The so-called tumor senescence is described as a resistance mechanism, which can be the basis for the non-response to most common chemotherapies. It is believed that the identification of so-called senescent tumors could improve treatment strategies for solid tumors and, in particular, avoid inefficient treatment of patients with highly toxic drugs.~The aim of this study is to investigate the safety, radiation exposure (dosimetry) and diagnostic accuracy of the novel diagnostic substance [18F]FPyGal if it is used before tumor imaging imaging (here: positron emission tomography combined with magnetic resonance imaging (PET / MRT) or in combination with computed tomography (PET / CT)).~Diagnostic substances used in imaging such as [18F]FPyGal are known as radiotracers, since their distribution in the tumor tissue can provide information about the special tumor biological processes taking place there.~In the context of this study, it is of particular interest to find out whether it is possible to use the novel radiotracer [18F]FPyGal to detect areas after standard tumor therapy that contain particularly resistant (therapy-resistant) tumor cells. This resistance phenomenon in tumor tissues, which may be visualized with the radiotracer [18F]FPyGal, is called tumor senescence.~The latest research results show that senescent tumor cells can not only evade different forms of chemotherapy or radiation therapy. Senescent tumor cells can also cause the cancer to come back later. That is why current therapeutic research is concentrating on developing new approaches to combat such senescent tumor cells. For this it is relevant to be able to first diagnose senescent tumor cells as well as possible using imaging.
It is of particular interest to find out whether it is possible to use the novel radiotracer [18F]FPyGal to be tested to detect areas after standard tumor therapy that contain resistant (therapy-resistant) tumor cells. This resistance phenomenon in tumor tissues, which may be visualized with the radiotracer [18F]FPyGal, is called tumor senescence.