(18)F-FDG and (18)F-FET uptake in experimental soft tissue infection.
The aim of this study was to compare the uptake of (18)F-fluoroethyl- L-tyrosine ((18)F-FET) with that of (18)F-fluorodeoxyglucose ((18)F-FDG) in activated inflammatory white blood cells. Unilateral thigh muscle abscesses were induced in 11 rats by intramuscular inoculation of 0.1 ml of a bacterial suspension ( S. aureus, 1.2 x 10(9) CFU/ml). Four animals were intraperitoneally injected with 130-180 MBq (18)F-FDG, four with 140-170 MBq (18)F-FET and three with a mixture of 140-170 MBq (18)F-FET and 1.8 MBq (14)C-deoxyglucose. Autoradiography (10 microm slice thickness) of the abscess and the contralateral muscle was performed and detailed spatial correlation of autoradiography and histopathology (haematoxylin-eosin staining) was obtained. Regions of interest were placed on the abscess wall and the grey values (digitised image intensities) measured were converted to kBq/cc per kBq injected activity per gram (SUV). Areas with increased (18)F-FDG uptake corresponded to cellular inflammatory infiltrates mainly consisting of granulocytes. The SUV was calculated to be 4.08+/-0.65 (mean+/-SD). The uptake of (18)F-FET in activated white blood cells was not increased: the SUV of the abscess wall, at 0.74+/-0.14, was even below that of contralateral muscle. The low uptake of (18)F-FET in non-neoplastic inflammatory cells promises a higher specificity for the detection of tumour cells than is achieved with (18)F-FDG, since the immunological host response will not be labelled and inflammation can be excluded.
Kaim
Achim H
AH
Nuclear Medicine, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland. Achim.Kaim@dmr.usz.ch
Weber
Bruno
B
Kurrer
Michael O
MO
Westera
Gerrit
G
Schweitzer
Alain
A
Gottschalk
Jochen
J
von Schulthess
Gustav K
GK
Buck
Alfred
A
D000038:Abscess / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D001345:Autoradiography; D002250:Carbon Radioisotopes / Q000493:pharmacokinetics; D003847:Deoxyglucose / Q000493:pharmacokinetics; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D007866:Leg / Q000000981:diagnostic imaging; D007962:Leukocytes / Q000000981:diagnostic imaging*; D009220:Myositis / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D012016:Reference Values; D013203:Staphylococcal Infections / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*
D002250:Carbon Radioisotopes; C117289:O-(2-fluoroethyl)tyrosine; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D014443:Tyrosine; D003847:Deoxyglucose