Calculation of the modulation transfer function in digital radiology for system of quality control

Authors

10.22052/3.1.25

Abstract

The usage of digital radiology systems with insufficient quality control of digital image detectors can efface inherent superiorities of digital systems in comparison with analogue radiology systems and even makes an increased level of patients’ radiation doses. Modulation transfer function (MTF) is one of the most important parameters related to image quality and digital detectors efficiency. In this study, MTFs of two digital radiology systems (namely, Swiss ray and Siemens) are measured using an edge reference block. The results then were used for the system evaluations. For MTF measuring, an edge reference block was constructed from a 0.8-mm-thick Cerrobend foil. The pre-sampled MTFs of the systems were measured using an edge method. The different MTF values were measured by changing dose levels at Siemens digital detectors surface. The Swiss ray digital detector slightly changed on that dose levels (less than 1%) and showed better results. These results are in good accordance with practical MTF measurements of Marshall et al research. Investigation showed that some quality control weaknesses existed in Siemens system. This is due to heavy work load and insufficient quality control of the system in proper time periods. Finally, this research showed the importance of quality control program and the importance of MTF parameter for quality control measurement of digital radiology systems.

Keywords

References

[1] J.T. Bushberg, A. Seibert, E.M. Leidholdt Jr., J.M. Boone and E.J. Goldschmidt Jr. The Essential Physics of Medical Imaging. Lippincott Williams & Wilkins. (2011). [2] E. Samei, M. Flynn, D. Reimann. A method for measuring the presampled MTF of digital radiographic systems using an edge test device. Medical Physics, 25-1 (1998) 102-113. [3] A. Konstantinidis. Evaluation of digital x-ray detectors for medical imaging applications, in medical physics and bioengineering. PhD Thesis, University College London, (2011). [4] E. Samei, M. Flynn. An experimental comparison of detector performance for computed radiography systems. Medical Physics,. 29-4 (2002) 447-459. [5] H. Fujita. A simple method for determining the modulation transfer function in digital radiography. IEEE Transactions on Medical Imaging. 11-1 (1992) 34-39. [6] A. Seibert. An analytical edge spread function model for computer fitting and subsequent calculation of the LSF and MTF. Medical Physics. 21-10 (1994) 962-966. [7] E. Samei. A method for modifying the image quality parameters of digital radiographic images. Medical Physics. 30 (2003) 3006-3017. [8] C. Walsh. Quality assurance of computed and digital radiography systems. Radiation Protection Dosimetry. 129-1-3 (2008) 271-275 [9] W. Muhogora. Performance evaluation of three computed radiography systems using methods recommended, American Association of Physicists in Medicine Report 93. J. of Medical Physics. 36-3 (2011) 138-146 [10] N.W. Marshall, A. Mackenzie and I. D. Honey. Quality control measurements for digital x-ray detectors. Physics in Medicine and Biology, 56-4 (2011) 979-999. [11] X. Kong, H. Liu, X. Rong, C. Sweet, Z. Yang, S. Edwards, T. Thai and J. Thomas. Optimaization of image quality and minimaization of radiation dose for chest computed radiography. Medical physics. 33-6 (2006) 2016-2016. [12] K. Alzimami. Optimisation of computed radiography systems for chest imaging. Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 600-2: (2009) 513-518. [13] J. Lee. Evaluation of the response of the modulation transfer function to a computed radiography photostimulable phosphor imaging plate for various numbers of X-ray exposures. Journal of the Korean Physical Society. 58-2 (2011) 326-333.

Files

Share

How to cite

Statistics