加馬刀與電腦刀應用於動靜脈畸形治療之臨床評估比較與劑量差異分析

Clinical Evaluation and Dosimetric Comparison of Gamma Knife and Cyberknife Treatment Plans for Arteriovenous Malformations

郭駿騵(Chun-Yuan Kuo) ； 蕭安成(An-Cheng Shiau) ； 蘇鈺凱(Yu-Kai Su) ； 張智傑(Chih-Chieh Chang) ； 余孝緯(Hsiao-Wei Yu) ； 黃聖芳(Sheng-Fang Huang) ； 陳黎臻(Li-Jhen Chen) ； 林家瑋(Jia-Wei Lin) ； 蔡若婷(Jo-Ting Tsai)

《放射治療與腫瘤學》 20卷4期 (2013/12) Pp. 281-292

https://doi.org/10.6316/TRO/201320(4)281

摘要

目的：分析比較加馬刀（Gamma Knife®）與電腦刀（CyberKnife®）兩種放射手術設備，應用於動靜脈畸形（Arteriovenous malformations, AVMs）病例之治療時，其兩者因臨床治療運用技術及機械結構迥異，所造成劑量分佈的變化情形；並探討與評估此劑量分佈的特性於臨床治療應用上之差異及其影響。材料與方法：選擇10位接受過電腦刀治療的AVM患者，單次處方劑量為20－25 Gy，取得其電腦治療計畫。此外，將電腦刀治療計畫的CT影像、靶體積與周邊危急器官輪廓檔案，自電腦刀電腦治療計畫系統輸出後，轉輸入加馬刀電腦治療計畫系統，依相同處方劑量，完成加馬刀的電腦治療計畫。比較10位病患的電腦刀與加馬刀治療計畫的劑量順形度、劑量梯度與劑量異質性指標，10、12 Gy所涵蓋範圍之體積，腦幹的最大劑量以及照射的時間。在統計分析的部分，劑量順形度與劑量梯度指標，10、12 Gy所涵蓋範圍之體積的比較是以Paired Samples t-test來執行，求取p值後評估兩種治療計畫在所比較之項目是否存在著顯著的差異。結果：加馬刀與電腦刀的劑量順形度指標統計值分別為0.626 ± 0.106及0.795 ± 0.087，p=0.004。加馬刀與電腦刀的劑量梯度指標統計值分別為3.082 ± 0.369及6.071 ± 1.698，p=0.001。加馬刀與電腦刀的劑量異質性指標分別為0.723 ± 0.055及0.275 ± 0.045。10與12 Gy劑量體積的統計分析p值分別為0.025與0.022。3位AVM位置鄰近腦幹的病例，在腦幹組織1 c.c.體積劑量與腦幹最大劑量比較，加馬刀皆小於電腦刀。在效能的比較上，電腦刀所需的照射時間則較短。結論：電腦刀因為使用逆向式治療計畫且形成類似強度調控的功能，因此較易求得較佳的劑量順形度。在周邊正常組織劑量豁免的部分，則是加馬刀有較佳的表現，可預期加馬刀可使正常腦組織與鄰近之危急器官得到較佳的保護。

關鍵字

加馬刀 ； 電腦刀 ； 動靜脈畸形

並列摘要

Purpose: To analyze and compare the dose distribution characteristic of two radiosurgery treatment devices of Gamma Knife®(GK) and Cyber Knife®(CK), in treating arteriovenous malformations (AVMs) and the influence on their clinical application.Material and Method: Ten AVM patients treated with CK of prescribed dose of 20-25 Gy in single fraction were evaluated. Each treatment plan CT images including the contours of the target and the surrounding critical organs were exported and loaded into the GK treatment planning system. GK treatment plan using the same prescribed radiation dose were generated. Dosimetric comparison of the two treatment devices including the conformity, gradient and heterogeneity index, volume of brain tissue covered by 10 Gy and 12 Gy, maximum dose of brain stem and the beam on time. Paired Samples t-test was used to statistical analyze and compare the conformal and gradient index, the dose coverage volume of 10 Gy and 12 Gy in both plans for significance (p value)Result: The conformal index was 0.626 ± 0.106 and 0.795 ± 0.087 in GK and CK, respectively (p = 0.004). The gradient index was 3.082 ± 0.369 and 6.071 ± 1.698 in GK and CK, respectively (p = 0.001). The heterogeneity index was 0.723 ± 0.055 and 0.275 ± 0.045 in GK and CK, respectively. The difference of coverage volume of 10 Gy and 12 Gy were significant (p = 0.025 and 0.022, respectively). For the 3 cases with AVM location adjacent ωthe brainstem, the dose of 1 c.c. and maximum dose of brain stem in GK plan were less than CK. CK had better treatment efficiency due to shorter beam on time.Conclusion: Cyber Knife using inverse treatment planning similar to intensity modulated function had better dose conformity. Gamma Knife should have better normal brain tissue and critical organs protection due to sharp dose fall-off gradient.

並列關鍵字

Gamma Knife ； CyberKnife ； Arteriovenous malfomations