Answer to Question #10773 Submitted to "Ask the Experts"

Category: Nuclear Medicine Patient Issues — Diagnostic Nuclear Medicine

The following question was answered by an expert in the appropriate field:


I had an injection of 969 MBq of 99mTc (technetium-99m). Then the technician sent me home and I had to go back to the clinic four hours later for a bone scan. Immediately after I had the injection I went home and stayed there for about an hour and 15 minutes. I have a 12-month-old boy and I kissed and hugged him during that time. I wasn't told not to do it. They said I could have a normal routine with no special precautions. They didn't ask me if I had children or not. Now I am researching online and everywhere I look, it says to avoid contact with children in cases where radioactive material has been administered.

Did I expose my 12-month-old son to enough radiation to cause any health problems for him? Would this exposure increase his risks in developing cancer?


I understand your concern for your son. It is also difficult to sort through Internet search results and find the best answer. My first hope is that you were able to talk to your doctor and get your questions answered. 99mTc, which is used in millions of medical imaging procedures every year, is considered the "work horse" in nuclear medicine. It's used this often because of its safety and effectiveness as a diagnostic tool. The Nuclear Regulatory Commission creates regulations and guidance for those licensed to use medical radioactive materials to ensure the safety of patients, exposed members of the public, and occupational workers such as technicians. For 99mTc patient instructions are not required until more than 5,550 MBq is injected.

Now, let's look at the radiation your son might have received. Assuming your son was within arm's reach of you for the whole 1.5 hours, your son might have received radiation equivalent to three days of natural background radiation. Comparing his exposure to natural radiation is based on the idea that living on earth we receive continuous amounts of radiation daily due to natural radiation from the soil, sun, and other natural sources.

Natural radiation exposure is not constant, so, if you go on a ski weekend in the mountains or hop on a plane flight, the natural radiation exposure is higher. Those living in Denver receive twice the natural radiation as those living at sea level. Therefore there is a range of natural background that can add many more days' worth to our existing typical exposure. With this in mind, your son's exposure to you during this time is well within normal background exposure fluctuations. There will be no direct health problems from this. The cancer risk is too low to be of concern and possibly there is no risk at this low dose.

I hope this response eases your mind that your son received no harmful radiation exposure.

Dawn Banghart, CHP
Sr. Health Physicist/Alternate Radiation Safety Officer

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 28 August 2013. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.