Introduction
Osteoporosis is a systemic disorder of the skeleton that is characterised by a reduction in bone mass and deterioration of bone micro-architecture. Although the condition affects a higher percentage of women, it is now known that substantial bone loss occurs with advancing age in men. The importance of osteoporosis lies in the fact that osteoporotic bones are more fragile and susceptible to fracture than normal bones. Osteoporotic fractures usually occur in skeletal sites that are rich in trabecular bone. The most common low-energy fractures are those of the vertebrae, wrist and hip. Studies show that the number of osteoporotic fractures is increasing worldwide mainly due to the extension of the average lifespan. The total number of hip fractures in the European Union is estimated to increase from 414,000 in 2000 to 972,000 in 2050 [1].
A wide variety of methods for the non-invasive assessment of skeletal status have been developed, most of which are based on the use of ionising radiation. Although the ionising radiation doses incurred during X-ray-based imaging techniques used in osteoporosis are relatively low, the use of radiological methods for the assessment of bone status has increased rapidly, and therefore merits attention with regard to radiation protection. The objective of this article was to briefly review the current X-ray methods used for the assessment of the skeleton, provide data that document the magnitude of radiation exposure and discuss radiation safety issues.