Published in the Red Journal, this study examined the CSI plans in the Pediatric Proton/Photon Consortium Registry (PPCR) to characterize proton CSI practice patterns in the US. CSI plans of 384 patients were evaluated in prescription dose and coverage of optic nerves, vertebral bodies, spinal nerve roots, sacral nerves, and cranial foramina. Significant differences among treating institutions (as well as substantial intra-institutional variations) were found in proton CSI practices in all assessed parameters, indicative of a lack of consensus in the field. The authors suggested that this data may serve as a baseline quantification of current proton CSI practices in the United States as they continue to evolve.