High accuracy measurements by consecutive readings of OSL dosimeter

The optically stimulated luminescence（OSL）dosimeter is a one of the useful detectors to measure exposed dose, and the information of dose is absolutely imperative to analyze the medical images. NanoDot dosimeter is a small‐type OSL dosimeter, 10mm×10mm×2mm, commercialized by Landauer, Inc. This dosimeter can be read by a microStar, in which weak LED light is exposed to the detector and then emitted luminescence is detected. Because the LED light is enough weak, the dosimeter can be read repeatedly. In this paper, we proposed the high accuracy measurements by consecutive readings. In order to verify our procedure, we used the diagnostic X‐ray equipment. Our experiments were carried out in the following conditions in which a minimum absorbed dose is assumed to be about 0.05 mGy or less: tube voltage of 80kV, tube current‐time product of 0.5mAs to 500mAs, and X‐ray source to detector distance of 1m. The dosimeters are read consecutive 100times, and then based on these data we discuss about the relationship between the measurement accuracy and repeated times. Then we concluded that the dosimeter should be read about 10times or less to reduce the error to a few percentages. Our procedure using nanoDot is available to estimate the absorbed dose in the clinical site.