Re: Rad worker training

[David Scherer <scherer@uiuc.edu>]

I couldn't let this one go by.  Sandy wrote, in part:

>I am not [t]rrying to equate a power plant with a medical facility. The 
>one thing in common though is that the workers should be trained and 
>they shoud receive requalification training at least annually, even 
>if it's only 20 hours a year.

This number is about an order of magnitude lager than common practice.  Is
it based on any analysis of the daily responsibilities and risks faced by
RTs and CNMTs?

I think you mentioned earlier in the thread that the exposures are very
low, which is consistent with my experience.  This is because the radiation
hazards do not change daily and are largely controlled by engineered
barriers.  If the training is commensurate with the hazard, 20 hrs per
years for radiation safety seems overboard.  As you say, the power plant
environment is quite different.  Hazards are quite variable throughout the
facility and a higher level of understanding is needed.

However, I do believe that, by and large, technologists DO need to
continually brush up on radiological physics.  Not so much on dosimetry and
occupational safety, but on technique selection, image quality, and patient
dose (e.g., high kVp).  Kent Lambert said that the technique factors are
determined in advance.  It is my experience that the techs depart from the
posted technique factors for a number of very good reasons: patient size,
pathology, whether the pt can remain still, etc.  Even the doctors can't
agree on what is optimal ("Dr. Smith likes his films a little darker.") so
techs have to adjust quite often.  They are not just button pushers.

As far as patient doses, I agree with Kent and Mike that this is not the
RT's job.  This is medical physics, not x-ray technology.  The problem is
that  MOST hospitals do NOT employ a diagnostic physicist or health
physicist.  The NRC and states do not require (or even encourage) in-house
physics expertise.  Why hire an MP/MHP when you can name a doctor as RSO
and have one or two techs do most of the routine functions (badges, QC
tests, waste, records).  

Political Commentary:  Mammography has begun to break this pattern by
requiring actual physics services.  When this kind of accreditation program
spreads to the rest of radiology, maybe these problems can be reversed.
When it becomes advantageous to have in-house physicists, then it might
bring a host of benefits, training being just the start.  Perhaps they
could sit down with the docs and get them to agree on what is acceptable
for each type of film so the techs won't have to second guess the technique
chart.

One comment about the lead apron used for a panoramic x-ray: the apron
should be on your chest, not your back.  The beam from the x-ray tube is
collimated.  The apron is not protecting you from the primary radiation,
but from the scatter.  Since your chin protrudes out from your neck, you
can place the apron under the chin to absorb scattered x-rays.  In the
rear, the beam intecepts your head just above the neck, where it does not
protrude.  Any scatter that will reach your body must passes through tissue
all along its path.  There is no place to insert the apron so that it will
intercept the scattered x-rays.

Regards,
Dave Scherer
scherer@uiuc.edu