Radiation Safety Question on Portable X-Rays

["Richard, Mack L" <mrichar@iupui.edu>]

Tim (Kensora), Chris (Alston), & Radsafers:

These types of questions and concerns crop up in most hospitals at one time
or another.  There are a few actions one can take to deal with these issues.
First, it's always best to take a few scatter measurements around a portable
x-ray machine.  Set the machine up to shoot the most common films and take
measurements at various locations around a phantom (use a bucket of water if
you don't have a true phantom).  I'm not sure where the 8 feet distance
recommendation came from, but I suspect you'll find that when you take
scatter measurements 8 feet from a phantom, you won't measure much scatter
radiation.

Once you get the measurements, compute how many times an individual would
have to stand at a particular location to exceed certain values such as 100
mrem (NRC's annual limit to a member of the public), 360 mrem (NCRP's
estimate of the average, annual effective dose equivalent to a member of the
general public from all sources), 500 mrem (NCRP's recommendation and NRC's
limit for pregnant individuals), and 5000 mrem (annual occupational limit).
These values are assuming that no shielding is provided.  If you want, you
can perform the same computations with Pb aprons, but if you do, you enter
the realm of partial body exposures, effective dose using the "Webster"
equation, etc., so you may want to keep it simple.

Develop some simple guidelines for non-radiography staff (e.g., nurses) to
follow when portable x-rays are taken.  Considerations such as wearing Pb
aprons when they're within 6 ft of the patient (alternatively, standing
behind the radiographer), standing at right angles to the primary beam, etc.

I would provide this information to your radiographers (politically correct
term for x-ray techs).  If you can summarize the aforementioned information
in a one or two page "handout", do so and give the radiographers copies to
hand out to the various departments where they perform portable films (be
sure to include your name and phone number for further questions).  You can
also send the written information to key individuals (e.g., OR nursing
director, ICU director, etc.).  

Aside from some very general statements on radiation risk, I would avoid
detailed information about radiation risk because that's too complicated to
address in a short document.  Simply provide references on the handout
(e.g., websites, NRC Reg. Guide, etc.) or instruct individuals to contact
you for copies and/or to discuss such information.

You could issue some personnel monitors (badges) to a few key individuals
(ideally, persons most commonly around when portable x-rays are performed)
for about 3 months to accumulate dosimetry information.  Even better, if you
have (or can borrow) some direct reading dosimeters that respond properly to
x-ray energies, give them to your radiographers who can in turn provide them
to other individuals in the room during a portable x-ray (if you only have
one, give it to the person closest to the patient being x-rayed).  For many
doubters, the ability to see a real measurements helps alleviate their
concerns.

You'll probably never be able to convince the truly "radiophobic" people,
but this type of effort and information goes a long way to help alleviate
some fears.  Hope this helps.

Regards,
Mack R.

Mack L. Richard, M.S., C.H.P.
Radiation Safety Officer - IUPUI/Indiana Univ. Med. Cntr.
Phone #: (317) 274-0330   Fax #: (317) 274-2332
E-Mail Address:  mrichar@iupui.edu

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