Scanning

Scanning

1. XRAY

   • Uses electromagnetic radiation. Machine emitts invisible beams to specific parts of the body placed infront of photographic paper in envelope to protect from light exposure. These beams penetrate soft skin and tissue so appear as grey on image, they are blocked and absorbed by the denser tissue so appear as white, digit image is produced and interpreted by radiologists
   • Identifys fractures
   • Good-can view structures inside the body, Quick
   • Bad- Use of radiation means limited use, radiologists must be protected
   • Mammography- Breast screening 45 years old+. Put breast one by one between 2 plates and photographic paper to flatten tissue out. 4 pics takes - 2 of each breast,one side one front
   • Barium- Barium medium meal/drink given containing opaque white dye that XRAYS cant penetrate giving a white outline of the gut. XRAYS taken in diff ways e.g. lying down, stood up in front of photographic paper. Electromagnetic radiation used (XRAYS) As XRAYS pass through gut it intensifies on the page , black and white clearly contrast identifying any abdnoramlities

2. ULTRASOUND

   • High frequency sound waves are sent from an transducer into the body.Oily gel on skin to ensure good contact. Penetrates skin and soft tissue but reflects from denser tissue e.g. gall stones. Reflections from inside the body are picked up by a computer which creates image/numerical date
   • Used for pregnacy, kidney stones and CVS guided needles
   • Good- Painless, Quick, Real time images produced
   • Bad- Poor quality images produced, Cant penetrate bone

3. MRI

   • Magnetic resonance imaging
   • Remove all jewellery, lie on bed pushed into cylinder. Machine uses magnetic field which causes protons in hydrogen nucleus to align. Short wave bursts cause them to move and then when stopped re align at different speeds indicating the type of tissue. Receiver sends info computer which generates image
   • Good- No radiation, frequent use
   • Bad- pacemakers cant use ,noisy ,expensive ,catrosphobic

4. CT

   • Computed Tomography
   • Patients lie on bed and are pushed into cylinder scanner. Scanner rotates around emitting XRAYS from many different directions. Detectors able t distinguish between the type of tissue by strength/number of XRAYS. Info sent to computer which builds slices into a 3D image
   • Good- View structures encased in bone e.g. brain, 3D image shows clearer more in detail image
   • Bad- Expensive, Not portable, Use of radiation means limited use

5. PET

   • Positron emission tomography
   • Radiotracer e.g. FDG for glucose is injected into body. Everywhere uses glucose however cancerous cells which are more active uses excessive amounts. As the radiotracer decays positrons mix with electrons to produce gamma rays. Receiver transmits info to computer to produce colour 3D Image. Able to identify problems by colour and brightness as well as to check for normal functioning.
   • Good-detects early stages

6. RADIO NUCILE

   • Isotope emits energy gamma rays
   • Specific isotopes are used for specific parts of the body
   • Injected into body e.g. iodine used for the thyroid gland, Most active areas of body e.g. cancerous cells uses the most radionucile. Gamma camera sent to the computer producing a colour image to identify hot spots and normal functioning