目的：本科為使胸部病患治療部位精確度提高，每天治療之再現性一致[9,13]，特別研發適合國人胸部固定之器具，能適用於食道癌、肺癌、乳房癌等等。材料與方法：首先選定模具（aquaplast），將其浸入熱水槽箱，待其軟化後，自熱水槽箱中取出並覆蓋在病患體表，配合自行研發之胸部固定器（chest holder），完成具有固定效果之固定模型。再使用模擬攝影機對病患實施模擬定位攝影，取得模擬定位片（portal film），及安排病患實施電腦斷層攝影，取得電腦斷層影像以製作病患之放射治療計劃。經醫師確認治療範圍和模擬驗證皆符合治療計劃及治療目標後，即可至直線加速器上實施驗證片（verification film）之工作，最後由醫師根據模擬定位片和驗證片的器官影像解剖的位置，來比較兩者之差異，得知固定模型之固定效果及準確度。結果：本科從87年12月至90年12月製作過200個胸部固定模具之病患，經由模擬定位片與驗證片比較結果，兩者誤差皆在1~3 mm以內。結論：本科製作的胸部固定模具優點是每天治療可正確、快速對準治療部位，而且可避免所作記號畫在病患體表上，造成病患美觀上的問題，並防止某些病患皮膚對膠布或奇異筆所量的記號會造成皮膚的過敏，進而影響治療品質。

Purpose: In order to increase the accuracy of radiotherapeutic treatment in the chest region and ensure the reproducibility of precise daily treatment portals [9,13], we design a chest immobilization device that better fits Chinese people and this is appropriate in the application for the treatment for esophageal cancer, lung cancer, breast cancer and so on. Materials and Methods: To design the chest holder, we measure the width of patient's body and the length of patient's head, shoulders, and weight. The material of the chest holder is the acrylic. The CT number of the acrylic is the same with the muscle tissue of our body. We use the aquaplast on patients for immobilizing and marking. Results: To verify the feasibility and quality of the chest holder, we compare the treatment portals taken in portal films and verification films. The discrepancy of the two figures are within 1~3 mm, which is clinically acceptable. Conclusion: The advantage of the chest holder is the assurance of a daily accurate treatment and also the avoidance of placing the markers on patient's skin, which may produce the allergic reaction in convenience in daily living and patient's outlook change.