P3

P3

1. X-rays in medicine

   • CT scans use x-rays
     • CT scans produce a high resolution image of soft and hard tissur
     • CT scans are 2D slices of the body
   • X-rays can be used to treat cancer
     • X-rays are ionising, therefore can can kill cancer cells
   • X-rays are used for medical diagnosis
     • They are high frequency, short wavelength electromagnetic waves
     • They are absorbed by denser material such as bones
     • They diagnosis bone fractures and dental issues
   • Radiographers take precautions
     • They do this to minimise the radiation dose they get
     • They wear lead aprons, and stand behind a screen
     • They lead shields they from the radiation

2. Ultrasound

   • It is higher than 20000Hz
   • When some of the wave is reflected off the boundary between two media
     • This is called partial reflection
   • The time taken for the waves to be reflected back to the detector can be used to measure how far something is
   • You can use an oscilloscope to find boundaries
   • S=V*T
     • S= Distance m
     • V= Speed m/s
     • T= Time s