A scanning and image processing system with integrated design for automated micronucleus scoring

Abstract

Purpose: Our aim was to design a compact and cost-effective optical microscopic system for automated non-fluorescent micronucleus (MN) scoring whose performance can reach the accuracy of visual scoring with the help of minimal user interaction and also gives an option for fully automatic scoring with an accuracy suitable for triage purposes.

Materials and methods: The concept of Radometer MN-Series (RS-MN) microscopic system designed by Radosys was to develop hardware and software layers in parallel in order to optimize the performance in automated MN scoring. A MN assay slide is automatically scanned by the RS-MN then the binucleated cells and micronuclei are automatically identified. Processing 1000 cells takes 10–60 minutes by automatic scoring (scanning plus image processing) depending on sample quality and required accuracy. The manual revision of the cell gallery takes an extra 10 minutes per sample. Dose response curves are determined for manual, automatic and semi-automatic scoring methods.

Results: The combination of object-sensitive autofocusing method and the multi-layer image acquisition is able to reduce the minimum resolvable dose by 14%. The MN yields obtained from the manual, semi-automatic and automatic scoring methods are well correlating (Pearson’s correlation coefficients are between 0.977 and 0.998). In order to compare the reliability of the results of visual and automatic scoring, an extended analysis on uncertainty contributors was performed. For a dose of 1 Gy, the estimated relative uncertainty from the Poisson characteristics of MN yield is 17–19% for the manual and 20–38% for the automated scoring. Other uncertainty factors (differences in donor radiosensitivity, scorer performance, and sample preparations) can contribute to this error fall within a similar range: 3–16%. Taking into account all of the possible uncertainties, the minimum resolvable dose for the manual (0.48 Gy) is the two-thirds of that of the automatic scoring (0.61 Gy).

Conclusions: The results verify that the fully automatic mode of RS-MN is suitable for triage purposes. The performance of the user interacted semi-automatic mode is comparable with the reference manual scoring. Its performance reaches up to other non-fluorescent automatic systems and offers a compact and cost-effective alternative.

Keywords:

• Automatic micronucleus (MN) assay
• uncertainty contributions
• biodosimetry
• dose–response curves
• radiation triage

Acknowledgments

The study was possible thanks to the assistance of managers and colleagues at Radosys Ltd., who made the prototype of the RS-MN microscope available and supported the research and development of the software. Special thanks to Prof. Francesco d’Errico for proposing the idea of adapting the Radosys microscopic technology to micronucleus counting in the first place and for his contribution to this manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research was partially supported by the Hungarian National Research, Development and Innovation Fund [Grant VKSZ 14-1-2015-0021].

Notes on contributors

Tímea Hülber

Tímea Hülber, MSc, is a PhD student at the Institute of Nuclear Techniques at Budapest University of Technology and Economics and works at as R&D physicist at Radosys Ltd. She is specialized in ionizing radiation measurements, including biodosimetry and solid-state nuclear track detectors.

Zsuzsa S. Kocsis

Zsuzsa S. Kocsis, PhD, works as radiobiologist in National Institute of Oncology, Centre of Radiotherapy, Department of Radiobiology and Diagnostic Onco-Cytogenetics.

Enikő Kis

Enikő Kis, MSc, is a PhD student at National University of Public Service. She works as a radiation biologist at the Department of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary.

Géza Sáfrány

Géza Sáfrány, MD, PhD, DSc, is a medical doctor specialized in radiation biology and radiohygiene. He is the head of the Department of Radiobiology and Radiohygiene of the National Public Health Center in Budapest, Hungary.

Csilla Pesznyák

Csilla Pesznyák, MSc, PhD, is a medical physicist specialized in radiotherapy, including dosimetry, radiation biology, radiation protection and education organization. She is an associate professor at the Institute of Nuclear Techniques at Budapest University of Technology and Economics.