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Photon Counting Digital Mammography
Photon Counting Digital Mammography is a diagnostic technique. The detector used combines photon-counting electronics with a parallel arrangement of high-quantum efficiency silicon strips. The method has recently been shown to provide a more accurate mammography diagnosis in comparison to the more conventional full-field digital mammography(FFDM) while allowing reduction in the radiation dose used in the process.

How It Works
The set up is generally composed of around 45 -48 photon counting detectors, each linear and orientation sensitive. The most commonly used detector consists of many parallel strips of silicon and all the detectors aligned in relation to the focal point of the X-ray. Each detector will receive an image of a certain area of the tissue. When activated these detectors scan continuously across the patient, each collecting a unique imagine from a different angle, this means only a section of the tissue can be imaged at one time. The area of tissue will be imaged completely once every detector line has scanned across it. This slot scan imaging reduces scatter radiation while also ensuring negligible loss of primary x-rays ,this is complemented by the fact that the detectors used are insensitive to scatter radiation.

Advantages
The images collected via this method are of high quality due to the unique characteristics of this detector technology. This procedure solves problems that are present with other imaging techniques, it reduces the appearance of artefacts as well as allowing true lesions to be more easily seen, this in turn improves the diagnostic accuracy of this technique. The slot scanning element of the process reduces scatter radiation. This is advantageous as scattered radiation reduces both the signal-to-noise ratio (SNR) and contrast within the image, this therefore degrades the image performance and its quality. This means that the SNR can be at its optimum while imaging which allows for a reduced radiation dose to be used while maintaining the quality of the image produced. In all radiological techniques it is desirable to reduce the dose radiation used providing this does not negatively impact diagnostic performance or feature detection. This is because ionizing radiation is used and exposure to this form of radiation is associated with an increased cancer risk. X-ray noise is an irregular granular pattern that can appear on any radiological image and is problematic as it degrades the information shown. X-ray noise occurs primarily due to secondary radiation, these unwanted x-rays lead to a reduced contrast quality in the image. Noise can also arise from poorly developed x-ray film, meaning the image can turn out overexposed or underexposed, again skewing the quality of the image.

Uses
The technology is used in order to image breast tissue and look for abnormalities present within it. This has applications in mammography and computed tomography as well as lump imaging which is used in the operating theatre.