Dosimetric Advantages of Proton Beam Therapy over Conventional X-ray Radiotherapy using Comparative Analysis in Pediatric Patients with Various Tumor Locations

Abstract

Objectives

To compare radiation dose to organs at risk, as well as total integral dose in proton beam therapy (PBT) when comparatively planned with conventional X-ray radiotherapy (XRT).

Methods

Data for 23 patients referred to the comparative planning service of the Australian Bragg Centre for Proton Therapy and Research (ABCPTR) between January 2022 and June 2023 were included in the analysis. Ages ranged from 0 – 17 years of age. 19 patients were referred from an Australian clinic and 4 patients from a New Zealand clinic. 18 patients had a target volume in the head and neck region, and 5 patients had a target volume outside this region. XRT plans were prepared by the referring clinic and PBT plans were prepared by the ABCPTR. Both plans underwent analysis of dose-volume metrics, including target volume coverage, dose to organs at risk (OaR) and integral dose.

Results

Dose prescriptions were identical between PBT and XRT in all cases, with comparable target volume coverage. PBT allowed for a reduction in the integral dose in all cases. A trend of OaR dose reduction with PBT relative to XRT was also evident, however, the degree of dose reduction with PBT strongly depended on location of the OaR with respect to the target volume.

Conclusion

Our data demonstrates the dosimetric advantages of PBT to OaR and overall integral dose when compared with XRT. In the setting of equal dose prescriptions, we hypothesize that this will result in a primary benefit from the reduction of late toxicities, which are especially impactful in paediatric populations.