectively. Advanced T stage, intracranial extension and tumor volume > $200cm^3$ were found to be important factors associated with decreased PTV coverage by 95% isodose line. Conclusions: 3D CRT results in adequate PTV dose coverage by 95% isodose line. However advanced T stage, intracranial extension and large target volume require more advanced techniques like IMRT for appropriate PTV coverage.

• Radiation Oncology Journal
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• 제30권1호
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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.

• 대한방사선치료학회지
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• 제26권1호
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• pp.91-98
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• 2014

목 적 : 본 연구에서는 기존의 방사선 치료 기법인 3D-CRT 방법을 기반으로 치료 Energy와 Wedge를 변형 시킨 Hybrid 치료계획을 세워, open rectangular field를 사용한 2D-RT와 현재 가장 많이 시행되고 있는 방사선치료의 형태인 3D-CRT, 그리고 Hyrid paln 의 각각의 치료계획에 따른 선량분포, 선량-체적 히스토그램을 이용하여 산출된 값들을 비교, 분석하여 Hybrid 치료계획의 유용성을 평가하고자 한다. 대상 및 방법 : 본원에서 방사선 치료를 받은 환자 5명을 대상으로 전산화 단층촬영장치(RT-16GE)를 이용해 CT모의치료를 시행하여 영상을 획득하였다. 치료계획실에서는 이미지 관심영역표시는 종양은 CTV으로, 정상장기는 폐, 심장으로 나타냈다. 치료계획은(pinncle-ver 9.2)은 표적에는 충분한 선량을 정상장기에는 선량이 최소화 되도록 치료계획을 세웠다. 결 과 : Homogeneity Index의 선량비교는 2D-RT (open rectangular field): 38.32, TW(conformal wedge field): 32.01 FIF(field in field): 29.22, HYBRID(energy combine, wedge combine): 30.57으로 나타났다. 2D-RT, TW, FIF Hybrid $V_{75_-lung}$은 각각 112.33, 125.14, 121.3, 123.78. $V_{50_-lung}$은 155.43, 159.62, 157.96, 159.06. $V_{25_-lung}$은 199.86, 200.22, 198.65, 200.31. $V_{50_-heart}$는 각각 26.07, 27.1, 26.85, 27.17 $V_{30_-heart}$ 33.71, 34.37, 34.15, 34.65로 나타났다. 결 론 : HYBRID planning에서 표적에는 3D-CRT 에 비해 비교적 뛰어난 선량분포와 유방을 보호함을 보여주지만 폐와 심장에 많은 선량이 조사됨을 치료계획 시 주의해야 하고 앞으로 해결해야 할 과제라 생각된다. HYBRID 으로 Energy를 혼합하여 사용한다면, 타겟에 보다 더 적절한 coverage가 이루어질 수 있을 것으로 보인다. breast 뿐만 아닌 Lung cacner 치료와 같이 불균질한 부위의 치료에 적용한다면 보다 더 최적을 결과를 이루어낼 수 있을 것으로 사료된다.

• Radiation Oncology Journal
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• 제35권4호
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• pp.368-379
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• 2017

Purpose: The purpose of this study was to explore the dosimetric difference between simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) and three-dimensional conformal radiotherapy (3DCRT), and the clinical outcomes of anal squamous cell carcinoma (ASCC) chemoradiotherapy featuring SIB-IMRT. Materials and Methods: This study included ten patients with ASCC who underwent chemoradiotherapy using SIB-IMRT with 5-fluorouracil and mitomycin C. SIB-IMRT delivered 54 Gy to each primary tumor plus metastatic lymph nodes and 45 Gy to regional lymph nodes, in 30 fractions. Four patients received additional boosts to the primary tumors and metastatic lymph nodes; the median total dose was 54 Gy (range, 54 to 60 Gy). We additionally created 3DCRT plans following the Radiation Therapy Oncology Group 9811 protocol to allow dosimetric comparisons with SIB-IMRT. Locoregional control, overall survival, and toxicity were calculated for the clinical outcome evaluation. Results: Compared to 3DCRT, SIB-IMRT significantly reduced doses to the external genitalia, bladder, and intestine, delivering the doses to target and elective nodal region. At a median follow-up time of 46 months, 3-year locoregional control and overall survival rates were 88.9% and 100%, respectively. Acute toxicities were treated conservatively. All patients completed radiotherapy with brief interruptions (range, 0 to 2 days). No patient experienced ${\geq}grade$ 3 late toxicity during the follow-up period. Conclusion: The dosimetric advantages of SIB-IMRT appeared to reduce the toxicity of chemoradiotherapy for ASCC achieving high locoregional control in the extended period.

• 대한방사선치료학회지
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• 제33권
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• pp.71-78
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• 2021

목 적: 폐암과 간암 환자에 대해 압력 기반 복부압박장치를 적용하여 입체적 세기변조 회전 방사선치료(VMAT)를 시행하였을 때의 치료 간(interfraction) 위치 재현성과 호흡 재현성을 평가함으로써 그 유용성을 평가하고자 한다. 대상 및 방법: 압력 기반 복부압박장치를 사용해 입체적 세기변조 회전 방사선치료를 받은 6명의 폐암 환자와 3명의 간암 환자를 대상으로 하였다. 치료 간 위치 재현성 평가를 위해 모의치료 CT 영상과 매일 획득한 CBCT 영상 174건을 비교하여 이미지 정합의 이동 값을 비교, 분석하였다. 치료 간 호흡 재현성 평가를 위해 모의치료 4DCT 영상과 매주 획득한 4D CBCT 영상 54건을 비교하여 호흡량 오차를 구하였다. 결 과: 수평수직 세 방향의 3D 벡터값인 전체 위치변화(Overall position variation, Overall VP)값은 폐와 간에서 각각 평균 1.1 ± 1.4 mm, 4.5 ± 2.8 mm로 나타났다. 호흡 변화(respiratory variation, Vr)값은 폐에서 평균 0.7 mm ± 3.4 mm (p=0.195), 간에서 평균 3.6 mm ± 2.6 mm (p<0.05)로 나타났다. 결 론: 흉복부 방사선 치료 시 압력 기반 복부압박장치의 적용은 복부 압박 재현을 통해 치료 간 종양의 호흡 변이뿐만 아니라 위치 변이를 안정적으로 조절하는 데에 유용한 것으로 사료된다. 보다 안정적인 재현성을 위해 치료 계획 시 적절한 PTV 여유가 고려되어야 하고, 매 치료 전 영상 유도에 따른 표적의 위치와 호흡 검증이 필요하다.