Nuclear medicine imaging plays an important role in new drug developments, both at preclinical and early clinical stages. Presently, fluorine-18( 18 F), and gallium-68( 68 Ga) are the most used positron emission tomography(PET) radionuclides for molecular imaging studies in nuclear medicine. PET permits non-invasive localization and quantification with relatively small amounts of radioactivity, due to its high inherent sensitivity. The short half-lives of both these radionuclides (110 and 68 minutes, respectively), however, pose limitations for imaging biochemical processes with slow pharmacokinetics, such as localization of macromolecules at targeted tissues in macromolecular-based (e.g. antibodies) cancer therapies. On the other hand, Zirconium-89 ( 89 Zr) is suitable for radiolabelling and in-vivo visualization of such processes due to its relatively long half-life (78.4h), which matches the slow pharmacokinetics of macromolecular therapeutics. Most emerging therapeutics are based on macromolecules rather than small organic moieties, especially macromolecules that specifically target cancer cells through monoclonal antibodies, cell tracking agents, nucleotides and nanoparticle systems. Nearly 115 clinical studies are currently ongoing with 89 Zr labelled molecules. Zirconium-89 can be produced in medium energy medical cyclotrons through the 89 Y(p,n) 89 Zr nuclear reaction. An ongoing International Atomic Energy Agency (IAEA) co-ordinated research project focuses on standardization of 89 Zr production procedures and quality control. Designing a radiopharmaceutical to transfer the radionuclide (such as 89 Zr) to specific cells and retain it there for a desire time, with minimum accumulation and faster clearance from other non-target tissues, is a challenging process.