Radiation Doses Associated With Cardiac Computed Tomography Angiography—Reply

In Reply: We agree with Dr Price that reliable information on radiation dose estimates in routine clinical practice is not readily available. The reasons for this include evolving dosimetry concepts and understanding of radiation biology and rapid turnover in medical imaging technologies. A recent catalog of effective dose estimates in radiology and diagnostic nuclear medicine¹ acknowledges these methodological difficulties yet provides a useful overview. However, it is perhaps more important for individual clinicians to learn the concept of performing the right imaging test for the right patient than to know the dose estimates for the latest generation of imaging equipment and protocols. This concept entails judicious consideration of the potential risks and benefits of performing a radiological diagnostic examination in each patient's individual situation rather than reflexively ordering tests to address remote diagnostic possibilities or even medicolegal concerns. A recent report from the National Council on Radiation Protection and Measurements² shows that, although the cumulative and per-capita medical radiation dose of the general US population has increased greatly over the last 2 decades, more than 80% of the cumulative radiation dose from CT was delivered in the hospital setting and to older and seriously ill patients.