Question

Suppose your nuclear medicine practice routinely performs a planar imaging study but you notice that most patient images appear to have quite a lot of noise that makes them difficult to interpret.

Discuss how the image noise can be reduced without compromising image spatial resolution and give details of how this can be achieved.

Answer 1

Spatial resolution of the image is about how well details can be distinguished. Noise refers to the interference of the signal with the structures of interest that obscures the constrast and affects quality of the image for diagnosis purposes. To reduce noise we can increase the examination time (but we have to keep in mind that patient has to be still during the whole time, because motion causes blurring) or use higher radiation dose (always within the safe levels of exposure for the organ). Pixel size can be increased only so much not to influence the spatial resolution. Image digital processing (background substraction and filtering) can be used to reduce noise and inscrease constrast.