In an image intensified fluoroscopy system, what happens to the exposure rate when switching to magnification mode?

In an image intensified fluoroscopy system, switching to magnification mode results in an increased exposure rate. This occurs primarily due to the way magnification works within the system. When in magnification mode, the input phosphor of the image intensifier is used over a smaller area, which requires a higher dose of radiation to maintain image quality.

The magnification process involves focusing the same number of X-ray photons over a smaller area, thereby increasing the demand for radiation to achieve a clear, detailed image. The system compensates for this by boosting the exposure rate to ensure adequate imaging quality and detail. Consequently, the output image becomes brighter, but at the expense of an increased radiation dose to the patient.

Thus, this phenomenon highlights the trade-off between image quality and patient radiation exposure in the use of fluoroscopy systems.