Table 1: 68Ga-DOTA-TBIA101 radiolabeling using a SnO2-based 68Ge-68Ga generator.

Peptide conjugate 68Ga-DOTA-TBIA101

Number of radiosyntheses 23
Generator elution
Total 68Ga-activity eluted (MBq)1437 ± 489
 Waste fraction (%)7.1 ± 2.2
 Generator use (days), (range )198 ± 113, (11–279, 13)
68Ga-activity added (MBq)1201 ± 475
Buffer solution/peptide concentration (µM)2.5 M Sodium acetate/40
Optimal pH value3.5 ± 0.4
Temperature (°C)/duration (min)95/10
SPE C18-unit type
 Small sample volume <0.5 mL C18 Sep-pak light 100 mg
 Large sample volume >0.5 mL C18 Sep-pak 500 mg
SPE C18-unit elution mixture
 Standard mix (v/v)EtOH/Saline (1 : 1)
 Alternative mix (v/v)CH3CN/PBS (1 : 4)
 Unit desorption ratio (%)77 ± 21
Specific activity (GBq/µmol)12.4 ± 6
Time EOL to purified product (min)39 ± 6
Recovery of radioactivity (%)102 ± 2
Radiochemical purity
 Crude/final product HPLC (%)>92/99
 Crude/final product ITLC (%)>90/99
 Loss to apparatus and colloids (%)18 ± 8
Reproducibility
 Average %LE ITLC (range min–max)64 ± 18.5 (16–85)
  LE <25%: (%)1, (4.3)
  LE 25–60%: , (%)6, (26.0)
  LE >70%: , (%)12, (52.0)
End product activity half scale (MBq)*668 ± 385

Unless stated otherwise results are presented as mean ± SD of 23 of radiosyntheses. %LE = percentage labeling efficiency. *Details are given in Section 2.