PET-CT for cancer: how it is used

A PET image highlights areas that take up a radiotracer, while CT shows their position and shape. Doctors may use the combined study to examine a known tumour, look for involved lymph nodes or distant sites, compare disease over time, or plan treatment. Bright uptake does not automatically mean cancer; infection, inflammation, healing, and normal activity can affect the appearance. A report needs to be interpreted with symptoms, examination, pathology, and other imaging.

The centre may ask you to avoid food for a specified period, limit strenuous activity, and discuss medicines or diabetes in advance. After a glucose check, the tracer is usually given through a vein. Quiet rest helps the tracer distribute before you lie still for the scan. Tell staff about pregnancy, breastfeeding, allergies, or trouble remaining still. Bring prior reports when requested, but do not change cancer medicines unless your care team instructs you.

Seek urgent medical help for severe breathing difficulty, collapse, new confusion, or rapidly worsening pain. Contact your cancer team about new symptoms such as persistent hoarseness, coughing blood, unexplained weight change, or neurological changes. These symptoms can have causes other than cancer, and urgency depends on the symptom and its severity, not on a scan concern alone.

Ask what question the scan is intended to answer, whether fasting or medicine changes apply to you, and when the report will be discussed. Clarify whether a suspicious area needs biopsy, another scan, genomic tumour profiling, or a change in chemotherapy, radiotherapy, surgery, or palliative care.