Sanjiv Sam Gambhir passed away from cancer on Saturday, July 18, just a day after receiving the Dean’s Medal, Stanford Medicine’s highest honor. Gambhir was known for having one of the brightest minds in medicine, fathering the field of molecular imaging and pioneering research in precision medicine and early cancer detection. The Daily attended the Dean’s Medal tribute, where his friends and coworkers gathered to celebrate his life and contributions. 

“Gambhir came to me one day and told me he did not believe that people would be interested in his [idea of] bringing physics, math and nuclear medicine together, that they would not have any interest in his work,” recalls UCLA professor Michael E. Phelps. “I said, ‘Sam Gambhir, you are bright, exciting, smart and extremely hardworking. You have a vision of the world that you see. They will not only be interested in what you create — you will change our field.’”

And Gambhir did. 

During his time at Stanford, Gambhir served as the chair of radiology, the head of the division of Nuclear Medicine, the chief of the Molecular Imaging Program and the director of the Canary Center for Cancer Early Detection. During his career, he co-authored over 700 papers, resulting in 40 patents, and mentored more than 150 postdocs and graduate students. Gambhir was celebrated for his achievements in interdisciplinary research, combining his background in physics, engineering and mathematics to improve early cancer detection.

“I was inspired by Sam the day we came together,” Phelps said. Phelps was the inventor of the PET (positron emission tomography) scanner. In 1994, Phelps recruited Gambhir to join the UCLA faculty, shortly after Gambhir received his M.D. and his Ph.D. in biomathematics. 

“I mean, you watch this natural curiosity, you watch him work so hard,” Phelps said. “He used to sleep on the PET scan, all through the night, to be there.” 

Positron emission tomography is a method by which radioactive particles are used to detect changes in organs and tissues. These particles “emit signals [which are then] transformed into an image.” 

“What Dr. Gambhir thought was important was that molecular changes in your body occur far earlier than a structural change,” said Michelle L. James, assistant professor of radiology. Gambhir worked for years to combine cellular and molecular biology and biomedical imaging, going beyond traditional PET imaging to develop ‘molecular spies.’ These ‘spies’ were PET reporter genes, which examine bodily errors at the molecular level. When an error is found, these spies send signals, which can be picked up by a scanner. 

Gambhir was also known for his creativity and his fearless, unconventional methods in approaching cancer research. 

“Sam [did] mental experiments, they’re called ‘What ifs.’ ‘So, what if I did this? What do I think would happen?’” Phelps said. “He would rather fail at true discovery and invention than succeed on the average,” adding that Gambhir always believed that if he worked hard enough, he could create and make real the thing he saw in his mind.

Gambhir needed to figure out a way to detect cancer in completely healthy individuals, without compromising their present quality of life. 

“If you’re talking about early detection of a disease, by definition it means detection before a person even knows that they have a disease,” said Norbert Pelc, emeritus radiology professor at Stanford Medical School. “You want to be making these measurements in a nonintrusive way, without the person’s daily life activities being affected.”

He began to think about ways to incorporate cancer detection in a person’s daily life. 

“He thought, ‘What are all of the things we do passively in our day-to-day life that we could collect data on?’” James said. “Whether it’s monitoring your sleep or looking in the mirror in the morning and having your mirror detect changes in your facial expression. He’d say, ‘Imagine if you’re in your shower and being scanned?’ — No one thinks like that.” 

In addition to developing the PET reporter genes, Gambhir worked on developing a smart toilet, which detects molecular changes in urine and stool, and a smart bra, which analyzes tissue to detect early signs of breast cancer. 

But Gambhir was known at Stanford not just as a brilliant physician-scientist, but also as one of the kindest, most sincere members of the medical community. 

“Sam’s commitment [was] to the betterment of humanity,” Pelc said. “He would rather medicine not be so involved in healing the sick, but rather preventing people from getting sick in the first place.” 

James recalled that Gambhir fundamentally changed the way that she viewed medicine and science. She said that he would often start their lab meetings by reminding them of why they were doing this research in the first place. 

“‘I want you all to remember why we’re here,’” James recalls Gambhir saying. “‘If anyone’s forgotten, I want you to come over to the clinic with me because this morning I saw patients who were suffering — there are real people at the other side of this who we’re trying to help. This is why we’re here.’” 

At the center of Gambhir’s passion for research and early cancer detection was his family. 

“Sam’s family immigrated to the U.S. when he was five, and they came from India. They were a wonderful family,” Phelps said. “They taught this young boy the right things about life — to work hard and to be extremely honest and sincere. I think he entered college at 15 and entered medical school at 18. He came with all of the passions and interests in the world.”

Gambhir’s wife, Aruna, had survived breast cancer twice. In 2013, his teenage son, Milan, was diagnosed with glioblastoma multiforme, a rare and aggressive brain cancer. Like his father, Milan was known for his brilliant mind and his determination, and Milan himself dreamed of developing a wristband that could detect a “recurrence of cancer through microbubbles that would attach to circulating tumor cells in the bloodstream.” 

“This brings me to Milan,” Gambhir said, in a speech, years after his son was diagnosed. “What motivates me is that if he had been born 100 years from now, the tools of precision health would have possibly allowed him to live much, much longer. I remain optimistic that the fundamental basic science that we all continue to do leads to new technologies that will help re-engineer our own bodies so that we can detect disease early.”

“Welcome to the revolution,” he said.

While Gambhir himself passed away after his own battle with cancer, he lives on in the memories of his friends, family members and students. 

“Sam has been one of those people against whom I try not to measure myself because I’ll lose,” Pelc said. “There are these people who we are very fortunate to come across in life, who are just so amazing that they’re inspiring in multiple ways. He’s one of those.”

“Sam was a true visionary and a scientist of the highest caliber,” said Lloyd Minor, Dean of Stanford Medical School. “His research and innovations have, with no uncertainty, founded modern medicine’s approach to early disease diagnostics and will continue to guide the future of precision health.” 

James said that Gambhir truly cared about each and every one of his students, and that, to her, his lab felt like a family.  

“I’ve never had a mentor like him, nor did I know it was possible for someone to be such a brilliant scientist and lead in his scientific boldness, but also just as a lovely human as well, somebody who clearly cares so deeply about all of his people in his lab,” she said. “All of his students, [we were] like his children. [He was] really like a dad to us.”

This article has been corrected reflect that Gambhir worked with positron emission tomography, not positive emission tomography. The Daily regrets this error.

Contact Sophia Nesamoney at nsophia ‘at’ stanford.edu.