Written by Dr. Sangamithra, MBBS | 

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


The dose depends on the tumour type, whether radiation is given alone or with chemotherapy, before or after surgery, the success of surgery etc. radiation oncologist treating the patient determines the radiation dose.

The amount of radiation absorbed by the tissues is called the radiation dosage. Before 1985, dose was measured in a unit called a "rad" (radiation absorbed dose). Now Gray (Gy) is a unit of radiation dose. One Gy is equal to 100 rads; one centigray (cGy) is the same as 1 rad.

In case ofcurative treatment of a solid epithelial tumor radiation dose raging from 50-70 Gy is administered in case of lymphomas 20-40 Gy is given. This dose is given in daily fraction called the fraction schedule. Typically adults receive 1.8-2 Gy per fraction. The typical treatment schedule is 5 days per week (no weekends). These small frequent doses allow healthy cells time to grow back, repairing damage inflicted by the radiation. Daily fractions of radiation are given using an external source or an internal source such as implants.

In case of palliative treatment a single dose of 6-10Gy may be given to painful superficial tumours, to releive pain.


  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)


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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