Although the use of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures, lack of proper optimized protocols could be an additional source of increased dose in developing countries. The aims of this study is to determine the variations of doses to patients undergoing CT scan using four different CT scanners with different CT scanning protocols for the purposes of optimizations and to compare with other available international standard and guidelines. The method involve the use of patients scanning protocol and image data to estimate patient body regional doses with four common CT examinations. These were obtained from four CT units/hospitals in Ghana. A large variation of mean body regional doses among different CT scanners were observed for similar CT examinations. These variations largely originated from different CT scanning protocols used, with different CT scanner type. The measured CTDIVOL with GE Lightspeed VCT 64 scanner for head, hest, abdomen and pelvis were 7.7mGy, 12.5 mGy, 14.4 mGy, and 12.9 mGy, respectively. Similarly, Philip 16 scanner recorded 6.6mGy, 13.1mGy, 14.8mGy, and 14.5mGy respectively. Furthermore, Siemen Emotion 16 scanner recorded 5.9mGy, 14.2mGy, 16.8mGy and 12.0mGy respectively. While, Toshiba Aquilion one scanner had CTDIVOL value which varies as 7.2mGy, 13.4mGy, 15.2mGy and 13.5mGy respectively. In conclusion the values were mostly lower than the values of CTDI and DLP as reported in literature for EC, IAEA, ICRP, ACR and AAPM Guidelines.
CT Angiography Source Images with Modern Multisection CT Scanners: Delay Time from Contrast Injection to Imaging Determines Correlation with Infarct Core