Comparison of pediatric lens dose measurements between axial and helical scan modes using a 160-mm volume computed tomography scanners.

Abstract

Purpose To compare the scatter dose for lenses between a helical scan with a 40-mm detector width and an axial scan with a 160-mm detector width when using different computed tomography (CT) scanners in pediatric chest CT examinations. Methods Two CT devices, Revolution CT and Aquilion ONE, and three pediatric anthropomorphic phantoms were used, with optically stimulated luminescence dosimeters (OSLDs) placed on the left and right lenses. The measured scatter dose values of the OSLD were compared between the helical scan with the 40-mm detector width and axial scan with the 160-mm detector width in the different phantoms during the pediatric chest CT examinations. Results With the Revolution CT, no significant differences in the scatter doses between the 40-mm detector width for the helical scan and 160-mm detector width for the axial scan in the newborn and 1-year-old phantoms were observed. However, the lens scatter dose for the helical scan with the 40-mm detector width was approximately 20% higher than that for the axial scan with the 160-mm detector width in the 5-year-old phantom (p < 0.01). With the Aquilion ONE, the lenses scatter dose for the 40-mm detector width for the helical scan was approximately 70%, 40%, and 30% higher in newborn, 1-year-old, and 5-year-old phantoms, respectively, than that for the 160-mm detector width for the axial scan (p < 0.01). Conclusions The lenses scatter doses for the 40-mm detector width for the helical scan was higher in all phantoms than that for the 160-mm detector width for the axial scan.