Final answer:
Steady state in medical imaging refers to techniques like SPECT, which uses gamma rays for 3D imaging with good contrast but poor spatial resolution, and PET, which offers better resolution and the ability to visualize physiological functions.
Step-by-step explanation:
When steady state conditions are considered in medical imaging, Single-photon-emission computed tomography (SPECT) is one such imaging technique that comes into play. This nuclear medicine tomographic imaging technique uses gamma rays and provides three-dimensional information. It is similar to a CT scan but uses nuclear activity to create images. SPECT has relatively poor spatial resolution of about 1cm but does provide good contrast, making it easier to differentiate between various structures in the body.
Another advanced imaging method is Positron Emission Tomography (PET), which uses radioactive substances to analyze metabolic processes in the body. PET scans can reveal how tissues and organs are functioning, which is crucial in diagnosing conditions such as heart disease, cancer, and brain disorders. Unlike SPECT, PET scans offer enhanced resolution by illustrating physiological activity and enabling observation of nutrient metabolism and blood flow.