Bieri S, Miralbell R, Nouet P, Delorme H, Rouzaud M
Department of Radiation Oncology, University Hospital, Geneva, Switzerland.
Radiother Oncol. 1996 Mar;38(3):223-30. doi: 10.1016/0167-8140(95)01699-6.
The reproducibility of 3-dimensional (3D) conformal therapy in localized prostate cancer was studied in 14 patients, based on retrospective analysis of 196 anteroposterior-posteroanterior (AP/PA) and lateral portal images. The patients were treated supine without rigid immobilization using six isocentric coplanar conformal fields. Three different observers independently compared the portal and simulation images, determining the deviation of each portal film from the corresponding simulation film. No significant deviations were observed in the cephalo-caudal or lateral axes (0 mm median values). However, a systematic median shift of 5 mm (0 to + 10, range) was observed in the anteroposterior direction, presumably as a consequence of a sagging in the treatment couch under the patient's weight. After modification of the treatment couch, no further systematic anteroposterior shifts have been observed. These results demonstrate that the daily setup of conformal prostate irradiation fields can be performed with acceptable reproducibility without the use of special immobilization devices.
基于对196张前后位（AP/PA）和侧位射野图像的回顾性分析，对14例局限性前列腺癌患者三维（3D）适形治疗的可重复性进行了研究。患者仰卧位，未使用刚性固定装置，采用六个等中心共面适形野进行治疗。三名不同的观察者独立比较射野图像和模拟图像，确定每张射野片相对于相应模拟片的偏差。在头足轴或侧轴上未观察到明显偏差（中位数为0 mm）。然而，在前后方向观察到5 mm（0至+10，范围）的系统性中位数偏移，推测这是由于患者体重导致治疗床下垂所致。调整治疗床后，未再观察到进一步的系统性前后偏移。这些结果表明，在不使用特殊固定装置的情况下，适形前列腺照射野的每日摆位可达到可接受的重复性。
