Question

(1) Fluorine-18 fluorodeoxyglucose (18FDG) is a radioactive tracer (half life of 1.83 hours) administered to patients who are undergoing PET imaging. This imaging modality, which creates images by detecting the positrons that are emitted when the fluorine-18 undergoes 8+ decay, permits physicians to monitor the metabolism of glucose in the body (a) Write down the decay chain for fluorine-18 when it undergoes β+ decay (b) A patient is given a dose of 18FDG prior to a PET scan to monitor the glucose uptake in her brain. The activity of the fluorine-18 is 320 MBq when the radioisotope is first administered to the patient. Determine the number of fluorine-18 atoms injected in the patient (c) If the fluorine-18 is considered safe once its activity has dropped below 185 MBq, can a patient who was administered 18FDG for a PET scan be safely discharged two hours after receiving the fluorine-labeled glucose (and not pose a risk to the general public)? (d) Assume that all of the beta particles (E 0.6335MeV) are absorbed by the woman (m = 100kg) in which this tracer was injected into. What is the absorbed dose for this patient? (e) What is the equivalent dose for this patient?

Answer 1

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