A flat panel detector (FPD) is a photographic element used in digital radiography. In the same way that a normal digital camera uses a CMOS sensor to receive light passing through a lens and convert it into an image, a flat panel detector converts X-rays passing through a shadow object into an image.

Flat panel detectors are used in X-ray CT, X-rays, mammography, etc., in place of conventional X-ray II (image intensifiers) and IP (imaging plates). The dynamic range is greater than that of X-ray II, and the images can be viewed in real time, without the need to remove the plate and extract the images as with IP.

There are two types of FPDs: indirect conversion flat panel detectors and direct conversion flat panel detectors. In the indirect type, the scintillator is laid flat and the light emission is detected by a PD (photodiode). It is characterized by the fact that it does not use a power source. In the direct type, a high voltage bias is applied to the selenium film, and the current flowing when X-rays enter turns on the TFT transistor, converting the signal into an image.

Matsusada Precision handles the power supply for applying high voltage to the selenium film.

FPD structure
Related words:
  • Direct Conversion
  • Flat Panel Detector (FPD)

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