PET-CT & PET-MRI
A PET scan uses a small amount of injected radiotracer to reveal how active tissues are — for example, how fast cells are using sugar. Combined with CT or MRI in a single session, PET-CT and PET-MRI overlay this activity onto detailed anatomical images, making them powerful tools for detecting, staging and monitoring cancer and assessing some heart and brain conditions.
Medically reviewed by the Florence Healthcare medical team · Last reviewed June 2026
Overview
Positron emission tomography (PET) shows how tissues are working rather than just how they look. A small amount of a radioactive tracer — most commonly a form of glucose — is injected and taken up more by metabolically active cells, such as many cancers. The scanner detects where the tracer concentrates, and by combining PET with CT (PET-CT) or MRI (PET-MRI) in one session, doctors see both the activity and its exact location. This makes the technique especially valuable for finding cancer, staging how far it has spread, checking whether treatment is working and detecting recurrence, as well as for some heart and brain assessments.
International patients are guided by a coordinator who arranges the scan, explains the preparation — including fasting and resting quietly after the injection — and the relatively short half-life of the tracer. If you have prior PET or other scans done abroad, our nuclear-medicine specialists and radiologists can provide a second-opinion reading, and you receive a transparent, personalised cost estimate before you travel.
Who is a candidate?
- People diagnosed with cancer who need accurate staging of how far it has spread
- Patients being monitored to see whether cancer treatment is working
- Those checked for cancer recurrence after previous treatment
- Patients with an unexplained lump or finding that needs to be characterised
- Selected people needing assessment of heart muscle viability or certain brain conditions
- Patients for whom combining functional and anatomical imaging in one session is valuable
What happens
- 1
Preparation
You are usually asked to fast for several hours and to avoid strenuous exercise beforehand. If you have diabetes, the team gives specific guidance, because blood sugar affects the scan. Tell us if you are or might be pregnant or are breastfeeding.
- 2
Tracer injection and rest
A small amount of radiotracer is injected through a cannula in your arm. You then rest quietly for about an hour, avoiding movement and talking too much, so the tracer can distribute and be taken up by active tissues.
- 3
During the scan
You lie still on a table that passes through the scanner, which acquires the PET images together with the CT or MRI. The scan itself is painless and typically takes 20–40 minutes; a contrast dye is sometimes given for the CT or MRI part.
- 4
Afterwards & results
You can return to normal activity, but are usually advised to drink plenty of fluids and to limit close, prolonged contact with infants or pregnant women for the rest of the day while the tracer clears. A specialist reviews the images and a written report is generally ready within 24–72 hours.
Benefits
- Shows the activity of disease, not just its appearance — often detecting cancer earlier or more precisely
- Combines functional and detailed anatomical imaging in a single appointment
- Highly useful for staging cancer, planning treatment and checking response to therapy
- Can reveal disease that may not be obvious on CT or MRI alone
- Whole-body imaging in one study helps map where disease has and has not spread
Risks & considerations
- Involves a small radiation dose from the injected tracer, plus X-rays from the CT component — kept as low as reasonably possible
- Generally avoided in pregnancy unless essential, and breastfeeding may need to be paused briefly
- Requires fasting and a quiet resting period, making the appointment longer than other scans
- Any added contrast dye can rarely cause an allergic reaction and is used with care in kidney impairment
- Some non-cancerous conditions, such as infection or inflammation, can also take up the tracer and need expert interpretation
Where it is performed
This procedure is delivered by our Nuclear Medicine & Theranostics.
Learn more before you decide
Provider-reviewed guides on the related conditions, symptoms and tests in our Health Library.
PET-CT & PET-MRI — frequently asked questions
The cost reflects the type of scan, the tracer used and whether it is whole-body or limited to one region. We provide a clear, personalised estimate before your visit and confirm what is included, so you know the price in advance.
Yes. If you bring or send your PET images and report, our nuclear-medicine specialists and radiologists can provide a second-opinion reading. Depending on how recent the scan is, this can sometimes spare you a repeat study.
The amount of radiotracer used is small and short-lived, and the overall radiation dose is kept as low as reasonably possible. As a precaution you will be asked to drink fluids and limit close contact with infants and pregnant women for the rest of the day while it clears from your body.
Most of the time is the quiet rest period after the injection, which lets the tracer distribute and be taken up by active tissues. The scan itself usually takes only 20–40 minutes, but you should plan for about two to three hours in total.
Both combine the functional PET images with detailed anatomical imaging. PET-CT pairs PET with a CT scan and is the most widely used; PET-MRI pairs it with MRI, giving superior soft-tissue detail and no CT radiation, and may be preferred for certain brain, liver, pelvic or paediatric cases. Your team recommends the most suitable option.
Yes — you are usually asked to fast for several hours, avoid strenuous exercise beforehand, and follow specific guidance if you have diabetes. You should also tell us if you are or might be pregnant or are breastfeeding. Your coordinator will give you full instructions.
Related treatments
Considering pet-ct & pet-mri?
Share your reports for a medical second opinion and a transparent, itemized cost estimate — usually within 48 hours.