Accuracy of IndoseCT for Measuring Effective Diameter from axial CT Images

Abstract

We investigated the accuracy of automatic measurements of the effective diameter (Deff) using IndoseCT software with axial computed tomography (CT) images of polyester-resin (PESR) phantoms of various diameters. The phantoms used PESR as the base material mixed with Methyl Ethyl Ketone Peroxide (MEKP) as the catalyst. The phantom diameters were 8, 16, 24, and 32 cm. The phantoms were scanned with a CT scanner from edge-to-edge position with field of views (FOVs) of 30, 35, 40, 45, and 50 cm. The Deff was measured from all slices along the z-axis. It was found that the automatic Deff measurements were very accurate. The Deff values were different by less than 0.02 cm for all diameters and all FOVs used. The maximum difference was obtained a ta diameter of 16 cm and FOV of 35 cm. We found that the precision of Deff measurements along the z-axis was very good with a maximum standard deviation of 0.01 cm. The relationships between phantom diameter and measured Deff for all FOVs had p-values < 0.001 and r2 = 1.000. Therefore, the IndoseCT is able to accurately and precisely measure Deff to facilitate estimating the patient dose in the SSDE metric.