Re[2]: Mammography Doses

[forrere@ccmail.orst.edu]

          In regards to a pre-employment "screening" to see whether or
          not a condition occurs, in Oregon such a practice is
          strictly FORBIDDEN!!  I do not know what the regulations in
          other states are but I would have a hunch that "screening"
          is also illegal elsewhere.  Now if an employer were to have
          you take the TB skin test and you got a positive reaction
          then there would be a medically indicated reason for a chest
          x-ray.  As far as the handling of men versus women in x-ray
          safety, my experience as a state inspector has been that,
          with the exception of mammography, men are more likely to
          have gonadal shielding used than women, even on follow-up
          films.  The big reason is that the way men are put together
          make it easier to shield there gonads without obscuring any
          part of the useful film.  Woman unfortunately have there
          gonads located in the middle of the area of interest.
          As to exposures received, most RT's should have a rough idea
          of what patients get, most should but unfortunately most do
          not.  Using my state reg book "Average Patient Exposure
          Guide" the following is an approximation of the
          entrance skin exposures you would receive for various
          projections with a 400 speed system.
          Abdomen-300 mR
          Lumbar Spine-350 mR
          Mammography-345 mR/no grid-690 mR/grid
          Full Spine-145
          Cervical Spine-95 mR
          Skull-70 mR
          Chest-15 mR
          By comparison an average dental bitewing will give you an
          ESE of about 150 mR, and a dental panoramic x-ray will
          result in an ESE of about 2000 mR.

          Gene Forrer