A quantitative study of the relationship between absorbed energy and DR pixel values based on the X-ray energy spectrum model

The characteristic curve to analyze the characteristics of the digital radiography (DR) detector generally shows the relationship between the pixel value and the X-ray exposure. Even though the exposures are the same, the pixel values may differ if the tube voltages are different. This study quantitatively examined the relationship between the pixel value and the energy absorbed in the detector by calculating the actual amount of energy absorbed in the detector rather than the level of radiation exposure. The SRS-78 program, which is a widely used X-ray spectrum generation computer software program was used as the X-ray energy spectrum model. A brief equation was used to calculate the absorbed energy in the DR detector, and the X-ray spectrum data were used for one of the variables of the equation. Experiments using a phantom were also performed to verify the relationship between the measured pixel values and absorbed energy. The results showed that the calculation of the energy absorbed in the detector could be calculated precisely and that the pixel value of the detector could be predicted using the characteristic curve under specific conditions.