| PrefaceBone metastasis is one of the important manifestations of malignant tumor in progress. It is critical for clinical scheme decided to detect bone metastases early and accurately. Radionuclide bone scintigraphy is the first choice to detect bone metastases for its high sensitivity. But if there are fewer lesions or untypical distribution showed, its diagnostic value will be lower because the specificity of bone imaging is rather poor.This study is to explore the clinical value of 24h-bone scintigraphy after dexamethason intervention for differentiating the benign bone lesions from the malignant ones. Thereby the specificity of radionu-clide bone scintigraphy will be improved.Materials20 patients with malignant bone lesion (242 foci) and 21 patients with benign bone lesion (102 foci) were randomly divided into nonintervention group and intervention group for comparative study respectively.SPECT (3200i XR/T) from GE was employed and dexamethason tablets were administrated.MethodsThe patients in the non-intervention group underwent bone scin-tigraphy 3h and 24h after the tracer administrated, while the patients in the intervention group took dexamethason 6. 75 mg orally after 3 fa-bone imaging, then underwent 24h-bone imaging. Different regions of interesting (ROI) were drawn in 3h- and 24h-imaging, then the radi-onuclide uptaking ratio ( RUR) for 24h to 3h was calculated. A focus was selected randomly, and region of interesting was drawn for 10 times, and then coefficient of variation ( CV) was calculated. Data were expressed in form of x+ s , Student-Newman-Keuls multiple range test was applied in inter-group comparisons.ResultsThere were no significant differences in RUR of benign lesions between the non-intervention group and intervention group (P>0.05). There were significant differences in RUR between the malignant lesions in the non-intervention group and that in the intervention group ( P < 0. 01) ; there were significant differences in RUR between the benign and the malignant lesions in the non-intervention group (P <0.05) ; and there were also significant differences in RUR between the benign and the malignant lesions in the intervention group ( P < 0.01). CV calculated was 2%. The sensitivity, specificity and accuracy of differentiating the benign bone lesions and the malignant ones by RUR with non-intervention and intervention were 75. 5% , 86.2% , 65.8% and 81.5% , 87.5% , 83.1% , respectively.DiscussionIt is very important for clinical scheme decided to detect bone metastases early and accurately. Radionuclide whole body bone scin-tigraphy is the first choice to detect bone metastases for its high sensitivity and feasibility. But if there are fewer lesions or untypical distribution showed, its diagnostic value will be lower for the specificity of bone imaging is rather poor. So many studies were put up for improving the specificity of radionuclide bone scintigraphy.Relative studies showed that there were differences in the time-activity curve of radionuclide uptaking between the normal and malignant bone lesion for their different pathological characters. So, 24h/ 4h RUR calculated by 24h-bone imaging were developed for telling the nature of bone lesions. But the studies in this field limited their objects within the lesions of spine, and the number of the cases was limited. And their result suggested there were overlaps in malignant and benign lesions in large extent. Thus the diagnostic efficacy was not satisfied.This study was to lessen the overlaps of RUR in malignant and benign lesions by 24h-bone scintigraphy after steroid hormone intervention. By using this technique, the specificity of bone scintigraphy increased from 61% which routine bone scintigraphy showed to 87. 5% , while the sensitivity and accuracy increased from 75. 5% and 65. 8% , which 24h-bone imaging showed to 81.5% and 83.1% , respectively. The diagnostic efficacy of radionuclide bone scintigraphy was improved greatly.In this study, we observed that after the steroid hormone interven...
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