Fig. 1.
18F-Fluoroestradiol (18FFES) PET images before and 3 days after treatment with Zendoxifen administered orally in a breast cancer patient with bone metastasis. Focal tracer uptake in ER+ bone lesions is seen before treatment, but is blocked on the subsequent scan. Physiologic activity is seen in liver, GI tract, bladder, and vascular collateral vessels from the left arm injection