Introduction to Medical Imaging

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First year PA students radiology course

Introduction to Medical Imaging

  1. 1. Introduction to Medical Imaging PAO 5003
  2. 2. Imaging Modalities
  3. 3. 3 D. Kotun, NSU Orlando PA Program
  4. 4. Objectives Recognize various types of imaging studies Discuss the mechanism for producing images with each modality List th Li t the common indications for different i di ti f diff t imaging modalities Describe the precautions for ordering imaging studies 4 D. Kotun, NSU Orlando PA Program
  5. 5. Pre – Test I am looking forward to this test because: I want to learn all I can I am demented It i a good time to catch a nap is di h I heard that Prof. Kotun is a wonderful lecturer 5 D. Kotun, NSU Orlando PA Program
  6. 6. Imaging modalities X-Ray Computerized Tomography Mammogram M Nuclear Magnetic Resonance Positron Emission Tomography Single Photon Emmission Computerized Tomography Ultrasound imaging 6 D. Kotun, NSU Orlando PA Program
  7. 7. Terms Tomography: a cross-sectional image formed from a set of projection cross- images. The Greek word tomo means cut. CT: Computed (or Computerized) Tomography MR, or MRI: Magnetic Resonance Imaging. This was first called nuclear magnetic resonance (NMR), but the mention of anything nuclear scared patients, so the “N” was dropped. PET: Positron Emission Tomography. Understanding this phenomenon requires acceptance of the theory that there is antimatter in the universe, and when antimatter meets matter, then both kinds of matter are annihilated, and pure energy is formed. SPECT: Single Photon Emission Tomography Ultrasound: Sonar in the body OCT: O ti l C h OCT Optical Coherent Tomography – th use of infrared light to image tT h the fi f d li ht t i (particularity) the walls of an artery. 7 D. Kotun, NSU Orlando PA Program
  8. 8. Principle of X-Rays p X- y 8 D. Kotun, NSU Orlando PA Program
  9. 9. The First X-Ray Exam X- William Conrad Roentgen 89 Nov 1895 Took a picture of his wife s hand and wife’s developed it on photographic film Ferdinand and Mazwell predicted X-Rays X- from Maxwell’s EM radiation theory 9 D. Kotun, NSU Orlando PA Program
  10. 10. Bill s Bill’s Lovely Wife 10 D. Kotun, NSU Orlando PA Program
  11. 11. Production of the Radiographic Image 11 D. Kotun, NSU Orlando PA Program
  12. 12. X-Ray Tube Figure 7-5 Drawing of a typical X-ray tube 75 X ray tube. 12 D. Kotun, NSU Orlando PA Program
  13. 13. Bremsstrahlung Radiation Figure 7-2 Deflection of high-energy electron by nucleus produces white radiation 13 D. Kotun, NSU Orlando PA Program
  14. 14. Photon Generation Figure 3-2 Illustration of the Compton scattering phenomenon 14 D. Kotun, NSU Orlando PA Program
  15. 15. Photoelectric Effect Figure 3-1 Drawing of photoelectric effect (from [Sung et al.]). 15 D. Kotun, NSU Orlando PA Program
  16. 16. Spectrum of Densities & Ability to Attenuate the X-ray Beam h X- 16 D. Kotun, NSU Orlando PA Program
  17. 17. Concept of Subtraction 17 D. Kotun, NSU Orlando PA Program
  18. 18. Aortogram Subtraction 18 D. Kotun, NSU Orlando PA Program
  19. 19. Magnification Closest part to the film is in best focus and least magnified 19 D. Kotun, NSU Orlando PA Program
  20. 20. In an X-ray tube, the photons are X- generated by what? db h? A high density nuclear source 1. 1 25% 2. An electron stream onto a metal 25% target 3. A focused heated metal plate 25% 4. Magic pixies in a glass tube (hence 25% the name pixels) 20 D. Kotun, NSU Orlando PA Program
  21. 21. Posterior Anterior (PA) The nomenclature follows the direction of the beam 21 D. Kotun, NSU Orlando PA Program
  22. 22. AP Chest Beam Direction 22 D. Kotun, NSU Orlando PA Program
  23. 23. Left Lateral Nomenclature is dictated by the closest body b d part t the film t to th fil 23 D. Kotun, NSU Orlando PA Program
  24. 24. Lordotic Nomenclature is by the position of the patient. 24 D. Kotun, NSU Orlando PA Program
  25. 25. Oblique – LAO and RAO 25 D. Kotun, NSU Orlando PA Program
  26. 26. Right Lateral Decubitus 26 D. Kotun, NSU Orlando PA Program
  27. 27. AP Recumbant (AP supine) 27 D. Kotun, NSU Orlando PA Program
  28. 28. Planes (Frontal) 28 D. Kotun, NSU Orlando PA Program
  29. 29. The left lateral view would mean: The beam goes from front to back 1. 1 25% 2. The beam goes from left to right 25% 3. Th patient’s left side is closest to the The ti t’ l ft id i l t t th beam 25% 4. The patient’s left side is closest to the 25% film 29 D. Kotun, NSU Orlando PA Program
  30. 30. Putting It On Film Figure 7-7 Scattered X-ray photons can be removed from the image by positioning a grid bet ee the patient and the detector (or between t e pat e t a d t e detecto (o film). ) 30 D. Kotun, NSU Orlando PA Program
  31. 31. Putting It On Film X-Ray Photons are not very good at exposing film There is some type of amplification system Photostimulable cassette Phospors coat a screen and emit light when struck by X-Ray photons X- These can be catured on film or amplified with an electronic amplification system l lf 31 D. Kotun, NSU Orlando PA Program
  32. 32. Computerized Axial Tomography – CT/CAT / Several X-Ray tubes in an array 32 D. Kotun, NSU Orlando PA Program
  33. 33. CAT Scan 33 D. Kotun, NSU Orlando PA Program
  34. 34. CAT Scan 34 D. Kotun, NSU Orlando PA Program
  35. 35. CT 35 D. Kotun, NSU Orlando PA Program
  36. 36. Helical CT Instead of going back and forth, this corkscrews itself down your body. 36 D. Kotun, NSU Orlando PA Program
  37. 37. CAT Scan Now multiple heads allow faster imaging with more resolution Chest in < 30 sec. with .5cm resolution sec 5cm Pictures are reconstructed using a digital reconstruction algorithm These must be digitalized Can be placed on film 37 D. Kotun, NSU Orlando PA Program
  38. 38. Reconstruction 38 D. Kotun, NSU Orlando PA Program
  39. 39. Mammography Specific to a woman’s or man’s breasts woman s man s Lower dose Used as cancer screening Two types Radiomammography d h Uses X-Ray technique X- Xeromammography X h Electrostatic image production 39 D. Kotun, NSU Orlando PA Program
  40. 40. VIEWS Cranio-caudal (CC) Medio lateral (ML) () Latero medial (LM) () view and mediolateral i d di l t l mammographic view mammographic view oblique (MLO) mammographic view Spot compression and cone down views 40 D. Kotun, NSU Orlando PA Program
  41. 41. Technique Mediolateral view Craniocaudal view 41 D. Kotun, NSU Orlando PA Program
  42. 42. Mammography 42 D. Kotun, NSU Orlando PA Program
  43. 43. (N)MRI Uses high strength magnets on hydrogen bonds (in water) Magnet strength is in Tesla Units (0.3 – 3) g g ( ) The magnetic field excites the protons and as it relaxes, it emits a radiofrequency , q y signal Non- Non-ionizing (very important) Fields are aligned in 3 planes but can be adjusted 43 D. Kotun, NSU Orlando PA Program
  44. 44. (N)MRI 44 D. Kotun, NSU Orlando PA Program
  45. 45. () (N)MRI High Quality three dimensional pictures Uses Voxels vs Pixels (What is the vs. difference?) Good for soft tissue water filled tissue tissue, 45 D. Kotun, NSU Orlando PA Program
  46. 46. Positron Emission Tomography) PET Uses a prepared positron emitting nuclide Positrons are emitted at 180° apart 180° 46 D. Kotun, NSU Orlando PA Program
  47. 47. PET Fair quality pictures Shows function well 47 D. Kotun, NSU Orlando PA Program
  48. 48. PET Uptake is where the tissue has the most activity Increased uptake shows increased tissue function f ti Great for mapping brain activity Nuclide is usually injected 20 y.o. vs. 80 y.o. 48 D. Kotun, NSU Orlando PA Program
  49. 49. SPEC/Nuclear Medicine Uses a gamma emitting radionuclide to take a 2 dimensional picture This is gathered on a scintillation camera picking up the photons Planar images can be combined from different angles to reconstruct a 3 – D image The nuclides are usually injected and are designed to go to the organ or system in q question 49 D. Kotun, NSU Orlando PA Program
  50. 50. SPEC/Nuclear Medicine 50 D. Kotun, NSU Orlando PA Program
  51. 51. Ultrasound Uses sound waves higher than detectable by humans Non- Non-invasive and non-painful non- Patients aren’t usually afraid of U/S 51 D. Kotun, NSU Orlando PA Program
  52. 52. Ultrasound Early ultrasound was only 1 dimentional Used for brain diagnoses 52 D. Kotun, NSU Orlando PA Program
  53. 53. Ultrasound 2 – D ultrasounds became more diagnostic because the transducers could produce a planar image 53 D. Kotun, NSU Orlando PA Program
  54. 54. Ultrasound Better hardware and improved technology made multidimensional images possible These are safe for fetuses and are not painful to the parent. 54 D. Kotun, NSU Orlando PA Program
  55. 55. If I wanted to see organ function I would use this type of imaging. ld hi fi i Plane X-ray X- 1. 1 25% 2. Nuclear medicine scan 25% 3. C Computerized tomography t i dt h 25% 4. Magnetic resonance tomography 25% 55 D. Kotun, NSU Orlando PA Program
  56. 56. To image an unborn fetus, the safest imaging is: i ii Ultrasound 1. 1 25% 2. Nuclear medicine 25% 3. P it Positron emission ii 25% 4. Computerized tomography 25% 56 D. Kotun, NSU Orlando PA Program
  57. 57. Did Ms Roentgen have a ring on? Ms. Yes 1. 1 33% 2. No 33% 3. M b Maybe 33% 57 D. Kotun, NSU Orlando PA Program
  58. 58. In the Future Cellular imaging uses a combination of MRT, MRT CT, and U/S Mouse done with cellular imaging 58 D. Kotun, NSU Orlando PA Program
  59. 59. Funny Bone… Bone 59 D. Kotun, NSU Orlando PA Program
  60. 60. Acknowledgements Dove, E. L., 2003, Physics of Medical Imaging – An Introduction. U. of Iowa, 53pp. Sep. 22, 2003 60 D. Kotun, NSU Orlando PA Program
  61. 61. Questions? 61 D. Kotun, NSU Orlando PA Program

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