The Affymetrix program is classified as a microarray image analysis application and is utilized for DNA analysis by scientific researchers and geneticists. Files saved in the CEL format are categorized as data files utilized by the Affymetrix software to source data whenever a .cel file is viewed and accesses features included into this application which corresponds to the details entered in those CEL files. The CEL file format and the Affymetrix software may be utilized to input numerous data points from this application, and it means that these CEL files usually have large file sizes. The content saved in these CEL files is comprised of Affymetrix GeneChip details coupled to probes entered by the author of these CEL files. Affymetrix GeneChips are biological chips created to save microarrays gathered from one experimental project. The creation of these biological chips involves glass or silicon materials manufactured and applied with probes. These probes are employed to gather and analyze expression level data that is then classified as values are categorized into two groups, namely MM (mismatch) and PM (perfect match). These values are incorporated into these CEL files as part of its content.
VOI Tool Utility was developed in PET Lab Institute intended to analyze Volumes of Interest (VOIs). This application has set of predefined anatomical VOIs that corresponds to all Talairach Atlas Labels but can save any VOI as SPM compatible image used for masking. Statisticians may also use the saved signal intensity data extracted from a set of VOIs as plain ASCII text file, but saving and extracting signal intensity data as plain ASCII text file are only limited to PET/SPECT models. This software is developed by Microsoft under Windows 98 operating system and only tested with MATLAB 6.0 Release 12. It can be used in any MATLAB supported platform and uses only features incorporated in MATLAB 5.3. VOI Tool utility can be installed by unzipping the file and adding installation folder to MATLAB's search path and should contain one subfolder "AnatomicalVoi", set of .m files and one .mat ihb_VoiDfl.mat file.