Log in

16 November 2010 @ 09:08 am
TSA and X-ray  

As a registered radiologic technologist (X-ray tech) I want to know:

What is the dose rate of these "body scanners?"

The FDA regulations state:  "The safety standard limits the dose per screening to 0.25 µSv (25 µrem) reference effective dose for general-use full-body security screening systems.  The annual dose limit is 250 µSv (25,000 µrem) over a 12‑month period.  To exceed this annual limit an individual would have to be screened more than 1,000 times in one year.  This annual dose limit is in accordance with the recommendations of the National Council on Radiation Protection and Measurements (NCRP) for the annual effective dose limit for individual members of the general public (NCRP report no. 116 Limitation of Exposure to Ionizing Radiation (1993)).  NCRP’s dose limitation recommendations for the general public were made with the understanding that the general public includes special populations that are more sensitive to radiation, such as children."

When I take a radiograph, I'm doing so on a piece of equipment that is calibrated and checked by an ABR board-certified physicist on an annual basis, inspected by the state's health department annually.

I'm trained in the use of equipment producing ionizing radiation,  the administration of ionizing radiation in a safe manner, using the minimal exposure required to produce a diagnostic image. My equipment has, in a location readily-visible to my patients, it's certificate that it meets State requirements.

Is there an automatic shutdown of the beam when the dose limit is reached?

If not, why?

Who, exactly, is running these machines?

Who trained them?

Who calibrated the equipment?

Were these machines calibrated by a board-certified physicist?

Are they regularly inspected and maintained?

Is the certificate of inspection and compliance readily visible to all? If not, why?

I note that in nothing I've read (and am willing to concede that I don't read everything) has the FDA stated publicly that these devices are safe. (And if anyone HAS seen that, please let me know.)

Finally, I ask "Cui bono?" Certainly not the traveling public, nor the taxpayers who are footing the tab for these devices AND the personnel to run them.

thinking outside the next box overbrownkitty on November 16th, 2010 02:19 pm (UTC)
Does that mean we can sue the TSA for practicing medicine without a license?
Leon Jester: CHRVlwj2 on November 17th, 2010 02:08 am (UTC)
No, but it does mean that I'd like to know who calibrates these units and what their qualifications are.

I'd also like to know what, exactly, the operators receive in the way of training.
murstein: Technology - No Place For Wimpsmurstein on November 17th, 2010 03:05 am (UTC)
Interesting observation: Apparently TSA forbids its screeners from wearing the dose-measuring tags that hospital radiology staff wear. I'm having trouble coming up with a benign reason for this refusal.
Sister Atom Bomb of Courteous Debateakiko on November 17th, 2010 03:10 pm (UTC)
There is a story of a baggage screener who got a stomach cancer at work.
Leon Jester: CHRVlwj2 on November 17th, 2010 08:25 pm (UTC)
Link goes to John Scalzi's blog about TSA scanners, I didn't see the reference to gastric cancer, if it's there, it's buried in a tonne of comments.

I will say that (1) gastric cancer is relatively rare and (2) for some odd reason, more prevalent amongst Japanese. Speculation has run mostly to diet-related.
Sister Atom Bomb of Courteous Debateakiko on November 17th, 2010 08:30 pm (UTC)
The link ought to go directly to the comment, and it will if you delete the trailing ".

It's indeed very rare, and this person and several of his coworkers at the same screening station developed cancers in their midsections. Hence a high suspicion of being directly related to the work.
Leon Jester: BOHICAlwj2 on November 17th, 2010 08:45 pm (UTC)
Ah. Okay.

They're using a fluoroscope, a completely different animal.

Does go to show what several of us have suspected/feared, (1) that the shielding on those units is not up to medical standards; (2) operators are not wearing film badges, otherwise, there'd have been a flag; (3) operators are not wearing lead aprons and thyroid shields; (4) there is no area monitor nor control monitor.

None of that would pass muster in a radiology department or, for that matter, a research reactor at a university.

Which leads one to speculate on (1) the calibration of the unit and (2) maintenance of same.

I'd say that particular unit is spraying the entire area with X-radiation.
Leon Jester: BOHICAlwj2 on November 17th, 2010 08:17 pm (UTC)
On the face of it, I'd say that's most definitely an OSHA violation.

Be interesting to see how that plays out.
Dekarchdekarch on November 17th, 2010 04:51 pm (UTC)

Apparently Nobel-Prize winning physicists share your concerns. And can't find any good answers to your questions.
Leon Jester: Est Mort Bold - Goudy OSBlwj2 on November 17th, 2010 08:19 pm (UTC)
I'm hoping to run into Dr. Anthony -- a medical physicist in my area who certifies & calibrates medical x-ray equipment -- and ask him his opinion.