FAO the Prof

[BertiWooster]

Hi prof - i see your'e around here somewhere

I would appreciate your opinion on this question

http://www.theanswerb...l/Question998818.html

[theprof]

Thank you Bertiwooster. I'll try my best.

As Sqad said, the risk for all the procedures is extremely small and in my view, can be disregarded. If you were having numerous investigations along these lines as a result of the intervention of different medical specialists, it may be a cause for concern over the period of any one year.

However, it's very unlikely that this is the case for any individual patient as safeguards are built into the protocols that allow physicians to see your exposure to radiation over a given period. Further potential exposure is based upon these figures and I can assure you that if there is any uncertainty about the issue, the requesting physician will pull out of radiator exposure rather than risk the health of the patient.

[theprof]

"radiator" exposure? lol Try radiation exposure!

[237SJ]

They say that peoples`s day to day exposure to radiation is 2.2 (sieverts - am I right or is it a fraction of a sievert). What is the safe dose? My work website shows that I have 2.8 over the last year. I`m not sure if that is including the everyday exposure or in addition to so I would be interested to know the safe levels if anyone knows.

[BertiWooster]

Thanks for that
I was under the impression that these procedures used significantly higher doses of radiation , than compared to , for example, a back x-ray

[theprof]

It is true BertiWooster that CT Scans do use considerably more radiation than a standard x-ray but it into perspective. Radiation exposure in CT scanning varies depending upon the type of CT scan performed. For example, a simple head scan uses considerably less radiation than someone who is undergoing a CT virtual colonoscopy. Furthermore, x-rays themselves do not emit exactly the same dose of radiation from procedure to procedure.

As result of these issues, no one can say precisely that a patient has been irradiated x number of times more following a CT Scan than an x-ray. The range is so wide that radiologists nowadays talk in terms of a CAT Scan radiation exposure being anything from around 100 times the exposure of an x-ray to about 600 times the exposure.

Yes there is a minute risk of cancer following CAT Scans but it would be unfair to discuss it in terms of percentages as academics admit that the current methodologies and statistical methods are far from ideal. Furthermore, there is a dearth of peer-reviewed academic papers on the subject for various reasons.

As I said earlier, radiologists do have protocols to follow before exposing a patient to a CAT Scan and I know that the team who work at my UK teaching hospital will advise the referring consultant to use other imaging techniques or diagnostic procedures if the patient has undergone excessive medical radiation exposure in any given year. The same applies in the USA and if anything, the guidelines are even stricter.

[theprof]

The current UK average NRPB figures are 2.6 milli-seiverts (mSv) annually. However, don't be too alarmed at your figure 237SJ as the figure can rise for reasons that you have no control over. For example, people that live in areas of Cornwall where there are emisions of radon gas, have been measured at up to 8 mSV annually.

2.8 is OK.

[BertiWooster]

thanks again prof.

I hear what you say .

In general what is the exposure to radiation in terms of lowest to highest for the following .

A simple Head CT Scan , Barium Enema , Barium Meal

[theprof]

Sorry I've been late getting back to you. The order from lowest to highest is Head CT, Barium Meal, Barium Enema. Mind you, the Head CT and Barium Meal can be very close to one another.