To decrease quantum noise in imaging, what should be done with mAs and section width?

Increasing mAs (milliampere-seconds) enhances the number of x-ray photons produced during the scan, which directly contributes to improved image quality by reducing quantum noise. Quantum noise arises from insufficient x-ray photons reaching the detector, leading to grainy images. By increasing mAs, more photons are available, which helps to create a clearer image with better signal-to-noise ratio.

Additionally, decreasing section width (slice thickness) can also help in improving image quality. Thinner slices allow for more detailed representation of structures and help to reduce partial volume effects, where multiple types of tissues may be included in a single voxel, leading to reduced image clarity. This combination of increased mAs for enhanced photon quantity and decreased section width for better spatial resolution minimizes quantum noise, resulting in clearer, more accurate imaging.

The rationale behind the other choices is less effective when considering the goal of reducing quantum noise. For example, decreasing mAs would reduce the overall photon count and potentially increase noise, which contradicts the intention of decreasing quantum noise. Similarly, increasing section width would lead to the inclusion of more tissue and greater partial volume effects, further degrading image quality. Therefore, the optimal approach to decrease quantum noise is to increase mAs while decreasing section width.