Assessing RadTriage Colorimetric Dosimeter Response to Low-Dose Gamma-Ray Exposure

Abstract

There is a need for instantly indicating, easy-to-read, and relatively inexpensive ionizing radiation casualty dosimeters for first responders and members of the general public. One such dosimeter is the RadTriageTM colorimetric dosimeter. Although colorimetric dosimetry has been studied over the past few decades, and widely applied in the medical field, there is a lack of research into understanding how well RadTriage colorimetric dosimeter cards quantify low doses of ionizing radiation (

We found an exponential dose response function to fit our RadTriage data with a chi-square value of 1.38 and a corresponding probability of fit value of P = 0.998. Our exponential fit shows a proportional, linear response at low doses that eventually plateaus at higher doses; this is consistent with the chemical basis of radiochromic dosimeters and with the results of prior research. In analyzing our results, we also found that the RadTriage cards responded with increased sensitivity, marked by a statistically significant differences, at lower dose rates and lower gamma energies. These results suggest that changes in certain exposure characteristics can impact the RadTriage dose response. The RadTriage dose response was also compared to the thermoluminescent detector response; in comparison, the thermoluminescent detectors had less response variation under different exposure characteristics. The results from this comparison suggest that both types of dosimeters, thermoluminescent and colorimetric, had strengths and weaknesses. RadTriage cards are able to be handed off rapidly without pre-testing, they allow for real-time indication of doses above a threshold, they are inexpensive, and they can be read visually and by commercially available digital scanners. However, our research shows that certain dose characteristics such as dose rate and photon energy impact the card’s response and would have to be considered in order to determine a comprehensive dose response function. Given the results of this thesis, it is most beneficial to have the two independent dosimeters coupled together, where the RadTriage cards would allow for real-time, visual dose determination and the thermoluminescent dosimeter would allow for a more robust dose determination post-exposure.