Mastella Edoardo, Szilagyi Klarisa E, Fabbri Sara, De Guglielmo Eleonora, Manco Luigi, Farina Eleonora, Giganti Melchiore, Stefanelli Antonio, Turra Alessandro
Medical Physics Unit, University Hospital of Ferrara, I-44124 Cona (Ferrara), Italy.
Medical Physics Unit, University Hospital of Ferrara, I-44124 Cona (Ferrara), Italy; Specialization School of Medical Physics, University of Bologna I-40127 Bologna, Italy.
Phys Med. 2025 Jul;135:105025. doi: 10.1016/j.ejmp.2025.105025. Epub 2025 Jun 12.
Advanced radiotherapy techniques require robust patient-specific quality assurance (PSQA). This study validated a secondary calculation software for plan dose verification, evaluating accuracy across different treatment sites, beam qualities, and plan complexities.
Data from two beam-matched VersaHD linacs were used to commission RadCalc-V7.3.2.0. 33 end-to-end tests in homogeneous and anthropomorphic phantoms compared RadCalc Monte Carlo (RC-MC) and Collapsed Cone Convolution Superposition (RC-CCCS) algorithms with Pinnacle TPS, using gamma analysis (1.5 %/2mm) and ionization chamber measurements. 140 clinical VMAT plans of varying complexities, including 35 head and neck (H&N) and 65 SBRT treatments, were evaluated using gamma analysis (3 %/2mm) and relevant DVH metrics for PTV (D98%, D2%). RadCalc calculations were compared with pre-treatment Octavius 4D measurements.
Phantom studies showed excellent RadCalc-TPS agreement for homogeneous plans and lung SBRT with flattened beams (mean passing rates > 98 %, mean measured dose differences < 1 %). Larger discrepancies were observed in the anthropomorphic thorax phantom for FFF SBRT. For clinical plans, mean passing rates exceeded 98.5 %. Site-specific differences emerged: RC-MC performed better for H&N, RC-CCCS for other sites. RadCalc calculated slightly less homogeneous dose distributions than Pinnacle, but averaging RC-MC and RC-CCCS results in reduced DVH discrepancies (mean ΔD98% -1.1 ± 1.1 %, mean ΔD2% +1.1 ± 1.5 %). Octavius measurements may underestimate calculation discrepancies due to tissue inhomogeneities.
RadCalc produced very consistent results with Pinnacle and can be integrated into our PSQA program for efficient 3D dose verification, reducing measurement workload while maintaining high standards of dosimetric accuracy. Using both RadCalc algorithms effectively reduced calculation uncertainties.
先进的放射治疗技术需要强大的患者特异性质量保证（PSQA）。本研究验证了一种用于计划剂量验证的二次计算软件，评估其在不同治疗部位、射束质和计划复杂性方面的准确性。
来自两台射束匹配的VersaHD直线加速器的数据用于调试RadCalc-V7.3.2.0。在均匀体模和人体模中进行了33次端到端测试，使用伽马分析（1.5%/2mm）和电离室测量，将RadCalc蒙特卡罗（RC-MC）算法和坍缩圆锥卷积叠加（RC-CCCS）算法与Pinnacle TPS进行比较。使用伽马分析（3%/2mm）和PTV的相关剂量体积直方图（DVH）指标（D98%、D2%）对140个不同复杂性的临床容积调强放疗（VMAT）计划进行评估，包括35个头颈部（H&N）和65个立体定向体部放疗（SBRT）治疗计划。将RadCalc计算结果与治疗前Octavius 4D测量结果进行比较。
体模研究表明，对于均匀计划和使用扁平射束的肺部SBRT，RadCalc与TPS的一致性极佳（平均通过率>98%，平均测量剂量差异<1%）。在人体胸部体模中，对于FFF SBRT观察到较大差异。对于临床计划，平均通过率超过98.5%。出现了部位特异性差异：RC-MC在H&N部位表现更好，RC-CCCS在其他部位表现更好。RadCalc计算的剂量分布均匀性略低于Pinnacle，但将RC-MC和RC-CCCS结果平均可减少DVH差异（平均ΔD98%-1.1±1.1%，平均ΔD2%+1.1±1.5%）。由于组织不均匀性，Octavius测量可能会低估计算差异。
RadCalc与Pinnacle产生的结果非常一致，可整合到我们的PSQA程序中，用于高效的三维剂量验证，减少测量工作量，同时保持高剂量学准确性标准。有效使用两种RadCalc算法可降低计算不确定性。
