Shingo Matsumoto1, Sonny Batra1, Hironobu Yasui1, Sankaran Subramanian1, Nallathamby Devasahayam1, Jeeva P. Munasinghe2, James B. Mitchell1, Murali C. Krishna1
1Radiation Biology Branch, National Cancer Institute, Bethesda, MD, USA; 2National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA
Angiogenesis is essential for solid tumors to grow beyond 1-2 mm3 and to switch from local vascular supply to novel microcapillary formation. During physiological angiogenesis, new vessels mature and become stable. However, in cancer, neovasculature is architecturally and functionally abnormal with large pores causing leakage of larger molecules. Increase in tumor microvascular permeability results in aberrant blood flow and regional hypoxia. Hypoxic tumors exhibit resistance to radiation therapy and so poor treatment outcome. In the present study, a novel technique for simultaneous imaging of tumor oxygenation and microvascular permeability using in vivo hyperpolarized 1H-MRI, known as Overhauser MRI (OMRI).