Radiotherapy uses high energy waves to treat cancer. The energy waves destroy cells and the purpose of radiotherapy is to destroy as many cancer cells whilst minimizing damage to healthy cells. Radiotherapy works on the basis that healthy cells are stronger and reproduce more quickly meaning that as cancer cells are killed off they are replaced by healthy cells.
Radiotherapy can be used to cure cancer (normally when limited to the original cancer) or provide palliative relief.
Radiotherapy can also be given internally in the form of radioactive pellets that are inserted directly into the tumour. This form of radiotherapy is known as brachytherapy.
Intensity-modulated radiation therapy (IMRT) is a relatively new form of external radiotherapy that that uses computer technology to deliver precise radiation doses to the tumour. IMRT uses CT images of the patients to provide a pattern of dosage that conforms to the tumour shape. By sending beams of energy from different directions it is able to provide a high radiation dosage to the tumour whilst minimizing the dose to adjacent normal tissues.
