Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA.
Med Phys. 2023 Mar;50(3):1766-1778. doi: 10.1002/mp.16137. Epub 2022 Dec 10.
Deformable dose accumulation (DDA) has uncertainties which impede the implementation of DDA-based adaptive radiotherapy (ART) in clinic. The purpose of this study is to develop a multi-layer quality assurance (MLQA) program to evaluate uncertainties in DDA.
A computer program is developed to generate a pseudo-inverse displacement vector field (DVF) for each deformable image registration (DIR) performed in Accuray's PreciseART. The pseudo-inverse DVF is first used to calculate a pseudo-inverse consistency error (PICE) and then implemented in an energy and mass congruent mapping (EMCM) method to reconstruct a deformed dose. The PICE is taken as a metric to estimate DIR uncertainties. A pseudo-inverse dose agreement rate (PIDAR) is used to evaluate the consequence of the DIR uncertainties in DDA and the principle of energy conservation is used to validate the integrity of dose mappings. The developed MLQA program was tested using the data collected from five representative cancer patients treated with tomotherapy.
DIRs were performed in PreciseART to generate primary DVFs for the five patients. The fidelity index and PICE of these DVFs on average are equal to 0.028 mm and 0.169 mm, respectively. With the criteria of 3 mm/3% and 5 mm/5%, the PIDARs of the PreciseART-reconstructed doses are 73.9 ± 4.4% and 87.2 ± 3.3%, respectively. The PreciseART and EMCM-based dose reconstructions have their deposited energy changed by 5.6 ± 3.9% and 2.6 ± 1.5% in five GTVs, and by 9.2 ± 7.8% and 4.7 ± 3.6% in 30 OARs, respectively.
A pseudo-inverse map-based EMCM program has been developed to evaluate DIR and dose mapping uncertainties. This program could also be used as a sanity check tool for DDA-based ART.
变形剂量累加（DDA）存在不确定性，这阻碍了基于 DDA 的自适应放疗（ART）在临床中的实施。本研究的目的是开发一种多层质量保证（MLQA）程序来评估 DDA 中的不确定性。
为每个 Accuray 的 PreciseART 中执行的变形图像配准（DIR）生成一个伪逆位移矢量场（DVF），开发了一个计算机程序。首先使用伪逆 DVF 来计算伪逆一致性误差（PICE），然后将其实施在能量和质量一致映射（EMCM）方法中，以重建变形剂量。PICE 被用作估计 DIR 不确定性的指标。使用伪逆剂量一致性率（PIDAR）来评估 DDA 中 DIR 不确定性的后果，并且使用能量守恒原理来验证剂量映射的完整性。使用从五个接受调强放射治疗的代表性癌症患者的数据测试了开发的 MLQA 程序。
在 PreciseART 中执行 DIR，为五个患者生成初始 DVF。这些 DVF 的保真度指数和 PICE 的平均值分别等于 0.028 毫米和 0.169 毫米。使用 3 毫米/3%和 5 毫米/5%的标准，PreciseART 重建剂量的 PIDAR 分别为 73.9%±4.4%和 87.2%±3.3%。PreciseART 和基于 EMCM 的剂量重建分别导致五个 GTV 中的沉积能量变化 5.6%±3.9%和 2.6%±1.5%，以及 30 个 OAR 中的沉积能量变化 9.2%±7.8%和 4.7%±3.6%。
已经开发了基于伪逆映射的 EMCM 程序来评估 DIR 和剂量映射不确定性。该程序还可以用作基于 DDA 的 ART 的合理性检查工具。
