The aim of curative radiotherapy is the administration of tumor-lethal dose to an exactly defined target volume with minimal surrounding healthy tissue toxicity. In the conformal radiotherapy it is possible to conform the shape of irradiated volume to an irregular target volume. It allows using more intensive tumor irradiation without increase of the surrounding tissue toxicity. Dose intensification for the tumor tissue significantly improves the local control and thus it can considerably increase the patient's chance for survival. Decrease of the surrounding tissue toxicity can bring about also a higher quality of the patient's life.