gallium-68 generator gallium-68 generator a germanium-68/gallium-68 generator is a device used to extract the positron-emitting isotope 68ga of gallium from a source of decaying germanium-68. the parent isotope 68ge has a half-life of 271 days and can be easily utilized for in-hospital production of generator produced 68ga. its decay product gallium-68 (with a half-life of only 68 minutes, inconvenient for transport) is extracted and used for certain positron emission tomography nuclear medicine diagnostic procedures, where the radioisotope's relatively short half-life and emission of positrons for creation of 3-dimensional pet scans, are useful. parent isotope (68ge) source the parent isotope germanium-68 is the longest-lived (271 days) of the radioisotopes of germanium. it has been produced by several methods. in the u.s., it is primarily produced in proton accelerators: at los alamos national laboratory, it may be separated out as a product of proton capture, after proton irradiation of nb-encapsulated gallium metal. at brookhaven national laboratories, 40 mev proton irradiation of a gallium metal target produces germanium-68 by proton capture and double neutron knockout, from gallium-69 (the most common of two stable isotopes of gallium). this reaction is: 69ga(p,2n)68ge. a russian source produces germanium-68 from accelerator-produced helium ion (alpha) irradiation of zinc-66, again after knockout of two neutrons, in the nuclear reaction 66zn(α,2n)68ge. mechanism of generator function when loaded with the parent isotope germanium-68, these generators function similarly to technetium-99m generators, in both cases using a process similar to ion chromatography. the stationary phase is either metal-free or alumina, tio2 or sno2, onto which germanium-68 is adsorbed. the use of metal-free columns allows direct labeling of 68ga without prepurification, hence making production of gallium-68-radiolabeled compounds more convenient. the mobile phase is a solvent able to elute (wash out) gallium-68 (iii) (68ga3+) after it has been produced by electron capture decay from the immobilized (absorbed) germanium-68. currently, such 68ga (iii) is easily eluted with a few ml of 0.05 m, 0.1 m or 1.0 m hydrochloric acid from generators using metal-free tin dioxide or titanium dioxide adsorbents, respectively, within 1 to 2 minutes. with generators of tin dioxide and titanium dioxide-based adsorbents, there once remained more than an hour of pharmaceutical preparation to attach the gallium-68 (iii) as a tracer to the pharmaceutical molecules dotatoc or dota-tate, so that the total preparation time for the resulting radiopharmaceutical is typically longer than the 68ga isotope half-life. this fact required that these radiopharmaceuticals be made on-site in most cases, and the on-site generator is required to minimize the time losses. however, new kits such as "netspot" for more rapidly preparing ga-68 edotreotide or dotatate from ga-68 (iii) ions have increased the flexibility of sourcing of this radiopharmaceutical for ga-68 endocrine receptor (octreotide) scans. with netspot the preparation of the ga-68 dotatate is immediate once the ga-68 has been acquired from the generator and mixed with the reagent. indications for gallium-68 pet scanning main article: gallium scan gallium-67 citrate salt imaging is useful for imaging old or sterile abscesses. gallium-68 is useful in direct tumor imaging, especially leukocyte-derived malignancies and prostate cancer metastases.