Dose Limit and ALARA

Dose limit gives support for the protection principle. Dose limit represents the judgement at the level of the individual harming or not harming which is on the border line of acceptability and unaacceptability. Continued exposure at a level just above a dose limit would result in risks which could be resonably ve described as unacceptable. Thus dose limits are those limits above which any person may cause radiaton hazard. Dose limits for the different people are different according to their employment or their occupation.It is categorized into three,they are:

1. Employees aged 18 years or above(Employees)
2. Trainees aged under 18 years(Trainees)
3. Any other person (Public)

The scientific basis for setting dose limit is  the comparative risk. There are signigicant differences between the risk of radiation and  other occupation al hazards. The persons whose occupation requires exposure to the radiation are called occupational exposure such as radiation oncologist, radiologists,nursing staffs etc working in a radiology or radiotherapy department are occupational exposure. On one hand, the staff has to receive the radiation dose and on other hand, the body has some tolerance limit for occupation of the injured cells. Hence many national and international organizations have recommended the maximum permissible limit radiation.

But ALARA principle should be followed in each department which means the risks we keep as low as reasonably achieavable taking into account the social and economic functions.