Siderophores for Imaging Infection Using 68Ga-DFO

This study is a first in human mechanistic study hypothesizing that siderophore complexes labelled with a radiotracer (Gallium-68) will be taken up in sites of infection in patients with a vascular graft. Study objectives are to: i) Determine if siderophore uptake occurs in sites of infection using the radiolabelled siderophore 68Ga-DFO in patients with a vascular graft on PET/CT scans. ii) Determine if siderophore uptake as measured by the radiolabelled siderophore 68Ga-DFO is specific for infection by exploring whether uptake occurs in individuals with vascular grafts without infection and by characterising the uptake in normal tissues. The injected substances are well-known licensed products. The study will involve performing 68Ga-DFO PET/CT scans in 30 patients with vascular grafts, including 25 patients with diagnosed infection according to current syndromic criteria and 5 patients with a vascular graft but no evidence of any infection. Patients with infection will be recruited from patients who have had a prior FDG-PET-CT scan performed as part of their routine care which shows suspected graft infection. All patients will have 'static' PET-CT scans following injection of the tracer. The scans will take 30 minutes. The first ten patients with graft infection will also have 'dynamic' scans performed immediately after tracer injection lasting for 90 minutes. The result of these scans (e.g. time activity curves) will inform the scan protocol of the subsequent patients (e.g. uptake time). Up to 10 of these patients will have venous blood sampling at 8 time points up to 120 minutes after injection. Patients will be followed up in person or by telephone 24 hours after the scan. Apart from this no specific follow up procedure outside standard of care is planned within this study.