rad t 110 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Rad T 110 PowerPoint Presentation
Download Presentation
Rad T 110

Loading in 2 Seconds...

play fullscreen
1 / 17

Rad T 110 - PowerPoint PPT Presentation


  • 209 Views
  • Uploaded on

Rad T 110. Sherer Ch. 3. Discovery of X-rays. November 1895 Crooke’s tube. Injuries. Dally First American fatality 1904 Early awareness of effects Radiodermatitis Lead to cancerous lesions Aplastic anemia Leukemia. Investigation into Safety.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Rad T 110' - blaze


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
rad t 110

Rad T 110

Sherer

Ch. 3

discovery of x rays
Discovery of X-rays
  • November 1895
  • Crooke’s tube
injuries
Injuries
  • Dally
    • First American fatality 1904
  • Early awareness of effects
    • Radiodermatitis
      • Lead to cancerous lesions
    • Aplastic anemia
    • Leukemia
investigation into safety
Investigation into Safety
  • 1921 – British X-ray and Radium Protection Committee
    • Had the idea and ‘recognized’ the dangers but did not have the technology to establish or measure guidelines.
skin erythema dose
Skin Erythema dose
  • 1900 -1930
    • Used to measure exposure
    • Does not account for individual differences or tolerance of dose.
      • Inaccurate
tolerance dose
Tolerance Dose
  • Based on keeping exposure below threshold dose for acute or early effects
    • The idea being that nothing bad was going on before early effects were noted.
  • Still resulted in a tremendous dose however
  • In 1934, tolerance dose limited to 0.2 R daily
  • 1936, tolerance further reduced to 0.1 R daily.
    • This was in response to the observation that late effects also occurred.
roentgen
Roentgen
  • In 1937 became the internationally accepted measure for exposure to x-ray and gamma radiation.
modern era of rad protection
Modern Era of Rad Protection
  • In the 50s, Maximum Permissible Dose (MPD) replaces tolerance dose.
  • REM
    • Allows for comparison between different types of radiation.
traditional units of exposure
Traditional units of exposure
  • Roentgen – unit of exposure
    • 2.58 X 10-4 coulombs/kg of dry air
    • Basically, how much air is being ionized
  • REM – radiation equivalent man
    • Any exposure that produces the same biologic effect as 1 rad of x-radiation
  • Rad – absorbed dose
    • 100 ergs per gram of tissue
si units of exposure
SI units of exposure
  • Roengten is a roengten
  • 100 rads = 1 Gray (Gy)
  • 100 rem = 1 Sievert (Si)
absorbed dose
Absorbed dose
  • Each tissue in the body has different absorption characteristics.
    • Based on
      • Effective atomic number, tissue or mass density, and part thickness
    • Produces differential absorption
      • Subject contrast
slide12
LET
  • High LET radiation deposits a large amount of energy in a small area.
    • This would be bad, thereby producing more damage
  • X-rays are a low LET form of radiation
quality factors
Quality factors
  • X-ray photons, beta particles, and gamma photons – 1
  • Thermal neutrons – 5
  • Fast neutrons – 20
  • Alpha particles – 20
  • Based on LET
equivalent dose
Equivalent Dose
  • Takes into account that different types of radiation are more dangerous than others and applies a radiation weighting factor to them.
  • Radiation weighting factor is based on RBE.
radiation weighting factors
Radiation weighting factors
  • Electrons, x-ray photons, gamma photons – 1
  • Neutrons < 10 keV – 5
  • Neutrons 10 keV – 100 keV – 10
  • Neutrons >100 keV – 2 MeV – 20
  • Protons – 2
  • Alpha particles - 20
effective dose
Effective Dose
  • This uses the equivalent dose and then factors in the types of tissue that have been irradiated.
  • Some tissues are more sensitive than others; thereby, potentially causing more damage.
weighting factors
Weighting Factors
  • We will focus on Equivalent Dose using weighting factors.
  • These are the same values presented in last weeks hand-out