The purpose of this study was the assessment of the feasibility of dynamic 
positron emission tomography (PET) studies with fluorine-18 fluorodeoxyglucose 
((18)F-FDG) to quantify effects of the cyclic Arg-Gly-Asp peptide cilengitide, 
which targets the ανβ 3 and ανβ 5 integrin receptors in rats with breast cancer 
bone metastases. Rats were inoculated with MDA-MB-231 breast cancer cells, 
followed by the development of lytic lesions in the hind leg. Rats with lytic 
lesions were treated with cilengitide five times weekly on a continuous basis 
from days 30 to 55 after tumor cell inoculation. Dynamic PET studies with 
(18)F-FDG were performed in untreated (n=9), controlled (n=4) and treated rats 
(n=6). The data were assessed using learning-machine two-tissue compartmental 
analysis. The (18)F-FDG kinetic parameters obtained by two-tissue compartmental 
model learning-machine showed significant differences when individual parameters 
were compared between the control group and treated animals. Quantitative 
assessment of the tracer kinetics and the application of classification analysis 
to the data provided us with evidence to identify those tumors that demonstrated 
effect of cilengitide treatment. The transport rate K1 and the phosphorylation 
rate k3 were significantly different (P=0.033 and 0.038, respectively). 
Classification analysis based on support vector machines ranking feature 
elimination of the combination of PET parameters revealed an overall accuracy of 
80.0% between treated animals and the control group. We were able to identify 
83.3% treated animals compared with the control group based on k2 and VB. In 
conclusion, the results revealed that cilengitide treatment of experimental 
breast cancer bone metastases had a significant therapeutic impact on (18)F-FDG 
kinetics.