van Herk M, Meertens H
Radiotherapy Department, The Netherlands Cancer Institute (Antoni van Leeuwenhoekhuis), Amsterdam.
Radiother Oncol. 1988 Apr;11(4):369-78. doi: 10.1016/0167-8140(88)90208-3.
It is very important to have a daily verification of patient setup during radiotherapy. Therefore, we have developed an on-line imaging device for high energy photons. It consists of a matrix of 128 x 128 liquid filled ionisation chambers and has a field of view of 320 mm x 320 mm. This device has an extremely flat cassette-like housing for easy handling and for application with existing radiotherapy equipment. A dedicated microcomputer is used to measure the currents of the 16384 ionisation chambers at high speed. The same computer is used to restore and process the images. With an imaging time of 3.1 s, an image quality comparable to film is obtained. Images of high and low contrast phantoms and of patients are presented. With this device, high quality portal images will be available within only a few seconds after the start of the treatment. This allows an almost instantaneous decision on the approval of patient setup. In addition, it enables observation of organ or patient motion during a single treatment. Analysis of these images at high speed will be an interesting new area of research.
在放射治疗期间对患者摆位进行每日核查非常重要。因此，我们开发了一种用于高能光子的在线成像设备。它由一个128×128的充满液体的电离室矩阵组成，视野为320毫米×320毫米。该设备有一个极其扁平的类似暗盒的外壳，便于操作且可与现有的放射治疗设备配套使用。一台专用微型计算机用于高速测量16384个电离室的电流。同一台计算机用于图像恢复和处理。成像时间为3.1秒，可获得与胶片相当的图像质量。展示了高对比度和低对比度体模以及患者的图像。使用该设备，在治疗开始后仅几秒内就能获得高质量的射野图像。这使得几乎能立即决定患者摆位是否合格。此外，它还能在单次治疗期间观察器官或患者的运动。对这些图像进行高速分析将是一个有趣的新研究领域。
