The purpose of this study was to assess the diagnostic value of scans with 99Tcm(V)-dimercaptosuccinic acid (DMSA) to localize bone metastases and to evaluate the capability to diagnose bone/joint infections with scans using 99TcmCitrate. Eighteen patients referred to bone metastases and eighteen patients referred to bone and joint in-fection were studied. In all patients

a bone scan of 99TcmMDP was obtained initially. Subsequently

comparative scans with 99Tcm (V)DMSA and 99TcmCitrate were conducted successively. Pathologic finding and/or microbi-ological finding

X-ray CT and /or MRI

and /or clinical follow-up (until symptoms disappeared) were considered to be proof of the presence of bone metastases and bone/joint infection. All of the eighteen patients with diagnosed bone metastases and of the eighteen patients with diagnosed bone and joint infection had positive 99TcmMDP scintigraphy. The fifteen patients with diagnosed bone metastases and the fifteen patients with diagnosed bone/joint infection had increased 99Tcm(V) DMSA accumulation at certain areas matched with those shown in 99TcmMDP scans

and only one patient with diagnosed bone metastases and the fifteen patients with diagnosed bone and joint infection had in-creased 99TcmCitrate accumulation at certain areas matched with those shown in 99TcmMDP scans. 99TcmMDP scans show 64 bone lesions in the bone metastases while 49 lesions by the 99Tcm(V) DMSA scans and only one le-sion by the 99TcmCitrate scans respectively. And 99TcmMDP scans show 22 bone lesions in the bone and joint infec-tion while 17 lesions by the 99Tcm(V) DMSA imaging and 16 lesions by the 99TcmCitrate imaging respectively. For bone metastases diagnosis

the sensitivity of 99Tcm(V) DMSA imaging and 99TcmCitrate imaging were 76.56% and 1.56%

respectively

and the specificity were only 22.73% and 27.27%

respectively. For bone and joint infection di-agnosis

the sensitivity of two kinds of imaging were 77.27% and 72.73%

respectively

and the specificity were 23.44% and 98.44%

respectively. Therefore

we should be cautious in the differentiating diagnoses of bone metasta-ses and bone/joint infection using99Tcm(V) DMSA imaging

for 99Tcm(V) DMSA scan actually could not discrimi-nate the malignant from the benign. On the other hand

99TcmCitrate scan showed a higher specificity for detecting bone and joint infection as compared with 99TcmMDP scan and 99Tcm(V) DMSA scan.