ESTRO 2024 - Abstract Book

S3215

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Figure 1: TLD response after irradiation with 1.8 Gy protons at magnetic field strengths of 0, 0.25, and 1 T and air gaps of 0.1 mm (green), 0.25 mm (red), and 0.5 mm (blue).

Conclusion:

The obtained results indicate that passive TLD 100 detectors are suitable tools for reference dosimetry in magnetic fields. In contrast to MR-Linacs, it appears altering the air gap does not lead to changes in the local dose. This effect was expected to be more pronounced for higher proton energies, due to the higher secondary energy spectrum. Consequently, for dosimetry in MR guided proton therapy, the use of solid-state phantoms and passive detectors is possible without having to account for variations in air gap. This paves the way for future use of TLD 100 detectors for end-to-end tests and dosimetric audits, which are key prior clinical implementation of MR-guided proton therapy.

Keywords: TLD, magnetic field, proton