Radiation dose in computed tomography.

The emergence of CT scanning as a routine diagnostic and radiation therapy planning tool has improved patient care by increasing the anatomic detail and diagnostic information available to clinicians. An increase in patient demand, availability and reimbursement practices have contributed to a dramatic escalation in the number of scans performed each year, and the risk and clinical justification for many of these procedures now is under debate. This Directed Reading will review recent events and trends in CT imaging and patient radiation dose, dosimetry, the biological effects of ionizing radiation, the principles of radiation safety and strategies for managing patient dose.