DQE measurements in magnification X-ray imaging

Article type: Research Article

Authors: Zhang, Da | Rong, John | Chu, Robert | Chen, Wei R. | Liu, Hong

Affiliations: Center for Bioengineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019, USA | Department of Radiological Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA | Department of Physics and Engineering, University of Central Oklahoma, Edmond, OK 73034, USA

Note: [] Corresponding author: John Rong, Ph.D., Tel.: +1 405 271 8001 Ext: 35419; E-mail: John-Rong@ouhsc.edu

Abstract: In radiographic imaging, the modulation transfer function (MTF), the noise power spectrum (NPS), and the detective quantum efficiency (DQE) are usually determined and expressed as functions of spatial frequency in the detector plane. Values thus specified would be insufficient for describing the performance of the imaging system when magnification is used to offer better spatial resolution. We are presenting a computation of DQE at the object plane as descriptor. The derivation of this quantity from measurements at the detector and object planes is presented. With source-to-image receptor distance (SID) remains constant, changes in the DQE with magnification are shown to be determined primarily by the corresponding changing MTF. Measurements with a small animal X-ray imaging system of constant SID agreed with theoretical analysis.

Keywords: Modulation transfer function, noise power spectrum, detective quantum efficiency, magnification x-ray imaging

Journal: Journal of X-Ray Science and Technology, vol. 14, no. 2, pp. 141-150, 2006