Associating dose–volume characteristics with theoretical radiobiological metrics for rapid Gamma Knife stereotactic radiosurgery plan evaluation

Purpose To examine general dose–volume characteristics in Gamma Knife (GK) plans which may be associated with higher tumor control probability (TCP) and equivalent uniform dose (EUD) using characteristic curve sets. Methods Two sets of dose–volume histograms (DVHs) were exported alongside an analytical purpose‐generated DVH: (a) single‐shot large collimator (8 or 16 mm) emulated with multiple shots of 4 mm collimator. (b) shot‐within‐shot (SWS) technique with isodose lines (IDLs) of 40–75%. TCP, average dose, EUD in single‐fraction (EUDT) and 2 Gy fractionated regimens (EUDR) were examined for trends with cumulative DVH (cDVH) shape as calculated using a linear‐quadratic cell survival model (α/β = 10.0 Gy, N0 = 1 × 106) with both α = 0.20 Gy−1 and α = 0.23 Gy−1. Results Using α = 0.20 Gy−1 (α = 0.23 Gy−1), plans in the analytical set with higher shoulder regions had TCP, EUDT, EUDR increased by 180%, 5.9%, 10.7% (11.2%, 6.3%, 10.0%), respectively. With α = 0.20 Gy−1 (α = 0.23 Gy−1), plans with higher heels had TCP, EUDT, EUDR increased by 4.0%,