For the most part, the recommendations and discussions set forth in the ICRP guidelines regarding the medical application of radiation to diagnose and treat human disease are reasonable and are not detrimental to patient care. The American College of Radiology (ACR) supports the concept of diagnostic reference levels described in section 254 of the ICRP recommendations. It is important to note that these are “reference levels” rather than absolute limits. Furthermore, we agree that the reference levels should be established by professional medical bodies, specific to a country or region and medically reviewed and revised as technology, utilization and practices change. In fact, the 2003 ACR Practice Guidelines for Diagnostic Reference Levels in Medical X-ray Imaging will be revised next year as a result of new CT dose data from the ACR CT Accreditation Program. Finally, any proposed changes to the ICRP recommendations and future US and state regulations should carefully consider any potential detrimental impact to patient care, including costs of patient care, before the recommendations are finalized.