Sunday, 17 August 2008

17 August 2008 - Some thoughts on radiotherapy


Exposure to radiation in the workplace is controlled by the Ionising Radiations Regulations 1999. Under these Regulations an employee of 18 years or over is limited to a radiation dose of 20milliSieverts (mSv) in any calendar year. If a person receives a dose greater than this permitted level then an immediate investigation must be carried out into the causes and the overdose reported to the HSE.
In each session Deb is receiving a dose of 1.8 - 2.0 Grays (Gy) of X-ray radiation. The total dose she will receive during her radiotherapy is 55 - 60 Gy. (Don't worry about the units; Sieverts measure the dose received, Grays measure the effect that dose has on the body i.e. to choose a boxing analogy Sieverts measure how hard you are hit, Grays whether you are knocked out or not. For gamma and X-ray radiation Sieverts and Grays are the same i.e. 1 Sv = 1 Gy.)
So in one session Deb is receiving a dose of 2 Gray or 2000 mSv that is 100 times the radiation exposure permitted in a whole year by the radiographers carrying out the therapy. Scary eh?

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