A gamma camera is an essential diagnostic imaging device used to detect gamma radiation emitted from radiopharmaceuticals inside a patient's body.
A lead collimator is positioned in front of the detector. Explain why the collimator must consist of long, narrow channels.
Immediately behind the collimator lies a scintillator crystal. State the function of this crystal.
When the light from the scintillator strikes the photocathode of a photomultiplier tube, a cascade of electrons is triggered. A single pulse of current of magnitude 0.15 μA0.15\text{ }\mu\text{A}0.15 μA is produced with a duration of 4.8 ns4.8\text{ ns}4.8 ns.
Calculate the number of electrons that constitute this electrical pulse.
State one medical diagnostic application of a gamma camera.
25 exam-style questions on OCR A A Level Physics Medical imaging, covering Using X-rays, Diagnostic methods in medicine, and Using ultrasound. Each one has a worked solution and a mark scheme showing where the marks go.