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FYS 4250 REPETITION PART 2

Learn about various imaging techniques in medical diagnostics and the principles of chemical biosensors. Topics include CT reconstruction, MRI, ultrasound, and pH measurement.

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FYS 4250 REPETITION PART 2

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  1. Fysisk institutt - Rikshospitalet FYS 4250 REPETITION PART 2

  2. FYS 4250 Kap.10 Chemical biosensors

  3. pH-measurement

  4. pCO2 (Severinghaus) electrode

  5. pO2 (Clark) electrode

  6. Fluorescent dye sensor

  7. pH-sensitive dyes

  8. Pulsoxymetry light absorption

  9. FYS 4250 Kap.11 Clinical laboratory instrumentation

  10. Spectrophotometer

  11. Flame emission/absorption

  12. Fluorometer

  13. Impedance- detectorfor cells

  14. FYS 4250 Kap.12 (1) Medical imaging systems, radiography

  15. X-ray tube

  16. Fotonspectrum X-ray tubes

  17. X-ray system

  18. Modulation transfer function (MTF)

  19. Geometrical resolution

  20. Resolution

  21. FYS 4250 Biomedical instrumentation Chapt 12b: Nuclear imaging methods

  22. Non-invasive surgery Heavy ion therapy (Proton-terapi) http://www.nature.com/nature/journal/v449/n7159/box/449133a_BX1.html Kilde: NIRS, Chiba, Japan http://www.triumf.info/public/about/virtual_tour.php?section=3&single=18 Fysisk institutt - Rikshospitalet

  23. Scintillation-detector

  24. Fysisk institutt - Rikshospitalet

  25. Fysisk institutt - Rikshospitalet

  26. X Blur Basic principle of CT-Reconstruction of 2 dimensional image- Projection Data curvilinear integral of absorption coefficient regarding Y y y X-ray detector array Y X x x object X X-ray tube Reconstruction field Data Acquisition field Simple Backprojection

  27. Back- projection (1)

  28. Back- • projection (2)

  29. MRI Source: Biomed resources

  30. Precession og relaxation

  31. Ref:www.simplyphysics.com

  32. Larmour frequency The energy difference between the two alignment states depends on the nucleus •  E = 2 z Bo  Eh • /2 known as Larmor frequency /2= 42.57 MHz / Tesla for proton Ref: James Voyvodic

  33. MRI scanner

  34. Important MRI equations • Larmorequation: ω=γB • Relationship between parallell / antiparallell protones : Nn/Ne = ehν/kT =1+410-6 represents net magnetization at room temperature and 1 Tesla

  35. T1 recording

  36. T2 recording

  37. 3D picture construction ω = γB

  38. FYS 4250 Kap.12 (4) Medical imaging systems: Ultrasound

  39. Ultrasound piezo crystal Kilde: Alejandro Frangi

  40. Ultrasound (US),A-mode (amplitude)

  41. Time motion US, M-mode

  42. M-mode Ultrasound (motion)

  43. B-mode

  44. B-mode (Brightness) • Same as A-mode, but twodimensional graphical display where brightness indicates the amplitude to reflected sound • Most modern US-systems is realtime 2D or 3D. Multiple crystals or mobile crystals • Up to 100 images per second

  45. 4 different probe-principles

  46. Sources of error (1)

  47. Sources of error (2)

  48. Sources of error (3,4,5)

  49. Ultrasound advantages • Muscles and soft tissue are suitable for US-imaging, especially transitions between solid substances and liquid filled areas. • Real time images = fast diagnosis. Can also be used for biopsy-guiding • Shows the organ structure • No well-known side effects, not unpleasant for the patient • Small scanners compared to other image modalities • Inexpensive compared to other image modalities • Spatial resolution is better at high-frequency US than most of the other modalities

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