Journal of Digital Convergence (디지털융복합연구)

The Society of Digital Policy and Management (한국디지털정책학회)
권호 표지
DOI QR코드

DOI QR Code

Quantitative Analysis of Spatial Resolution for the Influence of the Focus Size and Digital Image Post-Processing on the Computed Radiography

CR(Computed Radiography)에서 초점 크기와 디지털영상후처리에 따른 공간분해능의 정량적 분석

  • 성열훈 (청주대학교 방사선학과)
  • Received : 2014.08.23
  • Accepted : 2014.11.20
  • Published : 2014.11.28
Download PDF
⟨ Previous Next ⟩

Abstract

The aim of the present study was to carry out quantitative analysis of spatial resolution for the influence of the focus size and digital image post-processing on the Computed Radiography (CR). The modulation transfer functions of an edge measuring method (MTF) was used for the evaluation of the spatial resolution. The focus size of X-ray tube was used the small focus (0.6 mm) and the large focus (1.2 mm). We evaluated the 50% and 10% of MTF for the enhancement of edge and contrast by using multi-scale image contrast amplification (MUSICA) in digital image post-processing. As a results, the edge enhancement than the contrast enhancement were significantly higher the spatial resolution of MTF 50% in all focus. Also the spatial resolution of the obtained images in a large focus were improved by digital image processing. In conclusion, the results of this study should serve as a basic data for obtain the high resolution clinical images, such as skeletal and chest images on the CR.

본 연구의 목적은 컴퓨터 방사선영상에서 X-선 초점 크기와 디지털영상후처리에 따른 공간분해능을 정량적으로 분석하고자 하였다. 초점의 크기는 소초점(0.6 mm)와 대초점(1.2 mm)을 이용하였다. 공간분해능의 정량적 분석은 엣지 측정법의 변조전달함수(MTF)를 이용하였다. 디지털영상후처리는 다단계 이미지 대비 증폭 알고리즘을 이용하여 경계면 증강과 대조도 증강에 따른 50%와 10%의 MTF를 평가하였다. 그 결과 모든 초점에서 MTF 50%의 공간분해능이 대조도 증강보다 경계면 증강에서 유의하게 높았다. 또한 대초점에서 획득된 영상은 디지털영상처리를 통해 공간분해능이 향상되었다. 결론적으로 이러한 결과는 컴퓨터 방사선영상에서 골격계 및 흉부영상과 같은 고 공간분해능 임상영상을 얻기 위한 기초자료로 활용할 수 있다.

Keywords

References

  1. K. Doi, Diagnostic imaging over the last 50 years: research and development in medical imaging science and technology, Phys Med Biol, Vol. 5, pp. R5-R27, 2006.
  2. A. B. Wolbarst, Physics of Radiology, Medical Physics Publishing, 2005.
  3. Z. F. Lu, E. L. Nickoloff, J. C. So, A. K. Dutta, Comparison of computed radiography and film/screen combination using a contrast-detail phantom, J Appl Clin Med Phys, Vol. 4, No. 1, pp. 91-98, 2003. https://doi.org/10.1120/1.1524950
  4. K. S. Park, J. M. Park, Y. S. Yoon, B. W. Kim, J. Y. Kang, Semiconductor Detectors for Radiation Imaging Application, ETRI, Vol. 22, No. 5, pp. 95-107, 2007.
  5. P. Vuylsteke, E. Schoeters, Multiscale Image Contrast Amplification ($MUSICA^{TM}$), Proc. SPIE, Vol. 2167 pp. 551-560, 1994.
  6. C. S. Kim, S. S. Kang, S. J. Ko, Image Quality Evaluation of Medical Image Enhancement Parameters in the Digital Radiography System, J. of Korean Contents, Vol. 10, No. 6, pp. 329-335, 2010. https://doi.org/10.5392/JKCA.2010.10.6.329
  7. J. Y. Jung, H. S. Park, H. M. Cho, C. L. Lee, S. R. Nam, Y. J. Lee, H. J. Kim, Imaging Characteristics of Computed Radiography Systems, Korean J Med Phys, Vol. 19, No. 1, pp. 63-72, 2008.
  8. E. Samei, N. T. Ranger, J. T. Dobbins III, Y. Chen, Intercomparison of methods for image quality characterization. I. Modulation transfer function, Med Phys, Vol. 33, No. 5, pp. 1454-1465, 2006. https://doi.org/10.1118/1.2188816
  9. Y. H. Seoung, Evaluation of the Spatial Resolution for Exposure Class in Computed Radiography by Using the Modulation Transfer Function, J Digital Policy & Management, Vol. 11, No. 8, pp. 273-279, 2013.
  10. J. M. Boone, Determination of the presampled MTF in computed tomography, Med Phys, Vol. 28, No. 3, pp. 356-360, 2001. https://doi.org/10.1118/1.1350438
  11. J. Papp, Quality Management in the Imaging Sciences, MOSBY, 2011.
  12. P. J. Burt, E. H. Adelson, The Laplacian pyramid as a compact image code, IEEE Trans. on Communications, Vol. 31, No. 4, pp. 532-540, 1983. https://doi.org/10.1109/TCOM.1983.1095851
  13. B. Y. Lim, H. S. Park, J. H. Kim, K. H. Park, H. J. Kim, Evaluation of Unexposed Images after Erasure of Image Plate from CR System, Korean J Med Phys, Vol. 20, No. 4, pp. 199-207, 2009.
  14. E. Samei, M. J. Flynn, D. A. Reimann, A method for measuring the presampled MTF of digital radiographic system using an edge test device, Med Phys, Vol. 25, No. 1, pp. 102-113, 1998. https://doi.org/10.1118/1.598165
  15. J. A. Seibert, Tradeoffs between image quality and dose, Pediatr Radiol Vol. 34, No. 3, pp. S183-S195, 2004. https://doi.org/10.1007/s00247-004-1268-7
  16. H. S. Park, H. J. Kim, H. M. Cho, C. L. Lee, S. W. Lee, Y. N. Choi, Effects of Image Processing on the Detective Quantum Efficiency, J Korean Phys Soc, Vol. 56, No. 2, pp. 653-658, 2010. https://doi.org/10.3938/jkps.56.653
  17. Y. S. Kim, H. S. Park, S. J. Park, H. J. Kim, Effective Detective Quantum Efficiency (eDQE) Evaluation for the Influence of Focal Spot Size and Magnification on the Digital Radiography System, Korean J Med Phys, Vol. 23, No. 1, pp. 26-32, 2012.