Assessment of biological dosimetric margin for stereotactic body radiation therapy
Assessment of biological dosimetric margin for stereotactic body radiation therapy
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DOI：
10.1002/acm2.12843
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发表时间：
2020-04-01
影响因子：
2.1
通讯作者：
Nagata，Yasushi
中科院分区：
文献类型：
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作者：
Kawahara，Daisuke;Saito，Akito;Nagata，Yasushi
目的提出一种新的生物剂量学裕度（BDM）和生物转换因子（BCF），以补偿物理剂量学裕度（PDM）和BDM之间的差异，为直接从物理剂量（PD）分布估计BDM提供一种新的方法。10个肺立体定向体部放射治疗（SBRT）治疗计划的颅-尾（CC）方向，处方剂量为48戈伊。这些计划通过线性二次模型重新计算为生物等效剂量（BED），用于d = 3-20戈伊/fr的每部分剂量（DPF）和。定义BDM和PDM，以使满足覆盖95%（或98%）临床靶体积的剂量的区域分别大于或等于规定PD和BED的90%。的BCF的经验公式创建作为一个功能的DPF.ResultsThere LR和AP方向之间没有显着差异，无论是PDM也BDM。另一方面，CC方向的BDM和PDM显著大于其他方向。结论提出了一种利用BCF直接估计BDM的新方法。预计该技术将使用基于PD的治疗计划系统实现基于床的SBRT治疗计划。
PurposeTo develop a novel biological dosimetric margin (BDM) and to create a biological conversion factor (BCF) that compensates for the difference between physical dosimetric margin (PDM) and BDM, which provides a novel scheme of a direct estimation of the BDM from the physical dose (PD) distribution.MethodsThe offset to isocenter was applied in 1‐mm steps along left‐right (LR), anterior‐posterior (AP), and cranio‐caudal (CC) directions for 10 treatment plans of lung stereotactic body radiation therapy (SBRT) with a prescribed dose of 48 Gy. These plans were recalculated to biological equivalent dose (BED) by the linear‐quadratic model for the dose per fraction (DPF) ofd= 3–20 Gy/fr and . BDM and PDM were defined so that the region that satisfied that the dose covering 95% (or 98%) of the clinical target volume was greater than or equal to the 90% of the prescribed PD and BED, respectively. An empirical formula of the BCF was created as a function of the DPF.ResultsThere was no significant difference between LR and AP directions for neither the PDM nor BDM. On the other hand, BDM and PDM in the CC direction were significantly larger than in the other directions. BCFs ofD95%andD98%were derived for the transverse (LR and AP) and longitudinal (CC) directions.ConclusionsA novel scheme to directly estimate the BDM using the BCF was developed. This technique is expected to enable the BED‐based SBRT treatment planning using PD‐based treatment planning systems.