Single-isocenter Multi-target Stereotactic Radiotherapy: An MR Gel Dosimetry Protocol to Evaluate Accuracy

Motivation: Single-isocenter multitarget (SIMT) stereotactic radiosurgery (SRS) allows simultaneous treatment of multiple brain metastases, which increases treatment efficiency compared to conventional, sequential treatment. Its additional uncertainties have not been thoroughly investigated. Goal(s): To develop an MR Gel dosimetry protocol that can evaluate the spatial accuracy of SMIT SRS. Approach: Gels are irradiated with standardized radiation and calibration plans in a multicenter study (n=19). Results: Dose maps can be reconstructed despite unexpected quality loss in used gels and spatial accuracy is very high. Impact: This multicenter study aims to strengthen the trust in SIMT SRS, which has the potential to significant time savings for medical personnel and machine time as well as improvements to patient comfort.