This procedure measures the patient's bone mineral density (BMD). BMD will tell your doctor whether your bones are brittle or not. Brittle bones mean you will be more susceptible to fractures when you have a fall. For more information on brittle bones or osteoporosis, refer to Osteoporosis, Dept of Endocrinology. In 1963, the first machine to measure bone density used radionuclides. They have since been replaced by machines using X-rays.