Investigating the Effect of Different Metal Sheets on Reducing Radiation Behind Intraoral Digital Phosphor Plates During Intraoral Radiography using Gray Value

Abstract

Purpose: To assess the efficacy of metal sheets with different thicknesses on reducing the radiation behind the photostimulable phosphor plate (PSP) during intraoral periapical examinations. Materials and Methods: In this study, a phantom head was used to investigate the effect of using metal sheets of aluminum, stainless steel, and copper with three thicknesses of 0.5, 0.75 and 1mm on reducing the radiation behind PSP. Images were acquired at 66 kVp 8 mA, and 0.16 s using the long-cone paralleling technique. The images were saved and exported to DICOM format without any post-processing. Then, they were transferred to an image processing software (Mimics, Materialize, Leuven, Belgium), and their mean gray values (MGV) were determined. The acquired data were statically analyzed for accessing the significant difference in groups means using ANOVA, and the means of groups were compared using Tukey's test procedure. Results: The MGV of the second PSP differed significantly from those PSPs slotted with various metals (p<0.001). The MGV for lead and stainless steel at 0.5 mm thickness was insignificant (p = 0.852), but differed significantly from other metals. The MGV for PSPs with 0.75 mm stainless steel and 1 mm copper slots were varied significantly from those of all other PSP and metals. The 1 mm copper group was significantly different from all other groups (p<0.001). Conclusion: Using the mean gray value of the PSP, the use of various metal sheets of different thicknesses could effectively reduce the radiation behind the PSPs during periapical radiographs.