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Changes in Spatial Resolution at Position of the Detector in Digital Mammography System

디지털 엑스선유방촬영장치에서 검출기 위치에 따른 공간분해능의 변화

Kim, Hye-Min;Chon, Kwon Su
김민혜;천권수

  • Received : 2016.04.15
  • Accepted : 2016.04.25
  • Published : 2016.04.30

Abstract

X-ray mammography is the most effective method for the diagnosis of calcified lesions of various breast diseases. To reduce patient dose and to obtain optimal image required for diagnosis, the performance of the mammography system should be maintained continuously. Because the target (anode) angle of the X-ray tube is measured from the central X-ray, the effective angle can be slightly different in view of the position on the detector, which can result in degrading spatial resolution of the imaging within the field of view. In this study, we measured the MTF to examine spatial resolution for positions on the detector in the digital mammography system. For a tungsten wire of $50{\mu}m$ diameter, the highest spatial frequency was obtained. It meant that a wire diameter for measuring MTF through LSF should be small compared to the pixel size of the detector used in the mammography system. The spatial resolution showed slightly different performance according to positions on the detector. The center position gave the best spatial resolution and positions away from the center showed the degraded performance although the difference of the spatial resolution was small. The effective focal spot size of the full width at half maximum also showed similar result. It concluded that the slightly increase of the effective focal spot size gave the degradation of the spatial resolution for positions on the detector.

Keywords

Mammography;Modulation Transfer Function;Spatial Resolution

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