el-Khatib E, Hussein S, Nikolic M, Voss N J, Parsons C
Division of Medical Physics, British Columbia Cancer Agency, Vancouver, Canada.
Int J Radiat Oncol Biol Phys. 1995 Sep 30;33(2):469-74. doi: 10.1016/0360-3016(95)00112-C.
The influence of different scatterer-degraders and beam angulations on beam uniformity for total skin electron irradiation using the six dual beam Stanford technique is investigated.
The 6 MeV high dose rate total skin electron irradiation mode on a linear accelerator was used. Beam profiles and percentage depth doses in the patient plane for single, dual, and six dual beams were measured for different dual beam angulations and acrylic scatterer-degraders of different thicknesses mounted on the treatment head or in front of the patient in the treatment plane.
It is demonstrated that, with the same electron nominal energy, total skin irradiation techniques with different beam penetrations can be obtained by inserting various beam scatterer-degraders into the beam, either mounted on the accelerator head or close to the patient. For our patient treatment, a beam penetration was selected so that the 80% dose lay at 8-9 mm and the 50% dose at 15-16 mm depth. This was achieved by mounting a 0.32-cm thick acrylic beam scatterer-degrader on the accelerator head. A uniform vertical profile was obtained for gantry angulations of +/- 21 degrees.
To implement a total skin electron irradiation technique using the Stanford method, the required depth of penetration needs to be selected. Based on this, the appropriate combination of scatterer-degraders and dual beam angulations to produce a uniform beam in the treatment plane needs to be determined. Different techniques with different beam penetrations can be developed using the same high dose rate mode on the linear accelerator by a proper choice of scatterer-degraders and beam angulations.
研究使用斯坦福六双束技术进行全身皮肤电子照射时，不同散射体-降解器和射束角度对射束均匀性的影响。
采用直线加速器上的6兆电子伏特高剂量率全身皮肤电子照射模式。针对不同的双束角度以及安装在治疗头或治疗平面中患者前方的不同厚度的丙烯酸散射体-降解器，测量了单束、双束和六双束在患者平面内的射束轮廓和百分深度剂量。
结果表明，在相同电子标称能量下，通过在射束中插入各种射束散射体-降解器（安装在加速器头部或靠近患者处），可以获得具有不同射束穿透能力的全身皮肤照射技术。对于我们的患者治疗，选择了一种射束穿透能力，使得80%剂量位于8 - 9毫米深度处，50%剂量位于15 - 16毫米深度处。这是通过在加速器头部安装一个0.32厘米厚的丙烯酸射束散射体-降解器实现的。对于龙门架角度为±21度时，获得了均匀的垂直轮廓。
要采用斯坦福方法实施全身皮肤电子照射技术，需要选择所需的穿透深度。基于此，需要确定散射体-降解器和双束角度的适当组合，以在治疗平面内产生均匀的射束。通过适当选择散射体-降解器和射束角度，可以在直线加速器上使用相同的高剂量率模式开发具有不同射束穿透能力的不同技术。
