The first-in-human implementation of adaptive 4D cone beam CT for lung cancer radiotherapy: 4DCBCT in less time with less dose

Background and purposeWe present the first implementation of Adaptive 4D cone beam CT (4DCBCT) that adapts image hardware (gantry rotation speed kV projections) in response to patient’s real-time respiratory signal. 4DCBCT was applied on lung cancer patients reduce scan time imaging dose ADaptive Acquisition for Personalised Thoracic (ADAPT) trial.Materials methodsThe ADAPT technology measures signal uses mathematical optimisation external circuitry attached linear accelerator modulate gantry projection rate times dose. For each patient, scans were acquired two treatment fractions reconstructed with a motion compensated reconstruction algorithm compared current state-of-the-art four-minute acquisition (conventional 4DCBCT). We report time, quality four adaptive patients.ResultsThe reduced by 85% 73 ± 12 s representing 70% reduction 240 conventional scan. The contrast-to-noise ratio improved from 9.2 3.9 11.7 4.1 ADAPT.DiscussionThe trial represents have been adapted optimised changes breathing. demonstrates substantially clinical could enable more efficient radiotherapy.