What term describes the size ratio between the input and output phosphor screens of an image intensifier?

The term that accurately describes the size ratio between the input and output phosphor screens of an image intensifier is known as minification gain. This concept is essential in understanding how an image intensifier enhances the brightness of an image.

When an image is converted from the input phosphor to the output phosphor, the area of the input screen is typically larger than that of the output screen. This size difference results in a minification process, where the image is effectively "minified" or compressed into a smaller area, which enhances the brightness of the resulting image. The ratio of the sizes of the two phosphors directly influences the degree of this gain; a larger input relative to the output means that more light is concentrated, thereby boosting the illumination.

Minification gain plays a crucial role in medical imaging, particularly in fluoroscopy, as it allows for better visualization of anatomical structures by increasing image brightness without requiring higher radiation doses. Understanding this concept is vital for those working in radiography and fluoroscopy, ensuring efficient and safe imaging practices.