Potential benefits of intra-prostatic cancer-specific imaging to guide therapy and monitor outcome in patients treated with radiation-based treatments for localized prostate cancer.

Prostate cancer is a multifocal disease in 76–87% of patients [1,4,8]. Typically, 3 separate foci of cancer are seen in a prostate which has been surgically removed, but there may be as many as twelve [1,4, 8]. Standard prostate biopsies cannot reliably detect these foci [7]. Ultrasound imaging, in expert hands, has a receiver operator characteristic curve of 0.6 in determining whether a region of the prostate contains cancer [3]. MRI is marginally better at detecting the separate intraprostatic foci and CT is completely ineffective for such imaging [7]. (MR spectropscopy shows great promise and is discussed in this issue of Cancer Biomarkers.) Therefore, in contrast to most