The following bachelor thesis is a descriptive research on types of tumors and their clinical manifestation in humans. Current therapy methods, with special focus on radiation therapy, are discussed. The main emphasis of this study was the psychological situation of the cancer patients prior to the initiation of radiation therapy. Exceptional psychological states, such as denial, depression, fear and shock were monitored. Competence, trustworthiness, objectivity and intercultural tolerance are the most important qualities that hospital staff can possess. Broad theoretical knowledge is the basis for a working relationship between radiation technologists and their patients. The trust established with the patients has a positive influence on the treatment outcome, resulting in a higher level of patient satisfaction.