Meaning of Cylus: Cylus is a modern English respelling of the name Silas, which is a short form of the Greek name Silouanos, which is a variant of the Latin name Silvanus, which is derived from the Latin word silva, meaning wood, forest.
Overview. A positron emission tomography (PET) scan is a type of nuclear imaging test that shows the metabolic activities (energy usage) of your brain. While X-ray, CT, and MRI scans look at the anatomy of your brain, a PET scan can give your doctor information about how your brain is working.
A PET or SPECT scan can map the brain by measuring the distribution and density of neurotransmitter receptors in certain areas. Use of this technology has led to a better understanding of which brain regions regulate mood and how other functions, such as memory, may be affected by depression. Areas that play a significant role in depression are the amygdala, the thalamus, and the hippocampus (see Figure 1).