Biotechnology in nuclear medicine

Uwe Haberkorn

University Hospital of Heidelberg, Germany

With the advances in molecular biology and biochemistry new imaging and treatment modalities based on the biological properties of tissues have been developed. Pharmacogenomics will identify new surrogate markers for therapy monitoring which may represent potential new tracers for imaging. Also drug distribution studies for new therapeutic biomolecules are needed at least during preclinical stages of drug development. New treatment modalities such as gene therapy with suicide genes will need procedures for therapy planning and monitoring. Finally, new biomolecules will be developed by bioengineering methods which may be used for isotope-based diagnosis and treatment of disease.

The identification of useful new molecules out of huge libraries may be done by use of high throughput methods. Display systems are used for the selection of molecules from libraries in which peptides or proteins are physically linked to their corresponding encoding sequences. The attracting feature of the concept arises from the huge number of candidate molecules that can be used for further evaluation. After the characterization of the structure-function relationships for the lead compounds found in this process further improvement by rational design of analogs can be performed. In addition these systems can be used to modify the biophysical properties of the displayed molecules by evolution through cycles of mutation, selection and replication.

Radiolabelling of the resulting molecules allows their pharmacological characterization at early stages and therefore fastens preclinical development. Furthermore, the identification of tumor-specific peptides or antibodies offers new targets for radiopeptide based diagnosis and therapy.