PET/CT: nuclear medicine imaging in the future.

Nuclear medicine has evolved from the use of radioiodine compounds to visualise thyroid function to the use of radiopharmaceuticals that can visualise complicated intracellular molecular functions with very high sensitivity in order to be a part of personalised medicine with individualised treatment planning and evaluation of therapy early during treatment. The development has been taken place for the equipment and also of the chemistry of the labelled compounds used. Introduction of hybrid imaging--a combination of structural and functional or molecular imaging--has been an important step in the development of imaging in nuclear medicine. The combination of structural and molecular imaging adds important information and contributes to a better clinical handling of the patients. Hybrid imaging raises new demands of the competence of the personnel which have so far been solved by collaboration between nuclear medicine and radiology departments. It has been shown that hardware fusion of positron emission tomography (PET) and computed tomography (CT) is better than the fusion of the images in the evaluation by the physician allowing more accurate diagnoses. Patients with oncological diseases constitute the majority at a PET/CT department today, and approximately 25-35 % of the patients are treated differently by when PET/CT is added to the routine workup before treatment or follow up.