Transmission of Shielding Materials for Particle Therapy Facilities

A typical particle therapy facility consists of an injector, a cyclotron or a synchrotron, a high-energy transport beam line, several treatment rooms including fixed-beam and gantry rooms, and even a research area. During the operation of these facilities, radiation is produced with neutrons being the dominant component outside the shielding. These facilities have large amounts of shielding with concrete thicknesses ranging up to [approximately]5 m or more. Space required for shielding can be minimized by using composite shielding or high-density material such as Ledite® (manufactured by Atomic International, Frederick, Pennsylvania). Transmission data for radiation from protons and carbon ions incident on tissue targets with energies in the therapeutic energy range of interest were derived using the Monte Carlo code FLUKA for three different compositions of Ledite. Use of Ledite® or composite shielding results in space savings when compared to concrete.