LOD and LOQ were determined for the survey meter.
The proposed method proved to be accurate (CV of mean RCP 0.05). Readings obtained with the survey meter were also plotted against the scanner results. Linearity of the survey meter was determined for Tc-99m. Student’s paired t-test or ANOVA were used with ‘no significant difference’ designated at a 95% confidence-interval ( P ≥ 0.05). Internationally recommended validation parameters and acceptance criteria were used. The percentage RCP for each TLC strip was calculated using both counting methods. Each strip was first scanned on the chromatogram-scanner used at the UMCG (standard method), and immediately thereafter the strip was cut in two pieces and radioactivity from each portion was counted with a small survey meter from YGH. Samples of technetium-99m RP were spotted on 1 × 10 cm iTLC-SG strips and developed in appropriate mobile phases. Sestamibi, HMDP and DMSA kits currently used at YGH were reconstituted at UMCG with about 2000 MBq of freshly eluted sodium pertechnetate as described by the manufacturer, and spiked with eluate of the same generator to obtain a range of impurity concentrations. A GMP-compliant method used at the University Medical Center Groningen (UMCG), the Netherlands was used as the comparator. To ensure the efficacy of RP prepared at Yaoundé General Hospital (YGH) Cameroon, this study cross-validated a cost-effective routine chromatographic method using a simple survey meter technique. All radiochemical analysis methods should however be validated against compendial or otherwise proven methods. In low-income settings, it may not be possible to use compendial analytical methods or expensive equipment for radiochemical purity analysis. The radiochemical purity (RCP) of technetium-99m labelled radiopharmaceuticals (RP) is important to ensure optimal scintigraphic image quality.
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