“…Periodic QACT has been regarded as routine in the clinic. 10 , 11 , 12 , 13 , 14 Several methods have been published for predicting the time to replan based on the above-mentioned change variables. In-room CT and cone-beam CT (CBCT) range-based registrations, deformable image registrations, range-corrected dose distributions, intensity correction, gamma index, and water-equivalent thickness change on CBCT have been reported for adaptive proton therapy.…”