Oncological problems are so varied that it is very difficult to record all advances in different diagnostic branches in a comprehensive manner. In the first part the authors focus attention on an example of the possible use of imaging examination methods in conjunction with different types of three-dimensional imaging used in their hospital. The second part is devoted to volumetric resections of brain tumours with navigated demarcation. In 17 patients the authors used the PC working station equipped with navigation software STEREOPLAN PLUS for planning volumetric resection of different brain tumours in virtual reality. The demarcation proper of the brain tumour size during surgery was implemented by means of a stereotactic apparatus ZAMORANO-DUJOVNY and a pointer in the field of the microscope. The accuracy of navigation of the whole system for demarcation of the tumourous affection was +/- 1 mm. The intervention was supplemented by functional examination by means of surface electrodes during partial awakening of the patient for mapping the functional areas of the cerebral cortex. The result was resection of relatively precise volumes of tumourous tissue with the possibility of maximum preservation in particular of motor but also other functions of the CNS.