RESUMO
Many papers have demonstrated both the relevant impact of positron emission tomography (PET) on staging of many cancers, and the superior accuracy of the technique compared with conventional diagnostic methods for pre-treatment evaluation, therapy response evaluation, and relapse identification. But, PET/CT is a new imaging modality that integrates functional (PET) and structural (CT) information into a single scanning session, thus improving lesion localization and interpretation accuracy. PET/CT fusion images result in higher diagnostic accuracy with fewer equivocal findings. With attenuation correction performed by the CT component, PET/CT can provide higher quality images over shorter examination times than conventional PET. PET/CT is currently the most advanced technique of metabolic imaging and the most accurate tool for tumor staging in the pretreatment, post-treatment and follow-up phases. Although PET/CT offers many advantages, this dual-modality imaging also poses some challenges such as misregistration due to respiration, overattenuation correction due to metals, etc.