Comparative dosimetry of an epoxy resin pediatric head phantom and PMMA phantom for CT imaging

Abstract

A pediatric head phantom was created using epoxy resin to evaluate the amount of radiation exposure in computed tomography (CT) scans. The phantom's size resembled that of a child's head, with a diameter of 10 cm and a length of 15 cm. A comparative analysis was conducted to examine and compare the atomic composition, effective atomic number, electron density, and mass density of the epoxy resin material with those of polymethyl methacrylate (PMMA). To measure the radiation dose received by the phantom, a 100 mm pencil ion chamber was used at both the center and periphery. The weighted CT dose index (CTDIw) and volumetric CT dose index (CTDIvol) were determined for various tube potentials, keeping the current-time product constant. A standard calibrated phantom was also used for a comparable analysis. The results indicated that the physical properties of the epoxy resin material were similar to PMMA, and the phantom demonstrated equivalent dosimetric performance to the PMMA phantom across all tube voltages. Lastly, the CTDIvol values obtained from the fabricated and standard phantoms were compared with the corresponding values displayed on the CT console. The differences fell within the limits set by the American Association of Physicists in Medicine (AAPM). These findings demonstrate that the cost-effective pediatric phantom offers a practical and economical approach to assessing the radiation dose in CT scans for children, while exhibiting dosimetric properties comparable to those of commercially available phantoms.