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Half-life

Definition

noun, plural: half-lives

(1) Biological half-life, i.e. the period in which the amount of substance inside the living organism is metabolized and eliminated half of its initial amount by normal biological process

(2) (radiobiology) Effective half-life, i.e. the time required for a radioactive material taken in or administered to an organism to undergo radioactive decay and lose half of the amount of its original value

(3) (medicine) The time at which a drug, substance, or chemical is reduced to half of its original amount, effectiveness, or radiological activity in biological fluid


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