Dosimetric Evaluation of Multislice CT Using Anthropomorphic Head Phantom

The most general form to report dose in Multislice CT is the CTDI andDLP which are computed for several slices. The goal of the current study was toestimate actual doses and dose distribution during CT examinations in a head andneck anthropomorphic phantom. After construction of the head and neck phantom using natural bone andparaffin wax with NaCl as impurity, several places were considered in differentsites to fill with badges of Gafchromic film. These places include brain, Parotid,Thyroid and Lens of eye. Phantom was scanned at CT Angio and Spiral protocolswith 10 and 256 slice scanners. Our findings showed that in 10 slice scanner, selected organ doses werein the range of 0.09-23.1 mSv while in the 256 slice scanner, it was in the range of0.14-18.01 mSv. The CT Angio protocol has a higher organ dose at all. In CT Angio protocol, organ dose (except for the lens of eye) is lowerin 10 slice compared to 256 slice CT; the brain dose in both protocols has no differencestatistically. In the spiral protocol, the dose in 256 slice scanner is lowerthan the 10 slice scanner which might be due to higher number of detector arraysin 256 slice scanner.Thyroid dose is mainly due to scattered radiation and becauseof strict beam collimation;it has a small value in all protocols.