Performance Analysis and Cross-Calibration of PPC-40 and FC65-P Ionization Chambers in Low-Energy Electron Beams Absolute Dosimetry

Algorithm of electron beam dose delivery is dissimilar in comparison to X-ray radiation therapy. Therefore, absolute dosimetry of low energy like (≤9 MeV) is fundamentally effective in electron beam radiation therapy by a linear accelerator. This effectively needs evaluation of cross calibration by PPC-40 and FC65-P ionization chambers for accurate dosimetry to assure quality of treatment with clinical accuracy. Implications of results enunciated in this paper show that salient features are documented. The FC65-P chamber exhibited a deviation of up to 1.04% at shallow depths, indicating limitations for low-energy electron beams. In contrast, the PPC-40 demonstrated superior accuracy in surface dose and shallow-depth measurements due to its parallel-plate design and larger effective volume. The importance of cross-calibration yielded a new correction factor of 1.01, allowing conversion of FC65-P dose measurements to PPC-40 values. This relationship remained stable under controlled conditions. The clinical significance of the selection of ionization chamber for low energy electrons dosimetry is absolutely required for treatment precision and patient safety in electron beam radiation therapy (EBRT).