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A CMOS image sensor method of focal spot size measurement

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Abstract

A phosphor opto-coupled monochrome CMOS image sensor with a slit diaphragm was used to investigate focal spot characteristics. Images were captured during x-ray exposure with a triggered frame grabber and subsequently enhanced. Dimensions of the focal spot width (1.39mm) and length (1.92mm) were determined from the focal spot intensity profiles and their corresponding Full Width at Half Maxima (FWHM) in two orthogonal orientations. The CMOS image sensor measurements demonstrated differences in the measured width and length dimensions when compared to film measurements. The obtained nominal focal spot values however showed that image-sensor determined focal spot dimensions agreed with the direct film and film-screen methods when based on the AS/NZS defined nominal focal spot values. The CMOS image sensor tested appears to lack the measurement accuracy required for the measurement of small focal spot sizes due in part to its limited camera sensitivity.

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References

  1. Lu, T., Udpa, S. S. and Udpa, L.Tomographic reconstruction using optoelectronic architecture, IEEE Volume 4, 1991.

  2. Muirhead, I. T.,Developments in CMOS camera technology, IEE. 1994.

  3. Lake, D.,Why CMOS imagers are the rage: A revolution in the making, Advanced Imaging Magazine, 12–18, 1995.

  4. Fossum, E. R.,CMOS image sensors: Electronic camera on a chip, IEEE 1995.

  5. Denyer, P. B., Renshaw, D., Wang Guoyu and Lu Mingying,A single chip sensor and image processor for fingerprint verification, Proceedings of IEEE Custom Integrated Circuits Conference, San Diego, California, May 9–12, 1993.

  6. Speller, R. D., Martinez-Davalos, A., and Farquharson, M.,A CCD based focal spot camera, Phys. Med. Biol. 40, 315–321, 1995.

    Article  CAS  PubMed  Google Scholar 

  7. Rong, X. J., Krugh, K. T., Shepard, S. J. and Geiser, W. R.Measurement of focal spot size with slit camera using computed radiography and flat-panel based digital detectors, Med. Phys. 30(7): 1768-75, 2003

    Article  PubMed  Google Scholar 

  8. Everson, J. D. and Gray, J. E.,Focal spot measurement: Comparison of slit, pinhole and star resolution pattern techniques, Radiology, 165, 261–264, 1987.

    CAS  PubMed  Google Scholar 

  9. Australian/New Zealand Standard (AS/NZS),X-ray tube assemblies for medical diagnosis-Characteristics of focal spots, AS/NZS 4274, 1995.

  10. Nickoloff, E. L., Donnelly, E., Eve, L. and Atherton, J.V.,Mammographic resolution: Influence of focal spot intensity distribution and geometry, Med. Phys., 17(3),436–4477, 1990.

    Article  CAS  PubMed  Google Scholar 

  11. Schiabel, H., Ventura, A. and Frere, A. F.,A formal study of lateral magnification and its influence on mammographic imaging sharpness, Med. Phys., 21(2), 271–276, 1994.

    Article  CAS  PubMed  Google Scholar 

  12. Yaffe, M. J., and Rowlands, J. A.,X-ray detectors for digital radiography, Phys. Med. Biol. 42, 1–39, 1997.

    Article  CAS  PubMed  Google Scholar 

  13. Kandarakis, I., Cavouras, D., Panayiotakis, G., Agelis, T., Nomicos, C. D., Giakoumakis G. E,X-ray induced luminescence and spatial resolution of La 2O2 S:Tb phosphor screens, Phys. Med. Biol, 41, 297–307, 1996.

    Article  CAS  PubMed  Google Scholar 

  14. Giakoumakis, G.E., Nomicos, C.D., Yiakoumakis, E.N., Katsarioti, M.C., Kalikatsos, J.A., Rovithi, M., Panayiotakis, G. S., Evangelou, E. K.,Y 2O2 S:Eu phosphor screens evaluation, Med. Phys. 20(1), 79–83, 1993.

    Article  CAS  PubMed  Google Scholar 

  15. Giakoumakis, G. E., Nomicos, C. D., and Sandilos, P. X.,Absolute efficiency of Gd 2O2 S:Tb screens under fluoroscopy conditions, Phys. Med. Biol, 34, 673–8, 1989.

    Article  CAS  Google Scholar 

  16. Giakoumakis, G. E. and Nomicos, C. D.,Absolute efficiency of Y 2O2 S:Tb screens under fluoroscopy conditions, J.Appl.Phys. 58(7), 2742–2745, 1985.

    Article  CAS  Google Scholar 

  17. Russ, J.,The image processing handbook, 2nd Ed., CRC Press, Boca Raton, Florida, 1994.

    Google Scholar 

  18. Bankman, I. N.,Handbook of Medical Imaging, Academic Press, San Diego, California, 2000.

    Google Scholar 

  19. de Graff, C. N., and Viergever, M.A.,Information processing in medical imaging, Plenum

  20. Press, New York, 1988.

  21. Frei, W.,Image enhancement by image hyperbolization, Comp. Graph. Image Process, 6, 286–294, 1977.

    Article  Google Scholar 

  22. Hall, E. H.,Almost uniform distributions from image enhancement, IEEE Trans. Comp. C-23(2), 207–208, 1974.

    Article  Google Scholar 

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Authors and Affiliations

  1. Department of Medical Technology & Physics, Sir Charles Gairdner Hospital, Perth, Hospital Avenue, 6009, Nedlands, WA, Australia

    T. Tuchyna

  2. School of Information & Electrical Engineering, University of South Australia, Mawson Lakes, Australia

    D. Paix

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  1. T. Tuchyna
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  2. D. Paix
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Correspondence to T. Tuchyna.

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Tuchyna, T., Paix, D. A CMOS image sensor method of focal spot size measurement. Australas. Phys. Eng. Sci. Med. 27, 63 (2004). https://doi.org/10.1007/BF03178378

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  • DOI: https://doi.org/10.1007/BF03178378

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