sed in an other recently published study (Hall et al., British Journal of Radiology 81, 362-378, 2008), the relevant organ doses during CT scans are in the range for which there is now direct credible epidemiological evidence of an excess risk of cancer, without the need to extrapolate risks from higher doses. However, even for high-dose radiological procedures, the risk to the individual patient is small, so that the benefit/risk balance is generally in the patients' favor. Concerns arise when CT examinations are used without a proven clinical rationale, when alternative modalities could be used with equal efficacy, or when CT scans are repeated unnecessarily. According to this study, it is assumed that about one-third of all CT performed in the US could be avoided using alternative diagnostic tools. According to Hall, "at this time, the benefit/risk balance for any of the commonly suggested CT screening techniques has yet to be established."