The word radiotherapy is the abbreviated form of the word ‘Radiation therapy’. Different diseases like cancer, abnormal nature of thyroid gland, some diseases concerning blood are treated using it. Generally, radiotherapy destroys cancer cells utilizing highly energized X-ray. It destroys the power of multiplication of the cells by damaging the DNA inside the tumour cell. Mainly, it is the application of ionizing (radioactive) radiation in the treatment of disease.

Radiotherapy is of two types:

  1. External beam radiation or external radiotherapy
  2. Internal radiotherapy

In case of external radiotherapy highly energized X-ray, cobalt radiation, electron or proton beams are applied from outside the body. The beam is applied directing to that site of the body where a tumour is located. As a result, the growth and power of multiplication of the cancer cells get destroyed. In this process, a very few number of healthy cells also get affected. Yet, our aim is to destroy cancer cells as many as possible than the healthy cells. Most of the healthy cells that got damaged can repair themselves.


In case of internal radiotherapy, radiotherapy is applied from inside the body of a patient. In this process, the patient takes radioactive liquids as drinks or radioactive liquids are introduced into the body of the patient through injection. Radioactive phosphorus in case of blood cancer, radioactive strontium in bone cancer and radioactive iodine in thyroid cancer is used in the liquid. This process is called brachytherapy.