Functional imaging and detection of local recurrence in soft tissue sarcomas by positron emission tomography

Background: Besides anatomically-based radiodiagnostics, functional imaging may be used for characterizing soft tissue sarcomas (STS). This study eval uates positron emission tomography (PET) with three different radiotracers (fluorine-18 deoxyglucose [FDG], carbon-11 aminoisobutyric acid [AIB] and o xygen-15-labeled water [O15-water]) for imaging STS and the detection of lo cal recurrence. Patients and Methods: 21 patients presented with 9 primary STS, 5 recurrent STS and 10 lesions suspicious for local recurrence (radiol ogical tomography). Standardized uptake values (SW) were calculated in tumo r and normal tissues (muscle/blood vessels). Surgery with pathological exam ination or follow-lip data were referred to as control criteria. Results: A ll tracers accumulated in STS with no difference between primary and locall y recurrent tumors. The uptake in STS was increased compared to muscle (FDG , P < 0.0001; AIB, P = 0.0039; O15-water, P = 0.002) and to blood vessels f or FDG (P < 0.0001) as well as AIB (P = 0.0038). Of 10 patients with suspec ted recurrence, 6 presented neither PET criteria for recurrence nor local f ailure in the specimens ol during follow-up, while 4 cases with positive PE T scans were ultimately diagnosed with local failure. Conclusion: Besides F DG, AIB and O15-water were shown to accumulate in primary and recurrent STS of different histologic type. A precise differentiation from normal muscle was found for all tracers. FDG and AIB differentiated viable tumor from bl ood vessels. PET using FDG, AIB and O15-water is suitable for functional im aging of STS and the detection of sarcoma recurrence.