Question: Dr. Hibberd, thank you for your excellent column. My question is this: I had a bone scan about a year ago to monitor a deteriorated disk in my back. The pain has flared up again and my doctor wants me to have another scan. But I’m afraid of all this radiation from the tests. Is it too soon to have another scan?

Dr. Hibberd’s answer:

Bone scans used to be frequently ordered, but with recent concerns over long-term effects of exposure have sharply reduced the frequency of bone-scan testing.

Do not confuse this with a bone density scan (or DEXA scan) that uses no radioactive isotope. Bone density scans expose you to 1/10th the radiation dose of a standard chest X-ray, and they are safe for tracking osteoporosis and evaluating spinal fracture treatment.

Bone scans are no longer being done for disc disease detection or diagnosis. They involve the use of a radioactive isotope that is excreted, and I see no reason to use this type of scan when other safer imaging techniques are readily available.

The advent of MRI studies have sharply cut back the need for bone scans, and unless you have metal in your body (and an MRI is then not advised, as the metal may heat up during the MRI imaging procedure), an MRI will often show more detail without the radiation exposure.

If a malignancy is involved, ask your doctor whether a PET scan may be more appropriate.