An in-house timer for ART-specific extra time in gynecologic pelvic online adaptive radiation therapy

Online adaptive radiation therapy (ART) lengthens the session, but many published times report one interval and do not isolate ART-specific activity. We developed a console timer that records wall-clock timestamps for a defined event list, stores per-fraction ART settings, and exports Excel tables. ART-specific extra time extends from ART mode until plan approval. After verification on 100 simulated fractions, it was applied in 38 fan-beam CT-guided gynecologic pelvic online ART fractions (nine patients). Mean ART-specific extra time was 13.7 min within a 21.8-min session, dominated by optimization and target/organ-at-risk editing. It supports bottleneck audit under a shared event list.