New oncologic procedures are currently more focused on the biological features of tumors. The ideal objective is the administration of personalized effective treatments for each patient that affects not just the location and spread of disease but also special metabolic characteristics of tumoral cells. Radiologic diagnostic methods are extremely important in the management of the patient for staging, restaging, and evaluation of treatment response, and clinicians are avid for some additional functional and metabolic information. Further, they need more dynamic methods for follow-up. Nuclear Medicine and positron emission tomography (PET) in many cases can meet this requirement, although it is not perfect, at least at the present time. Currently 2-((18)F)fluoro-2-desoxi-D: -glucose positron emission tomography is being widely used for oncologic purposes. Its information can be very useful in abdominal diseases and must be taken into account with the results of radiologic imaging. Thus, many changes in the choice of treatment are seen. However, it is very important to know that sometimes there is a lack of specificity that has to be considered.