Gallium-68 DOTATATE

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Gallium-68 DOTATATE​​ (or Ga-68 DOTATATE) is a PET radiotracer that is useful for evaluating primary and metastatic well-differentiated neuroendocrine tumors. It is a form of somatostatin-receptor (SSTR) functional imaging and most often combined with cross-sectional imaging in the form of PET-CT.

Terminology

Gallium-68 DOTATATE is synthesized from three main components:

  • gallium (Ga) radiotracer
  • linked, via a chemical macrocyclic chelator, known as DOTA (or tetraxetan; IUPAC name: 1,4,7,10-tetraazacyclododecane-tetraacetic acid)
  • to the short-chain peptide Tyr3-octreotate (TATE)

    • Pathology

    Ga-68 DOTATATE​​ has shown improved accuracy for detection relative to indium-111 pentetreotide SPECT-CT ​. It binds SSTR subtype 2 and binds 100 times more avidly than indium-111 pentetreotide .

    There are other forms:

    • DOTATOC: DOTA-d-Phe1-Tyr3-octreotide
    • DOTANOC: DOTA-1-Nal3-octreotide

    These have an affinity for different somatostatin receptors, SSTR subtypes 3 and 5 and SSTR subtype 5, respectively .

    Radiographic features

    There is normal Ga-68 DOTATATE uptake in the pituitary gland, spleen, liver, adrenal glands, and urinary tract .

    The salivary glands and thyroid show faint to mild homogeneous uptake .