呼吸位移補償系統之設計與驗證

A compensating system of respiratory motion:design and verification

邱君洋(Chun-Yang Chiou)

指導教授 ： 莊賀喬 ； 田德之

國立臺北科技大學/機電學院/機電整合研究所/碩士(2011年)

https://doi.org/10.6841/NTUT.2011.00713

摘要

本研究藉由床台的反向運動來抵消因呼吸運動所造成的器官位移，以解決目前臨床上呼吸運動造成放射線欲完全照射腫瘤體積時，須加大照野、增加安全邊緣。因此本研究利用自行設計製作的呼吸模擬系統(simulated respiratory system (SRS))搭配輻射變色軟片(radiochromic EBT film)，進行本研究所開發的呼吸補償系統之驗證。壓力訊號透過SRS產生用以模擬人體呼吸時腹部起伏，呼吸補償系統是將壓力訊號的相位做為呼吸運動的相位，並調整壓力訊號的增益，使補償訊號振幅接近目標區域運動的位移大小。利用直線加速器照射 300cGy的劑量於EBT底片，由實驗結果，正弦波振幅5、10、15mm未補償前目標區域內平均劑量百分比經補償後較未補償提高6.9~20.3%，80%等劑量面積較未補償前改善22.8~77.2%，而呼吸運動行程5、10、15mm未經補償前目標區域內平均劑量百分比經補償後較未補償提高10.3~18.7%，80%等劑量面積較未補償前改善22.4~55.1%，且不論實驗中的何種運動經補償後Gamma值均在約85%以上。由補償後的目標區域平均劑量百分比結果得知，本研究所設計的呼吸補償系統的確有效改善因呼吸運動造成輻射劑量無法完全照射到腫瘤的問題。

關鍵字

即時追蹤 ； 呼吸運動補償 ； GafChromic軟片

並列摘要

Using the reverse motion of the treatment couch, this study offset the organ displacement generated by respiratory motion to solve the current clinical problem of increasing field sizes and safety margin expansions. This study used the self-designed simulated respiratory system (SRS) coupled with radiochromic EBT film to verify the self-developed respiratory compensation system. Pressure signals were generated from SRS to simulate abdomen movements during respiratory motion. The respiratory compensation system regards the phase of the pressure signals as the respiratory motion phase and adjusts the pressure signal gain to make the compensation signal amplitude close to the displacement of the target region. A linear accelerator is used to radiate a 300cGy dose on the EBT film. The experimental results suggested that the average dose percentage in the target region for the sine-wave amplitudes of 5, 10 and 15mm with compensation improved by 6.9~20.3% over the cases without compensation. The 80% isodose area with compensation improved by 22.8~77.2% over the cases without compensation. The average dose percentage in the target region with compensation for respiratory motion distances of 5, 10 and 15mm improved by 10.3~18.7%. The 80% isodose area improved by 22.4~55.1% after compensation. The average dose percentage of the compensated target region indicates that the proposed respiratory compensation system could better deal with the problem of being unable to fully radiate tumors due to respiratory motion.

並列關鍵字

Real-time tracking ； Respiratory compensation ； GafChromic film

參考文獻

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