Radiation Dose to cardiac stress lab techs

[Karin Gordon <kgordon@cc.UManitoba.CA>]

Hi, 

My hospital has a very busy nuclear medicine (NM) department, with one
section devoted to cardiac stress tests on patients being investigated for
heart problems.  For this procedure, we have recently switched the
radionuclide/pharmaceutical/activity injected from 74 MBq Tl-201 thallous
chloride to 1 GBq (27 mCi) Tc-99m MIBI. This change was made because of
the superior imaging qualities of the second agent and many NM 
departments world-wide have switched over.  We do 10 such procedures daily.

Our cardiac stress lab techs never handle the radioactive material, that
is the task of the NM technologist.  However, they do handle the
radioactive patients right after the injection, as they are required to
take a blood pressure reading once a minute during the recovery phase 
right after the patient has been physically or chemically stressed. This 
recovery phase lasts for about 10 minutes (it can be longer, depending on 
the patient), during which time the stress lab tech is in very close 
proximity to the patient.

The doses to our stress lab techs have risen considerably since we changed
the imaging agent, from an average of 0.7 mSv/yr to 2.6. Needless to say
we are monitoring the situation closely and taking measures (education, 
personal digital dosimeters, shielding, etc) to keep their doses ALARA. 
Doses seem to be dropping, but not to the previous levels before we 
changed over to Tc-99m.

I have several questions to pose to other hospital RSOs out there.

1. Are you monitoring radiation doses to stress lab techs?
2. If you have switched imaging agents like we did, are you seeing an 
increased dose to stress lab staff?
3. If so, what are you doing about it? 

I'd appreciate your wisdom on this. Thanks in advance.

Karin

*****************************************************************************
Karin Gordon
Radiation Safety Office		phone 	(204)787-2903
Health Sciences Centre		fax	(204)787-1313
820 Sherbrook St
Winnipeg, Manitoba		e-mail	KGordon@cc.umanitoba.ca
Canada R3A 1R9