Question 29 - 2002 HSC
(a) Briefly describe how an endoscope works. Explain how a CAT scan is produced. Using a graph of % decay of technetium 99m over time, determine the isotope's half-life. Calculate the amount of undecayed isotope when a scan is taken, given the amount injected and time of the scan. Propose reasons why scans are best taken between two and five hours after injection. (c) Given representations of an MRI, X-ray and CAT scan, identify advantages of MRI scans over CAT scans, explain why a doctor would order an X-ray to confirm the diagnosis of a fractured skull, and justify the choice of an additional scan if the patient develops symptoms of brain damage. (d) Assess the impact on society of medical applications based on ultrasound and the magnetic field of particles within the body.