Biological imaging is a broad term describing a set of techniques used in biological and health sciences to generate scientifically useful images of various aspects of organisms and biological systems that are not visible to the naked eye. Some imaging techniques are used to develop images of tissues below the skin, while others are used to mark and trace biologically important processes at a molecular level. Imaging methods are highly diverse and can be incredibly creative. While one method may use the rate of the chemical decay of a molecule to develop an image, another may use pulses of near-infrared light to create useful images representing brain activity over time.
There are many different methods of biological imaging used by medical professionals to gather information about the inside of a person's body in a non-invasive manner. One such method that has great importance in modern medicine is called magnetic resonance imaging, or MRI. This method of biological imaging uses a powerful magnetic field to magnetically align certain common atoms, usually hydrogen, in the water in an individual's body. This alignment is rotated, allowing scanners to pick up a rotating magnetic field that can be used to develop a relatively comprehensive image of the interior of an individual's body. This method is particularly useful for taking images of the brain or for detecting cancer.
Biological imaging is not strictly used in a health-care setting, however; many researchers in biological and biochemical laboratories use various methods in biological imaging to gather information relevant to their research. One particularly common and useful laboratory imaging method is known as bioluminescent imaging. Naturally luminescent proteins are used to tag cells and other biological components within an organism or system in order to observe various aspects of biological processes in a non-invasive manner that does not alter the process in any way.
There are many other methods of biological imaging which can be used either for diagnostic purposes or for pure research. Ultrasounds, for example, use high-frequency sound to create images of the internal systems of organisms. Some methods of biological imaging, such as gallium scans, use knowledge of radioactive decay to create internal images of organisms. Gallium, which binds to areas in inflammation within the body, is used as a radioactive tracer to mark various areas of the body; it is particularly useful for the detection of cancer. One very basic and important method of biological imaging used in almost all branches of science and medicine is microscopy, the goal of which is to produce much larger images of small, often incredibly tiny biological objects.