Evaluation of entrance surface dose and scattered dose to the pelvis for common radiological examinations in analog and digital radiography: A phantom study

Development of digital radiography revolutionized the field of medical imaging and increased the diagnostic accuracy. Despite its advantages, such as wide dynamic range and post-processing capacity, patient dosage has increased. The present study aimed to evaluate the entrance surface doses (ESDs) of primary beams to organs and the scatter dose received by pelvis in digital and analog systems with an emphasis on the radiation field size.

A whole body phantom PBU-50, and TLD GR-200 chips, were used to measure ESDs. Radiation techniques used in analog and digital systems were implemented, using a Pars Pad radiography unit. Exposure factors in digital radiography were applied for both standard and clinically used radiation field sizes. Radiography was performed in the extremities, skull, chest, abdomen, pelvis, and lumbar spine. In each view, three dosimeters were placed on the phantom body to measure primary dose. Three others were also placed on pubic symphysis to measure scattered dose.

In digital and analog techniques, the difference in primary doses was significant for limbs, unlike large organs (P=0.00). However, scattered dose to the pelvis was not significantly different (P=0.7417). Comparison of standard digital and clinically used field sizes showed significant differences in the scattered dose received by pelvis (P=0.014), while the primary dose differences were not significant (P=0.468).

Inadequate radiation protection, especially the use of an improper radiation field size and misuse of digital system capabilities, can result in increased patient dosage.