Development of In-House Head Computed Tomography Dose Index Phantoms Based on Polyester-Resin Materials

Computed tomography dose index (CTDI) phantoms are used to optimize CT examinations in terms of image quality and the received dose. In this study, we aimed to develop cost-effective head CTDI phantoms from polyester-resin (PESR) materials as alternative phantoms. The PESR was mixed with methyl ethyl ketone peroxide (MEKP) as a catalyst. The ratios of MEKP to PESR were 1:150, 1:200, 1:250, and 1:300, respectively. The phantom dimensions were designed similar to the standard CTDI phantom, i.e., length of 15 cm and diameter of 16 cm with five holes (diameter, 1.31 cm). The CTDI measurements using the PESR-MEKP phantoms were compared with the CTDI measurements using the standard polymethyl methacrylate (PMMA) phantom. The results showed that the CTDI valuesof the PESR-MEKP phantoms were slightly higher (up to 6%) than the standard PMMA phantom. It was found that the CTDI measured by the PESR-MEKP phantom with a ratio of 1:300 had the least significant difference from the standard PMMA phantom; also, at this ratio, the phantom was the most homogeneous. The head CTDI phantoms based on PESR-MEKP materials were developed and evaluated in this study. It was found that the PR-MEKP phantom with a MEKP-to-PESR ratio of 1:300 was insignificantly different from the standard PMMA phantom. Also, the phantom was constructed easily at a more reasonable cost, compared to the standard phantom.