Prospects for molecular imaging in humans

In 1906, Flexner and Jobling (1) established a tumor model by transplanting a spontaneously growing rat tumor into generations of rats. One of the tumor-bearing rats was shipped to Berlin where Warburg et al. (2) conducted their landmark studies on glucose metabolism of tumors, which revealed that the metabolism of tumors is predominantly one of anaerobic glycolysis. Thirty to forty years later, in the 1950s and 1960s, Sokoloff et al. (3) labeled deoxyglucose with carbon 14, and Reivich subsequently marked deoxyglucose with fluorine 18, thus providing radiolabeled analogs of glucose that could be used for tumor imaging. In the 1970s, Phelps et al. (5) built the first positron emission tomography (PET) scanner, enabling the translation of the fundamental discoveries by Warburg et al. (2) into the most innovative and exciting clinical imaging tool in oncology (6).