A PET CT scan, or Positron Emission Tomography-Computed Tomography scan, is a diagnostic imaging test that combines two types of scans: a PET scan and a CT scan.

During a PET scan, a small amount of radioactive material is injected into the body, which is taken up by cells that are actively using energy, such as cancer cells. The radioactive material emits positrons, which are detected by a special camera and used to create a 3D image of the body's metabolic activity.

During a CT scan, X-rays are used to create detailed images of the body's internal structures, such as bones and organs.

By combining the information from both types of scans, a PET CT scan can provide detailed information about the location, size, and activity level of tumors, as well as other types of diseases and conditions.

PET CT scans are an important tool in the diagnosis, staging, and monitoring of cancer, as well as other conditions such as heart disease and neurological disorders. They can help doctors determine the best course of treatment, evaluate the effectiveness of treatment, and detect disease recurrence