主動呼吸調控輔助設備在肝癌放射治療之應用

The Application of Active Breathing Coordinator in Radiotherapy for Hepatic Cellular Carcinoma

陳韋霖(Wei-Lin Chen) ； 梁雲(Wan Leung) ； 趙珮如(Pei-Ju Chao) ； 劉明祥(Ming-Hsiang Liou)

《中華放射線技術學雜誌》 31卷1期 (2007/06) Pp. 57-66

https://doi.org/10.30045/CJRT.200706.0007

摘要

隨著醫學的進步早期就被篩檢發現的小體積腫瘤病灶，和現行的放射治療技術都對治療靶體積的中心點有著高敏性的要求。高準確的放射治療訴求不只是殺死癌細胞，更重要的是降低癌症病患因不必要照射所引起的併發症，在不增加正常組織併發症機率(normal tissue complication probability, NTCP)的條件下，讓目標體積可獲得較高的放射劑量，提高腫瘤控制率(tumor control probability, TCP)。本實驗使用主動呼吸調控輔助設備(Active Breathing Coordinator, ABC)模擬肝腫瘤患者在放射治療中(intrafraction)，正常呼吸時肝臟位移對治療中心點之影響程度，與評估暫停呼吸時所減少位移之固定效果。一共11位肝癌病患包括7位男性4位女性，年齡層介於32歲到68歲，平均51歲。使用iViewGT電子影像驗證設備(Electronic Portal Imaging Device)照射正交定位片(Orthogonal film)，分別評估頭尾(Cranial-Caudal)、前後(Anterior-Posterior)及左右(Left-Right)等三個方向在正常呼吸情況下治療中心點位移之情形。結果顯示頭尾方向位移距離最大23.52±5.77mm、旋轉角度+5.5°~+11.0°，對體積較小肝腫瘤治療的確有一定程度的影響。使用呼吸調控減少治療中肝臟因呼吸而位移是可行的，藉著呼吸調控技術來縮減計畫目標區域(PTV margin)在臨床治療上是很有意義的，但需要每日給予驗證片再確認，以確保治療照野的幾何誤差不因此而增加。

關鍵字

主動呼吸調控輔助設備 ； 肝癌 ； 電子影像驗證設備

並列摘要

With the progress of medical science, the more precise localization request on the isocenter of target volume is absolutely demanded because of the modern radio-therapeutic techniques, and the early finding of small lesion disease. High accurate radiotherapy technology is not only for the reason to kill the cancer cell but also to reduce the treatment complications caused by the unnecessary irradiation on normal tissue. Taking significant advances to improve the tumor control probability (TCP) by escalating tumor dose have been made in the development without a concomitant deleterious escalation in normal tissue complication probability (NTCP). In this study, we investigated the affection of isocenter movement caused by routine free respiration during radiation therapy and temporarily immobilized the patient's breathing to account for the potential variation by using an active breathing coordinator (ABC) apparatus. Eleven patients with hepatocellular carcinoma (HCC) were studied. The group including 7 males 4 females, the age level lies between 32 to 68 years old average is 51 years old. We aim to assess the motion of target volumes in Cranial-Caudal 、Anterior-posterior and Left-right three direction under free breathing by using iViewGT an electronic portal imaging device from Elekta and taking orthogonal beam film respectively for comparison. The investigation results revealed the motion of Cranial-Caudal direction which had a maximum variation 23.52±5.77mm and with angle rotated from +5.5 to +11.0°. The breathing movement really has a certain degree influence on small volume of HCC radiation therapy. The results may allow us to reduce the influence of movement caused by free breathing during radiation therapy by using ABC apparatus. In practice, the reduction of the PTV margin in the treatment plans is generally desirable in radiotherapy, but must be accompanied by the daily assurance with ABC technique that the risk of geometric misses does not also increase.

並列關鍵字

active breathing coordinator ； hepatocellular carcinoma ； electronic portal imaging device