Barish R J, Donohue K E
Mary Immaculate Hospital Division, Catholic Medical Center of Brooklyn and Queens, Jamaica, NY 11432.
Med Dosim. 1994 Spring;19(1):1-3. doi: 10.1016/0958-3947(94)90026-4.
X-ray therapy of superficial rectal cancers using a hand-held 50 kV contact unit (Philips RT-50) in a technique first described by Papillon had reached a point of widening clinical acceptability when the manufacturer of this equipment discontinued its production. To pursue this endocavitary approach to rectal therapy, technical modifications have to be made to conventional superficial x-ray therapy machines. Advantages over the original Papillon method include remote viewing of the lesion through the proctoscopic cone and a lower radiation exposure for the operator. We have evaluated a Bucky Combination Therapy Unit under conditions in which the operating voltage (65 kV), target skin distance (23.6 cm), and added filtration (0.39 mm Al) were selected in order to match as closely as possible the beam penetration characteristics of the "standard" (Papillon) technique. With this equipment, the thermal characteristics of the tube anode and housing limit the amount of radiation that can be delivered before a "rest period" for the machine is needed. In practice, 3 minutes of irradiation at an exposure rate of 500 R/min can be performed followed by an interval of 3 minutes before irradiation can be resumed.
采用手持50 kV接触式治疗机（飞利浦RT - 50）对浅表直肠癌进行X线治疗，这一技术最初由帕皮永描述。当该设备制造商停止生产时，这种治疗方法已达到临床接受度不断提高的阶段。为了继续采用这种腔内直肠治疗方法，必须对传统的浅表X线治疗机进行技术改造。与原始的帕皮永方法相比，其优点包括通过直肠镜视锥对病变进行远程观察以及操作人员所受辐射剂量更低。我们在选定工作电压（65 kV）、靶皮距离（23.6 cm）和附加滤过（0.39 mm铝）的条件下，对一台滤线器组合治疗机进行了评估，以便尽可能接近“标准”（帕皮永）技术的射线穿透特性。使用该设备时，管阳极和管套的热特性限制了在机器需要“休息期”之前能够输出的辐射量。实际上，以500 R/min的照射率进行3分钟照射后，需要间隔3分钟才能恢复照射。
