Preliminary experience of ⁶⁸Ga-BPAMD for imaging distant bone metastases in cancer patients

Bone is known to be the third most common site of metastases, besides lung and liver. A non-invasive early diagnosis of bone metastases helps in deciding subsequent therapy for the patient. The present study aims to evaluate the potential of ⁶⁸Ga labeled BPAMD as a diagnostic agent for detection of distant bone metastasis. BPAMD kits available from BRIT were used for radiolabeling with ⁶⁸Ga in semi-automated fluidic module. ⁶⁸Ga was eluted in the form of ⁶⁸GaCl3 using 0.05 M HCl from commercially available silica based ⁶⁸Ge/⁶⁸Ga generator. The contents of the kit were dissolved in 400 µL of HPLC grade water. The solution was transferred to the reactor vessel of fluidic module and incubated with ⁶⁸GaCl₃ at 95°C for 20 minutes. Radiolabeling yield and radiochemical purity were calculated via paper chromatography using 0.5 M Na-citrate buffer as mobile phase. A total of 7 patients have undergone whole-body PET/CT scan from base of skull to mid-thigh 45 min post intravenous administration of 4-5 mCi of ⁶⁸Ga-BPAMD. Radiolabeling yield of >99% was achieved by incubating the reaction mixture in 2 ml at 95 °C. Uptake of ⁶⁸Ga-BPAMD was similar to ^99mTc-MDP. Abnormal intense and focal uptake of ⁶⁸Ga-BPAMD was observed in skeletal lesions. Good target to background ratio was observed at 45 min. ⁶⁸Ga-BPAMD was prepared with good radiolabeling yield and radiochemical purity. Better image quality was additional benefit due to PET imaging. BPAMD can further be explored for radiolabeling with ¹⁷⁷Lu for bone pain palliation. (author)