Physics Revision - X-Rays

KEY POINTS ABOUT X-RAYS:

• Have a high frequency
• Short wavelength (roughly the same size as the diameter of an atom)
• They are transmitted by (pass through) healthy tissue, but are absorbed by denser materials like bones and metal
• X-Ray photographs can be used to diagnose many medical conditions such as bone fractures or dental problems
• X-Ray images can be formed electronically using charged-coupled devices (CCD's). CCD's detect X-Rays and produce electronic signals which are used to form high resolution images. (The same technology can be used in a digital camera)
• CT scans use X-Rays to produce high resolution images of soft and hard tissue. CT scans use lots of X-rays (more than normal X-Ray photographs) to distinguish between the tiny variations in tissue density.
• X-Rays are used to treat cancer as X-Rays can cause ionisation - high doses of X-Rays will kill living cells. They can therefore be used to treat cancers, just like gamma radiation.
• Radiographers take precautions to minimise their radiation dose, as prolonged exposure to ionising radiation can be very dangerous as they can kill living cells.
• Radiographers wear lead aprons, stand behind a lead screen or leave the room.