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Principles of Radiology

Principles of Radiology. Daniel Podd RPA-C. Physics of Radiology. X-Rays produced by electron beam hitting tungsten film target Electrons strike film, metallic silver is precipitated if no obstruction to beam, resulting in bright film

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Principles of Radiology

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  1. Principles of Radiology Daniel Podd RPA-C

  2. Physics of Radiology • X-Rays produced by electron beam hitting tungsten film target • Electrons strike film, metallic silver is precipitated if no obstruction to beam, resulting in bright film • Obstruction in path of beam prevents silver precipitation; film remains dark • The negative of this film is known as the Plain X-Ray, or radiograph

  3. Positive Negative (Developed) Radiograph, “Plain Film”

  4. Radiodensity as a Function of Thickness

  5. Radiodensity as a Function of Composition with Thickness Kept Constant

  6. X-Ray A-D: Radiolucent or Radioopaque? Why?

  7. AP CHEST: Patient Position


  9. PA CHEST: Patient Position

  10. L: Lung R: Rib T: Trachea  AK: Aortic knob A: Ascending aorta H: Heart   V: Vertebra P: Pulmonary artery S: Spleen

  11. Lateral

  12. Bullet + PA only = ?

  13. Bullet + PA & Lateral =

  14. PA Chest Lordotic View

  15. Fluoroscopy X-ray beams from Mechanism: Continuous below patient, amp- lified by intensifier above patient; broadcast on high-resolution television screen • Provides live animation • Imaging reversed vs xray • Uses: Barium swallow to evaluate esophagus, small and large intestines, vessel catheter guidance

  16. Fluoroscopy Spot Film: Single X-ray during procedure. Film developed into negative

  17. Angiography Mechanism: Uses X-rays and intravascular injection of iodinated contrast to evaluate arterial (arteriogram) and venous (venogram) systems Vasoocclusive disease • Most approaches via femoral artery or vein

  18. Computerized Axial Tomography • Cross-sectional slice radiographs of the body using thin beam of X-rays through desired axial plane • Slices up to 1.0 mm that represent density values; no superimposed images • Viewed as if facing patient and looking up through feet • Density Less Dense: Air, Fat (black) More Dense: Bone (white)

  19. CT Scan

  20. CT Scan Angiography • 3DCT, 3-Dimensional CT scan • Injection of IV contrast to enhance vascular system • Useful for aortic aneurysms, coronary heart disease, carotid vascular occlusive disease

  21. CT Scan Angiography

  22. Ultrasound • Mechanism: High-frequency sound waves beamed directed into body, onto organs and their interfaces; transducer receives and interprets reflection of these beams from organs • Acoustic Impedance: beam absorption by tissues, based on density and velocity of sound through different adjoining tissue types

  23. Ultrasound • Image (echo) produced when different neighboring tissues reflect different acoustic impedances • Solid organs, fat, & stones: Echogenic (white) • Fluid & cysts: Anechoic (black)

  24. Ultrasound

  25. Ultrasound Advantages • No ionizing radiation • Applicable to any plane • Cost-effective • Portable • Real-time imaging Disadvantages 1. Time consuming 2. Poorer quality

  26. Magnetic Resonance Imaging (MRI) • Mechanism: Patient placed in magnet tunnel; radio waves passed through body in pulses. Pulses returned from tissues, transformed into 2D image based on relaxing times: T1 & T2 T1 T2 High Signal (brightness) Low Signal

  27. MRI Advantages vs CT: • Multiplanar scanning • Better soft-tissue differentiation 3. Contrast-free 3DMR Contraindications: Metals, clips, pacemakers

  28. MRI T1 T2

  29. Normal CXR

  30. Normal CXR

  31. Enlarged Hila

  32. Aortic Knob Hilar Mass (Left)

  33. Right vs Left Pulmonary Artery

  34. Kerley B-Lines • Fine horizontal opacified lines representing pulmonary edema • Seen in CHF, pulmonary fibrosis, heavy metal fibrosis, malignancy

  35. Blunted Costophrenic Angle

  36. Lung Mass: Cavitation

  37. Lung Mass: Solid Tissue

  38. Air Space (Alveolar) Disease

  39. Interstitial Disease

  40. Alveolar or Interstitial?

  41. Alveolar or Interstitial?

  42. Alveolar or Interstitial?

  43. Think anatomically 3 Lobes RUL and RML located Anterior to heart Obliteration of mediastinum and cardiac borders Right CoPhS intact Lobar Consolidation: Right • RLL located Lateral to heart, but anterior to diaphragm • Obliteration of right CoPhS • Right heart border intact

  44. LUL lies anterior to heart and superior to diaphragm (and LLL) Obliteration of left heart border only Left hemidiaphragm intact LLL located lateral to heart and anterior to diaphragm Obliteration of left hemidiaphragm Left heart border intact Lobar Consolidation: Left

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