Assessment of radiogenic risk from diagnostic X-ray examinations has several limitations. There is debate regarding whether low-level radiation provides a significantly increased risk of developing cancer. The biological effects of diagnostic radiation on humans have not been studied directly. Current information is based on studies of populations such as atomic bomb survivors, radiation workers and patients treated with radiation. Most individuals in these cohorts received effective doses that were much larger than the doses from diagnostic X-ray examinations. However, recent studies show a significant increase in cancer risk in a group of atomic bomb survivors who received doses of radiation comparable to those currently involved in diagnostic radiology [48, 59]. The potential risk to an individual associated with techniques used for the assessment of bone status is very small because radiation doses are low. Despite uncertainty about the true risks of exposure to radiation levels used in these techniques, radiation protection principles must be applied in everyday clinical practice.