ESTRO 2025 - Abstract Book

S2573

Physics - Detectors, dose measurement and phantoms

ESTRO 2025

were observed. Chamber-to-chamber variations for the cylindrical ICs were small (< 0.3%) while differences up to 1% were noticed for the IBA PPC40 chambers.

Figure 1: k Q -factors vs. beam quality TPR 20,10 for the cylindrical ionization chambers.

Figure 2: k Q -factors vs. beam quality TPR 20,10 for the plane-parallel ionization chambers.

Conclusion: Using water calorimetry, this study experimentally determined k Q -factors for a range of ICs that are not currently included in international dosimetry protocols. This work contributes to expanding the database of k Q -factors for high-energy photon beams, supporting more accurate dosimetry across a broader range of chamber types.

Keywords: water calorimetry, ionization chamber, photon beam

References: [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Absorbed Dose Determination in External Beam Radiotherapy, Technical Reports Series No. 398 (Rev. 1), IAEA, Vienna (2024), https://doi.org/10.61092/iaea.ve7q-y94k