The role of dual and multiple time point imaging of FDG uptake in both normal and disease states

Dual time point imaging (DTPI) and delayed time point imaging have been used for the differentiation of inflammatory and malignant processes and found to enhance the specificity of FDG PET imaging for diagnostic and prognostic purposes. It has been shown that the degree of FDG uptake at the second acquisition time point after the baseline scan increases in malignant cells; in inflammatory or infectious disorders, on the other hand, FDG uptake decreases or remains unchanged at the second time point. Many groups have investigated the application of DTPI and its potential and limitations have been discussed in detail with reference to a wide variety of malignant diseases, including those of the lung. The aim of this review is to describe the role of DTPI to assess both normal and disease states.