68Ga Generator
AN-1613-10
Summary of Method 68Ga is a positron emitting radionuclide which has garnered interest for use in positronemission tomography (PET). 68Ga (t1/2 = 68 min) can be readily isolated from its parent 68Ge (t1/2 = 271 days), which is
produced by cyclotron irradiation of gallium or zinc target material. Classic 68Ga generators consist of 68Ge adsorbed
onto an inorganic exchanger, such as Al2O3, SnO2 or TiO2. The 68Ga is then periodically eluted with 0.1-1.0M HCl ordilute EDTA. These generators are simple and robust, yielding 60-80% of 68Ga with minimal 68Ge breakthrough overmany elutions. However, the classic generator can be limited by the relatively large volume of solution needed to elutethe 68Ga and by metal ion impurities arising from the inorganic substrate. An alternative generator system has beendeveloped, in which the 68Ge source material is stored in dilute HCl. 68Ga is then selectively retained on cation exchange
resin, while the 68Ge is remains in solution for future use. A small amount of rinsing of the cation exchange column,
completes the 68Ge source recovery. 68Ga is then stripped from the cation exchange resin using a small volume of 4M
HCl and adsorbed on a second cartridge of UTEVA resin. A small volume of rinse with 4M HCl provides additional
decontamination from 68Ge, and 68Ga is recovered in a small volume of dilute HCl (0.05-0.5M HCl). The chemistry isrobust and scalable. The separation has been demonstrated using 0.5 - 2mL columns/cartridges. Typical decay
corrected yields of 68Ga are 95 + 1% in 2-5mL of 0.1M HCl, with <10-7% 68Ge impurity. Stable metal ion impurities are
typically in the low parts per billion range. Operation of the generator has also been demonstrated with the Northstar
Medical Radioistope automated generator system.
Reagents
UTEVA Resin Cartridges (Eichrom UT-R50-S)
Cation Exchange 2mL Cartridges (Eichrom C8-R50-H)
68Ge Source*
Deionized Water
HCl*Germanium chloride is relatively volatile and can bespread through the air. Care should be taken tominimize contamination of personnel and work
spaces. Use of sealed systems for steps during
separation is recommended.
68

Equipment
Glass vials for storage of 68Ge source.
Glass or plastic vials/bottles for collection 68Ga productand waste.
5, 10 or 20mL plastic luer lock syringes
Gamma spectroscopy system for measurement of 68Ga.
(The electron capture of 68Ge can be measured by liquid
scintillation or 68Ge can be determined after decay/ingrowth of 68Ga using the 511keV emission following
positron annihilation.)

68

68

Ingrowth of Ga from Ge
100

68

Decay of Ga
100

Ge
68

80

Ga

% Activity% Activity

80
60
40
2068

Ga

60
40
20000123Hours

4560123Hours

45668Ga/68Ge Separation*(1) Clean 2mL 50Wx8 cartridge with:-20mL DI water-20mL 4M HCl-20mL 0.5M HCl(2) Load 68Ge/68Ga sourcein 10-20mL 0.5M HCl.
68Ga is retained.
(3) Rinse cartridge with 1mL 0.5M
HCl. Collect in 68Ge source
vessel. Push remaining fluid tosource vessel with air.
(4) Seal 68Ge source vessel and set(6) Precondition 2mL UTEVA
cartridge with 5mL 4M HCl.
(7) Place 2mL UTEVA
cartridge below 2mL50Wx8 cartridge.

10(8) Strip 68Ga from 50Wx8
onto UTEVA with 20mL4M HCl. Dispose ofeluate as waste.
(9) Remove 50Wx8cartridge.

1050Wx8 Cation Exchange

54Ga103102k'110Ge010-110-2(10) Rinse UTEVA cartridgewith 20mL 4M HCl.

aside for future use.

5(5) Rinse cartridge with 20mL 0.5M
HCl. Dispose as waste.

-1

10100110[HCl],M

10UTEVA Resin

10(11) Strip 68Ga with 5-10mL
0.1M HCl.

410Ga
3*The separation may also be performed using 0.5mL or 1mL columns/cartridges and proportionally scaled eluate volumes to improve method
speed and reduce losses from 68Ga decay during separation.

102Ge10k'1

1010cpm/mL

107610510410310210168

Strip
Strip 50Wx8
Load UTEVA UTEVA
0.1 M
4 M HCl
HClRinse
0.5 M
HCl

Load 50Wx8 10 mL
68
68
0.5 M HCl + Ge/ Ga

68

Ge

510-1

1001

10Ga

10[HCl], M

95% Ga-7<10 % Ge

Background001015202530

3540

45505560

Bed Volumes

References1) McAlister and Horwitz, “Automated Two Column Generator Systems for Medical Radionuclides,” Applied Radiationand Isotopes, 67:1985-1991 (2009).
1955 University Lane Lisle, IL 60532, USA+1 (630)963-0320

www.eichrom.com