“…For the first or “baseline“ scan, the student was made to sit with eyes open in a quiet, dimly lit room for a period of 30–40 min and then injected intravenously with 20 mCi of 99m Tc labelled L, L-ethylcysteinate dimer ( 99m Tc-ECD), which has been widely used to study changes in relative rCBF using SPECT systems. [310] This technique is called brain perfusion, and it relies on the coupled behaviour of blood flow and metabolism, which is used as a marker of neuronal activity. [310] An hour later, the student was imaged on a dual-headed GE Infinia Hawkeye SPECT/CT.…”