Biohazards are produced by microorganisms or viruses which cause disease, or substances such as toxins or venoms prepared by living organisms.

A biokinetic model describes the time course of absorption, distribution, metabolism and excretion of material or radiation introduced into the body of an organism.

The biological half-life is the time required for the concentration of a substance in a biological system to be reduced by one half. A biological half-life includes usual processes for eliminating substances without radioactive decay.

See also Biological Radioactive Half-Life.

Time in which 50% of an administered dosage of a radioactive substance through biological (physiological) processes is removed.

See also Half-Life, Physical Radioactive Half-Life and Effective Radioactive Half-Life.

A biopsy is a procedure in which tissue samples are collected. This can be done with a needle, which is inserted into the abnormal area.
An example is the needle breast biopsy. Needle biopsies are usually guided by different imaging techniques like ultrasound, computed tomography, or magnetic resonance imaging. Stereotactic-assisted breast biopsies use computer maps to guide the needle. The location of the breast lump is provided from digital mammograms taken from two angles.
The cells can be removed and examined under a microscope to determine whether the abnormality is cancerous.

See also CT Guided Biopsy.