Keywords: TLD response, thermoluminescent dosimeters, calibration, quality dependence, Monte Carlo simulation, MCNP, scattered radiation, low radiation, scattered beam dosimetry
The Monte Carlo simulation of the TLD response function: scattered radiation field application
Thermoluminescent Dosimeters (TLDs) have various applications in nonprimary beam dosimetry. The Monte Carlo simulation of the TLD response was done in low energy beams to improve its clinical use in scattered beam dosimetry. The normalised values of the measured quality dependence factors for different X-ray beams were found to be 1.28, 1.24, 1.16, 1.07 and 1.03 for different beam qualities, respectively. Comparatively, the Monte Carlo for 'n' Particles (MCNP) simulated findings were 1.134, 1.96, 1.139, 1.052 and 1.034. The change of the calibration factor with energy follows the equation CF = B0 + B1E + B2E² + B3E³, where CF and E are the calibration factor and energy (keV), respectively, and B0, B1, B2 and B3 are the constants. Our findings show a significant deviation of the true dose value when the TLDs are calibrated at different beam qualities. The greatest deviation was 19.9 ± 2.1% with a beam quality of 120 kVp. Obtaining a dose-response curve may be helpful in calculating the calibration factor with more precision.