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Flat detector main parameters

1. Spatial resolution
The spatial resolution of a DR refers to the resolution or resolution within the image space, expressed in terms of the ability to distinguish between black and white lines in an image. Black and white lines are referred to as line pairs. A pair of black and white lines is called a line pair. The linear expression unit of resolution is line pair/mm (LP/mm).

Spatial resolution is affected and constrained by many factors. Pixel size is also one of the important factors affecting spatial resolution.

The size and distance of the detector element only provide us with the maximum spatial resolution of the system. Due to the scattering of light or the diffusion of charge, the effective spatial resolution of the detector will be lost, but for direct conversion detectors, effective spatial resolution The rate is close to the maximum spatial resolution.

2. Contrast resolution
Image contrast performance primarily reflects the ability of the system to capture and display the true contrast of an object.

3. Pixel size
In order to increase the spatial resolution under certain conditions of the detector area, the pixel size can be reduced, the unit pixel area can be reduced, and the pixel density can be increased. However, the smaller the area of ​​the unit pixel, the smaller the effective factor of the pixel, the lower the sensitivity of the pixel, the lower the signal-to-noise ratio, and the narrower the dynamic range. Therefore, such a method of reducing the pixel size cannot increase the resolution without limitation, and instead causes deterioration of image quality.

The increased spatial resolution is overwhelmed by the resulting noise. To compensate for this problem, it is necessary to increase the X-ray exposure dose, which is contrary to the development of X-ray imaging technology. Therefore, to choose the appropriate pixel size, you can do better.

Usually, the spatial resolution of the flat panel detector is mostly 2.5-3.6 lp/mm, corresponding to the detector pixel unit size of 139-200 um, and the pixel matrix is ​​between 2000*2000X-3000*3000.