Biological dosimetry (biodosimetry) is an imminent part of the countermeasures in the aftermath of radiation accidents. Based on the quantification of markers in the blood of affected victims (e.g., dicentric chromosomes, micronuclei, or translocations), the method allows for a precise and retrospective estimation of the dose the persons have received. The National Radiation Emergency Medical Center (NREMC) in the Korea Institute of Radiological & Medical Sciences (KIRAMS) recently hosted a MetaSystems workshop on the implementation of Metafer for biodosimetry imaging automation. The workshop has been supported by our Korean partner Mirax Corporation.
Metaphase Finding and Image Acquisition
Building imaging workflows in high-throughput laboratories.
Automation of metaphase finding and imaging is one of most efficient ways for improving throughput and quality in classical cytogenetics. Several independent studies have shown that the use of automated imaging systems in cytogenetics not only increases case turnover rates but also improves analysis quality. MetaSystems offers a modern and flexible imaging solution for routine applications which is based on automated metaphase finding (MSearch), unattended image acquisition (AutoCapt), and sophisticated case and image data management devices. The slide scanning platform Metafer with its open concept can be configured either as a stand-alone workplace or as part of larger, network-based multi-user environments. In both cases Neon, the case management dashboard for Metafer, maintains case data, tracks processing states of all cases, and exchanges case data with extrernal sources.
Neon, Metafer, Ikaros, and Isis can all be used as building bricks for a customized workspace that grows with demand. If Metafer is supplemented with the innovative slide frame exchanger SlideFeeder x80, and possibly with the bar code reader and the immersion oil dispenser, such a system can be configured to run as a 24/7 imaging server. Connected analysis stations access the image and case database through Neon, and analysis results are immediately fed back to the main server.
The Metafer-based metaphase finder (MSearch) automatically finds metaphases on any metaphase sample. Due to user-trainable classifiers it is easily adaptable to all kinds of preparations and contrasting methods (Giemsa staining, fluorescence, and even phase contrast). Detected metaphases are automatically displayed in an overview gallery and can be relocated with just one mouse click. Coordinates are easily transferred to any available manual microscope. The direct interface to Ikaros and Isis workstations makes the metaphase finder a powerful tool for convenient and fast chromosome analysis.
Easy adaptation and parameter optimization to different cell types and preparations is of crucial importance for making an automated system useful for routine analysis. To facilitate this task, the metaphase finder provides sophisticated training and optimization routines. The metaphase gallery, generated in real time during the search, provides fast overview of detected objects. Metaphases are easily relocated by clicking on the respective gallery image to allow for detailed inspection under the microscope, or using the digital live image. With the mouse, metaphases can easily be selected for acquisition, or they can be rejected or deleted in the gallery. Alternatively, the search classifier can be trained to assign quality scores to the metaphases, allowing for automatically selecting a defined number of best metaphases.
Additional parameters such as the mitotic index (MI) are automatically obtained during the scan. Positions of all metaphases and nuclei are displayed, and metaphases can be selected interactively or automatically. If clonal samples are scanned, the metaphase finder can even select a given number of objects per clone, and it assigns the clone number to the metaphase's metadata.
Automated acquisition of high-resolution metaphase images (AutoCapt) efficiently increases the degree of automation in routine metaphase analysis. Each Metafer metaphase finder generates position lists, representing the location of all detected objects. These positions are automatically relocated, and images of the objects at the position are acquired based on classifier-defined parameters. Once acquired, Neon immediately takes over the images and makes them available to any connected workstation.
The way how the images are acquired can be highly customized. After metaphase finding, for instance, all detected objects can automatically be sorted by their quality score. The system can acquire a pre-defined number of best metaphases. To provide a complete picture, however, some randomly selected metaphases can additionally be captured. Objects can be acquired as raw images, or they can be subject to image processing. Focus stacks are supported as well as up to 12 different color channels, for example to automatically acquire FISH or mFISH metaphases. Objects are automatically centered in the image, and if they are larger than one camera field it is possible to acquire more than one image per position.
The automated immersion oil dispenser (AutoOiler) eliminates any human interaction between metaphase finding and image acquisition. Thus, if the SlideFeeder x80 is installed, Metafer can find and capture images from up to 800 slides without any need for supervision by a researcher. Therefore the system can capture images through the nights and over weekends or holidays.