Bitewing radiography dosimetry of the PORTRAY stationary-intraoral tomosynthesis imaging system

Abstract

This study measured effective (E) and equivalent doses from adult and child 3-dimensional (3D) and 2D posterior bitewing (PBW) examinations using the PORTRAY stationary-intraoral tomosynthesis radiography system. Adult and child phantoms and optically stimulated luminescent dosimeters were used to measure doses for adult-4 and child-2 projection PBW examinations acquired without (W/O) and with (W) a direct digital sensor in the beam path. Child doses without and with thyroid shielding were measured. Three-dimensional examination E values (μSv) W/O and W were 16.7 and 7.3 for adult, 9.2 and 3.5 for child, and 8.7 and 3.0 with thyroid shielding, respectively. Two-dimensional examination E values W/O and W were 4.3 and 1.5 for adult, 2.1 and 0.6 for child, and 2.0 and 0.5 with shielding, respectively. Sensor presence reduced E for all adult and child examinations (P=.0001). Child E was reduced compared with adult E for both sensor conditions in 3D (P < .0001) and 2D (P ≤ .0043) imaging. Adult and child 3D W/O and W equivalent thyroid doses did not differ (P ≥ .9996). However, child 2D W/O and W doses were lower (P ≤ .0002). Shielding produced no reduction (P ≥ .1128) for either 3D condition or 2D with the sensor (P=.6615) but reduced child 2D dose without the sensor. Inclusion of a sensor yielded significant reductions in adult and child E. Sensor presence impacted thyroid dose reduction more than shielding.