Dr. Manoj Gupta is a highly respected Senior Consultant in Nuclear Medicine at the prestigious Rajiv Gandhi Cancer Institute and Research Centre (RGCIRC) in Delhi, one of Asia’s leading dedicated cancer hospitals. While the query specifies him as a radiation oncologist, his expertise lies in nuclear medicine—a closely allied field that often intersects with radiation oncology through advanced diagnostic imaging (like PET-CT) and targeted radionuclide therapies that deliver radiation precisely to cancer cells.

Imagine a young medical student in Delhi around 2000, fresh from University College of Medical Sciences (UCMS), stepping into the intense world of cancer care. “I remember thinking, ‘Cancer isn’t just a disease—it’s a puzzle that needs every tool we have,'” Dr. Gupta might reflect if asked about his early days. That drive led him to pursue post-graduation in Nuclear Medicine at the renowned Institute of Nuclear Medicine and Allied Sciences (INMAS) in Delhi.

His career took an international turn with advanced training and a fellowship in clinical Nuclear Medicine and radionuclide therapy at RWTH Aachen in Germany. Not content with that, he earned prestigious certifications: Fellow of the European Board of Nuclear Medicine (FEBNM) from Sweden and Fellow of the Asian Nuclear Medicine Board (FANMB) from China.

One of his proudest achievements? Pioneering the establishment of the first PET-CT facility in Sri Lanka—a landmark that brought cutting-edge cancer imaging to an entire region. “It was challenging, but seeing how it changed diagnosis and treatment planning for patients there made every late night worthwhile,” he could say with a modest smile.

Dr. Gupta didn’t stop at clinical work. He pursued a Ph.D. in Radiation Biology, focusing on the “Role of Radio-Ligand in Theragnostics of Metastatic Castration Resistant Prostate Cancer”—blending therapy (“thera-“) and diagnostics (“-gnostics”) in a personalized approach that’s revolutionizing prostate cancer care.

At RGCIRC, where he has been a key figure for years (with over 13+ years highlighted in his profile as a passionate nuclear medicine physician specializing in nuclear oncology and radionuclide therapies), Dr. Gupta contributes to multidisciplinary teams fighting cancer daily. Picture a typical day: reviewing a PET scan that reveals hidden metastases, then guiding a patient through peptide receptor radionuclide therapy (PRRT) or Lu-177 PSMA therapy for advanced cases. “When a scan lights up exactly where the cancer is hiding, and we can target it without harming healthy tissue, that’s the moment that keeps me going,” he might share in a quiet conversation with colleagues.

PRRT (Peptide Receptor Radionuclide Therapy) is a smart, targeted form of treatment that’s become a game-changer for certain neuroendocrine tumors (NETs), especially those in the gastrointestinal tract or pancreas (called gastroenteropancreatic or GEP-NETs).

Think of it like a precision missile: it seeks out cancer cells that have a specific “landing pad” on their surface and delivers a small dose of radiation right where it’s needed, sparing most healthy tissue.

How PRRT Works (The Mechanism)

Many NETs overexpress somatostatin receptors (SSTRs) on their cell surfaces—these are like docking stations for the hormone somatostatin.

PRRT uses a man-made version of somatostatin (a peptide analog, such as DOTATATE or octreotate) chemically linked to a radioactive substance (the radionuclide, most commonly Lutetium-177 or Lu-177). This combo is called a radiopeptide (e.g., 177Lu-DOTATATE, sold as Lutathera).

• The peptide acts like a key → it finds and binds tightly to the somatostatin receptors on NET cells.
• Once attached, the whole complex gets pulled inside the cancer cell (internalized).
• Inside the cell, the radionuclide decays and emits beta radiation → this damages the cancer cell’s DNA, leading to cell death or slowed growth.

The beauty? Normal cells have far fewer of these receptors, so they receive much less radiation. To protect the kidneys (which can take up some of the drug), patients get an amino acid infusion during treatment to block kidney uptake.

A typical course involves 4 infusions spaced about 8 weeks apart, done as an outpatient or short hospital stay. Before starting, doctors confirm the tumors express somatostatin receptors using a special scan (like Ga-68 DOTATATE PET-CT).

Who It’s For (Indications)

PRRT is mainly approved and used for:

• Well-differentiated, progressive, unresectable or metastatic GEP-NETs that are somatostatin receptor-positive.
• Often after or alongside somatostatin analogs (like octreotide or lanreotide), and in some cases as first-line for higher-grade tumors.

It’s particularly effective for midgut, hindgut, or pancreatic NETs. Ongoing research explores its use in lung NETs, pheochromocytomas, and even combinations with other therapies. As of 2025–2026, 177Lu-DOTATATE remains the standard, with emerging alpha-emitting versions (like 212Pb or Ac-225 labeled peptides) showing promise in trials for tougher cases.

Side Effects and What Patients Experience

PRRT is generally well-tolerated compared to traditional chemotherapy—most side effects are mild to moderate.

Common ones (from clinical trials like NETTER-1 and NETTER-2):

• Nausea and vomiting (usually short-lived, prevented with anti-nausea meds)
• Fatigue
• Decreased blood counts (e.g., low white cells, platelets, or anemia—monitored closely)
• Mild hair loss or taste changes
• Temporary drop in kidney function (rarely permanent, thanks to kidney protection)

Less common but serious:

• Long-term risks like myelodysplastic syndrome (MDS) or acute leukemia (rare, <5–10% in long follow-up)
• Liver issues if heavy liver metastases
• Hormonal crisis (rare flare of symptoms from hormone release)

Patients often say the infusions feel routine after the first one—”It’s like getting an IV drip with some extra precautions.” Many report better quality of life because it controls symptoms (like diarrhea or flushing in carcinoid syndrome) and delays progression significantly. In trials, it extended progression-free survival by months to years compared to standard care.

If you’re exploring this for yourself or a loved one (perhaps in the context of experts like Dr. Manoj Gupta at RGCIRC, who specializes in radionuclide therapies), the key is confirming receptor positivity via imaging and discussing with a multidisciplinary team. It’s not a cure for everyone, but for the right patients, it’s often a powerful way to fight back against NETs with precision and relatively few side effects.

He’s also an active researcher, with publications on topics like exceptional outcomes in neuroendocrine tumors treated with PRRT, incremental value of gallium-68 PSMA PET-CT, and more—often collaborating with RGCIRC’s radiation oncology team on integrated care.

Beyond the lab and clinic, Dr. Gupta embodies the compassionate side of oncology. He understands the fear in a patient’s eyes when facing a cancer diagnosis. In one heartfelt exchange, he might reassure a worried family: “We’re not just treating the disease—we’re fighting alongside you, using every precise tool science offers, so you can get back to living your life.”

Today, as a senior consultant at RGCIRC, Dr. Manoj Gupta continues to blend global expertise, innovation, and genuine care—helping turn the tide against cancer one targeted therapy at a time. His journey reminds us that behind every advanced scan or treatment is a dedicated doctor committed to hope and healing.