Cyclotron-produced 68Ga from enriched 68Zn foils

Clinically Applicable Cyclotron-Produced Gallium-68 Gives High-Yield Radiolabeling of DOTA-Based Tracers

“…68 GaCl 3 was produced via the 68 Zn(p,n) 68 Ga and purified according to our previous method [13], except with an addition of 500 mg of sodium ascorbate (Apotekets Produktion och Laboratorier (APL), Stockholm, Sweden), divided between the HCl dilution and wash solutions as shown in Figure 2. In short, 110 mg 68 Zn enriched (98.7 ± 0.2%) foil (Isoflex, San Francisco, CA, USA) was pneumatically transferred using a transfer module (Comecer EDS) to the cyclotron's irradiation station (GE Healthcare, Uppsala, Sweden, PETtrace 800 and Comecer PTS).…”

“…Irradiation was performed with a proton beam current of 25 µA for 68 min. Dissolution and separation were fully automated using a cassettebased Taddeo PRF module (Comecer, Castel Bolognese, Italy), and all materials and acids used were of metal-free quality, as stated in [13]. The RNP of the eluate was determined by gamma spectroscopy using a high-purity germanium detector (Canberra with Cryo-Cycle II Hybrid Cryostat), radionuclidic identity was determined by half-life measurement using a dose calibrator (Capintec CRC-55tR, LabLogic, Sheffield, United Kingdom), as described in [13].…”

“…AMA results for titrations with DOTA, NOTA, and HBED are summarized in Table 1 and illustrated in Figure 5. For comparison, the AMA results for titrations with DOTA using generator-produced 68 Ga from [13] are also shown in Table 1. The AMA values were 2-, 3-and 16-fold higher with ascorbate for DOTA, NOTA, and HBED, respectively, verifying a considerable improvement.…”

“…Incompletely removed metal ion impurities compete with Ga 3+ in the complexation with different chelators, which negatively affects the radiolabeling yields. In addition to the zinc that must be removed, predominantly, the metal ion of concern is the trivalent Fe 3+ [13], which has a higher stability constant (log K ML ) for the chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-acetic acid (DOTA), for example, than Ga 3+ [14,15].…”

“…Our group has recently developed a solid-target 68 Ga production purification sequence based on double anion exchange Uranium and TEtraValents Actinides (UTEVA ® ) resin columns, washed in an effective last step with hydrochloric acid (HCl) (2.5 N) to minimize the content of Zn 2+ (target material) ions remaining in the 68 GaCl 3 eluate [13]. All quality requirements, according to the European Pharmacopoeia monograph for cyclotron produced 68 Ga [16], were fulfilled.…”