Ambient dose during intraoral radiography with current techniques: Part 1 conversion factor for scattered radiation using a rectangular collimator

Abstract

The conversion factor established for scattered ambient radiation was 0.05 µSv per mAs at 1 meter. This factor is 3-fold lower than the conversion factors reported previously.

Ambient dose during intra-oral radiography with current techniques: Part 2 quantifying the remnant beam - an in vivo study

“…The frequencies of exposure types were found to be different for children as well. 3 The proportion of intra-oral exposures of adults and children that are bitewing exposures in our institution are approximately 50% and close to 80%, respectively. This difference should be taken into account for determining the ambient radiation dose in offices that predominantly treat children.…”

“…Leakage radiation and scattered radiation can be estimated based on the manufacturer's specifications and a conversion factor for the scattered radiation, which was described in a previous report from our research group. 3 This present study obtained a transmission factor for the average patient, to be used to assess the dose from the remnant beam. With a known workload it is possible to make a safe estimation for the environmental dose.…”

“…Bitewing exposures are the most frequent exposures, with an almost 50% contribution to the total workload, as shown in our previous study. 3 Therefore the highest dose, and thus the most critical area for the risk evaluation performed by the RPE will be found in the area of the remnant beam of the left and right bitewing exposures.…”

“…As commented upon in part 1 of this series, the doses reported in their study were unrealistically high, being higher than expected from values obtained by the inverse square law. 3 Intra-oral radiography performed with the patient in a supine position results in a remnant beam projecting in different directions. Kuroyanagi et al studied the dose around a supine phantom but did not measure the dose in the area of the remnant beam.…”

“…The description of how the conversion factor was derived for converting the workload of dental X-ray devices to the ambient scattered radiation dose was presented in part 1 of this series of articles. 3 The amount of leakage radiation is specified by the manufacturer of an X-ray device and should be checked upon installation. It can be measured and is easily quantified in relation to the workload of the X-ray device.…”