Dosimetric Comparison of VMAT for Craniospinal Irradiation across Multiple Linac Platforms and Flattening Filter Modes.
Abstract
Purpose
This study evaluates craniospinal VMAT plan quality and deliverability for FFF beams on the TaiChiPro accelerator versus Elekta Axesse FFF/FF plans. Gamma analysis validated the results to guide clinical implementation.
Methods
Ten CSI patients were selected from the Fourth Hospital of Hebei Medical University between January 1, 2022, and December 31, 2024. Group A comprised TaiChiPro FFF VMAT plans; Groups B and C comprised Elekta Axesse FFF and FF VMAT plans, respectively. All plans were prescribed 36 Gy in 20 fractions. Dosimetric parameters for PTV and OARs and the monitor units (MU) were collected; the gamma passing rates for Group A plans were verified using third-party software.
Results
All plans satisfied clinical dosimetric requirements. Group A showed significantly higher V95% (PTV-all/PTV-1), lower Dmax (lenses/optic nerves), reduced Dmean (spinal cord/lungs), and decreased V5/Dmean (right kidney/normal tissue) versus Groups B/C (P95% in 9 of 10 cases, with one case at 93.93%.
Conclusion
For craniospinal irradiation, the group A technique is recommended as the primary clinical option. It provides adequate target coverage, reduces OARs doses and MU, and improves workflow efficiency via auto-couch. However, group A is slightly inferior to B and C in junction-region HI and high-dose control. Groups B and C show no significant difference in target coverage or OAR sparing.