PET/CT Scan: A Powerful Tool in Cancer Diagnosis and Treatment
Advances in medical imaging have brought about significant progress in the diagnosis of cancer. From simple X-rays to detailed scans, the instruments to diagnose, understand, and cure cancer have come a long way. The PET/CT scan is one of the most accurate and sensitive technologies available for this purpose: It’s a type of combined imaging that provides detailed anatomical and functional information about the body being scanned.
What is a PET/CT Scan?
When PET is combined with CT (positron emission tomography/computed tomography, or PET/CT), this hybrid modality offers an infrastructure to enhance early diagnosis, treatment planning, and treatment monitoring.
A PET/CT scan is a combined scan that brings together two scanning techniques to provide patients with one of the most powerful diagnostic tools used by modern medicine. The CT scanner combines many X-ray images to make cross-sectional images of the inside of the body. The PET scan, by contrast, entails injecting a small amount of radioactive material (a tracer) that helps to identify active areas of metabolism as well as where tumours may be most active.
With a combination of the two, doctors are able to see the precise locations of disorderly activity in relation to the anatomy of the body. This combination provides a much more complete picture than either scan could individually and is considered the gold standard for cancer imaging.
How Does It Work?
CT Scan Component:
The CT scan collects several X-ray images from various vantage points around the body. These are then interpreted by a computer to create detailed 3D images of organs, bones, and tissue. It aids doctors in pinpointing the exact size, shape, and location of tumours or abnormalities.
PET Scan Component:
In a PET scan, the patient is injected with a tracer, usually a compound like fluorodeoxyglucose (FDG), which acts like glucose. Because cancer cells often use more energy than healthy cells, they take up more of these tracers. The PET scanner reads this activity, generating images that reveal metabolic hotspots—often where tumours are growing or have established a presence.
Putting them together, the PET and the CT scans provide a layered image that’s both anatomical and functional—showing not just what the inside of the body looks like, but also what it’s doing.
Why is a PET/CT Scan Used?
Cancer Diagnosis and Staging:
When initial PET/CT scans or tests are inconclusive, a PET/CT scan helps determine cancer diagnosis. It can determine whether a suspicious mass is cancerous, as well as if cancer has spread (metastasised) to another part of the body.
Treatment Planning:
PET/CT scans help doctors plan cancer treatment after cancer is diagnosed. Pinpointing where and how much cancer is present can guide how radiotherapy, chemotherapy, or surgery is used, leading to more effective care.
Treatment Response Monitoring:
Do doctors rely upon PET/CT to see how well the body is responding to treatment? If cancer cells are still active, changes can be made. This prevents unnecessary treatments and instead focuses on the best means.
Detecting Recurrence:
PET/CT is very sensitive in the detection of recurrence, usually before symptoms develop. Early detection allows patients to be treated promptly, improving prognosis.
What Happens During the Test?
The usual radiographer/nuclear medicine technician employed in a hospital radiology department performs a PET/CT. The scan is performed on an outpatient basis, so you won’t need to spend the night.
Here’s a quick rundown of what occurs:
- Preparation: You may need to fast for 4–6 hours prior to your scan. You will likely be told to drink normally but avoid vigorous exercise the day before.
- Tracer Injection: A tiny amount of radioactive tracer is injected, often into a vein in your arm. Then you rest quietly as the tracer moves through your body (about 30–60 minutes).
- The Scan: You will lie on a flat table that moves in and out of the scanner. The scan itself takes about 30 minutes. It doesn’t hurt, but you will need to lie still for precise images.
- Aftercare: You can go about your business after the scan, though you’ll be told to drink extra fluids to help clear your system of the tracer.
Availability and Accessibility
PET/CT scanners are highly specialised and typically located in large NHS and private cancer centres throughout the UK. At Chase Lodge Hospital, we can refer and coordinate with specialist imaging centres to offer prompt access.
Due to the complexity of the instruments used, PET/CT scanning may require:
- A recommendation from your oncologist or specialist.
- Travel to a facility that has PET/CT technology—particularly if you live in a rural area.
That being said, waits can be reasonable for the most part, and patients can typically be seen within a few weeks of calling for an appointment.
Safety and Side Effects
A PET/CT scan is very safe. It uses a rather small dose of radiation, nothing to worry about in terms of possible medical consequences.
There are several caveats, however:
- Radiation exposure is low; however, some people, particularly if getting multiple scans, might be worried about the small amounts of radiation exposure associated with the test.
- Allergic reactions to the tracer are extremely rare, but be sure to tell your care team about any allergies you may have or any medical conditions.
- Pregnant women should avoid PET/CT unless the examination is essential, as it could entail risk for the foetus.
Medical professionals always make sure that the benefits of a scan outweigh any potential risks, so we advise against avoiding the scan.
Conclusion
For the diagnosis and staging of cancer, PET/CT is one of the most cutting-edge and powerful tools available. Providing multiple perspectives of structure and function, they enable clinicians to make informed treatment decisions at each point of care—from initial diagnosis and treatment planning to late-stage monitoring.
We at Chase Lodge Hospital think that the more you know, the better. If your specialist orders a PET/CT scan, it’s because it can provide essential information that could shape your best course of treatment. Contact us today to schedule an appointment or referral via Chase Lodge Hospital.
