Which element of an image intensifier enhances brightness?

The element of an image intensifier that enhances brightness is the output phosphor. In the functioning of an image intensifier, X-rays enter the system and are converted into light by the input phosphor. This initial light is then converted into electrons by the photocathode. The role of electron optics comes into play as these electrons are accelerated and focused onto the output phosphor.

The significant enhancement of brightness occurs when the electrons strike the output phosphor, which emits an increased intensity of light. This is primarily due to the concentration of electrons being significantly higher than that of the incoming light photons. Thus, the output phosphor effectively amplifies the image brightness in a manner that allows for clearer visualization, especially in low-light conditions. This process is crucial in fluoroscopy, where real-time imaging is required, and enhancing visibility is vital for accurate interpretation and diagnosis.