Lumbar spine radiography: lower organ dose with the use of PA projection

The purpose of the research was to determine the effect of the posteroanterior (PA) patient position in lumbar spine imaging on effective dose and the absorbed organ dose. The study was performed on 100 patients that were referred to the lumbar spine radiography that were divided into two equal groups of 50. Body Mass Index, Dose AREA Product (DAP), exposure index (EXI), tube time-current (mAs), image field size and the source-patient distance were acquired for each patient. The entrance surface dose (ESD), the effective dose and the absorbed organ doses were calculated. There was no statistically significant difference in the BMI and EXI between the AP and PA projection. The results showed a significant reduction of ESD by 33% and the effective dose by 53% when the PA projection was used. Furthermore, there was a 64% average reduction of the absorbed organ doses to the selected organs. (authors)