A Practical Guide for the Production and PET/CT Imaging of 68Ga-DOTATATE for Neuroendocrine Tumors in Daily Clinical Practice.

Abstract

Neuroendocrine tumors are a rare form of cancer that arise from neuroendocrine cells and can be present at almost any location throughout the body. Although heterogeneous in presentation, a common denominator among these tumors is the overexpression of somatostatin receptors. 68Ga-DOTATATE is a somatostatin analog labeled with the positron emitter gallium-68 (68Ga). For well-differentiated neuroendocrine tumors, 68Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) imaging is used for diagnosis, determination of disease burden, and therapy selection. This protocol details the radiolabeling of 68Ga-DOTATATE, quality control, patient preparation, and subsequent PET/CT imaging. Radiolabeling of 68Ga-DOTATATE is performed with a fully automated labeling module coupled to a germanium-68 (68Ge)/68Ga generator. Quality control of the final product evaluates radiochemical purity with instant thin-layer chromatography and solid-phase chromatography, and pH prior to patient injection. Periodic quality control is performed to determine 68Ge breakthrough, sterility, and (4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) content. Patient preparation includes patient instructions, a protocol for 68Ga-DOTATATE during treatment with somatostatin analogs, and intravenous administration of the radiopharmaceutical. For PET/CT imaging, the acquisition and reconstruction settings are described. For each step, radiation safety will be highlighted, as well as time constrictions due to the short half-life of 68Ga. Fully automated in-house production and quality control of 68Ga-DOTATATE leads to very high success rates (95%) and produces two to four patient dosages per batch, depending on the yield of the generator. In conclusion, 68Ga-DOTATATE PET/CT imaging is a noninvasive and fast method of providing information on the tumor burden of neuroendocrine tumors (NETs) while also assisting in diagnosis and therapy selection.