Written by Dr. Sangamithra, MBBS | 

Medically Reviewed by Dr. Ramya Ananthakrishnan, MD on Jul 28, 2021


There are over 10,000,000,000,000 cells in your body. Each one has a nucleus with the same set of 46 chromosomes. By copying the original 46 chromosomes, your body has created more than a hundred billion kilometers of DNA.

Cancer is a disease that originates in our own cells. A change in the DNA causes a special gene called an oncogene to be switched on irreversibly leading to uncontrollable cell reproduction. The uncontrolled growth of cells forms a lump called a tumor. Malignant tumors are called cancers.

Cancer can start anywhere in the body and there is a danger that, if not treated early enough, they can spread to form secondary tumors. High-energy gamma radiation is aimed at the growing tumor. This damages the DNA in rapidly dividing cells and so helps to destroy the tumor. There are many different types of radiation. Exposure to ultraviolet, alpha, beta and gamma radiation can cause cancer.

Ionizing radiation can damage chromosomes and cause mutations that may trigger a tumor to develop. Different types of radiations that are used in radiotherapy are gamma, beta and X-rays. Beta radiations are weakly ionizing. Gamma radiation is only really hazardous if it is very intense and this happens after a nuclear explosion.


  1. About Cancer - (http://www.cancerhelp.org.uk/help/ default.asp?page=166)
  2. WHAT IS RADIOTHERAPY? - (http://www.cancernet.co.uk/rxt-what.htm)

Latest Publications and Research on Radiotherapy


nizamzualiz Tuesday, September 25, 2012

There is opinion saying Radiotherapy and Chemotherapy treatment are not actually killing the cancer cells but the cells are kept [or maybe deactivated] for a period of time... It will strike back. At that point of time, we may be able to do the same treatment/s, but the attack usually more severe than the first. Possibly, the patient may have no energy to go through the second episode of treatment (due to age and/or tiredness and/or cost incurred). If you are not lucky, the second cancer will strike due to the treatment itself. So, instead of killing the cancer cells the treatment may create second cancer. Appreciate comments please

faranak Saturday, February 11, 2012

could IMRT done near an organ cause the organ a condition that can not be transplanted if needed?

linac Saturday, July 17, 2010

can i ask what's the difference between conventional fractionated XRT versus stereotactic radiosurgery vs external beam radiation therapy?

ahpeng Friday, April 16, 2010

My skin is itchy and scratches now and then please advise

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