%0 Journal Article %A Wei-Ann Hsueh %A Amanda L. Kesner %A Anne Gangloff %A Mark D. Pegram %A Malgorzata Beryt %A Johannes Czernin %A Michael E. Phelps %A Daniel H.S. Silverman %T Predicting Chemotherapy Response to Paclitaxel with 18F-Fluoropaclitaxel and PET %D 2006 %J Journal of Nuclear Medicine %P 1995-1999 %V 47 %N 12 %X Paclitaxel is used as a chemotherapy drug for the treatment of various malignancies, including breast, ovarian, and lung cancers. To evaluate the potential of a noninvasive prognostic tool for specifically predicting the resistance of tumors to paclitaxel therapy, we examined the tumoral uptake of 18F-fluoropaclitaxel (18F-FPAC) in mice bearing human breast cancer xenografts by using small-animal–dedicated PET and compared 18F-FPAC uptake with the tumor response to paclitaxel treatment. Methods: PET data were acquired after tail vein injection of approximately 9 MBq of 18F-FPAC in anesthetized nude mice bearing breast cancer xenografts. Tracer uptake in reconstructed images was quantified by region-of-interest analyses and compared with the tumor response, as measured by changes in tumor volume, after treatment with paclitaxel. Results: Mice with tumors that progressed demonstrated lower tumoral uptake of 18F-FPAC than mice with tumors that did not progress or that regressed (r = 0.55, P < 0.02; n = 19), indicating that low 18F-FPAC uptake was a significant predictor of chemoresistance. Conversely, high 18F-FPAC uptake predicted tumor regression. This relationship was found for mice bearing xenografts from cell lines selected to be either sensitive or intrinsically resistant to paclitaxel in vitro. Conclusion: PET data acquired with 18F-FPAC suggest that this tracer holds promise for the noninvasive quantification of its distribution in vivo in a straightforward manner. In combination with approaches for examining other aspects of resistance, such quantification could prove useful in helping to predict subsequent resistance to paclitaxel chemotherapy of breast cancer. %U https://jnm.snmjournals.org/content/jnumed/47/12/1995.full.pdf