SU-E-T-266: Shielding Measurements for a Proton Therapy Facility

This paper is a follow up on the analytical calculations for the Roberts Proton Therapy Center with empirical data to determine the precision of the calculations from Avery, et al.

Neutrak dosimeters were placed in two sets around the facility while it was in operation at points of interest examined in Avery, et al. The doses to these dosimeters were recorded over one month for one set and two months for the other. Dosimeters that both recorded a dose and could be practically examined were compared to the doses predicted via the analytical method of Avery, et al. at their point of placement.

Two points showed a less than 10% difference to the calculated doses. One point shielded by both concrete and pre-cast blocks and one point shielded by both concrete and the facility's cyclotron were not as precise.

The analytical calculation method explored in Avery, et al. is fairly precise in describing the dose at various points in the facility shielded only by concrete. for materials other than concrete, such as the make-up of the cyclotron or varying wall material, it warrants follow up calculations using the same method.