What Is a CT Scanner Used For?

Inside the scanner, an X-ray source and detectors rotate around you while you lie on a moving table. A computer processes the measurements into slices of the body. These slices can be viewed separately or combined into different image planes, helping the clinical team assess structures that may overlap on a plain X-ray.

In oncology, CT imaging can help investigate a symptom, describe a known tumour, support staging, guide procedures, or compare findings over time. Some examinations use contrast material to make selected organs or vessels easier to distinguish. Low-dose CT lung screening is a separate screening pathway with specific eligibility requirements.

Follow instructions about food, drink, medicines, and arrival time. Tell the team about pregnancy or possible pregnancy, kidney disease, diabetes, metal devices, and previous contrast reactions. During the scan, remain still and follow requests to hold your breath briefly; movement can blur the images.

The scanner is open at both ends, and staff can see and speak with you. If contrast is planned, ask how it will be given and what sensations to expect. The CT Scan page explains the wider examination and preparation.

Report breathing difficulty, facial swelling, widespread itching, or faintness immediately if contrast has been given. Seek advice for persistent pain, swelling, redness, or leakage where an injection was placed. Emergency help is needed for severe breathing difficulty, collapse, or rapidly worsening symptoms.

Ask what body area will be scanned, whether contrast is needed, how the images will answer the clinical question, and when the report will be available. If screening is being discussed, ask whether low-dose CT lung screening is appropriate for you.