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How Nuclear Medicine Detects and Treats Cancer — Dr. Vikram Lele, Jaslok Hospital
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How Nuclear Medicine Detects and Treats Cancer — Dr. Vikram Lele, Jaslok Hospital

| 28 July 2026

Cancer is a word that brings immediate fear to most people — but early detection dramatically improves treatment outcomes and prognosis. In this episode of Just Health for the People, a public health awareness initiative by Jaslok Hospital, Dr. Vikram Lele, Director of the Nuclear Medicine Department at Jaslok Hospital and Research Centre, Mumbai, explains how nuclear medicine plays a central role in detecting cancer early, tracking its spread, and increasingly, treating it directly.

 

Why Early Cancer Detection Matters

Detecting cancer at an early stage makes treatment significantly easier and improves prognosis substantially. This is precisely why advanced detection technology — capable of identifying cancer before it spreads — plays such a critical role in modern oncology. Nuclear medicine is one of the key specialties enabling this early, precise detection.
 

How Nuclear Medicine Works

Nuclear medicine uses radioisotopes, which are injected into the body intravenously. Specialized imaging equipment — including PET scanners and gamma cameras — then detects where these radioactive tracers accumulate in the body, revealing the location and spread of cancer.
 

Exploiting Cancer's Sugar-Hungry Metabolism

Cancer cells are remarkably adaptive and mutate readily, but they share certain exploitable characteristics. One of the most useful is their metabolism: because cancer cells multiply extremely rapidly, they require significantly more energy than normal cells — and that energy comes primarily from glucose (sugar).

Dr. Lele explains that normal body tissues, like the brain and heart, also require glucose for energy. However, cancer cells demand roughly 15 times more glucose than normal body cells due to their rapid multiplication. By creating a radioactive version of glucose and injecting it into the body, doctors can track exactly where this glucose accumulates abnormally — revealing what's known as a "hot spot," a strong indicator of cancer activity.
 

What Is an FDG PET Scan?

This technique — injecting radioactive glucose and scanning the entire body from head to toe — is known as an FDG PET scan. Wherever abnormal glucose accumulation appears on the scan, it signals a likely cancerous area requiring further evaluation.
 

The Power of Combining PET and CT Scans

PET-CT combines two complementary imaging technologies:

  • PET reveals where cancer activity is occurring (based on abnormal glucose uptake)
  • CT reveals precisely which organ is affected, how close the area is to major blood vessels, and whether lymph nodes are involved

Together, this combination makes PET-CT an exceptionally powerful tool for accurate cancer detection and staging.
 

Beyond Glucose: Targeting Cancer-Specific Surface Receptors

Not all cancers are best detected through glucose metabolism alone. Many cancer cells express specific surface receptors that can be targeted with specialized tracers:
 

Prostate Cancer and PSMA

Prostate cancer cells express a protein called Prostate-Specific Membrane Antigen (PSMA) on their surface, which can be directly imaged using a specialized PSMA PET scan.
 

Neuroendocrine Tumors

Neuroendocrine cancers — once considered rare and difficult to detect — express somatostatin receptors on their surface. Modern PET-CT technology can now identify these receptors with much greater ease, significantly improving detection of this previously elusive cancer type.
 

Monitoring Early Treatment Response to Chemotherapy

One of the most valuable applications of FDG PET-CT is early treatment response monitoring. Previously, chemotherapy would typically run for six months before a follow-up CT scan revealed whether it was effective — meaning patients could endure months of chemotherapy side effects only to learn the treatment wasn't working.

With FDG PET-CT, doctors can now assess treatment effectiveness after just one or two chemotherapy cycles. If a tumor that was previously showing aggressive glucose uptake suddenly shows little to no uptake after treatment, it's a strong sign the chemotherapy is working — allowing doctors to confirm or adjust treatment plans far earlier than before.
 

Tracking Treatment Progress in Lymphoma

This approach is especially valuable in conditions like lymphoma (cancer of the lymph nodes), where PET scans are typically performed after every three chemotherapy cycles. If the scan shows good response, treatment continues; if not, doctors can switch to an alternative chemotherapy regimen promptly, rather than waiting for a full treatment course to conclude.
 

Routine Follow-Ups and Recurrence Monitoring

After successful treatment, regular follow-up PET scans help detect any recurrence at a very early stage — allowing for prompt intervention rather than discovering a relapse only once it has progressed significantly.
 

Detecting Slow-Growing, Low-Sugar Cancers

Not all cancers are equally aggressive. Some grow slowly and don't significantly utilize glucose, making them harder to detect via standard FDG PET scans. For these cases, doctors rely on the cancer's other unique characteristics — such as PSMA expression in prostate cancer — using targeted tracers like PSMA PET-CT to pinpoint where the disease has spread.
 

Theranostics: Combining Diagnosis and Treatment

One of the most significant recent advances in nuclear medicine is theranostics — using the same targeting mechanism for both diagnosis and treatment. For example:

  1. A Gallium-PSMA PET scan first confirms the presence and location of prostate cancer
  2. Once confirmed, the diagnostic Gallium isotope is replaced with a therapeutic isotope called Lutetium-PSMA
  3. This Lutetium isotope travels precisely to the same locations identified during diagnosis and destroys the cancerous cells directly — functioning much like a "precision-guided" treatment that targets only the cancer sites already mapped out
     

Advanced Radioisotope Treatments: Lutetium-PSMA, DOTA, and FAPI

This theranostic approach is expanding rapidly, offering new hope for patients with prostate cancer, neuroendocrine tumors, and other cancer types that don't respond well to conventional chemotherapy, radiation, or surgery. Newer therapeutic isotopes — including Lutetium-PSMA, Lutetium-DOTA, and Lutetium-FAPI — allow doctors not only to diagnose these cancers with precision but to directly treat them, offering patients additional years of good-quality life even in advanced or treatment-resistant cases.
 

Key Takeaways: The Role of Nuclear Medicine in Cancer Care

Nuclear medicine plays a valuable role across multiple stages of cancer care:

  • Early diagnosis and precise staging of where cancer has spread
  • Monitoring treatment response early in the course of chemotherapy or other therapies
  • Detecting recurrence at an early, more treatable stage through routine follow-up scans
  • Direct treatment of certain cancers through targeted radioisotope therapy (theranostics)

As these technologies continue to advance, nuclear medicine is increasingly central not just to diagnosing cancer, but to treating it with precision.

 

This article is based on an episode of Just Health for the People, a public health awareness initiative by Jaslok Hospital, featuring Dr. Vikram Lele, Director of Nuclear Medicine. Watch the full video here: Nuclear Medicine and Cancer Detection Explained by Dr. Vikram Lele

 

For consultation regarding cancer screening, PET-CT imaging, or radioisotope therapy, please reach out to Jaslok Hospital's Department of Nuclear Medicine.