[What is the contribution of PET in tumor diagnosis today?]

Positron emission tomography (PET) permits qualitative and quantitative measurements of tumor metabolism in the patient. In the clinical setting, the present studies suggest that tumors with a potential for proliferation can be differentiated from scar tissue, soft tissue and benign lesions. Accumulation of tracer by lymph nodes identifies them as metastatic. On the basis of a quantification of the accumulation of tracer and its metabolites, information can be provided about the biological activity of a tumor, and presumably also about the prognosis. The response of a tumor to treatment can be monitored, in particular in combination with CT. Possible selection of resistant parts of the tumor can be determined, so that modification of treatment is possible. Modes of application can also be individualized by identifying pre-treatment advantages of intraarterial or systemic administration; recurrent tumors can be detected with a high degree of accuracy. However, to date, only limited numbers of cases are available, so that, in view of the very promising aspects of this modality, more widespread application followed by the evaluation of larger numbers of patients is needed.