Cancer continues to be one of the most serious diseases and the second leading death cause around the globe: each year more than 11 million people are diagnosed with some kind of tumors and over the half of them die from cancer. The global cancer rates are increasing due to the aging population and longer life expectancy, as well as the changes in the life style in the developing world.  The most common cancer types are currently: colorectal cancer, lung cancer, prostate cancer and breast cancer. Not all cancer diseases are terminal. An early detected tumor can be treated effectively using chemotherapy, surgery or radiation therapy.

Radiotherapy uses ionizing radiation to destroy cancerous cells which have a much lower regeneration ability that the healthy tissue. The most common tumor sites treated with radiotherapy include: prostate, cervix, breast, head and neck, lung, eyes and skin. There are two forms of the radiation treatment: external beam radiotherapy (EBRT) called also teletherapy or percutaneous radiotherapy and brachytherapy. The differences relate to the position of the radiation source: by the external radiotherapy the source is located outside the body, while the brachytherapy uses radioactive sources placed precisely in the area under treatment (around or inside the tumor).