Kosztyla Robert, Raman Srinivas, Moiseenko Vitali, Reinsberg Stefan A, Toyota Brian, Nichol Alan
1 Department of Medical Physics, BC Cancer - Vancouver , Vancouver, British Columbia , Canada.
2 Department of Physics and Astronomy, University of British Columbia , Vancouver, British Columbia , Canada.
Br J Radiol. 2019 Jul;92(1099):20180901. doi: 10.1259/bjr.20180901. Epub 2019 May 14.
To determine whether dose painting with volumetric modulated arc therapy for high-grade gliomas using 3,4-dihydroxy-6-[F]fluoro-l-phenylalanine (F-FDOPA) positron emission tomography (PET) could achieve dose-escalated coverage of biological target volumes (BTVs) without increasing the dose to cranial organs at risk (OARs).
10 patients with high-grade gliomas underwent CT, MRI, and F-FDOPA PET/CT images for post-operative radiation therapy planning. Two volumetric modulated arc therapy plans were retrospectively generated for each patient: a conventional plan with 60 Gy in 30 fractions to the planning target volume delineated on MRI and a dose-escalated plan with a maximum dose of 80 Gy in 30 fractions to BTVs. BTVs were created by thresholding F-FDOPA PET/CT uptake using a linear quadratic model that assumed tracer uptake was linearly related to tumour cell density. The maximum doses and equivalent uniform doses of OARs were compared.
The median volume of the planning target volume receiving at least 95% of the prescribed dose ( ) was 99.6% with and 99.5% without dose painting. The median was >99.2% for BTVs. The maximum doses and equivalent uniform doses to the OARs did not differ significantly between the conventional and dose-painted plans.
Using commercially available treatment planning software, dose painting for high-grade gliomas was feasible with good BTV coverage and no significant change in the dose to OARs.
A novel treatment planning strategy was used to achieve dose painting for gliomas with BTVs obtained from F-FDOPA PET/CT using a radiobiological model.
确定使用3,4-二羟基-6-[F]氟-L-苯丙氨酸（F-FDOPA）正电子发射断层扫描（PET）的容积调强弧形放疗对高级别胶质瘤进行剂量描绘是否能在不增加对颅内容易受损伤器官（OARs）剂量的情况下实现生物靶区（BTVs）的剂量递增覆盖。
10例高级别胶质瘤患者接受CT、MRI和F-FDOPA PET/CT图像用于术后放射治疗计划。为每位患者回顾性生成两个容积调强弧形放疗计划：一个传统计划，对MRI上勾画的计划靶区给予60 Gy，分30次照射；一个剂量递增计划，对BTVs给予最大剂量80 Gy，分30次照射。BTVs通过使用线性二次模型对F-FDOPA PET/CT摄取进行阈值化创建，该模型假定示踪剂摄取与肿瘤细胞密度呈线性相关。比较OARs的最大剂量和等效均匀剂量。
接受至少95%处方剂量（ ）的计划靶区的中位体积在剂量描绘时为99.6%，未进行剂量描绘时为99.5%。BTVs的中位 >99.2%。传统计划和剂量描绘计划之间OARs的最大剂量和等效均匀剂量无显著差异。
使用市售治疗计划软件，对高级别胶质瘤进行剂量描绘是可行的，BTV覆盖良好，对OARs的剂量无显著变化。
采用一种新的治疗计划策略，使用放射生物学模型对从F-FDOPA PET/CT获得的BTVs的胶质瘤进行剂量描绘。
