Radiation dosimetry performance appraisal of the optimal concentration of nitro blue tetrazolium dye in PVA composite film at low X-ray doses.

Purpose: Due to the extensive use of radiation in various fields, such as food safety, sterilizing surgical materials, and medical diagnostics, it is essential to minimize radiation exposure for both patients and healthcare professionals, even at low doses. To meet this requirement, a composite film has been developed using polyvinyl alcohol (PVA) polymer and nitro blue tetrazolium (NBT) dye to measure low radiation doses effectively.

Methods: Various concentrations of NBT dye (ranging from 0.75 to 15 g/L) were tested to determine the optimal concentration for maximum efficiency. The films were exposed to low doses of X-rays ranging from 20 to 100 mGy.

Results: The PVA/NBT films exhibited good stability for 30 days after irradiation when stored in darkness. UV-visible absorption spectra showed a peak at 376 nm, shifting to 384 nm after exposure to X-rays. Furthermore, the response curve based on UV-Vis absorptions revealed a linear increase in absorbance with increased radiation doses up to 60 mGy (R = 0.99). XRD analysis indicated significant structural rearrangements in films with higher NBT concentrations and radiation doses. Specifically, X-ray irradiation caused two distinct peaks to shift from 2θ = 20.12° and 40.18° to 2θ = 19.66° and 41.24°. SEM analysis revealed that exposure to increased radiation doses resulted in significant morphological changes in PVA/NBT films, resembling torn tree trunks, especially with higher NBT concentrations. The preparation method was validated by XRF analysis, and the solubility of the NBT salt was excellent, with an R value of 0.9656. Results from Spectro colorimetric studies indicated that different CIEL∗a∗b∗ coordinates, as well as the total color difference (ΔE∗) and color strength (K/S), were directly proportional to the applied dose intensity, correlating with increasing NBT concentration.

Conclusion: The PVA/NBT dosimeter containing 10 g/L of NBT shows promising potential as an effective alternative for the prompt and accurate detection of low X-ray doses in diagnostic radiology.