Answer to Question #10988 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
I have reviewed some questions and answers on this site concerning myoview stress tests and I am concerned about the dosage I was given for this test being a young female, age 42.
I received 474 MBq of 99mTc at rest and 1,406 MBq during stress. This dose is given to all patients according to the nuclear medicine technologist. This seems kind of high compared to other dosages for this procedure on your site. Does my risk of cancer/leukemia increase with single dosages over 10 mSv? Is this test more risky since the radiation is injected into the blood stream versus a CT (computerized tomography) scan of the arteries?
Through the years I have been exposed to approximately 45 mSv of radiation from diagnostic procedures; not adding this myoview test to the total. I figured this myoview test was a miniscule amount of radiation seeing as it is injected into the blood stream.
I asked the nuclear technologist the amount of radiation exposure and he replied "it is no different than background radiation" so after the test I decided to do some investigating. I have read that artificial ionizing radiation is a major cause of leukemia. What is my risk of leukemia/cancer from this test added to the 45 mSv of other diagnostic tests through the years? Does artificial ionizing radiation have the same effect on cells as natural background radiation? Can this single dose have a more dramatic effect since it is four to five times higher than what I would receive in one year?
I am glad that you have found the health physics website and are using it to ask good questions. The information provided on the website is intended for ballpark radiation dose estimates, but as you can imagine, each individual is unique. Have you discussed your concerns with your doctor?
Your doctor can provide specifics for the studies as they relate to you. The estimated exposure from the tests you described equals about 4.5 years of natural background radiation (exposure from natural radiation in the ground, sun, and water). This exposure was necessary to obtain the medical information desired in your case.
Radiation exposures from airplane trips, CT scans, or myoview studies are all considered similar and are minimal as far as risk goes. The bigger question to ask is what might be the risk for not having the medical studies? Ask your doctor about procedures that involve
radiation. Ask, how will this exam improve my care? Are there alternative imaging exams that don't use radiation?
Dawn Banghart, CHP