Continuous monitoring of CT dose indexes at Dubai Hospital

Experience of continuous monitoring and control of patient doses in CT in Dubai Hospital over a period of approximately 4 years (January 2008 through August 2011) is presented.

Dose measurements-in particular, weighted and volumetric CT dose index, dose-length product (DLP), and estimated effective dose-were regularly monitored using head (16 cm diameter) and body (32 cm diameter) CT phantoms. Patient radiation dose indexes were manually recorded during 2008 for common CT examinations: head, chest, and abdomen and pelvis scans. In 2009-2011, these CT dose data were recorded within the radiology information system and the PACS. Dose reduction actions were taken while maintaining a watch on image quality. The effects of these factors were monitored through change in average DLP on a monthly basis and third quartile annually. Adapted diagnostic reference levels were used for comparison.

The reduction in adult dose indexes in 2010 as compared with 2008 was 52%, 16.4%, and 34.8% for head, chest, and abdomen and pelvis examinations, respectively. For the pediatric group, the reduction was 45.23%, 39.6%, and 43.34% for head, chest, and abdomen and pelvis examinations, respectively.

Substantial reduction in DLP for common examinations of adults and children is shown through a program of continuous monitoring and action. The results indicate the need to introduce local diagnostic reference levels to substitute for the adapted ones.