Joseph H Pilates was 11 when X-rays were discovered by the Nobel Prize winner; Wilhelm Conrad Röntgen in Nov 1895. Apparently, a week after Wilhelm’s discovery, he took an x-ray photograph of his wife’s hand which clearly revealed her wedding ring and her bones.
Since then, technology has managed to reduce the amount of radiation needed to take x-rays by a factor of 1500ish. So nowadays the amount of radiation used during a bone density scan is typically less than 2 days’ exposure to natural background radiation (NBR).
By comparison, a chest X-ray according to the NHS uses the equivalent of about 3 days’ exposure to NBR, and a flight to North America is equivalent to approximately a week’s exposure.
