MEASUREMENT OF SCATTER FRACTIONS IN ERECT POSTEROANTERIOR AND LATERALCHEST RADIOGRAPHY

Scatter fractions (SFs) measured in patients undergoing erect posteroa nterior (PA) and lateral chest radiography with a 12:1 antiscatter gri d are reported. Modifications to the posterior beam-stop (PBS) techniq ue allowed measurement of scatter in these patients, without altering the diagnostic image and without additional radiation exposure. The SF measurements are reported by anatomic location on 42 clinical chest i mages. Average SF values ranged from 0.27 to 0.90 on lateral radiograp hs and from 0.27 to 0.68 on PA radiographs. Scatter measurements with the 12:1 grid were found to be greater than estimates from previous PA chest phantom experiments. To the authors' knowledge, they were the f irst to measure radiation scatter with the PBS technique in patients u ndergoing PA and lateral chest radiography with the antiscatter grid.