Detective quantum efficiency (DQE) is a measurement of image quality combined with dose. How is DQE determined?

Detective quantum efficiency (DQE) is an important parameter that quantifies the effectiveness of a radiographic system in converting the incident x-ray photons into a quality image while considering the radiation dose applied. DQE is specifically determined by comparing the signal-to-noise ratio (SNR) at the output of the detector to the SNR at the input of the detector.

In this context, the correct approach to determining DQE involves calculating the SNR after the image has been processed by the detector and relating this to the SNR of the initial input signal (which is the x-ray photons interacting with the detector). This ratio effectively reflects how well the system preserves the quality of the image based on the amount of radiation used, indicating both the performance of the imaging system and its efficiency in utilizing dose.

The other options focus on different aspects of imaging performance that are relevant but do not directly address how DQE itself is computed. For example, the modulation transfer function (MTF) relates to the spatial resolution of the imaging system, which is a different consideration compared to the overall efficiency represented by DQE. Line pair phantoms are used to test different imaging parameters but do not inherently describe the calculation of DQE. Thus, understanding DQE as