Imaging Methods - Radiography

552 views

Published on

Published in: Health & Medicine, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
552
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
32
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Imaging Methods - Radiography

  1. 1. Imaging Methods in Monitoring and Diagnosis Walter Hall School of Health Sciences University of Ulster
  2. 2. Imaging Modalities • X-Rays • Nuclear Medicine • Medical Ultrasound • Magnetic Resonance Imaging
  3. 3. X-Rays
  4. 4. X-Rays • Discovered in 1895 by Roentgen • An ionising radiation at a higher level on EM spectrum • Higher frequency or shorter wavelength
  5. 5. X-Ray Production
  6. 6. Plain Digital Radiography
  7. 7. Computerised Tomography
  8. 8. CT X-ray Beam
  9. 9. Helical CT
  10. 10. Computerised Tomography
  11. 11. X Rays: Pros and Cons • Non-Invasive • Well established technology • Still evolving • Flexible • Readily available and therefore relatively cheap • Ionising Radiation • Not good at imaging soft tissue on its own
  12. 12. Nuclear Medicine • Use of unsealed radioisotopes • Attached to pharmaceuticals • Drugs absorbed preferentially by target organ(s) • Gamma emitter so can be detected • Images digitally produced from data gathered
  13. 13. Nuclear Medicine Images
  14. 14. PET-CT
  15. 15. Nuc Med: Pros and Cons • Can image wide variety of tissue types • Easy to target specific tissue • Can image function • Utilises by-products of other processes so cost effective • Uses ionising radiation • Could be described as invasive • Has many radiation protection issues associated with it • Better applications are expensive
  16. 16. Magnetic Resonance Imaging • Manipulation of natural magnetic field • Nuclear magnetic resonance is detectable and measurable • Data detected can be digitally converted to an image • Utilises tomographic techniques of CT
  17. 17. MRI Principle • Atoms have magnetic moments • They spin in a magnetic field – Precession • Spin frequency depends on the type of atom or molecule – Larmor Frequency • Examine the spin of hydrogen atoms • Hydrogen atoms in different tissues have different Larmor Frequencies
  18. 18. MRI Advantages • X-rays are absorbed in different amounts by different tissues • Variation between tissues is very small • MRI measures three different quantities • Some or all are very different for different tissues • MRI can penetrate bone
  19. 19. MR Imaging
  20. 20. Using Data Manipulation
  21. 21. Image Manipulation
  22. 22. Pros and Cons • Non-Invasive • Does not use ionising radiation • Excellent for soft tissue imaging • Can image function • Very Expensive • Has its own health and safety issues • Has “acceptability” issues with some patients
  23. 23. Medical Ultrasound • Utilises sound waves at ultrasonic frequency • Above 20KHz is ultrasound but usually 3 - 10 MHz for medical imaging purposes • Echoes from tissue can be detected and data interpreted digitally to produce image • Position and depth of the echoes builds up a complete picture
  24. 24. MU Imaging
  25. 25. Image Manipulation
  26. 26. Doppler Imaging
  27. 27. Pros and Cons • Non-Invasive • No ionising radiation • Dynamic technique • Can image soft tissue effectively • Flexible equipment • Relatively cheap • Limited in what can be imaged • VERY user dependant
  28. 28. Which do we use? • What information do we require? • Do we wish to see function or structure? • What can the patient tolerate? • What would the clinician prefer? • What is available for use? • Is there a safer/cheaper alternative? • Can potential risks be justified?
  29. 29. QUESTIONS?

×