體積調控弧形治療用於攝護腺癌電腦治療計畫準直儀角度之比較

Comparison of collimator angles for VMAT plans of prostate cancer

鍾鎮鴻(Chen-Hung Chung)

指導教授 ： 張寶樹

高雄醫學大學/健康科學院/醫學影像暨放射科學系碩士在職專班/碩士(2015年)

摘要

目的：放射治療為當今攝護腺癌根治的方法之一，而體積調控弧形治療已經成為放射治療的主要選項。有文獻指出，準直儀角度會影響治療計畫的優化結果。本研究將針對攝護腺癌患者之電腦治療計畫，利用不同準直儀角度的體積調控弧形治療技術，及一組強度調控放射治療技術作為對照組，以評估電腦治療計畫結果與劑量學的差異。
材料與方法：本研究蒐集6位曾在東港安泰醫院進行放射治療的攝護腺患者的電腦治療計畫，進行各種準直儀角度的比較。所有病患在治療計畫優化的過程中，對於靶體積及各危急器官皆使用相同的劑量限制，以減少實驗的變數。根據文獻及臨床經驗，挑選0°、5°、15°、25°、45°等五個角度進行比較，並分析其劑量學參數的差異。
結果：本研究的結果顯示，計畫靶體積不管使用強度調控放射治療或體機調控弧形治療旋轉各準直儀角度，包覆率皆能達到95%。在危急器官的部份，體積調控弧形治療將準直儀旋準5°，直腸的V40體積為25.3%及小腸的V40為6.57%，為各角度中最低的。監測單位以及治療時間，體積調控弧形治療的各準直儀角度間並無顯著差異。
結論：對於攝護腺癌病人，在設計治療計畫時，將準直儀旋轉5°，較易比其他四種角度得到較佳的優化結果。但臨床上實際進行治療計畫優化參數，還是依照每位病人的情況而有所不同，本研究僅提供實驗結果作為參考。

關鍵字

體積調控弧形治療 ； 準直儀角度 ； 攝護腺癌

並列摘要

Purpose：Radiation therapy is one of the curative treatments for prostate cancer today, and volumetric-modulated arc therapy(VMAT) is a newly developed technique in the radiotherapy. Some paper review showed that the collimator angles would affect the optimization results of radiation treatment plans(RTP). This study is in accordance with the RTP for prostate cancer patient. The different collimator angles were applied in order to compare the VMAT plans, and set intensity modulated radiation therapy(IMRT) plan as a control group. The results of the RTP were evaluated, and the dosimetry were also compared.
Materials and Methods：In this study, the RTP were collected from six prostate patients who were taken radiation therapy in Dong-gang Aetna Hospital. Different collimator angles were compared. In the optimization process for RTP, the planning target volume(PTV) and organs at risk (OAR) are with the same dose constraints in order to reduce experimental variables. According to the paper review and clinical experience, the selection of 0°, 5°, 15°, 25° and 45° were compared and analyzed of its dosimetric parameters.
Results：The result of this study showed, when IMRT and VMAT rotated to each collimator angles, they had similar PTV coverage (V100%>95%).At the portion of OAR, when the collimator angle of IMRT rotated 5°, the V40 is the lowest , there were 25.3% for rectum and 6.57% for small intestine. It seem no significant differences MU and treatment time for each collimator angeles of VMAT.
Conclusion：In conclusion, the collimator rotation 5° which designed in the RTP for prostate patients could have better optimization results than the other four collimator angles.
Keywords: volumetric-modulated arc therapy(VMAT), collimator angle, prostate cancer.

並列關鍵字

volumetric-modulated arc therapy(VMAT) ； collimator angle ； prostate cancer

參考文獻

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