dosimetric and biological outcomes of gamma knife radiosurgery and volumetric modulated arc therapy

Introduction: this research aimed to evaluate the radiation-induced secondary cancer risks in normal tissues following gamma knife radiosurgery (gkr) compared with the volumetric-modulated arc therapy (vmat).material and methods: eleven patients with meningioma (2 males, 9 females; median age 30 years) were analyzed. for each case, gamma knife radiosurgery (gkr) and volumetric modulated arc therapy (vmat) plans were created and compared using dosimetric-metrics and radiobiological modeling. the organ equivalent dose (oed) was estimated using linear, linear-exponential, and plateau dose–response models, and the excess absolute risk (ear) was calculated for organs at risk to estimate secondary cancer risk.results: dose coverage, conformity, and homogeneity in the planning target volume (ptv) improved significantly ('p'< 0.05) with gkr and vmat. higher oed was observed in the optic nerve due to proximity to the target. while the ear of the optic nerve increased by 11.23%, 13.17%, and 14.86% in gk compared to vmat for the linear, plateau, as well as linear-exponential models, respectively, in gk plans compared to vmat, the ear for the brain stem increased by 54.4%, 17.14%, and 30% in vmat. gkr had a considerably greater tumor control probability (tcp) (95.76%±2.86) than vmat (84.29%± 2.27, 'p'= 2.8×10-6).conclusion: gkr provided better ptv dose coverage and conformity, whereas vmat achieved superior dose homogeneity. according to ear, vmat had a greater second cancer risk than gk. for young patients, advanced radiotherapy techniques should be evaluated in consideration of dosimetric, radiobiological, and secondary cancer risks.