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RADIOLOGY

University of South Carolina School of Medicine. RADIOLOGY. ICM. Introduction To Clinical Medicine. Francis Neuffer M.D. U.S.C. School of Medicine. Radiology Website : http://radiology.med.sc.edu. Overview . GOALS. Image creation Different modalities

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RADIOLOGY

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  1. University of South Carolina School of Medicine RADIOLOGY ICM Introduction To Clinical Medicine Francis Neuffer M.D. U.S.C. School of Medicine Radiology Website: http://radiology.med.sc.edu

  2. Overview GOALS • Image creation • Different modalities • Strengths and weakness

  3. RADIOLOGY TOOLS X- RAY ULTRASOUND NUCLEAR MEDICINE MAGNETIC RESONANCE COMPUTED TOMOGRAPHY

  4. HOW IS IMAGING DONE? • IONIZING RADIATION X-ray, CT, Nuclear Medicine • SOUND WAVES Ultrasound • MAGNETIC FIELDS / RADIO WAVES Magnetic Resonance

  5. X-ray, visible light and radio waves are all electromagnetic radiation and only vary in frequency.

  6. X-RAY • High Energy Photon --Kilo Electron Volts • Ionizing Radiation • Exposes Film / Detector • Projection Data X-ray beam detector

  7. X- RAY • Bone • Soft tissue • Fat • Air

  8. UPPER GI--(GASTRO INTESTINAL) ORAL BARIUM CONTRAST STOMACH WITHOUT CONTRAST-plain or scout film ARTERIOGRAM INTRAVASCULAR IODINE CONTRAST

  9. HIGH ENERGY PHOTON IONIZING RADIATION EXPOSES DETECTOR TOMOGRAPHIC DATA COMPUTED TOMOGRAPHY 9

  10. SOFT TISSUE WINDOW LUNG WINDOW

  11. THE HOUNSFIELD SCALE -1000 1000 0 -20 - -80 +20 - +80 AIR BONE WATER FATTY TISSUE SOFT TISSUE

  12. LT

  13. ARTERIOGRAM CT WITH INTRAVENOUS IODINE CONTRAST WITHOUT CONTRAST INTRA-ARTERIAL IODINE CONTRAST

  14. AXIAL SAGITTAL

  15. ENHANCING RING LESION NON-CONTRAST STUDY IV IODINE CONTRAST STUDY

  16. NUCLEAR MEDICINE • High Energy Photon • Ionizing Radiation --Radiopharmaceutical • Dynamic / Physiologic

  17. Normal Bone Scan Metastatic bone disease

  18. NORMAL LUNG SCAN

  19. NUCLEAR MEDICINE Exposure • Physical half-life • Biological half-life • Effective half-life • Definitions: • The effective half-life for a radionuclide is the time needed for the compound to be decreased by 50%. This is the combined biological half-life and the physical half-life . • • The biological half-life is excretion dependent. • • The physical half-life is due to nuclear decay.

  20. RADIATION Ionizing radiation: X-Ray CT Nuclear Medicine / PET Non-ionizing radiation: US MR

  21. WHICH ONE DOESN’T THAT’S MORE LIKE IT. FIT?

  22. 22

  23. RADIATION RISK CT scans contribute approximately 45% of the U.S. population's collective radiation dose from all medical x-ray examinations. CT is the LARGEST contributor to medical exposure to the U.S. population. Estimated Number of CT Scans Performed Annually in the United States

  24. Increased CT Utilization • Indications • Availability • Certainty • Speed • Demand—patient / physician / insurance Emergency Radiology 2006 Oct: 13(1); 25-30

  25. RADIATION RISK IONIZING RADIATION Ionizing radiation can cause free radicals which can break DNA. Incomplete DNA repair can be lethal to cell or increase cancer risk or increase genetic defects in fetus.

  26. RADIATION DOSAGE RADS REMS GRAYS SIEVERTS

  27. NCRP 160 Report (2009)Background Population Radiation Adapted from: Radiology 2009;253:293-296 Figure 2

  28. RADIATION DOSAGE CXR= 1/100 Background Radiation/Yr. CT Scan= 1-4x Background Radiation/Yr. Denver = 2x Background Radiation/Yr.

  29. RADIATION RISK Deterministic effects—dose dependent. Stochastic effects—probability of event

  30. DETERMINISTICTHRESHOLD - DOSE RELATED Cataracts, Skin Erythema & Burns, (very rare -interventional procedures) Acute Radiation Sickness-(Radiation accidents) Bone marrow-depression GI tract sloughing Cerebral edema Death

  31. STOCHASTIC EFFECTS LOWER DOSE: probability increase - population effect Cancer incidence Hiroshima Nuclear Bomb survivors

  32. Excess Risk of Cancer 50-100 mSv exposure Nuclear Bomb Survivors

  33. Small Statistical Increased Risk The estimated lifetime cancer mortality risks from a single full-body CT examination at age 45.

  34. CT DOSE IS IN RANGE OF HIROSHIMA BOMB SURVIVORS DOSE There is an excess cancer risk seen in large groups of Hiroshima survivors. Statistically CT scans WOULD increase risk of cancer.

  35. PEDIATRIC EXPOSURE Children are considerably more sensitive to radiation than adults by about 3 times. Children also have alonger life expectancy than adults, resulting in a larger opportunity for effect. Radiation-induced cancers effects delayed1 to 2 decades or longer after exposure. Children can receive a higher dose( ADULT SCAN) than necessary. Thus risk for developing a radiation-related cancer can be several times higher for a pediatric patient.

  36. FOR MORE PHYSICS… www.youhavenolife.com

  37. University of South Carolina School of Medicine RADIOLOGY ICM Introduction To Clinical Medicine Francis Neuffer M.D. U.S.C. School of Medicine Radiology Website: http://radiology.med.sc.edu

  38. NO IONIZING RADIATION • SOUND WAVES Ultrasound • MAGNETIC FIELDS / RADIO WAVES Magnetic Resonance

  39. ULTRASOUND • Sound Wave - high Frequency-megahertz • No Ionizing Radiation

  40. B Mode-brightness • Most common use • Presents “real time”image • Ultrasound Sector Scanning

  41. ULTRASOUNDideal for fluid filled structures Gallbladder Kidney Obstetrics

  42. PLAX VIEW OF THE HEART

  43. CAROTID ARTERY color doppler

  44. MAGNETIC RESONANCE • HYDROGEN PROTONS ALIGN IN MAGNETIC FIELD • RADIO FREQUENCY EXCITATION and TRANSMISSION • NO IONIZING RADIATION

  45. RF

  46. T1 SCAN MR SIGNAL T2 SCAN SCANS ARE MADE TO SEPARATE TISSUE BASED ON THEIR T1 AND T2 TIMES.

  47. MRI OF THE LUMBAR SPINE Sagittal views

  48. MR ANGIOGRAPHY WITHGADOLINIUM Standard catheter Angiogram

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