Re: Use of syringe shields

[Ccja@aol.com]

I assume that you're asking about the sort of thin, tungsten, syringe shields
used for injection, not the leaden variety, which are used to park syringes
on counters, or carry doses about the hospital (and for shipping unit doses
in ammo cans by radiopharmacies). Firstly, 10 CFR 35.60, and the equivalent
Agreement State regulations, require the use of syringe shields, ". . .
unless the use of the shield is contraindicated for that patient or human
research subject."

I have no hard data ready to hand, but the answer is yes, they do
significantly reduce the finger/hand dose, for the nuclides that are
currently most common in nuclear medicine and administered by injection,
i.e., Tc-99m, Tl-201, Ga-67. Note that the Rad Health Handbook (1970 ed.)
gives the half-value layer of tungsten, for the 141 keV Tc-99m gamma, as
0.2mm. For a 511 keV PET pharmaceutical, however, that 1/2 layer becomes
~2.8mm. Awfully hefty when you're trying to hit those tricky veins. I' ll try
to find a paper in the J Nuc Med Technology with "in vivo" measurements.