半弧與全弧射束在低分次攝護腺放射治療計畫之劑量比較

Comparison Dose Distribution between Full/Partial Arc Plans of Prostate Cancer by Hypofractionated Radiotherapy

陳威君(Wei-Jun Chen)

指導教授 ： 謝雅茹

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(2019年)

摘要

攝護腺癌(Prostate Cancer)的放射治療療程約42至45次不等，大多的患者在剛過療程的一半，開始出現腸道、泌尿道等副作用，又或是療程將近3個月的時間，導致患者可能會自行休息甚至中斷治療。本研究是採用低分次放射治療(Hypofractionated Radiation Therapy)方法，使用體積弧形強度調控放射治療(Volumetric Modulated Arc Therapy，VMAT)之半弧(Partial-arc)及全弧(Full-arc)射束技術來評估在腫瘤區域及鄰近危及器官劑量分布的比較。
本回溯性研究收集10位已接受過放射線治療的攝護腺癌病患，利用同一組影像，由放射腫瘤專科醫師所圈選之相同靶區及危及器官輪廓，使用VAMT的治療技術，以兩組不同的射束旋轉角度重新設計新的治療計畫。且利用劑量-體積直方圖(Dose Volume Histogram，DVH)、順型指數（Conformity Index，CI）、劑量均勻指數（Homogenate Index，HI）和治療時間等，來做為評估治療計畫之方法。
結果顯示，兩組射束角度皆可在靶區達到足夠的劑量；全弧(Full-arc)射束在膀胱、直腸以及股骨頭的吸收劑量相較於半弧(Partial-arc)射束之下有明顯減少。在劑量均勻性全弧射束較佳，比較特別的是在治療時間上半弧射束並沒有佔比較多的優勢。
　　從本實驗結果，在低分次治療方式使用全弧射束，除了能大幅的縮短治療次數，相對於半弧射束也可以減少危及器官的吸收劑量。期望能使病人降低副作用，進而能夠完成整個療程。

關鍵字

攝護腺癌 ； 體積弧形強度調控放射治療 ； 低分次放射治療

並列摘要

A complete radiation therapy treatment for prostate cancer takes 42-45 times normally.While most of the patients would got side effect as acute GI toxicity in the half of the treatment,or while the procedure kept over three months,Which may cause the patient pause the treatment,even cause a treatment failure. The purpose of this research stick on how the situation goes when adapting hypofractionated radiation therapy in volumetric modulated arc therapy (VMAT).Analyzing the difference of result between partial-arc and full-arc beam,about the dose distribution among tumor margin and critical organ.
This research collects 10 patients with prostate cancer,who has treated in radiation therapy previously. Choosing the same ROI target by radiation oncologist then redesign a brand new treatment plan by adapting grants in two different cycle angle for retrospective study in dosimetric comparison.The plans were evaluated by dose volume histogram (DVH),conformity index (CI),homogenate index (HI) and therapy time.
The study results,both treatment plan accomplish the same target coverage.Plan in full arc obviously has a lower dose distribution in bladder,rectum and femoral head. Besides,plan in full arc obtains a better homogenate index (HI).Meanwhile,plan in partial arc do not obtain advantage in therapy time.reduce critical organ dose.
With the respect of this research, adapting Hypofractionated radiation therapy with full arc could not only decrease the number of therapy highly,but also reduce critical organ dose comparing to partial arc,which alleviate the side affect and lead the patient to take a complete treatment.

並列關鍵字

Prostate cancer ； Volumetric Modulated Arc Therapy ； Hypofractionated Radiation Therapy

參考文獻

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