PET/CT - oncological diagnostics by synthesis of morphological and molecular imaging

Due to its orientation to function and the insufficient contrast it affords of anatomic structures, the interpretation of differential tracer accumulation in PET data can pose difficulties. These tend to become more serious with growing tracer specificity. Knowledge of the precise location of a conspicuous PET finding is essential if one is to be able to differentiate between physiological and pathological hyperfunction, and it is also indispensable for carrying out accurate interventions. Precise knowledge of the anatomical site is particularly important in the case of oncological disease. One way to compensate for this shortcoming is to fuse images from PET scans with morphologically oriented tomograms (CT, nuclear magnetic resonance tomography). For various reasons however the practice of image fusion has often proven unpracticable retrospectively. A number of problems at least can be solved by routinely combining PET with CT images. Image data sets acquired with these two technologies are intrinsically compatible with respect to slice thickness and slice centre. In addition, the position of the patient, including that of his inner organs, is identical and the image datasets are immediately available on one and the same computer. Furthermore, using the CT data for correction of the attenuation and radiation scatter contained in the PET emission data results in a significant reduction of acquisition time by around 30%, since this renders transmission measurements with germanium sources superfluous