Radiology and Effect in Health

• Radiation is energy emitted from a body or source that is transmitted through an intervening medium or space and absorbed by another body
• Radiation is classified as either non-ionizing or ionizing
• Non-ionizing radiation is longer wavelength/lower frequency lower energy
• Ionizing radiation is short wavelength/high frequency higher energy
• Ionizing radiation has sufficient energy to produce ions in matter at the molecular level
• Ionizing radiation can cause significant damage to humans, including damage to DNA and denaturation of proteins
• Non-ionizing radiation can cause thermal damage, such as burns
• The visible spectrum is essentially the divide between ionizing and non-ionizing radiation
• Non-Ionizing radiation comes in the forms of: (Lowest to Highest)

  • ELF (extremely low frequency)
  • Radio Frequencies
  • Microwave Frequencies
  • Lasers
  • Infrared
  • Visible Spectrum
  • Ultraviolet
• ELF:

  • Power plant or line workers
  • Inconclusive evidence of leukemia link
• Radiofrequency and Microwave Frequency Exposures:

  • Occupational Exposures: Radar and communications equipment, industrial and commercial ovens
  • Other Exposures: Cell Phones
  • Clinical Effects: Controversy regarding potential cancer risks, exposure can cause burns
• LASER (Light Amplification by Stimulated Emission of Radiation):

  • Beams of coherent light with single wavelength and frequency
  • May be in the IR, Visible or UV spectrum
  • Four classes by risk of injury
• Infrared:

  • Penetrates superficial layers of the skin, causes thermal injury
  • Potential for damage to the cornea, iris, lens of the eye
• Visible Spectrum:

  • 400 to 750nm wavelengths
  • ROYGBIV (Red, Orange, Yellow, Green, Blue, Indigo, Violet)
  • Possibility of retinal injury from 400-500 nm blue frequencies
• Ultraviolet Radiation:

  • 200nm to 400 nm
  • Bridge between Non-Ionizing and Ionizing Radiation
  • UV-A, UV-B, UV-C bands produce biologic effects on the skin and eyes
• Ionizing radiation is emitted from radioactive atomic structures as high energy electromagnetic waves (gamma and x-rays) or as actual particles (alpha, beta, neutrons)
• Types of Ionizing Radiation:

  • Gamma Rays
  • X-Rays
  • Alpha Particles
  • Beta Particles
  • Neutrons
• Penetration of Radiation:

  • Gamma Rays, Xrays, and Neutrons penetrate body easily
  • Alpha and Beta Particles are essentially blocked by the skin
  • Alpha particles can cause significant damage if taken internally
• Radiation Measurement:

  • Roentgen (R)
  • Rad
  • Gray (Gy)
  • Rem
  • Sievert (Sv)
• Ionizing Radiation Exposure Limits:

  • Occupational exposure limit
  • Background exposure for a US resident
• Four Ionizing Radiation Exposure Categories:

  • Radioactive Contaminates on Intact Skin
  • Local Radiation Injuries
  • Whole Body Exposure
  • Internal Deposition
• Acute Radiation Syndrome:

  • Progressive predictable series of signs and symptoms
  • Lethal dose for 50% of healthy humans
  • Prodromal Period, Latent Period, Manifest Illness, Death or Recovery
• Long Term Effects of Radiation Exposure:

  • Chronic Radiodermatitis
  • Cataracts
  • Sterility
  • Prenatal Effects
  • Cancer
  • Genetic Effects
  • Shortened Life Span
• Management of Radiation Exposures:

  • Radioactive Contaminates on Intact Skin
  • Local Radiation Injuries
  • Whole Body Exposure
  • Internal Deposition
• Three regions and their units of Ultraviolet

  UV-A 315nm-400nm

  UV-B 280nm-315nm

  UV-C ‹280nm
• Roentgen (R)- Describes a radiation field in terms of the amount of ionizations produced in air, not in common use today
• Rad- Conventional unit of absorbed dose of radiation per unit mass.
• 1 Gray = 100 Rads
• Rem- Absorption measure to whole body or specified organ, takes into account

  radiation quality
• 1 SV = 100 Rem
• Occupational- National Council on Radiation Protection (NCRP) annual exposure 5 rem

  Background Exposure for a US resident is 360mrem
• Common Occupational Exposures:

  • Medicine- Radionuclides, X-Ray

  • Nuclear Power Industry 13

  • Document Dating

  • Food Preservation

  • Airplane/Space Flight

  • Transportation of Radioactive Material
• Acute Radiation Syndrome

  Over 100 rad in a single exposure or within 24-48 hours, progressive predictable series of signs and symptoms developing over a period ranging between a few hours to several weeks
• Prodromal Period - 1 to 6 hours after exposure
• Latent Period - Variable in duration hours to 30 days
• Whole Body Exposure

  100 rem or less - Complete history for record

  Advise regarding potential late effects (cancers)

  Follow as outpatient, counseling

  100 rem to 200 rem - Complete exposure history radiation source and strength

  Consider Lab testing CBC with diff

  200 rem to 300 rem - Hospitalize

  300 rem or more - Transfer to Tertiary Care Center

  Supralethal exposure of more than 5000 rem - Supportive care at any hospital will do will die in a few days
• Internal Deposition

  Reduce Absorption- Binding Agents, Antacids

  Expedite Elimination- Cathartics

  Organ Saturation- Potassium Iodide

  Displacement- Calcium, Iodide

  Chelation