Opportunistic screening for osteoporosis and vertebral fracture using CT attenuation from 18F-fluorocholine PET/CT in patients with prostate cancer.

OBJECTIVE: Androgen deprivation therapy (ADT) for prostate cancer (PCa) induces bone loss and increases fracture risk, yet baseline bone mineral density (BMD) assessment is rarely performed. Opportunistic BMD evaluation using routine imaging could improve osteoporosis screening in this population. We aimed to assess the feasibility of using trabecular attenuation (TA) in Hounsfield units (HU) from the low-dose CT component of 18F-fluorocholine (FCh) positron emission tomography (PET)/CT for opportunistic osteoporosis and vertebral fracture screening in men with PCa, compared with stand-alone diagnostic CT. METHODS: In this retrospective single-centre study, 81 patients with PCa who underwent both FCh-PET/CT and stand-alone CT within 6 months were included. TA(HU) was measured at L1-L3 vertebral levels on both scans. ADT exposure and duration were recorded to assess their associations with TA. Primary outcomes were intraclass correlation coefficients (ICC) and Bland-Altman agreement between TA values from FCh-PET/CT and stand-alone CT. Secondary outcomes included associations between TA, ADT duration and vertebral fractures. RESULTS: TA values from FCh-PET/CT and stand-alone CT were comparable (ICC: 0.72, 0.70 and 0.67, for L1-L3; p<0.001). Mean FCh-PET/CT TA were 121 HU (L1), 122 HU (L2) and 118 HU (L3). Lower attenuation correlated with longer ADT duration (r=-0.43; p=0.008). Vertebral fractures were observed in 18.5% of patients and were associated with lower TA (87.8 vs 127.5 HU; p=0.01). CONCLUSIONS: FCh-PET/CT provides a feasible, readily available approach for opportunistic osteoporosis and fracture risk screening in men with PCa, supporting its integration into routine imaging workflows to promote bone health assessment and fracture prevention.