In a AAPM physicist member survey during an oral presentation at the Annual Meeting, 33% of respondents agree that range uncertainty is a primary barrier to further adoption of proton therapy, and an obstacle to the replacement of X-ray therapy by Proton Therapy. And the AAPM Task Group Report 202 – Physical Uncertainties in the Planning and Delivery of Light Ion Beam Treatments – concluded (p. 53) that “It can be seen that there are quite large differences in the determined RLSTPs between the various facilities, indicating that the uncertainty in converting x-ray CT numbers to RLSTPs is significantly larger than indicated by the single facility experiments.”
