Somatostatin Receptor- PET/CT
Somatostatin receptor- PET/CT (68Ga-DOTA-TOC, -TATE, -NOC) for the imaging and diagnosis of neuroendocrine tumors and their metastases
Neuroendocrine tumor cells have special receptors on their surface, which serve as "docking sites" for the hormone somatostatin, also known as somatostatin receptors. These also occur naturally in certain normal tissues, but their density at the tumor cell surface is particularly high. Nuclear medicine makes use of this fact by means of a radiolabeled peptide (small protein), which binds to these receptors. The peptide (+ chelator; variants are DOTANOC, DOTATOC or DOTATATE) is radiolabeled with the PET radionuclide 68Ga (gallium). During the examination, a small amount of the 68Ga-labelled somatostatin receptor ligand (68Ga-DOTANOC, sometimes also -DOTATOC, or -DOTATATE) will be injected into a vein. After the injection, the 68Ga-DOTANOC reaches the diseased tissue via the bloodstream and accumulates significantly more in the diseased cells than in normal tissue. The short-lived radioactive nuclide 68Ga is used as a label in order to observe and visualize the receptor-rich tumor in the body. The physical half-life of 68Ga is 67.6 minutes
Preparation for the examination
You do not have to appear in a fasting state for the examination, but should have a light breakfast.
Documents
Please bring all relevant documents with you on the day of examination (especially images and findings from preliminary examinations, preferably also in digital form on CD and doctor's letters). For the possible intravenous administration of contrast media for a CT (computed tomography), please have the recent creatinine level in the blood determined by your family doctor - IDEALLY within the week before the examination. You should be guided by the result of the blood test.
Examination procedure
To perform the examination, the radioactively labeled 68Ga-DOTANOC is injected into an arm vein. After a minimum waiting time of 30 minutes, during which the medication is distributed in the body, the image acquisition is started on the PET scanner. During the acquisition time (approx. 20 - 30 min) you must lie still. No other inconveniences are to be expected. The PET-CT scanner is open at both ends (towards the head and the legs) unlike an MRI scanner, which is in form of a closed space at one end. In cases of pronounced claustrophobia, however, an anxiety-relieving premedication may be necessary or advisable. Please bear in mind that under the influence of an anxiolytic medication you will not be able to drive on the day of the examination! If there is no persistent "claustrophobia" (in 99% of cases), no such medication is required and you can drive your own vehicle (before and after the examination).
Side effects
No side effects are to be expected from the injection of the radioactive tracer itself.
Side effects may arise from the administration of iodine-containing contrast medium in case of a possible contrast administration within the scope of the accompanying CT (intolerance reaction, hyperthyroidism, worsening of a pre-existing renal insufficiency). During the consultation with our physicians, please make sure to point out if you have experienced a contrast agent reaction in the past (reddening of the skin, itching, swelling, shortness of breath, etc.).
