CT radiation dose optimization and reduction for routine head, chest and abdominal CT examination

Abstract

The purpose of this study is to find an optimization approach to minimize the absorbed dose to adult patients undergoing CT examination, while maintain the diagnostic image quality. A single detector CT was considered, to represent typical practice in King Hamad University Hospital. We included 626 patients in this study and investigated radiation dose for three anatomical regions, head, chest and abdomen and pelvis. For each type of CT examination, two groups of patients were considered. 383 patients in Group I: were imaged according to the protocols set by the manufacturer. Group II: 243 patients were imaged according to the protocols set by our team after optimization. We were able to adjust the adjustable factors such as noise index, scan time, pitch, rotation time and slice thickness. For each examination the weighted volume CT dose index (CTDIvol) and dose length product (DLP) were recorded and noise is measured. Each study was also reviewed for image quality. Measured (CTDIvol, DLP) were compared to international reference levels. For Group I, the CTDIvol and DLP values were higher than the reference levels. After Dose optimization the CTDIvol and DLP values were significantly reduced to have lower values than the reference levels. The results of our study showed that the CTDIvol and DLP values taken from images done using the protocols set by the Ct machine developers are higher than the reference levels which indicate that manufacturers are focusing their efforts toward improving image quality rather than the minimizing the dose that can be given to the patient.