Answer to Question #2702 Submitted to "Ask the Experts"

Q

My wife was suffering from lower backache and recently she was examined by an expert. After the x ray she was diagnosed as suffering from sclerosis on both sides of the lower one-third sacroiliac joint. Joint margins are normal. Unknowingly, at the time of the x ray she was five weeks pregnant. At the same time the doctor advised an MRI (magnetic resonance imaging). Please advise: (1) Is it harmful to go ahead with the MRI? (2) Are sclerosis and cancer the same deadly killers? (3) Should the pregnancy be terminated for treatment of sclerosis? (4) Was the x ray harmful?

A

I'll take the questions one at a time. Is it harmful to go ahead with MRI? There are no known fetal biological effects of magnetic fields used for diagnostic MRI scans. Are sclerosis and cancer the same deadly killer? Sclerosis and cancer are not the same thing. What I wonder is whether you mean scoliosis—which is a condition of the bones, typically the spinal bones, and not sclerosis which is a disease that affects the brain and spinal cord. In any event, this is a question for you to ask your or another physician. I'm not qualified to answer. Should pregnancy be terminated for treatment of sclerosis? Again, this is not a decision for me to make. This needs to be decided with additional information you can obtain from your physician about the disease. Was the x ray harmful? You didn't say what type of x ray or how many were taken. I will assume one x ray was taken of the pelvic area, so the estimated fetal dose would be 0.2 rad according to a book by L.K. Wagner, et al., titled Exposure of the Pregnant Patient to Diagnostic Radiations (Medical Physics Publishing Madison, Wisconsin). The precise dose depends on the type of machine and techniques used as well as the size of the patient. According to recommendations in this book, there should be no concern below 15 rad. In addition, the National Council on Radiation Protection and Measurements issued a statement saying that the risk of abnormality is considered negligible at 5 rad or less and the risk of malformation is increased if the doses exceed 15 rad. They went on to say that exposure of the fetus to radiation arising from diagnostic procedures would rarely be cause for terminating pregnancy. I hope this information is useful in helping you make your decisions. Kelly Classic Certified Medical Health Physicist