How accurate is a pet scan?

PET scans are a very accurate means of identifying the presence and activity of some cancers, within limitations. A PET scan would normally be used in conjunction with a CT scan to obtain an effective overlay of the images. As the CT will show any abnormal growth the PET scan would reveal if there are any live cancerous cells in the given area.
However, PET scans are not full proof as they may not accurately identify cancerous growth that is less than about 8mm in size. This equates to approximately 1 million (1x10^6) cancerous cells that may go undetected. Therefore, to ensure the accuracy of a PET scan, the active cancerous growth would need to comprise of 1x10^9 cancerous cells. This would equate to a tumour size of between 1-2cm.

Hope this helps.

It is a very thorough test that also includes CT scans of the body. The test is done on patients with a diagnosis of cancer to see if cancer has spread to other parts of the body. A radiologist who specially trained reads the results of the PET scan test. I trust the results of the PET scans done at our hospital....

It's very accurate and precise, a great tool to use.