Answer to Question #193 Submitted to "Ask the Experts"

Q

My son has a growth in his scrotum that is currently being evaluated. I was exposed to extensive x rays including tomagrams, IVP, abdominal, and other types before we discovered I was four months pregnant. Could the exposure of radiation be creating problems for him at this time?

A

Thank you for your question. The direct answer is no, it is not likely that your radiation exposure while pregnant is causing problems for your son. Let me explain. Here is some general information since I don’t know how much you know about radiation and exposure during pregnancy.

• Only x-ray procedures of the abdominal or pelvic area have potential to expose the fetus to measurable radiation (e.g., a properly performed chest x ray will not expose the fetus to radiation).
   
• The fetus receives about 30 percent of the radiation exposure entering the mother during abdominal or pelvic x rays; maternal abdominal tissue provides ‘shielding’ for the fetus.
   
• The sensitivity of the fetus to the radiation depends on what cells are active (e.g., what organs are forming), how much and the rate at which radiation is delivered, and the fetal age.
   
• There are no proven fetal biological effects from radiation doses below about 10 rad (rad is the unit used to describe radiation dose; 0.3 rad is about what each of us receives each year from radiation in our natural environment).

I don’t know how many x rays you underwent that might have exposed the fetus. I also don’t know the time frame but am assuming these x rays were performed during or around the time you were four months (16 weeks) pregnant. At 16 weeks, the fetus is much less sensitive to radiation because the body has already undergone major organ formation. By this time too, the genitals have formed so are not in an active state of development; therefore they are not very sensitive to radiation exposure and the potential for biological effects is greatly reduced. As for the dose the fetus might have received, two scientific agencies have estimated the average dose to the uterus to be 0.3 rad for a pelvis or abdominal x ray and 0.75 rad for an IVP (the IVP includes kidney tomograms and abdominal x rays). If you had an IVP and a few abdominal x rays, the dose to the uterus would approach 1.7 rad, well below radiation levels shown to cause fetal biological effects. Kelly Classic Certified Medical Health Physicist