Bratova Iva, Paluska Petr, Grepl Jakub, Sirak Igor, Petera Jiri, Vosmik Milan
Department of Oncology and Radiotherapy, University Hospital Hradec Kralove, Hradec Kralove, Czech Republic.
Department of Radiobiology, University of Defence in Brno, Brno, Czech Republic.
Rep Pract Oncol Radiother. 2022 May 19;27(2):268-274. doi: 10.5603/RPOR.a2022.0039. eCollection 2022.
The purpose of this work is to improve a sweeping beam technique for total body irradiation (TBI) on a low flat couch using a varying patient thickness model. We designed a flat couch for total body irradiation in supine and prone position. Three generic arcs with rectangular segments for a patient torso thickness of 16, 22 and 28 cm were generated with respect to varying patient thickness of four particular parts of the body: head, torso, thighs and calves.
Longitudinal and transversal dose profiles were measured using an ionization chamber and the EBT3 gafchromic film in a solid water slab phantom. The robustness of the method was examined in phantoms of different thicknesses.
Measured dose homogeneity stays within ±10% of prescribed dose for all of the three patient thickness models. The robustness of the method was evaluated as the increase in dose in the phantom center of 0.7% per 1 cm reduction in phantom thickness.
The method is applicable for the broad range of patient sizes, comfortable for patients, robust and suitable for standard treatment rooms with a standard linear accelerator. It requires minimal investments into equipment.
本研究的目的是使用可变患者厚度模型改进在低平床上进行全身照射（TBI）的扫描束技术。我们设计了一种用于仰卧位和俯卧位全身照射的平床。针对身体四个特定部位（头部、躯干、大腿和小腿）不同的患者厚度，生成了患者躯干厚度分别为16厘米、22厘米和28厘米的带有矩形段的三个通用弧形。
在固体水模体中使用电离室和EBT3变色膜测量纵向和横向剂量分布。在不同厚度的模体中检查该方法的稳健性。
对于所有三种患者厚度模型，测量的剂量均匀性保持在规定剂量的±10%以内。该方法的稳健性评估为模体厚度每减少1厘米，模体中心剂量增加0.7%。
该方法适用于广泛的患者体型，对患者舒适，稳健且适用于配备标准直线加速器的标准治疗室。它对设备的投资要求最小。
