EXPERIMENTAL AND MATHEMATICAL MODELING OF HALF-VALUE LAYER MEASUREMENTS FOR X-RAY EQUIPMENT

A linear mathematical modeling of half-value layer measurements for X-ray equipment is discussed. The consistency check shows that a linear model is consistent with the value of an exponential model, provided that the thickness of the aluminum absorber used in the calculations is close to 2.5mm. To validate the linear model, a methodology for determining the half-value layer in conventional X-ray equipment was introduced. The study was based on the measurement of only two exposure values, with and without aluminum absorber, using lithium fluoride thermoluminescent dosimeters (TLD-100). The corresponding description through a straight line is given. Aluminum absorber of 2.40mm thickness was used in the measurements in 11 X-ray equipment. A Pearson statistical analysis used to determine the correlation between data obtained with an ionization chamber and TLD-100 provided a statistically significant r=0.812 and p-value = 0.004.