PET CT Scan in Delhi

A PET CT scan is two examinations captured in one sitting. The CT half maps your anatomy — where every organ, node and lesion physically sits. The PET half maps activity: a small amount of a radioactive tracer is injected into a vein, it collects wherever cells are behaving abnormally, and the scanner records where it went. The two images are then laid over one another, so your doctor can see not only that something is there, but whether it is metabolically active.

That distinction is the whole point. A CT or an MRI can show a 2 cm node in your chest. Only a PET CT can suggest whether that node is live disease, scar tissue left over from treatment, or an old infection. It is why PET CT is used for staging a newly diagnosed cancer, for checking whether treatment is working, for finding recurrence when a tumour marker starts rising, and for locating an unknown primary when a secondary has already been found.

PET CT is not a general health check-up, and it is not a substitute for a CT or an MRI your doctor has separately asked for. It answers a specific question, and it answers it well.

We want to be straight with you about this, because a PET CT is not something every diagnostic centre can run. It needs a cyclotron supply chain, a licensed hot lab and a nuclear medicine team.

Your PET CT is performed at our nuclear medicine unit, Neurad Diagnostic & Healthcare LLP, in Paschim Vihar — the same group as Edge Imaging & Diagnostics, a short distance from our Paschim Vihar centre. Booking through either brand reaches the same team and the same scanner.

One practical advantage of that unit is a Gallium-68 generator on the premises. Ga-68 has a half-life measured in about an hour, so a centre without its own generator has to buy in each dose and schedule around a delivery. Having the generator in-house is why PSMA, DOTANOC, FAPI and Exendin studies can be scheduled on working days rather than only when a shipment arrives.

Knowing the sequence takes most of the anxiety out of it. Here is the shape of a typical FDG appointment.

1. Registration and consent. Your prescription and previous records are checked, you are asked about pregnancy, breastfeeding, diabetes, recent surgery, chemotherapy and radiotherapy dates, and you sign consent.

2. Blood sugar check. A finger-prick test. If your reading is too high the technologist and the nuclear medicine doctor decide whether to wait, correct it, or reschedule — scanning at a high sugar simply wastes your money.

3. Injection. A cannula is placed and the tracer is given. It is a normal intravenous injection; it does not burn, and it does not make you feel anything.

4. The uptake period. You rest quietly in a dedicated room for roughly an hour while the tracer distributes. This is the part people are not expecting. No phone scrolling with a raised arm, no walking about, no talking at length — muscles that work now will glow later. Just sit or lie still.

5. Emptying your bladder. Tracer is cleared through the kidneys, so you are asked to pass urine immediately before the acquisition.

6. The scan. You lie on the couch with your arms usually above your head and the table moves slowly through the ring. The acquisition itself commonly takes twenty to forty minutes depending on the study and your height. The scanner is an open ring, not a tunnel, so it is far less confining than an MRI.

7. Going home. Drink plenty of water for the rest of the day to flush the remaining tracer. As a routine precaution, keep a little distance from pregnant women and infants for the rest of the day. You can eat normally, drive and go back to work.

Plan on being at the centre for about two to three hours in total. Reports for routine studies are typically ready within 24 hours; a complex case read against prior imaging can take longer, and we will tell you which yours is when you book rather than after.

• It is not proof of cancer. A PET CT reports metabolic activity, not a diagnosis. A hot spot raises a suspicion; a biopsy confirms it. Where a tissue diagnosis is needed, PET CT is often used to choose the best site to biopsy, not to replace it.

• Infection and inflammation look like cancer on FDG. This matters a great deal in India. Active tuberculosis, sarcoidosis, an abscess, a recent surgical wound and even an inflamed joint can all be intensely FDG-avid. This is the single most common reason a PET CT is over-read, and it is why your clinical history and previous imaging matter so much.

• Some cancers are quiet on FDG. Many prostate cancers, low-grade lymphoma, mucinous adenocarcinoma, some renal and hepatocellular cancers, and certain neuroendocrine tumours take up little FDG. That is precisely why the other tracers exist — a normal FDG scan does not always mean no disease.

• Very small lesions can be missed. Below roughly five to eight millimetres, a deposit may sit under the resolution of the scanner regardless of how active it is.

• The brain, kidneys and bladder are normally bright. These organs take up or excrete FDG as part of normal physiology, which can mask disease in and around them. Different tracers and different protocols are used when those areas are the question.

• High blood sugar degrades the study. If glucose is high at the time of injection, FDG is diluted through the body and tumour uptake drops. It is not a formality when reception asks to check your sugar.

None of this makes a PET CT a poor test. It makes it a precise instrument that answers a precise question — which is how it should be used, and how a good nuclear medicine report will read.