THE PLACE OF TECHNETIUM 99M RADIOPHARMACEUTICALS FOR IMAGING OF NEUROENDOCRINE TUMORS

Abstract

Neuroendocrine tumors, NETs are a heterogeneous group of neoplasms with different anatomic locations: in the gastrointestinal tract, bronchopulmonary in origin and in other sites, e.g. thyroid, breast, genitourinary system, head and neck. Usually, these tumors are locally advanced with distant metastases. They grow slowly and are therefore not easy to detect.
Beside Galium-68 labelled somatostatin-receptor analogues, the most commonly used to locate NETs, their metastases and evaluate lesion nature and extension, some peptides have been used as molecules carrying Technetium-99m radioactive atoms. Radioactive peptides are the future of imaging and therapy for neuroendocrine tumors because they are specific and have a receptor-ligand interaction. They have greater stability because the changes are not natural/ changing the order of amino acids. Currently only few radiopharmaceuticals are capable to image cancer processes at the sub-cellular level. Diagnostics is possible because of gamma radiation emitted Technetium-99m radioactive atoms bound to molecules of the peptides. The radiation may be used to image the distribution of tumor cells in the patient body.
After evaluation of the published literature and our very limited experience, we can conclude that the clinical role of SPECT imaging using Technetium-99m radiopharmaceuticals in patients with NETs is very important, especially when PET is not available.