filtration

1. The process of passing a liquid or gas through a filter. 2. In radiology, the process of attenuating and hardening a beam of x- or gamma rays by interposing a filter (3) between the radiation source and the object being irradiated; inherent f. is that which is caused by the apparatus itself, such as the glass of an x-ray tube, without addition of a filter. SYN: percolation (1).

- gel f. separation of molecular sizes by passage of a mixture through columns of beads of cross-linked dextrans or similar relatively inert material of a well-defined pore size range; the larger the molecule, the less time it spends in the interior of the beads, thus emerging earlier from the column than smaller molecules.

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fil·tra·tion fil-'trā-shən n

1) the process of filtering

2) the process of passing through or as if through a filter also DIFFUSION <the kidney produces urine by \filtration>

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fil·tra·tion (fil-traґshən) 1. the passage of a liquid or gas through a filter. 2. in radiology, the use of a solid screen usually made of metal (aluminum, copper, tin, lead, etc.) to absorb beta particles and photons of longer wavelengths.