Abstract: A method and apparatus for autofocus on a target layer contained within a microplate well is provided. The instrument is capable of optically sensing a reference point on the underside of a microplate. This reference point is then used to focus light onto a target layer within the microplate well, the target layer having a location that is in defined relation to the reference point. The reference point is either a surface of the bottom of the microplate well or is an optically detectable mark on the underside of the microplate. In an alternate embodiment, a light position sensitive detector is used to enable deterministic autofocus for a plurality of wells on a microplate.

Abstract: An apparatus and method of use for assaying cellular motility in response to a concentration gradient of a chemotactic agent. Generally, the apparatus includes a chamber having a region for receiving a biological sample containing cells of interest and, spaced apart from such region, another region for receiving a chemotactic agent. Between these regions, a concentration gradient of chemotactic agent is established. The apparatus further includes an optical system for detecting and mapping the positions of individual cells responsive to such concentration gradient. Means for processing and analyzing the collected data are also provided. Motility determinations may be made on purified or unpurified samples. Single-site assay devices and multi-site, high-throughput assay devices are disclosed.

Abstract: A method and assay system for the displacement of background from the area surrounding target material allows more sensitive detection. The invention is for use with a system in which specific targets localized at a depth within a container are detected in a liquid containing background material that produces an optical background signal. A displacement liquid is introduced that has a density selected to form a layer encompassing the target material and displacing the material that produces the background signal. The layer of the displacement liquid is sufficient to displace background material from a depth exceeding the depth of field of the detection system. The target material is then optically detected at the depth containing the target material with diminished background allowing greater detection sensitivity.

Abstract: A method and apparatus for autofocus on a target layer contained within a microplate well is provided. The instrument is capable of optically sensing a reference point on the underside of a microplate. This reference point is then used to focus light onto a target layer within the microplate well, the target layer having a location that is in defined relation to the reference point. The reference point is either a surface of the bottom of the microplate well or is an optically detectable mark on the underside of the microplate. In an alternate embodiment, a light position sensitive detector is used to enable deterministic autofocus for a plurality of wells on a microplate.

Abstract: An assay and sample mixture for the enumeration of fluorescently stained target components of a whole blood sample by an imaging instrument. The sample preparation method ensures that the amount of target components per unit of volume of the whole blood sample is preserved by elimination of certain non-quantitative preparation steps while producing an even hematocrit layer within a scan capillary. Typical target components include white blood cells that express certain surface antigens, such as CD-4 and CD-8 proteins. To inhibit aggregation of the red blood cells, a reagent is added to an aliquot of whole blood sample. The aliquot of whole blood is mixed and with a preselected amount of a fluorescent dye and ligand complex which tags the target components.

Abstract: Analytes can be detected from among closely related substances by reacting the analyte in a test sample with a labeled binding agent which specifically binds to the analyte to form a complex. The labeled binding agent is supplied in excess, and the complex is identified through a time window relative to the detection of the excess unbound agent. The complex and labeled binding agent are isolated on a separation media and identified by the differential rate of migration.

Abstract: An assay and sample mixture for the enumeration of fluorescently stained target components of a whole blood sample by an imaging instrument. The sample preparation method ensures that the amount of target components per unit of volume of the whole blood sample is preserved by elimination of certain non-quantitative preparation steps while producing an even hematocrit layer within a scan capillary. Typical target components include white blood cells that express certain surface antigens, such as CD-4 and CD-8 proteins. To inhibit aggregation of the red blood cells, a reagent is added to an aliquot of whole blood sample. The aliquot of whole blood is mixed and with a preselected amount of a fluorescent dye and ligand complex which tags the target components.

Abstract: A system and method for performing a rapid, automatic, quantitative assessment of the image quality of a radiographic image is disclosed. The present invention utilizes a stepped calibration target made of differentially attenuating disks that is exposed to a beam of radiation simultaneously with the exposure of an object of examination. The recording medium is developed, if necessary, and the image of at least the calibration target is read, as with a laser scanner or a CCD. The optical density characteristics of the image of the calibration target are then analyzed with respect to reference optical density criteria associated with the type of recording medium used and indicative of an optimal signal pattern. If the optical density characteristics of the calibration target image meet the reference criteria, then an indication is made to show that the radiographic image has been approved as meeting the quality assurance threshold.

Abstract: The apparatus and method of the present invention disclose a scanning imaging cytometer wherein an unprocessed biological fluid sample is reacted with a fluorescently-labeled binding agent. The reacted sample undergoes minimal processing before it is placed into a capillary tube. The sample is optically scanned and fluorescence excitation is recorded from a plurality of columnar regions of the capillary tube, each columnar region generally defined by the spot size of the excitation beam and the depth dimension of the capillary tube. A spatial filter of a sufficient pinhole diameter is selected to allow simultaneous volumetric detection of all fluorescent targets in each columnar region.

Abstract: A method for digital imaging employing a green light laser. The method comprises obtaining a digitized picture image, modulating a green light laser beam in accord with the digitized picture image, and directing the modulated laser beam onto film that is sensitive to green-blue light. The film is then developed to create a gray-scale image useful in radiography and other imaging fields.

Abstract: An electrophoresis-based assay system for detection of one or more target substances, i.e. an analyte tagged with fluorescent binding agents. The analyte is reacted with an excess amount of fluorescently tagged binding agent. The reaction mixture is subjected to electrophoresis and the migration of bound and free fluorescent substances are timed at a location where there is a spatial and optical differentiation of the two substances. An optical detector supplies signals corresponding to fluorescent amplitudes of the two substances. The free fluorescent substance arrives at a time expected from calibration runs. This optical signal is a marker for a second time, either earlier or later, when the bound substance should have arrived. Recorded data is searched to establish the relation between free and bound dye among the recorded optical signals. An absence of a bound dye signal infers the absence of target analyte in a sample.

Abstract: A system and method for processing images viewed on radiographic film. Such images include mammograms, CAT scans, or other standard x-ray type images. The system includes a scanning laser film digitizer for reading the optical density of pixels in an original film image; a controller which analyzes the image data based on input film type and scanned optical density in order to compute an exposure correction factor which enhances the original image quality; and a laser film writer which creates a new copy of the original data in the improved form. The system is capable of writing several proportional non-overlapping images on a single sheet of film. This feature facilitates diagnostic evaluation of related subject matter such as multiple angle views of an injury, simultaneous views of right and left side mammograms, or several CAT scans on a single exposure. The system uses a look-up table to store and access optical density vs. exposure characteristics for several types of radiographic film.

Abstract: An electrophoresis-based assay system for detection of one or more target substances, i.e. an analyte tagged with fluorescent binding agents. The analyte is reacted with an excess amount of fluroescently tagged binding agent. The reaction mixture is subjected to electrophoresis and the migration of bound and free fluorescent substances are timed at a location where there is a spatial and optical differentiation of the two substances. An optical detector supplies signals corresponding to fluorescent amplitudes of the two substances. The free fluorescent substance arrives at a time expected from calibration runs. This optical signal is a marker for a second time, either earlier or later, when the bound substance should have arrived. Recorded data is searched to establish the relation between free and bound dye among the recorded optical signals. An absence of a bound dye signal infers the absence of target analyte in a sample.

Abstract: A method and system for imaging unstained smaple material constituents on a gel electrophoresis unit. The system includes a gel electrophoresis unit, preferably having a pH gradient gel thereon, phase detection optics including a collimated light source, shearing interferometer, phase contrast microscope or schlieren microscope, an image digitizer, and data processing electronics, such as a computer, for determining the concentration of sample constituents at each position on the electrophoresis unit. The method relies on the difference in index of refraction between sample material and gel material to introduce optical path differences in light rays passing through the material. The modified light is subjected to shearing interferometry to locate gel-sample boundaries, phase imaging to directly image the sample, or a laser scanner for directly measuring the deviation in a light beam due to the sample.

Abstract: A beam scanning system having a beam reflecting element, such as a mirror, disposed in the path of an incident beam defining an optical axis, which is pivotable about two perpendicular axes so as to provide for scanning a reflected beam in two dimensions. A pivot axis is perpendicular to the optical axis and may be provided by a spindle supporting a galvanometer mirror. The second axis coincides with the optical axis and may be provided by a meter driven shaft attached to the mirror support which is rotatable about the optical axis. The reflecting element reflects the beam toward an image plane that is parallel to the incident beam so as to scan a sequence of parallel lines without pincushion errors. An optical f-.theta. correcting lens may be provided in the reflected beam path to correct for tangential spacing errors in the image plane.

Abstract: An apparatus for reproducing a digitized image from a semiconductor memory onto a light sensitive material using a plurality of movable equally spaced light sources. The sources direct light beams through apertures in a mask, movable with the sources, onto a sheet of the material disposed on a drum. The light sources emit beams of variable intensity responsive to image data recorded in memory devices. As the drum rotates, the mask and light sources move in unison longitudinally at a rate of one pixel width per drum revolution. One embodiment of a recording module comprises only light sources and mask, while another embodiment also includes a pair of lens arrays that image the beam onto the sheet. There are an integral number of pixel widths between adjacent beams. A plurality of parallel lines on the mask and a scanner fixed relative to the drum sense the relative position between the mask an the drum for providing corrective feedback information to a motor moving the mask and light sources.

Abstract: An apparatus for digitizing an image on a film material using a plurality of movable equally spaced light detectors. Light sources direct light through a sheet of the material disposed on a transparent drum. The light which is transmitted is imaged onto light detectors through apertures in a mask. As the drum rotates, the mask and light detectors move in unison longitudinally at a rate of one pixel width per drum revolution. One embodiment of a scanning module comprises only light detectors and mask, while another embodiment also includes a pair of lens arrays that image the sheet onto the detectors. There are an integral number of pixel widths between adjacent detectors. A plurality of parallel lines on the mask and a scanner fixed relative to the drum sense the relative position between the mask and the drum for providing corrective feedback information to a motor moving the mask and light detectors.