Indications:
Gastro-entero-pancreatic neuroendocrine tumours (GEP-NET)
Pituitary adenomas
Tumours origination in a sympathetic system; pheochromocytoma, paraganglioma, neuroblastoma, ganglioneinoma etc.
Medullary carcinoma of thyroid
Principle:
Tc-99m Tektrotyd 9HYNIC-[D-Phel, Tyr3-Octreotide]) is intended for identifying pathological lesions in which over expression of somatostatin receptors occurs (especially subtype 2 and, to a lesser extent, subtypes 3 and 5). ) Tc-99m Tektrotyd attaches to somatostatin receptors in tissues where, as a consequence of the disease, the cell surfaces contain these receptors in more than the physiological density.
Preparation and Procedure:
Short acting somatostatin analogues should be stopped 3 days prior to the scan.
Lanreotide (long acting analogue) should be stopped at least 3 weeks prior to the scan.
Octreotide (long acting analogue) should be stopped at least 5 weeks prior to the scan.
A light diet the day before the examination, patient should fast on the day of examination until the end of the study.
Patients should increase fluids and empty their bladders frequently.
If the patient does not have diarrhoea a laxative should be taken the day before the scan.
Scanning is performed at 2 and 4 hours post injection; this includes whole body imaging and SPECT/CT.
Comment:
Radiolabeled tracers provide a functional imaging technique to identify neuroendocrine tumours. Currently there are several single-photon techniques available using either 123I-MIBG, 111In-DTPA-pentetreotide (Octreoscan) or 99mTc-EDDA/HYNIC-try3-octreotate. While this is an expensive procedure and has only a limited role in the assessment of these tumours, it can be useful in treatment planning.