Which term is used to express spatial resolution in imaging?

The term that is used to express spatial resolution in imaging is Modulation Transfer Function (MTF). MTF is a critical parameter that quantifies how well an imaging system can reproduce (or transfer) different levels of detail from the object being imaged to the image itself. It is a measure of the contrast of the image at different spatial frequencies, allowing for the evaluation of how sharply and accurately an imaging system can depict fine details.

High spatial resolution corresponds to a greater ability to distinguish closely spaced objects; MTF provides a clear representation of this capability across various frequencies, making it an essential tool in assessing image quality in medical imaging and other fields.

The other options focus on different aspects of imaging. Kiloelectronvolts (keV) refers to the energy level of photons used in imaging and is not indicative of spatial resolution. Relative speed pertains to the sensitivity and response of the imaging system to radiation, while latitude refers to the range of exposure levels an imaging system can accommodate effectively. These concepts do not directly measure or express spatial resolution in the same way that MTF does.