Instituto de Fı́sica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Instituto de Radioproteção e Dosimetria, IRD/CNEN, Rio de Janeiro, Brazil; Oncologia D'Or São Cristóvão, Rede D'Or São Luiz, Rio de Janeiro, Brazil.
Phys Med. 2021 Jul;87:1-10. doi: 10.1016/j.ejmp.2021.05.028. Epub 2021 Jun 3.
This study aims to use GATE/Geant4 simulation code to evaluate the performance of dose calculations with Anisotropic Analytical Algorithm (AAA) in the context of lung SBRT for complex treatments considering images of patients.
Four cases of non-small cell lung cancer treated with SBRT were selected for this study. Irradiation plans were created with AAA and recalculated end to end using Monte Carlo (MC) method maintaining field configurations identical to the original plans. Each treatment plan was evaluated in terms of PTV and organs at risk (OARs) using dose-volume histograms (DVH). Dosimetric parameters obtained from DVHs were used to compare AAA and MC.
The comparison between the AAA and MC DVH using gamma analysis with the passing criteria of 3%/3% showed an average passing rate of more than 90% for the PTV structure and 97% for the OARs. Tightening the criteria to 2%/2% showed a reduction in the average passing rate of the PTV to 86%. The agreement between the AAA and MC dose calculations for PTV dosimetric parameters (V; V; Homogeneity index; maximum, minimum and mean dose; CI and D) was within 18.4%. For OARs, the biggest differences were observed in the spinal cord and the great vessels.
In general, we did not find significant differences between AAA and MC. The results indicate that AAA could be used in complex SBRT cases that involve a larger number of small treatment fields in the presence of tissue heterogeneities.
本研究旨在使用 GATE/Geant4 模拟代码，在考虑患者图像的情况下，评估各向异性分析算法（AAA）在肺部 SBRT 中对复杂治疗进行剂量计算的性能。
选择 4 例接受 SBRT 治疗的非小细胞肺癌患者进行本研究。使用 AAA 生成照射计划，并使用蒙特卡罗（MC）方法从头到尾重新计算，同时保持与原始计划相同的场配置。使用剂量-体积直方图（DVH），根据 PTV 和危及器官（OARs）评估每个治疗计划。使用 DVH 获得的剂量学参数，比较 AAA 和 MC。
使用 3%/3%的通过标准进行 AAA 和 MC 的 DVH 伽马分析比较，PTV 结构的平均通过率超过 90%，OARs 的通过率为 97%。将标准收紧至 2%/2%，PTV 的平均通过率降低至 86%。对于 PTV 的剂量学参数（V、V、均匀性指数、最大、最小和平均剂量、CI 和 D），AAA 和 MC 剂量计算之间的一致性在 18.4%以内。对于 OARs，最大的差异发生在脊髓和大血管。
总体而言，我们没有发现 AAA 和 MC 之间有显著差异。结果表明，在存在组织异质性的情况下，对于涉及大量小治疗野的复杂 SBRT 病例，可以使用 AAA。
