A low-cost emergency dosimetry technique using radiophotoluminescence glass

Abstract Radiophotoluminescence (RPL) dosimeter of Ag-doped alkali-phosphate glass is widely used for personal and environmental monitoring. However, reading the RPL requires a large and expensive reading system, which makes it difficult to promptly assess accidental high-dose exposure in radiological emergencies. Therefore, in this study, we present a low-cost emergency dosimetry technique that uses an RPL glass, portable UV illuminator, and smartphone. Plate-type samples of commercially available RPL glass (FD-7) were irradiated with X-rays (160 kVp, 6.3 mA) at 0.5–10 Gy. The irradiated samples were stimulated using a portable UV illuminator (λ = 254 nm), and their RGB color images were captured using two types of smartphones (Galaxy S23 and Note 8) under changing camera settings of ISO sensitivity (ISO), white balance (WB), and shutter speed (SS). Among the RGB components, the red channel showed the strongest and most consistent dose responses for both smartphones, whereas the green and blue channels exhibited rapid saturation and poor dose discrimination. Optimized photographing conditions (ISO 800–1600, WB 9000–10000 K, SS 0.1 s) achieved high sensitivity and minimal background noise that enabled accurate measurements of RPL intensities. Reproducibility analysis showed less than 5% variation across three independent measurements. These results indicate the potential of this novel technique could be used effectively for emergency dosimetry following the occurrence of a radiological accident. Further investigations are necessary to establish standard protocols that can cover a variety of possible combinations of UV illuminators and smartphones.