Tsujii H, Inada T, Maruhashi A, Hayakawa Y, Tsuji H, Ohara K, Akisada M, Kitagawa T
Nihon Igaku Hoshasen Gakkai Zasshi. 1989 May 25;49(5):622-9.
It has been recognized that, for precise localization and verification of radiation fields, a marking drawn on the skin surface is not entirely reliable because its position relative to bony structures or internal organs is not stationary. This is especially true when treating deep-seated tumors located below the clavicle. In proton beam radiotherapy at the University of Tsukuba, we ristrict the margins around the target volume. Therefore, special care in field localization and verification is needed, and we make it a rule to take X-ray pictures on each treatment day. To accomplish this, we have developed a localize-and-verify system by using fluoroscopic techniques and combining it with a real-time digital image processing device. This allows for the formation of a digital image of the proton field and storage it in the optic disc. By using this system as well as verification films, filed placement errors were measured in 10 patients with deep-seated tumors. Out of a total of 190 localizations, 22% exhibited a field placement error of more than 5 mm, where patient positioning and field localization were done by using skin drawings aligned with laser beams. This result strongly suggests the necessity for daily localization and verification of radiation fields, as is being done by us, for precision in the execution of proton beam radiation therapy.
人们已经认识到，对于辐射野的精确定位和验证，绘制在皮肤表面的标记并不完全可靠，因为其相对于骨骼结构或内部器官的位置并非固定不变。在治疗位于锁骨下方的深部肿瘤时尤其如此。在筑波大学的质子束放射治疗中，我们限制靶区周围的边界。因此，在射野定位和验证方面需要特别小心，并且我们规定在每个治疗日都要进行X光拍照。为了实现这一点，我们通过使用荧光透视技术并将其与实时数字图像处理设备相结合，开发了一种定位和验证系统。这使得能够形成质子束野的数字图像并将其存储在光盘中。通过使用该系统以及验证胶片，对10例深部肿瘤患者的射野放置误差进行了测量。在总共190次定位中，22%的射野放置误差超过5毫米，其中患者定位和射野定位是通过使用与激光束对齐的皮肤标记来完成的。这一结果有力地表明，正如我们所做的那样，为了精确实施质子束放射治疗，有必要对辐射野进行每日定位和验证。
