ZD4054 With Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) for Prostate Cancer

All patients will be treated with ZD4054 at 10 mg PO daily, repeated in four week cycles (1 cycle = 28 days). All patients will initially undergo NaF and FDG PET/CT and MRI imaging at baseline (scan#1), and then again after 4 weeks (scan#2) of ZD4054 exposure. Subsequently, ZD4054 will be held for 2 weeks followed by the final NaF and FDG-PET/CT and MRI acquisition (scan#3). After the final PET/MRI is obtained, patients will resume ZD4054 and be assessed for safety prior to each new cycle of therapy. Standard disease evaluation assessments will be conducted after cycle#3, and repeated after every third cycle (sooner if clinically indicated). Therapy will continue until radiographical/clinical disease progression or unacceptable toxicity