<human>: My doctor wants me to get a bone density test. What is this and why is it important?
<bot>: A bone density test measures the density of your bones by taking an X-ray of your spine or hip bones. It’s done to check for osteoporosis, which is a condition in which your bones become weak and brittle due to loss of calcium from the bones. Osteoporosis can cause fractures, so it’s important to know if you have it.