After some recent medical radiation exposure horror stories, the US government is finally talking about mandating the tracking of medical exposure levels. The case in question resulted from a woman seeing 5 doctors, all of which were ordering CT's. Her bone marrow dose was about 25 rem, that's 25,000 mr, or 5 times the max. permissible yearly dose for radiation workers: This is where they send you home, or give you a desk job after exceeding 5 rem in any year. The current estimate is that in every year there are 10,000 extra cases of cancer and leukaemia etc. in the United States alone, from unnecessary from medical exposure.
The studies on unnecessary patient exposure have shown that 80% of all of this unnecessary patient exposure is from two general exam groups: Abdominal CT's or cat scans, and T-L spine X-rays. If you fall off the roof, or if you suffer some severe trauma, a complete 5 view l-spine x-ray series is still the best diagnostic tool for the job, and indicated. The benefit vs risk ratio is still very favourable in this case. If on the other hand your back just hurts, then you need an MRI, and not an X-ray series. X-rays will show nothing except normal wear and tear, or arthritis. The MRI to boot involves zero radiation exposure, and it shows all of the soft tissues in addition to the bone. Soft tissues are where 90% of the problems are, in non trauma cases. One problem is, that we have a whole generation of MD's, and providers, which went to med. school in the pre-MRI era, and getting many of them to change their diagnostic tools, in order to keep up, has been a real struggle. It is like the old saying of teaching an old dog new tricks. Now throw in the lawyers, and you can double the number of diagnostic exams ordered just for legal reasons. As far as non-MD's like Chiropractors go, I will present one statistic from the boys at the state dept of noise and radiation safety in my state, and let you make up your own mind: When they go inspect, most violations result in no fine, and only a simple written letter of mandated corrective actions from the state. The last year when I asked them, they had issued only 9 actual fines for what were deemed very serious violations. The breakdown was 8 chiropractors, and one dentist.
I do not want to make people paranoid, but in the present climate, it is up to you to track your exposure, and they will give you the numbers if you only just ask. My reason for posting this is because we tend to be so careful at home in the lab, with normally miniscule amounts of exposure, yet we sometimes do not even bother to ask when we have test, after test, ordered by the doctor, or other provider. In a nutshell, extremity X-rays like hands, feet, shoulders, knees, etc. are very low exposure, and the lead apron is not so much for physics, but more for psychological reasons due to an under educated public, I have had patients ask me if we use "uranium" to do their chest X-ray, seriously. Chest X-rays are so miniscule in exposure, that they can be done on a pregnant woman safely, for the average size male you will get about 50-80 mr. The exams to watch out for are: Abdominal CT's, and lower back X-rays, and fluoroscopy. Angio heart cath procedures can be very high also, in these cases a single exam can be between 1.5 - 5 rem, or 1,500-5000mr, which is very substantial, when compared to a chest at about 50-80mr. The new unit of measurement is sv, so to convert: one centi sv = about 1 rem, or 1000mr.
Also ask about the operating room, they can fluoroscope you there, and you will not know a thing, since you are under. This can be up to 5,000-10,000 mr in some complex hip operations. Last year a few patients in the US actually had X-ray skin burns, from fluoro, and angio procedures, these are the ones that were reported, who knows how many others occurred. I was also surprised to learn that most nuclear medicine procedures where you get injected with a radioactive isotope in the several mCi level range on average, are not that bad, maybe due to the short half lives of the isotopes used .So do not be afraid, but just ask, if you are concerned. The moral is don't be shy, and make sure the answer is a number, and not an analogy : )