DOTANOC

DOTANOC, or Ga-68 DOTANOC, is a radiopharmaceutical used in PET imaging to visualize somatostatin receptor–expressing tumors. It is a DOTA-conjugated somatostatin analogue radiolabeled with gallium-68, enabling high-resolution PET/CT imaging of abnormal uptake in the body.

Mechanism and scope: DOTANOC binds primarily to somatostatin receptor subtypes 2, 3, and 5 with high affinity, allowing detection of neuroendocrine tumors and other lesions that express these receptors. The DOTA chelator permits labeling with various radiometals, supporting diagnostic imaging and, in theranostic contexts, pairing with therapeutic isotopes for targeted radiotherapy.

Clinical use: Ga-68 DOTANOC is widely used for imaging well-differentiated neuroendocrine tumors and their metastases, aiding staging and treatment planning. It can detect lesions that may be missed by other tracers and is useful in evaluating suspected recurrence. Compared with other Ga-68–labeled somatostatin analogues, DOTANOC has a broader receptor affinity profile, particularly incorporating SSTR3.

Procedure and interpretation: The tracer is administered intravenously, and PET/CT imaging is typically performed about 1 hour after injection. Results are interpreted in the context of somatostatin receptor expression and can inform decisions on surgery, peptide receptor radionuclide therapy, or additional imaging.

Availability and safety: DOTANOC is available in centers with radiopharmacy capabilities, particularly in Europe, with growing use elsewhere. It is generally well tolerated; adverse effects are rare and usually mild. As with other radiopharmaceuticals, there are radiation safety considerations, and pregnancy or lactation is a contraindication.