[en] For years, bisphosphonates (BP) were known for their role in reducing the risk of skeletal related event in patients with bone metastases by accumulating and inhibiting the osteoclastic activity. Hence, since the emergence of germanium-68/gallium-68 generator for positron emission tomography (PET) imaging, developments in gallium-68 labelled BP for bone imaging have been looked into. Through the conjugation of a stable bifunctional chelator to a BP namely 2,2′-(7-(1-carboxy- 4-((2,5-dioxopyrrolidin-1-yl)oxy)-4-oxobutyl)- 1,4,7-triazonane-1,4-diyl)diacetic acid (NODAGA) and Pamidronic acid, this research aims to study the preparation, characterization, and in-vitro studies of [⁶⁸Ga]NODAGA-Pamidronic acid ([⁶⁸Ga]NODPAM) for PET bone imaging. NODAGA was conjugated to Pamidronic acid via NHS ester strategy. The conjugated precursor was characterized using tandem mass spectrometry (MS/MS) and purified using high performance liquid chromatography (HPLC). The conjugated NODAGA-Pamidronic acid was radiolabelled with gallium-68 in acetate buffer forming [⁶⁸Ga]NODPAM complex. The percentage radiochemical purity (%RCP) was assessed using radio-thin layer chromatography scanner (stationary phase: TLC-SG 60; mobile phase: acetonitrile:0.4M Phosphate (7:3)). The human plasma stability was studied 0.5 hourly for 2.5 hours. The bone binding assay of [⁶⁸Ga]NODPAM was performed using synthetic hydroxyapatite (HA) and was compared with [^99mTc]MDP. To visualize the retention of [⁶⁸Ga]NODPAM on bone, a preliminary PET image of fresh bone incubated in [⁶⁸Ga]NODPAM was performed.

[en] ${}^{18}$F-fluorination using aluminum-fluoride ([${}^{18}$F]AlF) chelate technique has been reported to give a low-to-moderate radiochemical yield, between 5 and 20%. Therefore, the work described here outlines the optimum ${}^{18}$F-fluorination condition for the formation of [${}^{18}$F]AlF${}^{2+}$ and [${}^{18}$F]AlF-NOTA-NHS complex with the radiochemical yield (RCY) and purity (RCP) of more than 90% as a prerequisite step before proceeding with the radiopharmaceutical preparation using the [${}^{18}$F]AlF-bifunctional chelator technique. As well as being simple, the suggested method is practical and relevant for beginners interested in ${}^{18}$F-fluorination with [${}^{18}$F]AlF-chelate complex technique or also for a researcher who aims to proceed on an extensive scale.