According to a memo on Radiation Safety Advisory 99-1 from the
	 Department of Health Services (California):
		The dose to a surgeon from a three-hour procedure involving
		a one mCi Tc-99m sulfur colloid lymphoscintigraph
		procedure is less that a 0.1 mrem.  Radiation-absorbed
		doses to others in the operating room is no more that that
to
		the surgeon, and absorbed doses to staff in the pathology
		department are much lower.

		.........even though these low level due to Tc-99m are not
		safety concerns.

	Jennifer MacDonald

> This topic of radiation safety with sentinel node biopsy specimens has
> been
> discussed here on Histonet several times. Somebody ought to put it on a
> Web
> site - I hesitate to do that myself because I have no experience with the
> technique.
>
> Sentinel node biopsy is presently used to evaluate metastasis of breast
> cancer and melanoma. The tumor area is injected with a mixture of a blue
> dye
> and a radioactive colloid, both of which drain into the nearest lymph node
>
> (the "sentinel node") where they are detected either visually or with a
> gamma
> counter. If the sentinel node is negative, it is unlikely that the lymph
> nodes above it contain cancer. The technique is somewhat arduous for the
> surgeon, and it takes every surgeon a while to learn it, and stresses may
> be
> high during the learning period.
>
> The radioactive colloid is labelled with technetium 99m, which has a half
> life of six hours, emitting a gamma particle and becoming technetium 99,
> which is also radioactive but with a half life so long that its
> radioactivity
> is negligible.
>
> According to radiation safety people I have talked with, and that others
> on
> Histonet have talked with, no special handling of the specimen at all is
> required, and rubber gloves give quite adequate protection from the small
> amount of radiation received.
>
> Frozen section examination is medically inadvisable, but is not
> contraindicated because of the radioactivity.
>
> Bob Richmond
> Samurai Pathologist
> Knoxville TN
>