Final answer:
Increasing slice thickness from 3mm to 5mm in medical imaging such as MRI will improve the Signal-to-Noise Ratio (SNR) because more signal photons are captured relative to the increase in noise. This results in clearer images, albeit with potential reductions in spatial resolution.
Step-by-step explanation:
Increasing slice thickness from 3mm to 5mm will increase SNR (Signal-to-Noise Ratio) because thicker slices increase the number of signal photons contributing to the image without a corresponding increase in noise. This is due to the fact that noise increases by the square root of the signal increase. Therefore, a thicker slice effectively gathers more signal relative to the noise, thereby improving the SNR.
This principle is particularly relevant in magnetic resonance imaging (MRI), where slice thickness can have a significant impact on image quality. Thus, it's a trade-off: a thicker slice will provide better SNR but can potentially reduce the spatial resolution and increase partial volume effects.