Answer to Question #3063 Submitted to "Ask the Experts"

Q

Thank you for this wonderful site and for answering my question. I went into the hospital to have my gallbladder removed. It was full of stones. I went in, they withdrew blood, and I was immediately sent to the radiology department in the hospital to get a radionuclide Tc-99m scan. I was injected with 6.2 millicuries. The next day, as I was being prepared for the operation to remove my gallbladder, they said they could not touch me because I was pregnant. I went to my gynecologist, and he said he was concerned about the radionuclide scan given, but he said it is an all-or-nothing type of situation. Either the body will automatically have a miscarriage, or everything should be fine. I am not happy with that answer. I need to know what danger the fetus is in. I read all of your postings but they all say they were not pregnant while having this procedure done, and I was and am five weeks pregnant. Please help!!!!!!!!

A

Let's look at some doses and then discuss fetal possible biological effects of those doses. According to Wagner, et al. (Exposure of the Pregnant Patient to Diagnostic Radiations, Medical Physics Publishing, Madison, WI, 1997), doses to the fetus from various Tc-99m scans vary from 0.02 to 0.03 rad per millicurie (rad is a unit of radiation dose). You indicated you were given 6.2 mCi which means the fetus received between 0.12 and 0.18 rad of radiation dose.

According to Dr. Wagner's book, there should be no concern about radiation exposure below 15 rad. Additionally, the National Council on Radiation Protection and Measurements has stated that the risk of abnormality is considered negligible at 5 rad or less. Your fetus received far below that exposure. So even if it occurred during a sensitive period there sould be no concern about birth defects.

You indicated you are at week five of the pregnancy so you are beyond the stage for the "all or none" effect which occurs up to about day eight post conception and with radiation doses many times higher than what you received.

Kelly Classic
Certified Medical Health Physicist