Stanford’s Division of Nuclear Medicine and Molecular Imaging is changing the way cancer is diagnosed and treated. Their work centers on the fast-growing field of theranostics, a word combining “therapeutics” and “diagnostics,” which merges two key steps of cancer care: imaging and treating tumors, into one highly targeted process.
To understand theranostics, it helps to start with what nuclear medicine is. Traditional imaging, such as X-rays or CT scans, uses an external energy source to obtain structural and anatomical information about the patient’s body. In contrast, nuclear medicine looks at how the body is functioning from the inside at a molecular level.
To start, a low-radiation molecular compound called a radiotracer is injected into the patient. This compound is designed to travel and bind to specific molecules or cells, such as cancer cells, where its weak radioactive signal can be detected by a positron emission tomography (PET) scanner, allowing clinicians to see exactly where the cancer cells are and how much the cancer has spread throughout the body. Next, the same radiotracer molecule is readministered to the body, this time carrying a different, stronger radioactive isotope, which is the form of an element that slowly releases radiation.
The radiotracer targets only cancer cells, sparing nearby healthy tissues from the cancer-killing radiation it emits. It’s a search-and-destroy approach. Doctors first use one form of the compound to locate the cancer, and then use another form to deliver targeted radiation therapy to those exact spots.
“If we can see it, we can treat it,” said Stanford Cancer Institute member Erin Grady, MD, clinical professor of radiology and interim division chief for Nuclear Medicine and Molecular Imaging.
Precision treatments for prostate and neuroendocrine tumors
Currently, the Stanford team primarily uses theranostics to treat prostate cancer and neuroendocrine tumors, a rare group of cancers that can grow in the stomach, intestines, pancreas, and other organs.
For patients with advanced prostate cancer, doctors use a drug called Pluvicto, also known as lutetium-177 vipivotide tetraxetan. The key ingredient, lutetium-177, is a radioactive isotope of the element lutetium, a silvery metal that occurs naturally in the earth’s crust. It emits low-energy beta radiation, a form of radiation that can travel only a few millimeters in tissue. Because of its short travel distance, healthy tissues are further protected from radiation exposure.
Pluvicto works by linking lutetium-177 to a molecule that specifically seeks out a protein on prostate cancer cells called prostate-specific membrane antigen (PSMA). Once the drug attaches to the cancer cell, the radiation from lutetium-177 damages the cell’s DNA, stopping its ability to divide and grow.
Patients with neuroendocrine tumors are treated with a similar compound called Lutathera, or lutetium-177 dotatate. Like Pluvicto, Lutathera also uses lutetium-177 to deliver radiation directly to cancer cells. However, instead of targeting PSMA, it attaches to a protein on the tumor’s surface called the somatostatin receptor. These receptors are highly expressed in neuroendocrine tumors, making them ideal targets for therapeutics. Once Lutathera binds to the receptor, the lutetium-177 emits radiation to damage and kill the cancer cells.
The clinic also uses other radioactive elements for different cancers. Radium-223 dichloride, commonly known as the drug Xofigo, contains the isotope radium-223, which behaves like calcium and naturally accumulates in bones. This makes it especially useful for prostate cancer that has metastasized to the bone, allowing the radiation to precisely target those areas. Similarly, the team uses radioactive iodine (iodine-131) to treat thyroid cancer, since the thyroid naturally absorbs iodine from the bloodstream.
This pairing of element and disease (iodine with thyroid, radium with bone, lutetium with prostate and neuroendocrine tumors) is the foundation of modern theranostics.
Earning world-first accreditation
In 2025, the Stanford team became one of the first programs in the world to be officially accredited for theranostics care by the Inter-Societal Accreditation Commission (IAC), a national organization that reviews hospitals and clinics to ensure they meet the highest standards in patient care, safety, and quality control.
“That was major. They looked at absolutely everything, from how we care for patients to how we handle radiation safety and document procedures,” said Grady. “We’re really grateful for that.”
The result is that Stanford’s theranostics clinic is now considered a global leader in setting the standard for how this specialized care should be delivered.
Collaboration and clinical research
Stanford’s theranostics clinic is also a hub of research and innovation.
“The field is blossoming before our eyes,” remarked Stanford Cancer Institute member Hong Song, MD, PhD, assistant professor of radiology. “With this new wave, there’s a lot of new findings and interest in the field. We’re trying to push these products into FDA approval to benefit these cancer patients.”
Song manages the theranostic team’s clinical trials portfolio and helps coordinate research across departments. He emphasizes that the depth of the theranostic team’s portfolio speaks to the strength of the entire team, from technologists to nursing staff and clinical trial coordinators.
The team is involved in several active clinical trials, exploring new radiopharmaceuticals and imaging techniques that could improve both the accuracy of cancer detection and the effectiveness of targeted treatments.
“There’s no way to be successful in this field without collaboration,” said Song. “We work closely with colleagues in medical oncology, radiation oncology, urology, and surgery. Every new therapy or trial depends on that teamwork.”
“Our partnerships are what make this possible,” Grady added. “Each specialty, from our committed technologists, staff, and trainees, brings a unique perspective, and together we’re able to offer patients access to the most advanced treatments available. It takes a village.”
Moving forward
With new accreditation, national recognition, and a growing research portfolio, Stanford’s Nuclear Medicine and Molecular Imaging division is poised to continue leading the way in theranostics. This means more precise treatments, fewer side effects, and a growing sense of hope for patients.
“Theranostics brings together everything we strive for in medicine. It’s about using the most advanced science available, but doing it in a way that’s deeply personal, compassionate, and focused on each individual patient."
The theranostics program could not have been created without the contributions of Sanjiv S. Gambhir, a physician-scientist who helped build Stanford’s molecular imaging into a national hub. He founded and led the Molecular Imaging Program at Stanford, championing in vivo modalities such as PET and optical imaging and translating imaging probes to clinical use. Through interdisciplinary leadership and mentorship, he and his wife, Aruna, expanded Stanford’s nuclear medicine research, infrastructure, and global collaborations, elevating the program’s reach and impact.
After a national search for his replacement, Stanford welcomed Umar Mahmood, MD, PhD, as the new chair of the Stanford Medicine Department of Radiology, effective January 16, 2026. Mahmood is an internationally recognized clinician and researcher, specializing in the translation of molecular imaging to understand the drivers of cancer and its application in guiding precision medicine. He is dedicated to advancing imaging through innovative and collaborative approaches, which is essential for a world-class theranostics program.
“Theranostics brings together everything we strive for in medicine,” said Grady. “It’s about using the most advanced science available, but doing it in a way that’s deeply personal, compassionate, and focused on each individual patient.”
