RADIATION DOSE IN WHOLE BRAIN COMPUTED TOMOGRAPHY IN COMPREHENSIVE STROKE IMAGING USING AXIAL VOLUMETRIC 320-DETECTOR CT

Abstract

The 320- detector row CT scanner enables a larger z-coverage (16 cm), competently entire whole brain imaging to be acquired. Dynamic series of CT Angiography, CT Venography and CT Perfusion in single exam after contrast medium injected with intravenously at a very rapid acquisition time increase the effectiveness of stroke’s patient management. At Advanced Diagnostic Imaging Center (AIMC), Ramathibodi Hospital, the patients have been serviced on the diagnostic in comprehensive stroke imaging by using axial volume mode which produce relatively high patient dose. The purpose of the study is to determine the radiation dose in whole brain Computed Tomography in comprehensive stroke imaging using Axial Volumetric 320-detector MDCT. The patient data is collected on scan parameters and radiation dose for CT Perfusion of the brain examination in comprehensive stroke imaging using the combo protocol in axial volume mode. The effective dose, E, is determined and compared with others. 21 patients of 11 male and 10 female, age range, 6-77 years; mean age, 45.4 years were studied. Range of cumulative radiation dose for CTDIvol, DLP and E were 142.9-313.4 mGy, 2286.6-5014.2 mGy.cm and 4.80-10.5 mSv respectively. The cumulative dose, average dose, and average dose per volume scan of CTDIvol, DLP and E were 200.5, 40.8 and 10.7 mGy; 3206.8, 652.6 and 171.3 mGy.cm and 6.7, 1.4, and 0.4 mSv consecutively. In conclusion, the radiation dose in whole brain Computed Tomography in comprehensive stroke imaging using Axial Volumetric 320-detector MDCT in this study is high due to large z-coverage, high tube current and large number of total volume scans. The data had been compared with DRLs and other studies for the setup of the dose reduction protocols at various patient age and size in future study. Although the high radiation dose is one of the main concerns, the advantage can eliminate the brain coverage limitation, reduce volume of contrast media and decrease the acquisition time. Besides, the first and also last volume can be used as with and without contrast enhancement head CT.