Biodistribution and predictive value of (IF)-I-18-fluorocyclophosphamide in mice bearing human breast cancer xenografts JOURNAL OF NUCLEAR MEDICINE Kesner, A. L., Hsueh, W., Htet, N. L., Pio, B. S., Czernin, J., Pegram, M. D., Phelps, M. E., Silverman, D. H. 2007; 48 (12): 2021-2027


In mice bearing human breast cancer xenografts, we examined the biodistribution of (18)F-fluorocyclophosphamide ((18)F-F-CP) to evaluate its potential as a noninvasive prognostic tool for predicting the resistance of tumors to cyclophosphamide therapy.(18)F-F-CP was synthesized as we recently described, and PET data were acquired after administration of (18)F-F-CP in mice bearing human breast cancer xenografts (MCF-7 cells). Tracer biodistribution in reconstructed images was quantified by region-of-interest analysis. Distribution was also assessed by harvesting dissected organs, tumors, and blood, determining (18)F content in each tissue with a gamma-well counter. The mice were subsequently treated with cyclophosphamide, and tumor size was monitored for at least 3 wk after chemotherapy administration.The distribution of harvested activity correlated strongly with distribution observed in PET images. Target organs were related to routes of metabolism and excretion. (18)F-F-CP uptake was highest in kidneys, lowest in brain, and intermediate in tumors, as determined by both image-based and tissue-based measurements. (18)F-F-CP uptake was not inhibited by coadministration of an approximately x700 concentration of unlabeled cyclophosphamide. PET measures of (18)F-F-CP uptake in tumor predicted the magnitude of the response to subsequent administration of cyclophosphamide.Noninvasive assessment of (18)F-F-CP uptake using PET may potentially be helpful for predicting the response of breast tumors to cyclophosphamide before therapy begins.

View details for DOI 10.2967/jnumed.107.045716

View details for Web of Science ID 000252895100020

View details for PubMedID 18006620