The field of imaging has changed dramatically over the past few years and molecular imaging has increasingly become more prominent. Nuclear medicine makes molecular processes in the body visible to detect disease processes early and enable a targeted treatment. Examination techniques such as positron emission tomography (PET) or single-photon emission computer tomography (SPECT) cover this area. These methods are also able to illustrate tumor metabolism, that being a tumor’s response to a specific treatment, much sooner than an MRI or CT.
Both of these nuclear medicine imaging techniques focus on showing the function of individual organs by illustrating their metabolism. To do this, so-called radiopharmaceuticals that bind to specific antibodies, protein compounds, or sugar molecules are being introduced into the body.
"Radiopharmaceuticals have two components," explains Professor Torsten Kuwert, Director of the Erlangen University Hospital Department of Nuclear Medicine. "The first one is a radioactive isotope and the other another molecule that is attached to the radioactive isotope. It connects to target structures that are expressed in tumors, for example."
A typical example of a radiopharmaceutical for diagnostic use is fluorine-18-deoxyglucose. Fluorine-18 is a radioactive fluorine isotope that decays by positron emission. This irradiation can be detected by positron emission tomography and its distribution in the tissue illustrated. The second molecule part – deoxyglucose – is sugar. The radiopharmaceutical is absorbed by the cells by this sugar content which exhibits an elevated glucose concentration. Certain types of cancers have an increased glucose metabolism. Conglomerations of malignant tumors can be detected with this.