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LAI Sperm Finding and Documentation System
Background | System Description | Features | Identifying Sperm | Reviewing | Reporting
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Benefits
- Automated scanning facilitates quicker, less labor intensive analysis of slides from sexual assault cases
- Improves laboratory productivity
- Decreases cases turn-around time
- Saves time and money
Call 410-876-8055 for current pricing or have a quote sent.
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System Description
 Image analysis experts at Loats Associates, Inc., working in cooperation with scientists at the Vermont Forensic Laboratory, have developed a system for the automated screening of evidentiary slide preps for the presence of spermatozoa. The system consists of:
- Robotic microscope with computer controlled servo-driven 4 slide stage and focus,
- High resolution color digital firewire camera,
- Windows based computer with mouse, full size keyboard, and large flat panel monitor, and
- Sperm finding and documentation software.
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Features
The system can process multiple slides in a single run and uses a 40X objective magnification to systematically search defined sample regions on each slide for the presence of spermatozoa. Individual database files are created by the system for each slide scanned and are tracked according to a user specified Case and Item number. Access to the system for run initiation, results review and verification and report generation are all password protected to assure good evidentiary control.
- Secure password protected operation,
- Automatic, unattended scanning of Christmas Tree stained slides for the presence of spermatozoa,
- Batch processing of multiple slides,
- Easy user-review and verification of automated scan results using saved picture gallery of located candidate cells,
- Automated relocation enables viewing of candidate sperm cells through the microscope eyepieces,
- Results archived according to case and evidence item number,
- Hardcopy reports available immediately after user-review and verification.
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Background
The analysis of a sexual assault case by a forensic laboratory is a multi-step procedure. One step in this process is an often lengthy manual microscopic examination of slides of vaginal smears or smears from other crime scene evidence to determine the presence or absence of spermatozoa. This step is important since identification of the presence and quantity of sperm available is a good indicator of the potential success of a DNA extraction and Short Tandem Repeat (STR) analysis.
However, manual screening of slides for sperm is labor intensive and can take considerable time, depending upon the nature of the slide. This often creates a workflow bottleneck, which impedes rapid turn around of sexual assault cases. There is consequently need for effective automated procedures to facilitate swift and less labor intensive analysis of slides. Such automated methods can improve laboratory productivity, decrease case turn around time, provide valuable information to more effectively determine which evidence items would be suitable for autosomal or Y STR analysis, and assist forensic scientists in making better use of limited crime scene samples and laboratory resources. In addition, automated processing and analysis can save valuable time and money that can be re-directed to address other important analyses.
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Identifying Sperm
In recognizing sperm, the system has been designed to utilize visual cues revealed by "Christmas Tree Stain", the most common staining protocol used by the forensic community in the US for smear screening. Much like a human reader, the system’s software uses characteristic features of color, size and shape to identify candidate spermatozoa on the slides.
The system dynamically displays the current image frame analyzed, marking the positions of any candidate sperm identified with a red box, along with summary statistics for each slide: number of cells found and number of frames processed. |
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As each candidate sperm is identified, the system automatically records the coordinates of the cell location, and an image of the cell is displayed in an on-screen picture gallery, and this image is saved into a database for subsequent user review.
Automated scanning continues until a user-specified number of candidate sperm cells have been located on each slide or the designated sample region on the slide is exhausted. At that time, the system proceeds with scanning of the next slide or stops scanning operations if all slides in the run have been processed.
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Reviewing
Upon completion of automatic slide scanning, the system user can review the candidate sperm found by the system in the on-screen picture gallery and verify those cells that are spermatozoa. If needed, the user can easily direct the system to return to the actual slide position of an identified cell so that a detailed visual examination of the cell can be made through the microscope eyepieces.
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Reporting
Developed in cooperation with scientists at the Vermont Forensic Laboratory, Eric Buel, PhD, Director, www.dps.state.vt.us/cjs/forensic.html, and supported in part by NIJ Grant 2004-DNBXK003
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Loats Associates, Inc. 201 East Main St Westminster, MD 21157
Phone (410) 876-8055 • FAX (410) 876-5843 • e-mail
loats@loats.com
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