Edexcel Extension Physics

  • Created by: Hannah
  • Created on: 04-04-13 10:33

Ionising and non-ionising radiation is both used in medical physics by doctors. Their use in medical physics isn't always good as I compromised has to be made. They can give you clear images, but can risk damage to the patients body.

X-rays: They are high energy EM waves which are absorbed by dense materials such as bones and metals. Radiographers use their properties to take X-ray photographs which can then go onn to diagnose patients with problems such as bone fractures. They are a type of ionising radiation which means their is a health risk when exposed to them.

Cat Scans (Computerised Axial Tomography): uses x-rays to produce a two dimensional slice through the body. The images are not real time. The patient lies on a moving bed so that it moves in and out of the ring that rotates to produce intense x-ray beams. Detectors around the ring determines which x-rays have been absorbed and send the information to a computer. The computer generates a high quality image. Each individual image can create 3D image. These can be used to detect and diagnose tumours, cancers. blood clots and Alzheimer's disease.

Endoscopes: These are thin flexible telescopes which uses tow bundles of fibre optics that are connected to a light source outside the body so that it can shine the light into the body and to carry the image back to the camera or computers outside the body. Devices such as scalpels and lasers can be attached to perform surgery inside the body. It's a way of looking inside the human body through a narrow flexible scope. It is mostly used to diagnose problems in the oesophagus, stomach and small intestine including ulcers, bloods and tumors (cancer). Keyhole surgeries can be used to treat Hermia's and remote tumors and is often used in sport stars injury as the recovery time is faster than normal open surgery. They are generally painless, but they may cause some discomfort. Compared with the stress experienced by the body in full surgical procedures an endoscope is simple, low risk and cost effective. Advantages: no scars as a natural body opening is used, quick recovery time, less hospital or often no time in hospital is required  as the procedure occurs in a doctor room. Risks: Infection, punctured organs, over sedation, hole in colon.

Ultrasound: A non-invasive technique and is used for diagnosis and treatment. It is a high frequency sound that we cannot hear . Typically they are 20kHz. In medicine, doctors use a frequency of 1.5MHz. Advantage: non-ionising safer than using imaging technique that use radiation. It can be used for: cysts, tumours, kidney stones, blocked arteries, foetal abnormalities.

Kidney Stones:

  • Ultrasound focused onto the stone
  • Shock waves are sent towards the stone.
  • Several treatments the stone broken down.
  • They become small enough to pass through the uretha.

Pre-natal scanning of foetus

  • Diagnose soft tissue problems and to performs pre-natal scans of the foetus in the womb.
  • The waves are reflected off the different tissue…




amazing!! thank you and good luck for tomorrow !! x