Oxygen-15 is a radioactive isotope frequently used in positron emission tomography (PET) scans.
Explain the physics of electron-positron annihilation that occurs inside the patient's body and how it allows the PET scanner to locate areas of high tracer concentration.
The half-life of oxygen-15 is 122 s. Calculate the time ttt, in seconds, required for the activity of the oxygen-15 radiopharmaceutical to decrease to 15% of its initial value.
Suggest why a hospital performing PET scans with oxygen-15 must have a cyclotron (particle accelerator) located very nearby.
90 exam-style questions on OCR A A Level Physics Nuclear and particle physics, covering The nuclear atom, Fundamental particles, Radioactivity, and Nuclear fission and fusion. Each one has a worked solution and a mark scheme showing where the marks go.