Re: quarterly vs. monthly TLDs revisited

[Erick Lindstrom <avrel@trex.oscs.montana.edu>]

MSU was on a monthly film-based system when I got here in January.  We switched
to quarterly TLDs this July.  It actually saves us money, and more importantly
time (i.e., cutting the yearly "changeout" effort by two-thirds).

Also, it seems that similar numbers of dosimeters are lost (or not returned) 
for each monitoring period, regardless of the duration of the monitoring period
(this is strictly a personal observation).  Hence, if you're on a quarterly 
system you'll spend less time playing "detective" (interviewing, reconstructing
potential dose, adjusting records, and negotiating with regulators).  When you
are dealing (for the most part) with a monitored population that has a low 
potential for significant exposure, there is clearly an advantage to this 
system.  There may be some folks that will argue with that logic, but that's 
what I've experienced.

TLDs are probably less prone to non-rad environmental influences that can give 
false indications of dose (than film).  I've never had any problems with TLDs,
but I've had problems with film.

-Erick

+------------------------------+
| Erick Lindstrom              |
| Radiation Safety Officer     |
| 309 Montana Hall             |
| Montana State University     |
| Bozeman, MT  59717-0244      |
| Phone: (406) 994-2108        |	
| Fax:	 (406) 994-4792        |
| avrel@TREX.oscs.montana.edu  |
+------------------------------+