The most accurate assessment of a tumor is given by combining computed tomography with positron emission tomography.

One of the UK's most advanced imaging systems is being used at the Alliance Medical Imaging Centre in London to give highly accurate information on the location and extent of a wide range of tumors. The system combines computed tomography (CT) with positron emission tomography (PET). CT is a widely-used technique which gives the location of suspicious masses and abnormalities within the body. PET involves injection of a radioactive 'tracer' compound which can be tracked to locate biochemical activity within tissue.

In combined PET-CT used for cancer imaging, radioactive glucose (FDG) locates the malignant area within a tumor as this takes up more glucose than surrounding tissue (cancer cells divide rapidly and need more glucose fuel than normal cells). Superimposing the PET image on the CT scan, using specialized software, gives a very accurate outline of the tumor. It guides surgery or radiotherapy so that only malignant tissue is treated, sparing the surrounding tissue. A recent study in the New England Journal of Medicine (19th June 2003) shows PET-CT to be more accurate than either PET or CT alone at staging non-small-cell lung cancer. The same is likely to be true of many other cancers.

Source

Alliance Medical Imaging Center, London, 24th June 2003