設計輔助性感測系統以提升呼吸調控及移動監測一系列放射線治療之品質

Abstract

立體定位放射治療指使用高劑量的輻射來殺死癌細胞或縮小腫瘤，其治療次數小於六次。然而，對於這種技術，器官的運動是一個具有挑戰的問題。因此我們研究並開發一種以藍芽技術的控制系統，來模擬和校正治療期間器官的運動情形。 利用自行研發用於監視位置及表面運動的晶片與一組透過3D列印製成的模擬模組系統進行模擬。透過EBT3底片對此晶片做直線加速器的劑量影響評估之外，也對其無線傳輸的方式做測試。再經由八位先前接受過治療的患者的呼吸紀錄與八位健康志願者進行驗證。 其自製的模擬系統由兩個線性驅動器和一個可移動平台組成，最大移動範圍為12.5 cm x 6.5cm x 5 cm，可以精確模擬8位患者的呼吸模式，誤差小於6.3％，最大運動差為1.16 mm，晶片的傳輸信號以波形的方式顯示。經由八位志願者的測試，該晶片可以檢測深度到達3mm的深呼吸運動。晶片對6 MV光子的400 MU和10 MV光子的200 MU的輻射劑量的影響結果顯示穿透率分別達98.8% 及98.6%，其對光束衰減的影響小，數值小於1.4％。 我們發明了一套無管線無管路的呼吸門控偵測晶片，其特點對於治療角度的影響小且具有良好的抗噪性外，也易於穿透各種材料。經由線性執器組成的模擬系統還可以成功模擬真實患者的呼吸模式。我們也為與MR環境配合使用的治療系統開發了類似的系統。整個過程大約需要一年的時間。

Stereotactic ablative radiotherapy (SABR) aims to deliver high doses of radiation to kill cancer cells and shrink tumors in less or equals to 6 fractions. However, organ motion during treatment is a challenging issue for this kind of technique. We try to develop a control system via Bluetooth technology to simulate and correct the body motion during SABR. A homemade chip to monitor position and surface movement was made and a simulation system was assembled by 3D printing technique. Radiation doses were analysis and the capability of radiation damage protection was checked by EBT3 films irradiated by a linear accelerator. Wireless signal test was also done. Validation was done by 8 previous treated patients respiratory pattern records and 8 healthy volunteers. The home-made simulation system was consisted of 2 linear actuators and one movable stage with maximal moving distance 12.5 cm x 6.5cm x 5 cm could simulate the 8 patients’ respiratory pattern precisely with less than 6.3% error and maximal difference of motion was 1.16 mm, and chipset transited signals to displays them as a waveform. From 8 volunteers test, the chip could detect the deep respiratory movement up to 3 cm. The effect of the chip on the radiation dose 400 MU by 6 MV photon and 200 MU by 10 MV photon were all showed high penetration rate 98.8% and 98.6%, respectively. In the other word ,the least influence on the beam attenuation, less than 1.4%. We invented a tubeless and wireless respiratory gating detection chip. It has minimal interference to the treatment angles, good noise immunity and easily penetrate variety of materials capability. The simulation system consisted by linear actuators also simulates the real patients’ respiratory pattern successfully. We also developing similar system for the treatment system cooperate with MR environment. It will be done the whole things with about one year.