[Fusion SPECT/CT in clinical practice]

Fusion consists in a combination of images obtained using different diagnostic techniques, usually functional (SPECT, PET) and structural (CT, MR) imaging. It may be performed as a software fusion of images obtained not the same time by different devices or as a hardware fusion of images obtained the same time using as a hybrid system enabling both the functional and structural imaging (SPECT/CT, PET/CT). Fusion enables precise anatomical location of lesions detected by SPECT, functional verification of lesions found by CT. It is a useful tool in the assessment of effectiveness and dosimetry for radioisotopic therapy. Additionally fusion of functional and structural examinations reduces diagnostic difficulties appearing in independent interpretation. In spite of inconveniences resulting from technical aspects of software fusion (positioning differences, spontaneous movements of internal organs) it is more and more commonly used in clinical practice in centers not possessing hybrid systems.