Comparison of Central, Peripheral and Weighted Size Specific Dose in CT to Dose Results from IndoseCT Software

Abstract

The purpose of this study was to calculate the average dose of a phantom with a diameter of 16 and 32 cm, as well as the dose distribution in the center and periphery. The results were then compared to those from the IndoseCT software. In this study, a standard PMMA phantom with a diameter variation of 16 and 32 cm was used. The phantom was scanned using fixed parameters, namely 120 kVp voltage, 100 mAs time current, 10 mm collimation width, 100 mm scan length, and 1 s tube rotation. This research was conducted at the Indriati Solo Baru Hospital using the GE CT scanner type Revolution EVO 64/128 slice. The results of this study show that for a 16 cm phantom diameter at the center position the difference in detector measurements with IndoseCT is 1.34% at the phantom edge position is 4.38% and the weighted dose is 2.59 %, while for a 32 cm phantom diameter, the difference is 8.1 percent, at the edge of the phantom it is 1.26 %, and the weighted dose is 0.62 %. Based on the results obtained from IndoseCT, it showed an insignificant difference with the measurement of radiation dose using a phantom. Overall, the difference in percentage is ±10% while the difference in percentage that is still acceptable is ±20%. Keywords: Pencil ion chamber, PMMA phantom, dose distribution, size-specific dose estimate (SSDE), central dose, peripheral dose, weighted dose, IndoseCT 20.b..