Abstract
The purpose of the study was to (1) estimate the amount of underestimation of radiation dose using conventional CT dose index theory; (2) to implement the methodology of wide beam CT dosimetry suggested by report of AAPM task group 111 on a 320-detector row CT scanner. The derived values of equilibrium dose, equilibrium dose-pitch product, and equilibrium dose constant and related dose indexes using a thimble ionization chamber and 600 mm length cylindrical phantom were provided as reference tables for users who has the same CT scanner. (3) to assess the radiation dose distribution of clinical CT examinations with latest CT dose and image quality optimization techniques which included automatic tube current modulation (ATCM) techniques, adaptive iterative dose reduction 3D (AIDR3D), and dynamic wide volume scan mode. The database of our study can be an reference for improving the radiation dose measurement for wide collimation width computed tomography.