During radiotherapy, radiation beams attack cancer cells while minimizing impact on the surrounding healthy cells. This is because cancer cells are more sensitive to radiation.
Radiotherapy is rather similar to having an X-Ray. It is targeted specifically to the part of the body being treated and it is painless.
Modern advances in imaging techniques and computer systems have allowed radiotherapy to be conducted at a higher complexity. It allows for better imaging and localisation of tumours at its specific coordinates. This allows for more accurate and effective delivery of radiation into the tumour while minimizing impact on the surrounding healthy tissue.