Broggi Sara, Fiorino Claudio, Chiara Anna, Salvadori Giovannella, Peccatori Jacopo, Assanelli Andrea, Piementose Simona, Pasetti Marcella, Simone Selli, Ciceri Fabio, Di Muzio Nadia G, Calandrino Riccardo
Medical Physics, San Raffaele Scientific Institute, Milan, Italy.
Radiotherapy, San Raffaele Scientific Institute, Milan, Italy.
Phys Imaging Radiat Oncol. 2019 Dec 16;12:74-79. doi: 10.1016/j.phro.2019.11.009. eCollection 2019 Oct.
The topotherapy technique was recently suggested as a robust alternative to helical radiation delivery for total body irradiation (TBI). It allows to deliver a discrete number of beams with fixed gantry. A Topotherapy-based low-dose TBI technique was optimized and clinically implemented.
TBI delivery was split in two parts: the first treating from the head to half thigh and the second the remaining legs. An in-silico investigation aimed to optimize plan parameters was first carried out on four patients. For the upper plan, field width and pitch were fixed to 5 cm and 0.5: the combined impact of five modulation factor (MF) values and different field configurations (6/8/12 fields) was investigated. For the lower plan, two anterior/posterior beams (field width: 5 cm; pitch: 0.5; MF:1.5) were used. After assessing the optimal technique, set-up/quality assurance/image-guidance procedures were defined and the technique clinically implemented: 23 patients were treated up to now.
The best compromise between treatment time and planning target volume (PTV) coverage/homogeneity was found for MF = 1.5 and 8 fields. All clinical plans were automatically optimized using an "ad-hoc" plan template: excellent PTV coverage (PTV95%>98.5%) and homogeneity (median SD:4%) were found with a median beam-on time of 17/9 min for the upper/lower plan. All patients were successfully treated and transplanted.
TBI delivered with the topotherapy approach robustly guarantees adequate coverage and dose homogeneity. Semi-automatic clinical plans can be quickly generated and efficiently delivered.
最近有人提出顶线治疗技术是全身照射（TBI）中螺旋放射治疗的一种可靠替代方法。它允许使用固定机架输送离散数量的射束。一种基于顶线治疗的低剂量TBI技术得到了优化并在临床上得以应用。
TBI治疗分为两部分：第一部分治疗从头部到半大腿，第二部分治疗其余腿部。首先对4名患者进行了旨在优化计划参数的计算机模拟研究。对于上部计划，射野宽度和螺距固定为5厘米和0.5：研究了五个调制因子（MF）值和不同射野配置（6/8/12个射野）的综合影响。对于下部计划，使用两个前后射束（射野宽度：5厘米；螺距：0.5；MF：1.5）。在评估了最佳技术后，确定了设置/质量保证/图像引导程序并在临床上应用了该技术：到目前为止已治疗了23名患者。
发现对于MF = 1.5和8个射野，在治疗时间与计划靶区（PTV）覆盖/均匀性之间取得了最佳折衷。所有临床计划均使用“专用”计划模板自动优化：对于上部/下部计划，PTV覆盖率极佳（PTV95%>98.5%）且均匀性良好（中位标准差：4%），中位照射时间为17/9分钟。所有患者均成功接受治疗并进行了移植。
采用顶线治疗方法进行的TBI有力地保证了足够的覆盖范围和剂量均匀性。可以快速生成并高效实施半自动临床计划。
