title: Cell detection in phase-contrast images used for alpha-particle track-etch dosimetry: a semi-automated approach.
abstract: A novel alpha-particle irradiator has recently been developed that provides the ability to characterize cell response. The irradiator is comprised of a collimated, planar alpha-particle source which, from below, irradiates cells cultured on a track-etch material. Cells are imaged using phase-contrast microscopy before and following irradiation to obtain geometric information and survival rates; these can be used with data from alpha-particle track images to assess cell response. A key step in this process is determining cell location within the pre-irradiation images. Although this can be done completely by a human observer, the number of images requiring analysis makes the process time-consuming and tedious. To reduce the potential human error and decrease user interaction time, a semi-automated, computer-aided method of cell detection has been developed. The method employs a two-level adaptive thresholding technique to obtain size and position information about potential cell cytoplasms and nuclei. Proximity and geometry-based thresholds are then used to mark structures as cells. False-positive detections from the automated algorithm are due mostly to imperfections in the track-etch background, camera effects and cellular residue. To correct for these, a human observer reviews all detected structures, discarding false positives. When analysing two randomly selected cell dish image databases, the semi-automated method detected 92-94% of all cells and 94-97% of cells with a well-defined cytoplasm and nucleus while reducing human workload by 32-83%.
authors.affiliation: Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL 60637, USA. mbaltman@midway.uchicago.edu
authors.forename: Michael B
authors.initials: MB
authors.lastname: Altman
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Wang
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Whitlock
authors.forename: John C
authors.initials: JC
authors.lastname: Roeske
mesh_terms: D000465:Algorithms; D000818:Animals; D001185:Artificial Intelligence; D002452:Cell Count / Q000379:methods*; D018929:Cell Culture Techniques / Q000379:methods; D045744:Cell Line, Tumor; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018499:Linear Energy Transfer; D008858:Microscopy, Phase-Contrast / Q000379:methods*; D010051:Ovarian Neoplasms / Q000473:pathology*; D010363:Pattern Recognition, Automated / Q000379:methods*; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity