以應變規應用於呼吸位移補償系統之補償精度改善及實驗驗證

The improvement and verification of position accuracy of the respiratory compensation system by the strain measurement

黃碇洋(Ding-Yang Huang)

指導教授 ： 莊賀喬

國立臺北科技大學/機電學院/製造科技研究所/碩士(2012年)

https://doi.org/10.6841/NTUT.2012.00216

摘要

本研究旨在驅動床台做與目標反向的運動，使其能抵銷因呼吸而造成的器官位移。並藉由更換呼吸訊號擷取裝置，以應變規取代壓力傳感器，藉此提升呼吸訊號與腹部起伏之間的線性關係，而將呼吸模擬系統位置誤差縮小到0.45mm~1.42mm，呼吸補償系統位置誤差縮小到0.48mm~1.42mm，與壓力感測器做為擷取方法的呼吸補償系統比較，誤差改善率最高可改善67.7%。同時以三種驗證方式驗證呼吸補償系統抵銷目標位移的效果，首先以呼吸模擬系統模擬器官位移與人體呼吸，並以呼吸補償系統進行補償，藉由螢光透視影像分析呼吸補償系統的補償效果，其結果顯示，系統補償率最高可達85.72%；其次以直線加速器照射300cGy的劑量於輻射變色軟片，分析軟片劑量分布情形，結果顯示，若輸入訊號為正弦波信號，補償後目標區域內的平均劑量百分比較未補償前提高1.4%~24.4%，95%等劑量面積較未補償前改善15.3%~76.9%，若輸入訊號為人體呼吸訊號，補償後目標區域內的平均劑量百分比較未補償提高31.8%~67.7%，95%等劑量面積較未補償前改善15.3%~86.4%，而經補償後的Gamma通過率皆可提升至100%；最後由實際病患擷取呼吸訊號，同時以螢光透視觀察病患體內橫膈膜，並以呼吸補償系統抵銷橫膈膜位移，結果顯示可抵銷約67.3%~75.6%的位移。綜合以上驗證結果可顯示出本研究在抵銷因呼吸而造成的器官位移上能有所貢獻。

關鍵字

即時追蹤 ； 呼吸運動補償 ； 應變規 ； GafChromic EBT軟片

並列摘要

This study drove the treatment couch for reverse motion, opposite from the direction of the targets, in order to offset organ displacement generated by respiratory motion. A strain gauge was used to replace a pressure transducer as a respiratory signal capture device to obtain abdomen respiratory signals. The simulated respiratory system (SRS) position error is approximately 0.45~1.42mm, while the respiratory compensating system (RCS) position error is approximately 0.48~1.42mm. Compare with the pressure transducer RCS, the position error can be improved by an amount of 67.7%. This study verified the effect of RCS in offsetting the target displacement by three methods. The first method was using the SRS to simulate organ displacements, human respiratory and being compensated by RCS. Then the target movement was analyzed by fluoroscopy images and the results suggested that compensated rate can be improved to 85.72%. The Second method was using LINAC to irradiate 300cGy dose on the EBT film. The results show that when the input respiratory signals of SRS are sine wave signals, the average dose in the target area and the 95% isodose area after compensation is improved by 1.4~24.4% and 15.3~76.9%, respectively. If human respiratory signals are input to the SRS, the average dose in the target area and the 95% isodose area after compensation is improved by 31.8~67.7% and 15.3~86.4%, respectively. Gamma passing rate after compensation can be improved to 100% only when the displacement of the respiratory motion is within 10~30mm. The third method was capturing patients’ respiratory signals, while using the fluoroscopy to observe their diaphragm and activating RCS to offset the displacements of targets. The experimental results suggested that, a displacement of 67.3~75.6% can be offset. The results proved that the proposed RCS can contribute the compensation of organ displacement caused by respiratory motion.

並列關鍵字

Real-time tracking ； Respiratory compensation ； Strain gauge transducer ； GafChromic EBT film

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