Sorry Uncle Sam, I Refuse To Be Ionized
10 Jan 2010
"Don’t even think of agreeing to it", I recently said to a friend who is a frequent flyer to the U.S. I was referring to the recent announcement that Canadians travelling to the our friendly neighbour will be subjected to full body scans. It’s the latest attempt to ensure aviation safety, but how safe is this ionizing procedure to the passenger?
30 years ago I reported in this column a shocking discovery. Some X-ray machines were exposing patients up to 60 X the amount of radiation needed for some procedures. X-ray equipment was often old, rarely calculated for radiation exposure, and some technologists were incompetent. The column resulted in a big crackdown by government health authorities.
Now Transport Canada reports that over 40 scanners will be installed in Canadian airports. Fortunately, all of these scanners will use "millimeter wave" technology. This means travellers will be exposed to radio frequency waves that produce a three-dimensional image of a person’s body to detect hidden weapons or explosives. Radio waves are not the same as harmful X-ray ionizing radiation to be used in the U.S.
X-rays that use ionizing radiation can trigger sufficient energy to displace electrons from an atom. Experts say this has the potential to cause mutations in cells that can lead to malignancy. But no one can be sure how much exposure is needed to cause this change.
And U.S. authorities have not announced how much radiation their scanners will emit.
I’m sure that U.S. authorities will downplay the risk of ionizing radiation to the flying public. I vividly remember this reaction 30 years ago, and I have no doubt the same scenario will play out today.
During the earlier research of X-rays I repeatedly asked radiologists and technicians how much radiation patients received from common diagnostic procedures. Usually they did not know the amount. And I got tired of hearing that dental x-rays caused the same amount of radiation received from a Caribbean vacation. Or the amount received from cosmic radiation during an international flight. I wasn’t impressed by these vague answers.
Neither was a nuclear engineer who asked a technologist how much radiation he would receive from back X-rays. He was told it was the same as a two hour plane trip. Later, the engineer calculated it would take 1,120 plane trips, to equal the amount he had received from the X-ray exposure!
A few days later, his radiologist called and said the exposure was 2.8 roentgens. The engineer advised him that he was only allowed 0.1 roentgens of exposure a year at the nuclear plant where he worked. This time he calculated it would require 28 years in the nuclear plant to receive the same dose as at the hospital!
My frequent flyer friend must realize that ionizing radiation is like an elephant. It never forgets. Every roentgen an individual receives from dental X-rays, chest X-rays, an increasing number of diagnostic procedures and airport scanners contributes to the overall amount.
I’ve discussed this matter with several radiation experts and there is no general agreement on this matter which is not surprising. Some say the dosage is low and will not be a health hazard. Other radiation experts are concerned that there has never been a study about the additive effects of low dose ionizing radiation. This means a roll of the dice, particularly if you are a frequent flyer.
I’m amused that for some travellers the main concern is privacy. Ionizing radiation does indeed show "all". But my prediction is that if any airport employee gets a vicarious thrill from gazing at "private parts", this interest will evaporate in the first hour. He will speedily conclude that no private parts are that pretty and that 99.9 percent of the population look better dressed than naked.
My advice for all travellers is to tell Uncle Sam they want a pat down as authorities claim this choice will be available. Besides as one of my 70 year old patients said, "At my age, if anyone wants to pat me down, be my guest!"
