The 'As Low as Reasonably Achievable' (ALARA) Principle

The ALARA principle is a general principle – though used most for medical staff and patients - to ensure the safety of workers and the public as much as possible, when the risk is well known. Though radiation is needed to carry out certain treatments – radiotherapy is a principle cancer treatment and X – rays one of the principle imaging techniques - the use of radiation involves risk to everyone involved. In fact, everything we do involves risk – every year, around 100 people die choking on ballpoint pens. The risk from all types of harm is impossible to eliminate, but it can be reduced.

For example, the risk from nuclear radiation experienced by workers and patients in the hospitals can be reduced by:

  1. Reducing the time ofexposure to nuclear radiation. If the same effect can be achievedwith a lower dose of radiation, it is the lower dose that should beadministered. Between Exposure incidents, the body's repairmechanisms go to work to reduce the damage caused.

  1. Increasing the distancebetween you and the radiation source will reduce exposure becausethe radiation dose received decreases at least as fast as the squareof the distance.

  2. Shielding people fromsources of radiation. People often do not need to be shielded fromalpha and beta sources since these are short range. Exposure togamma radiation however is increased in the absence of shielding andmedical staff in hospitals are often shielded from by lead fromgamma ray sources (and X – ray sources too) when these sources areused to treat or take images of patients.

  3. Ensuring that the halflife of the radiation is about the same as the length of thetreatment. Less long and the treatment migh not be effective. Longerand the total radiation exposure will be increased.

  1. Using other imaging techniques where possible. Theinclude ultrasound (quite cheap), MRI and CAT scans (bothexpensive). These techniques involve no exposure to nuclearradiation and very little risk (though some people may die fallingoff the bed).

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