Reduction of dosimetry for P-32

[fegallag@uci.edu (Frank E. Gallagher, III)]

A few additional comments in favor of eliminating dosimeters used by
individuals who only work with small quantities of P-32 in well-shielded
experiments in research labs:

1.     The cases of cancer that might occur following low doses of radiation
that could result in litigation primarily involve leukemia or deep solid
tumors from penetrating (gamma) radiation.  Since P-32 is a beta emitter, we
are talking about the potential for skin cancer of the fingers or, to a much
lesser extent, the other areas of the skin not protected by clothing.

2.      The minimum detectable dose for a TLD ring badge from our vendor is
on the order of 30 mrem/month.  This translates to 360 mrem/y as the
potential "missed" dose.  Still negligible compared to the current limit of
50 rems/y, but not necessarily "zero".

3.      The cost of dosimeters is not just the cost of the badges.  You have
to include all of the administrative costs, including distribution and
collection, investigation of late and lost badges, assigning doses (even
zero doses) to lost badges, and obtaining radiation exposure histories
(again, mostly zeros).

4.      The reengineering programs in many of our institutions are concerned
with short-term savings, and that makes arguments based on future costs
(most likely to some other unit of the institution, perhaps decades from
now) very hard to sell.

Out of 800 badges processed each month, we routinely end up with about 790
with no detectable dose.  I would like to reduce the number of badges we use
to 250 to 300 per month.  If a person is nervous about working with small
amounts of P-32, we will, of course, still provide that person with dosimetry.


Frank E. Gallagher, III, CHP
RSO, Univ. of California, Irvine   92717-2725
Voice: (714) 824-6904, Fax: (714) 824-8539
E-mail: fegallag@uci.edu