BD FocalPoint GS User Manual page 93

Tray Handling System (not pictured) The tray handling system moves trays from the input
hopper to the microscope stage, to various scanning positions on the stage, and to the output
hopper. Trays are lowered with an input hopper elevator, pulled onto the stage with a transport
chain, positioned on the stage, and when processing is complete, raised to the output hopper.
Sensors detect the presence of a tray in the bottom of the input hopper, the position of the tray
on the stage, and the presence of a tray at the top of the output hopper. For safety, door interlock
switches detect when one of the hopper doors is open, which causes all mechanical motion to
stop.
Microscope System (not pictured) The microscope system uses a high-speed video
microscope, which is able to capture 25 images per second. During scanning operations, small
motors move the microscope stage in minute increments. The stage movement is synchronized
with a strobe light to provide stop-motion image capture and to automatically focus the image.
The microscope turret carries the low power (4x) and high power (20x) objectives, plus a
barcode reader and touch sensor assembly. The barcode reader reads the barcode labels
affixed to each slide and tray. The touch sensor determines if a slide is present in each slot in the
tray.
The microscope assembly also contains a calibration plate mounted on the microscope stage.
This calibration plate is moved under the microscope during system calibration and system
integrity verification. A target on the calibration plate is used to:
• calibrate the correction for centering between the low power and high power objective
imaging paths.
• test that the motors repeatedly move the stage to the same position.
• measure image resolution.
• measure the performance of the microscope system.
• identify any dust contamination in the optical system and on the calibration plate.
When required, the calibration plate is automatically rotated in and out of the calibration position.
(See Section 23 for a complete discussion of the calibration plate.)
A vibration isolation system protects the microscope from external vibrations.
FOV Computers (not pictured) Captured images are transferred to a series of Field of View
(FOV) computers for analysis. Using predetermined parameters and image interpretation
programs, the FOV computers analyze the images on each slide. Image analysis results are
then passed from the FOV computers to the main computer, which determines a composite
result for each slide. Cellular elements that may be evaluated include:
• squamous epithelial cells
• endocervical cells
• squamous intraepithelial lesions (SIL)
• adenocarcinoma cells
• squamous carcinoma cells
• various other atypical cell conditions as defined by The Bethesda System
Certain physical characteristics of the slide and the specimen are also measured to determined
suitability for automatic processing.
The BD FocalPoint™ Slide Profiler
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