EP-1749: Real-time 4D ultrasound tracking of liver and kidney targets for external-beam radiotherapy

S819 ________________________________________________________________________________ monitored with Calypso (Varian) for gating and tracking treatments, and compensated with the PerfectPitch couch (Varian) for tracking. The dose in the moving tumor was measured with Gafchromic EBT2 (ISP) films. Changes in homogeneity indices (ΔH1-99) between the films and the planned dose distributions and their gamma agreement scores using 3%/3mm (GS3%/3mm) were evaluated. The film areas receiving more than the planned minimum dose (A>Dmin) were calculated. OAR doses from the treatment plans were compared.