Hyperarc Deliverability: A Comparison to Clinical Plans Using Gamma Analysis
Abstract
Purpose
HyperArc is an automated planning and delivery technique for single and multiple-target stereotactic radiosurgery (SRS) treatments that creates highly conformal plans and has potential for saving time. This study evaluates whether HyperArc SRS plans have a non-inferior deliverability compared to clinical plans based on patient specific quality assurance (PSQA) metrics.
Methods
HyperArc SRS treatment plans were created for 14 patients previously treated with clinical plans. Verification plans without couch rotations were created for HyerArc and clinical plans, and were delivered on a Varian EDGE machine, with dose measured using Electronic Portal Imaging Device (EPID) and an Octavius 4D system. PSQA results were obtained using gamma analysis for all plans with a criteria of 3%/1mm. Deliverability difference was assessed by comparing the gamma passing rate (GPR) between HyperArc and clinical plans using a two-tailed Wilcoxon signed-ranked test with a significance level of 5%.
Results
Analysis of plans indicate no statistically significant difference in GPR between HyperArc and clinical plans, regardless if measurements were taken using EPID or Octavius. For clinical plans the average GPR measured using EPID was 96.2% with a standard deviation of 8.7%, and an average and standard deviation of 99.4% and 0.4% respectively when measured using Octavius. HyperArc plans had an average and standard deviation of 95.0% and 8.6% respectively when measured using EPID, and when using Octavius these values were 99.6% and 0.3%.
Conclusion
This work shows HyperArc SRS plans have at least equal deliverability compared to manually created clinical plans. Results comparing HyperArc to clinical plans remained consistent regardless of measurement method. This suggests that HyperArc has potential time saving advantages for SRS treatments in addition to its non-inferior deliverability compared to clinical plans.