Characterization of X-ray Beams: Determination of Ka,e for Comparison with DRLs

Aims: The aim of this experimental study was to quantify the entrance surface air kerma (Ka,e) of X-ray beams in radiographic examinations, and the obtained values were compared with national and international Diagnostic Reference Levels (DRLs).

Place and Duration of Study: Sample: Department of Medical Physics and Radiology, Franciscan University (UFN), between June 2023 and August 2024.

Methodology: Initially, the main quality control (QC) tests were applied to characterize the radiographic equipment. During the evaluation of the X-ray beam, a dosimetric set was used, and for the same QC geometry, Air Kerma Rate (KAIR) measurements were obtained to determine the output of the X-ray tube. Under the same conditions, a phantom without water and the same filled with water were used to determine the backscatter factor (BSF), which was then used to estimate the Ka,e for the main radiographic examinations.

Results: The results of this study are consistent with other studies and identified the region/anatomy with the highest radiation exposure, highlighting the importance of its optimization and verifying that continued professional training should be integrated into best practices to ensure greater safety in procedures. The results obtained evidence the necessity for adjustments in image acquisition protocols, as the Ka,e values found in this study, although within the limits established by the national DRLs, exceed the reference values of countries such as the United Kingdom and Japan in the areas of the skull, abdomen, and lumbar spine. This discrepancy highlights the importance of the periodic review and update of DRLs, in accordance with international recommendations and the technological evolution of equipment. Dose optimization is an ongoing process that involves the evaluation of image quality, the appropriate selection of technical parameters, and the implementation of specific dose protocols. The continuous training of radiology professionals is essential to ensure the correct application of imaging techniques and the minimization of patient exposure to ionizing radiation.

Conclusion: This study shows the importance of evaluating radiation dose in diagnostic imaging and the need for a multidisciplinary approach to dose optimization. Implementing quality assurance programs, updating DRLs, and providing ongoing training for professionals are essential to ensure patient safety and high-quality diagnostic imaging. The methodology adopted in this study can contribute to the ongoing education of radiology professionals, promoting the correct application of imaging techniques and reducing patient exposure to ionizing radiation.