Abstract
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Objectives As a positron emitter Ga-68 imaging plays pivotal role in diagnostic imaging. The ITG 68Ge/68Ga silica based adsorbent generator system exhibits grater elution yield of 68Ga. On site easy availability of 68Ga permitted multiple elutions in a single day. Hence, we studied elution profile of this system at 1hr to 6hrs to know optimum period to be kept between two elutions to achieve the desired elution yield as per our requirement. It will help us to utilize generator system more efficiently with minimising the cost of generator.
Methods Elution of gallium 68 was performed with 5ml of 0.05MHCL (1). Eluate was pumped through the generator column manually. Elution was performed in two sets. 1) With 3ml followed by 2ml of 0.05MHCL (n=5). 2) With 5ml of 0.05MHCL (n=20). Elution profile was generated by eluting the system at different time intervals (1hr to 6hr). % elution yield was measured (n=25). Surface dose rate was measured over the reactor and cartridge to ensure proper delivery of activity from reactor to cartridge and into the vial.
Results 68Ge/68Ga generator showed reliable elution yield. With 5ml of 0.05MHCL yield was 67.98% (n= 20) and with fractionation it was 72.63% (n=5). Elution profile at different time interval showed consistent results. % elution yield at 1hr= 104.42% +1.58 (n=5), 2hr= 93.28% + 3.08 (n=5), 3hr= 103.85% +5.81 (n=5), 4hr= 95.5% +2.3 (n=5), 5hr=100.80% + 1.23 (n=5), 6hr= 96.39% +1.41 (n=5).During the elution process surface dose rate over the reactor was 23 to 30 mR/hr. After passing the air into the reactor 4 times it came down to 0.3 to 0.5mR/hr. At the end over the cartridge it showed as 0.9 to 1.2 mR/hr.
Conclusions Our data indicates reliable elution profile for ITG silica based 68Ge/68Ga generator system. Ga-68 is a promising agent for labelling of various pharmaceuticals. Elution profile at different time interval showed good consistency. It will give us flexibility to do elution as per our convenience and optimise use of this generator more effectively.