| 摘要 |
A system for assessing platelet viability in a transparent flexible bag. The apparatus employed consists of a support for clampingly receiving the bag and defining an optically exposed constricted region in the bag. A laser beam is passed perpendicularly through the constricted region of the bag. The opposite side portions of the bag are alternately periodically compressed and released to provide laminar fluid flow through the constricted region to align platelet discs face-on with respect to the beam. Scattered light from the beam is passed through an annular gate, defining a selected scatter angle relative to the beam axis. The selected scattered light is directed by a lens onto a photodiode detector. The output of the detector is processed and furnished to a computer, which is employed to derive respective quantities indicating the concentration of non-aggregated platelets and the percentage that are discs. These quantities are obtainable by (1) averaging the output during a period when said laminar flow is provided, to obtain a value Il, and (2) stopping the periodic compression and allowing the platelets to thereafter become randomly oriented, to obtain a value Io. The quantity representing disc percentage is calculated for (Il-Io)/Io, whereas the concentration of non-aggregated platelets is calculated from Io.
|
