Patient FAQs

A **PET-CT Scan** (Positron Emission Tomography - Computed Tomography) is a highly advanced hybrid imaging technique. It combines a metabolic PET scan (which visualizes cellular chemistry and metabolic rate, usually via a sugar-based tracer) with a structural CT scan (which maps precise physical anatomy). Together, they allow nuclear medicine doctors to pinpoint the exact location of metabolically active diseases, such as cancer cells, long before structural anomalies appear.

Proper preparation is crucial to ensure accurate diagnostic results, especially for F-18 FDG scans:

Fasting: You must maintain strict fasting (no food or sweetened beverages, only plain water) for at least **6 hours** prior to your appointment time.
Hydration: Drink plenty of plain water before your scan. This hydrates kidneys and aids in flushing out unabsorbed radiopharmaceutical tracer elements post-scan.
Dietary Restrictions: Avoid strenuous physical exercise and heavy carbohydrates/sugars for **24 hours** prior to the scan.
Medications: If you are diabetic, notify our staff immediately during booking. We will schedule you for an early slot and provide specific instructions on managing your insulin doses to keep blood glucose below 150 mg/dL.

Yes, PET-CT scans are highly safe. The radioactive tracers utilized (such as Fluorine-18 or Gallium-68) have exceptionally short half-lives (typically between 68 and 110 minutes). The isotope decays and flushes out of the body naturally within a few hours. Additionally, our AI-reconstruction scanner employs advanced low-dose CT attenuation, and our physicists calibrate doses strictly to safety guidelines (ALARA - As Low As Reasonably Achievable).

A **standard CT scan** uses X-rays to generate static structural slices of the body. It shows what organs and physical tissues *look like* physically. A **PET-CT scan** is a hybrid scan. The PET component evaluates biochemical *function and metabolic rate* of cells, while the CT provides the physical framework. Many tumors look physically normal on a standard CT scan but reveal high metabolic activity on a PET scan, enabling early detection.

The actual time spent inside the scanner ring is only **10 to 15 minutes**. However, the entire diagnostic process takes about **2 to 3 hours**. Once you arrive, we check your blood sugar, inject the tracer intravenously, and ask you to rest quietly in a private uptake room for approximately **60 minutes** while the cells absorb the tracer. After the scan, you will be monitored briefly before release.

Gamma Camera preparations depend entirely on the specific organ being scanned:

Whole-Body Bone Scan: No fasting required. You can eat and drink normally. However, you must drink 3-4 glasses of water during the 2-hour tracer absorption gap.
Renal DTPA / EC Scan: No fasting is needed. Patients must drink 2-3 glasses of water about 30 minutes before the scan to ensure excellent hydration for clearance calculation.
HIDA (Hepatobiliary) Scan: Requires strict fasting of **4 to 6 hours** before the scan to allow the gallbladder to accumulate bile normally.

At IRIS, we prioritize rapid clinical pathing. Standard PET-CT scans and Gamma Camera diagnostic reports are fully compiled, verified by our double directors, and released **within 24 hours**. In urgent clinical oncology cases, accelerated reporting can be arranged upon request.

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Patient FAQs

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Answers to Your Diagnostic Questions

What is a PET-CT Scan?

How should I prepare for a PET-CT scan? (Fasting & Hydration)

Are PET-CT scans safe? What about radiation exposure?

What is the difference between a standard CT scan and a PET-CT scan?

How long does the entire procedure take?