Intensity-modulated Radiation Therapy Technique for Adenocarcinoma of the Prostate

攝護腺腺癌的強度調控放射治療技術

張東浩(Tung Hao Chang) ； 林招膨(Jao-Perng Lin) ； 劉幕台(Mu-Tai Liu) ； 陳宛蓉(Yuan-Rong Chen) ； 游澄清(Cheng-Ching Yu) ； 黃昭源(Chao-Yuan Huang) ； 謝長堯(Chang-Yao Hsieh)

《The Changhua Journal of Medicine》 8卷2期 (2003/04) Pp. 109-117

摘要

背景及目的：本文的目的在於說明對攝護腺腺癌作強度調控放射治療分段照野技術的方式，並就不同分段照野數目比較其危急器官劑量分佈之情況。
方法：本科以靜態的分段照野技術對攝護腺腺癌個案進行順形治療已經發展一段時日。其原理是利用調整同一方向中的數個不同形狀照野的比重製造出不同劑量強度分佈，使鄰近的危急器官得以降低劑量。首先，採用六個共平面照野，將設計六個旋轉臂(gantry)角度分別為45°、90°、135°、225°、270°、315°的射束。再者，利用這些射束方向增加多個分段照野而成為第二階段的治療計畫。這階段所用的分段照野包括了只遮擋直腸部分的照野、只擋膀胱的照野、以及直腸與膀胱都擋掉不照的照野。
結果：計畫所得到的等劑量曲線比傳統治療在計畫靶體積(PTV)與直腸邊界上更加順形。對於直腸的正常組織併發症機率(NTCP)，這樣的分段照野是比無分段照野計畫佳。
結論：此分段計畫亦顯現出以降低給予鄰近組織劑量使攝護腺腺癌治療技術上的精進。另外，分段照野數量也依據治療計畫議定書，劑量限值與臨床狀況的複雜情況而有所不同。

關鍵字

攝護腺腺癌 ； 分段照野 ； 強度調控放射治療

並列摘要

Background and purpose: The aim of this work is to describe segmental fields for the treatment of prostate cancer and compare the dose delivered to adjacent critical structures for varying numbers of segmental fields.
Methods: Conformal treatment of static multisegmental fields was developed for adenocarcinoma of the prostate. It makes use of fixed fields to create intensity- modulated fields from several different-shaped beam portals of the same direction in order to minimize doses to the critical structures. First, the plan was six coplanar fields with gantry angles of 45°, 90°, 135°, 225°, 270°, and 315°. Then the multisegmental fields were added to the previous frame in order to create the second plan. It has three segment levels: sparing only the rectum portal, sparing only the bladder, and sparing both the rectum and bladder portals.
Results: The isodose distributions of multisegment plan were more conformal to the planning target volume (PTV) and the rectum boundary than the conventional plan. For rectal normal tissue complication probability (NTCP), the segmental plans were superior to the non-segmental plan.
Conclusion: The segmental plan represents a technical improvement in the treatment of prostate cancer by minimizing the dose delivered to adjacent structures. The number of segments depends on the complexity of the treatment planning protocol, dose constraints, and clinical situation.

並列關鍵字

prostate cancer ； multisegmental field ； intensity-modulated radiation therapy