Biography
Sanjiv Sam Gambhir is a Professor of Radiology and Bio-X at Stanford University. He is the Head of Nuclear Medicine and Director of the Molecular Imaging Program at Stanford (MIPS). He trained at the University of California Los Angeles (UCLA) Medical Scientist Training Program, where he obtained both his M.D. and Ph.D. He completed his Medicine and Nuclear Medicine training at UCLA and was a Professor of Molecular Pharmacology, Vice-chair of Molecular & Medical Pharmacology and Director of the Crump Institute for Molecular Imaging before moving to Stanford University in 2003. Dr. Gambhir, his wife Aruna and six-year-old son Milan live in Portola Valley, California.
Dr. Gambhir has a translational laboratory that focuses on molecular imaging including new probe development for positron emission tomography (PET) and multimodality molecular imaging including the use of optical imaging. His laboratory has developed methods to image gene therapy in living subjects including humans. He has also developed many strategies for imaging basic cell/molecular biology events including signal transduction, gene expression, and cell trafficking. Dr. Gambhir also has extensive experience with FDG PET and has developed many of the management algorithms for cancer patients including cost-effectiveness models.
Dr. Gambhir currently oversees the activities of over 20 graduate students and post-doctoral fellows in his own lab and over 50 scientists in the Molecular Imaging Program at Stanford. He is funded by the National Institutes of Health and the Department of Energy. He recently received the 2004 gold medal award by the Society of Molecular Imaging, the 2004 distinguished scientist award by the Academy of Molecular Imaging, and the 2003 Holst Medal for his contributions to the field of molecular imaging. He is also President Elect of the Academy of Molecular Imaging (AMI).
Abstract
Molecular Imaging of Cancer with a Voltage Sensor
My laboratory has been bridging the fields of biomedical imaging with cell/molecular biology, oncology, molecular pharmacology, and chemistry in order to advance molecular imaging of cancer in living subjects. My lab has developed several assays which allow for imaging of cell surface receptors, intracellular enzymes, and reporter genes in living subjects including humans. Through use of technologies such as positron emission tomography (PET) it is becoming increasingly possible to monitor events related to cancer progression and efficacy of anti-cancer therapies. The next generation of imaging tools/assays should allow for customized imaging in which specific imaging agents are available for each individual based on their underlying molecular abnormalities.
In the current proposal, I would like to test in human volunteers and cancer patients a new class of imaging probe that accumulates in cancer cells that have up-regulated their mitochondrial membrane potential. Many types of cancer are currently imaged with 18F-2-fluoro-2-deoxyglucose (18F-FDG) which measures glucose utilization in tumors. 18F-FDG has limitations due to poor uptake by several tumor types and reduced specificity due to accumulation in inflammatory tissues, skeletal muscle, bowel, as well as many normal tissues which depend on glucose. My lab has recently validated that a Fluorine-18 labeled tetraphenylphosphonium analog (18F-TPP) can accumulate very well in many tumor types, that this accumulation is correlated with mitochondrial membrane potential, and has excellent pharmacokinetics because it clears from blood and other tissues very rapidly. Furthermore 18F-TPP has almost no uptake in inflammatory tissues and bowel, which should lead to a much better specificity than 18F-FDG. In the current proposal we will test 18F-TPP with PET in human volunteers for stability, biodistribution, pharmacokinetics, and radiation dosimetry (Aim 1). Subsequently we will test 18F-TPP against 18F-FDG in patients with rising CEA levels and GI malignancies to determine its ability to outperform 18F-FDG (Aim 2). Finally, we will compare 18F-TPP and 18F-FDG in predicting response to treatment in colorectal cancer patients undergoing chemotherapy.