Positron Emission Tomography Imaging of Tumor Hypoxia

Hypoxia, a condition of insufficient O-2 to support metabolism, occurs when tumor outgrows its vascular supply. As the tumor cells gradually become hypoxic, they adapt by up-regulating the production of numerous proteins that promote their survival and metastatic spread. These changes result in patients with hypoxic tumors invariably experience poor outcome to treatment. Accordingly, the development of assays for the detection of hypoxia in patients in order to predict outcome and identify patients with a worse prognosis and/or patients that would benefit from appropriate treatments is of potential interest to researchers and clinicians. A variety of invasive and noninvasive approaches have been developed to detect tumor oxygenation. These approaches including oxygen-sensitive electrodes and hypoxia marker techniques using various labels that can be detected by different methods such as autoradiography, immunohistochemistry, nuclear medicine imaging and magnetic resonance imaging. In this review, we will discuss the non-invasive, potentially providing a quantitative and high resolution three-dimensional molecular imaging modality with positron emission tomography which is available to measure tumor hypoxia.