Integrated PET/CT, the imaging modality of the new millennium and its clinical impact

The rapid technological advances in positron emission tomography is a challenge for radiologists, nuclear physicians and clinicians who have to integrate these techniques into the cost-efficacy strategies. The cancerology networks have validated a number of indications of the use of FDG-PET from the malignancy-benignity differentiation of the tumoral lesions, to the spread evolution, the detection of recurrence and to the evaluation of the therapeutic effectiveness of chemotherapy drugs. The usefulness of PET imaging was initially demonstrated with cameras equipped with BGO detector rings in circular geometry. The range of camera considerably extended, allowing now hybrid imaging by using double heed SPECT cameras working in coincidence (CDET). The optimal fusion of functional and anatomical images is obtained by PET- CT combined imaging systems with sequential acquisitions but without moving the patient. It allows to optimize the attenuation correction and to accurately locate the lesions with hyper-metabolism. This powerful technology offers a new field of diagnostic and therapeutic applications. The diagnostic precision is increased about 50% owing to a better detection, a better localization of lesions and an easier identification of physiological fixations. It modifies the therapeutic patient management in about 20% of cases (biopsy and guided surgery, radiotherapy protocol modulation). Over the post few years, the FDG-PET clinical indications considerably grow in Europe and United States and the rapid PET-CT technical progress open the horizon to new indications in the future. (author)