SOMATOSTATIN RECEPTOR IMAGE

OctreoScan

INDICATIONS:

Functional imaging, detection, follow-up and monitoring tumors that contain somatostatin receptors such as carcinoids, islet cell tumors, small cell lung tumors, CNS (neuroendocrine tumors) and some thyroid carcinomas.

PATIENT PREPARATION:

None.

RADIOPHARMACEUTICAL:

In-111 pentatreotide: 3.0 mCi, I.V. injection

SCANNING TIME:

Planar images are obtained 4 hours post injection and planar and SPECT are also obtained at 24 hours post injection.

Initial planar images take about 40 minutes. SPECT/planar images take about 2 hours.

In addition, whole body images can be obtained which may add 40 minutes to the procedure.

RATIONALE:

Somatostatin is an endogenous neuropeptide that acts as a regulator of growth hormone secretion. Neuroendocrine tumors contain a high density of somatostatin receptors. OctreoScan, a radiolabeled form of the somatostatin analog octreotide, shares the same binding site as naturally occurring somatostatin which makes it a sensitive indicator for somatostatin receptor-bearing neuroendocrine tumors. Since the concentration of receptors on tumors may vary, the sensitivity of OctreoScan may vary among tumor types.