Photoelectric effect Vs Compton Effect

 The photoelectric effect is an interaction between a low to intermediate energy X-ray beam and the inner shell electron.

Inner shell electron is ejected, the outer electron goes into inner orbit to occupy the space, and the extra energy is ejected as characteristic radiation and is called the photoelectric effect.

The photoelectric effect is of fundamental importance in diagnostic radiography since it is the primary method by which contrast is developed in radiographs. It allows for the differentiation of different types of tissues on the X-ray film.

Very low-energy X-rays are not capable of producing the photoelectric effect. High energy X-rays are also not capable of photoelectric effect due to random scattering of electrons from the outer shell. This is known as the Compton effect and it can lead to distortion of the image.


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The goal of X-ray imaging should be to minimize the Compton effect and maximize the photoelectric effect.

The penetrating power of X-rays increases with increasing energy, which is directly proportional to the frequency and inversely proportional to the wavelength.

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