Robert Flavell, MD, PhD

Robert Flavell, MD, PhD, is the Chief of Molecular Imaging and Therapeutics Clinical Section in the Department of Radiology and Biomedical Imaging at the University of California, San Francisco. He received his medical degree from Weill Cornell Medical College, and his PhD from the Rockefeller University as part of the Tri-Institutional MD PhD program. He completed his one-year internship at the Memorial Sloan­Kettering Cancer Center in New York. Dr. Flavell completed his radiology residency at UCSF, including an NIH T32 funded research fellowship, and subsequently completed a one-year fellowship in nuclear medicine. In June 2016. he joined the faculty as an Assistant Professor in Residence.

Dr. Flavell’s laboratory, the Molecular Imaging Lab, focuses on the development of new molecular imaging tools for better understanding of disease progression in patients with prostate and other cancers. One area of interest is the relationship between acidic interstitial pH and disease progression. Solid tumors are poorly perfused and secrete acids into the adjacent interstitium, resulting in a pH which is mildly acidic, typically ranging from 6.5 – 7.0. This property has been associated with high-grade malignancy, local invasion, and metastasis in animal models. Therefore, it would be desirable to have a method which could be used in patients for monitoring tissue pH. Therefore, one focus of Dr. Flavell’s research is developing methods of imaging acidic interstitial pH with potential for clinical translation. Specifically, two methods are being developed, one of which permits whole body evaluation of areas of acidic pH using positron emission tomography (PET) imaging, and one method which permits quantitative, local determination of interstitial pH based on hyperpolarized 13C magnetic resonance spectroscopy (HP-MRS). The PET method is based on pro-drug glycosylamine derivatives of the commonly used oncologic tracer, [18F]FDG, termed [18F]FDG amines, which are blocked with an acid-labile protecting group. When exposed to the mildly acidic pH present in the interstitium of a solid tumor, the caging group decomposes, liberating native [18F]FDG, which is subsequently absorbed by the adjacent cancer cell (Flavell R.R. et al., Bioconjugate Chem., 2016). The HP-MRS method is based on the administration of a 13C labeled probe which has a predictable change in its chemical shift based on pH. By comparison to a standard curve, quantitative pH measurements can be obtained (Flavell R.R. et al. Chem. Comm. 2015). These techniques are being optimized and ongoing directions include application in animal models, with the long term goal of clinical translation. Other areas of developing interest in the laboratory include techniques for imaging of metals in the microenvironment, and imaging of a metabolic signature associated with immune activation.

Expertise:
Nuclear Medicine and Molecular Imaging and Therapeutics

Specialty:
Novel radiotracer development, oncologic imaging, PET imaging, hyperpolarized 13C magnetic resonance imaging

Professional Interests:
Radiology, molecular imaging, PET imaging, prostate cancer, nuclear medicine, radiochemistry, hyperpolarized 13C magnetic resonance imaging

Education and Training:
• Medical School: Weill Cornell Medical College, New York
• PhD: The Rockefeller University, New York
• Internship: Memorial Sloan­-Kettering Cancer Center, New York
• Residency: University of California, San Francisco
• Fellowship: University of California, San Francisco – Nuclear Medicine