[Integrated PET/CT scanner in oncology applications: a radiologic perspective]

To describe our experience with an integrated PET/CT system in the clinical applications in Oncology.

An integrated PET/CT scanner is an in-line system combining a full-ring detector PET and a multidetector row helical CT in one machine. This is a multidisciplinary technique involving a nuclear medicine physician, a radiologist, a radiopharmacologist, and a physicist, with distinct tasks and working together. The clinical indications for PET scans are determined by the National Health System, which in Madrid is coordinated by Agencia Laín Entralgo, and are performed by a nuclear medicine physician with the help of a radiologist for CT interpretation. The combined PET/CT scans are supervised and interpreted by both a nuclear medicine physician and a radiologist.

Between September 2003 and August 2005, a total of 2459 examinations were performed at our institution: 2200 were PET scans with low-dose noncontrast-CT for attenuation correction (clinical indications approved by NHS), and 259 were combined PET/CT scans with full-diagnostic enhanced-CT (in the setting of research programmes). The overall distribution of clinical indications for the 2459 examinations were: lung cancer 14.7%, solitary lung nodule characterization 7%, lymphoma 23.5%, colon cancer 18.5%, gastric cancer 1.9%, brain tumors 2.6%, head-neck tumors 5.5%, thyroid cancer 5%, breast cancer 4%, unknown origin cancer 4.3%, epilepsy 1.4%, others 11.6%.

In our experience, the integrated PET/CT system has advantages over the stand-alone PET and/or CT. However, more studies, as the ongoing research programmes at our facility are needed for the diagnostic validation of this technique.