Development of a head CT dose index (CTDI) phantom based on polyester resin and methyl ethyl ketone peroxide (MEKP): a preliminary study

摘要

This paper aims to develop phantoms for measurement of computed tomography dose index (CTDI) based on a polyester resin mixed with methyl ethyl ketone peroxide (MEKP) as catalyst. CT number and CTDI values of the polyester resin phantoms were compared with a standard polymethyl methacrylate (PMMA) phantom as reference. The percentage of MEKP was varied from 0.3 to 0.6 wt%. The polyester resin phantoms had diameter of 160 mm, length of 150 mm and five cylindrical holes with diameter of 13.5 mm. One hole was positioned at the centre of the phantom and the other four near its periphery, 10 mm from the edge. The results show that the CT number of the polyester resin phantom was about 1%-9% higher than that of the standard PMMA phantom. Among the polyester resin phantoms, the one with 0.3 wt% MEKP is closest to the standard PMMA phantom in terms of CT number. In addition, the difference in weighted CTDI value between the 0.3 wt% polyester resin phantom and the PMMA is less than 5%. Thus, the 0.3 wt% polyester resin is potentially used as an alternative to the standard PMMA, with the advantage of a lower cost.