## 2 Cyclotron-Produced \({}^{68}\)Ga Using a Solid Target
### \({}^{68}\)Ga Production Using a Solid Target with ACSI Cyclotron
The dissolution of a solid target from works using a GE PETtrace cyclotron is presented in Table 4. Thisgaard and co-workers heated concentrated HCl to 90 \({}^{\circ}\)C using the QIS Dissolution System to dissolve the target [32]. In contrast, [PERSON] and group [34] dissolved the foil target in 9.5 M HCl for 2 min, the fastest of all methods in this review. Studies using single-column purification indicated respectable yields for peptide radiolabeling, which took less than 45 min [38; 46]. The single-column strategy purifies \({}^{68}\)Ga, separates \({}^{68}\)Zn, and finally formulates to [\({}^{68}\)Ga]GaCl\({}_{3}\) in 0.05 M HCl using octanol-based TK400 resin. Before elution, the column was washed with 0.7 mL of 0.05 M HCl to remove acid residues from 7 M HCl that could affect the [\({}^{68}\)Ga]GaCl\({}_{3}\) eluate. The final volume and concentration of [\({}^{68}\)Ga]GaCl\({}_{3}\) were 3.5 mL in 0.05 M HCl, corresponding to the generator eluate resulting in an AMA of 7.1 GBq/\(\upmu\)mol. However, the group reported significant radiolysis in their study [38]. This may occur during radiolabeling or chelation reactions where radiosensitive precursors are degraded [47; 48; 49]. Other studies have used two-column methods with a strong cation-exchange column and UTEVA resin. [PERSON] and co-workers utilized 4% cross-linking of 5 g AG 50W-X4 [22], while [PERSON] and his group used 8% cross-linking of 5 g AG 50W-X8 of a strong cation-exchange column [27]. The same solution was used in both studies, although [PERSON] and their group added ethanol when conditioning both columns. In contrast, [PERSON] and his colleagues [34] eluted [\({}^{68}\)Ga]GaCl\({}_{3}\) with 1 mL of water, producing the highest AMA of 86 \(\pm\) 22 GBq/\(\upmu\)mol. In this method, two UTEVA columns were used to purify and formulate [\({}^{68}\)Ga]GaCl\({}_{3}\). [\({}^{68}\)Ga]GaCl\({}_{3}\) was trapped with 4 M HCl, and both 4 M HCl and 2.5 M HCl were used for washing. The volume and residual acidity of the final [\({}^{68}\)Ga]GaCl\({}_{3}\) may have contributed to the high AMA. The method contributed to an activity recovery of 76 \(\pm\) 8% at EOP. The AMA in this work demonstrates the effect of highly concentrated [\({}^{68}\)Ga]GaCl\({}_{3}\) at a presumably low acidic molarity [34]. Apart from [PERSON] and co-workers, the use of hydroxamate resin was also investigated by [PERSON] and group [32]. They used a three-column strategy with the addition of LN resin between hydroxamate (ZR resin) and TK200 resin. The specific role of LN resin in this setup was to trap excess iron impurities before \({}^{68}\)Ga was retained in TK200 resin. The setup produced [\({}^{68}\)Ga]GaCl\({}_{3}\) in 2.5 mL of 0.1 M HCl with an AMA of 25 GBq/\(\upmu\)mol [32]. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Target** & **Separation of Target Material** & **Formulation** & **Time** & **EOP GEqb** & **[FOOTNOTE:]Footnote : **Formulation**[ENDFOOTNOTE]** & **EOS GEqcCl3** & **AMA** & **(GBg/imm)** & **Ref. ** \\
**Dissolution** & **and Purification** & **(min)** & **EOP GEqb** & **Majority (Volume)** & **EOS GEqb** & **AMA** & **(GBg/imm)** & **Ref. ** \\ \hline \multicolumn{1}{c}{R: TKT00 resin} & & & & & & & \\ \hline S: 7 M HCl & C: 7M HCl (5 mL) & & & & & & & \\ V: 0.5 mL & W: 7 M HCl (28 mL), 0.05 M & NA & 32 * & 3.31 & 0.05 M HCl (3.5 mL) & 1.56 * & 7.1 & [38] \\  & H: 0.05 M HCl (3.5 mL) & & & & & & \\ \hline S: 10 M HCl & C: 95 of SW:X4 & R: 100 mg UTEVA\({}^{\rm a}\) & & & & & \\ V: 10 mL & C: 10 M HCl (25 mL) & C: 4 M HCl (10 mL) & & & & & \\ V: 10 mL & W: 10 M HCl (20 mL) & W: 4 M HCl (10 mL) & & & & & \\ T: -40 min & E: 4 M HCl (12 mL) & E: 005 M HCl (2 mL) & & & & & \\ \hline \multicolumn{1}{c}{R: TUEVA} & & & & & & & \\ L: pre-dilution M HCl & & & & & & & \\ (11.5 mL) & & & & & & & \\ S: 95 M HCl V: 2 mL & W: 10 mL of 4 M, HCl & & & & & & \\ T: 2 min & 10 mL of 25 M HCl & W: 20 mL of 25 M HCl & 23 & 18 \(\pm\) 2 & Water (1 mL) & & 86 \(\pm\) 22 \({}^{\rm c}\) & [34] \\  & E: 2 mL.