Answer to Question #1324 Submitted to "Ask the Experts"

Category: Nuclear Medicine Patient Issues — Diagnostic Nuclear Medicine

The following question was answered by an expert in the appropriate field:

This will probably seem a simple question to most but how do the uses (medical) relate to the chemical properties of the isotope Technetium-99m?

The imaging applications/medical uses are only indirectly related to the chemical properties of ^99mTc. Usually, ^99mTc is chemically attached to a tissue-specific carrier molecule for targeting for a specific application (that is, heart, kidney, or tumor imaging). Thus, the properties of the total molecule and its stability are deciding factors for a potential medical application. The success in radiolabeling of such molecules is dependent upon the ingenuity of a wide variety of different methods which are now available for attachment of ^99mTc. On the other hand, the other requirement is that the agent will retain its tissue/targeting specificity when the relatively large groups required for binding ^99mTc are introduced into the molecule.

F.F. (Russ) Knapp, Jr., PhD
Nuclear Medicine Program
Oak Ridge National Laboratory

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