Exposure

    Subdecks (8)

    Cards (836)

    • Speed of light = wavelength x frequency
    • 3x10*8 m/s is the constant speed of light
    • speed of light = lambda nu
    • photon = small, discrete bundle of energy
    • photons is measured in units of election volts ( eV )
    • X-rays behave like particles and move as photons or quanta
    • Decreasing wavelength and/or frequency will increase x-ray energy
    • Dr. Wilhelm Conrad Roentgen discovered x-rays by accident.
    • X-rays = unknown rays
    • x-rays act like both waves and particles
    • Dr.Wilhelm Conrad Roentgen discovered x-rays November 8 , 1895
    • Crooke's tube -glass tube : glows when energized
    • Photons leave the x-ray tube but upon impact to matter it can change and turn into particles
    • Fluorescence - production of light between energy and matter
    • Dr. Wilhelm tested x-rays on wood ( went straight through ) however platinum was stopped by x-rays
    • Dr.Wilhelm wrote a research paper on the danger December 28 , 1895
    • Erythema = reddening from radiation
    • 1901 he received a Nobel prize in physics
    • Energy - the ability to do work
    • Forms of energy : Kinetic , Electrical, Thermal, Electromagnetic
    • Electrical energy applied to x-ray tube results in heat
    • Wavelength = the distance between two successive crests or troughs of a wave
    • ionization refers to removal of electrons from atoms
    • C/kg - used as unit of measure for output intensity R- used as unit of measure for input
    • Air Kerma = how much kinetic energy is released in matter
    • Air Kerma = kinetic energy released in matter
    • Absorbed Dose - the transfer of radiation energy into matter
    • Amount absorbed dependent on :
      Energy of ionizing radiation
      type of interaction tissues. ( air, muscle, bone , fat )
    • Dose Equivalent - units of radiation exposure used in measuring occupational exposure in radiation equivalents in man ( rem ) and sieverts ( Sv )
    • X-ray and Gamma rays have same quality factors
    • Fast Neurons and Alpha particles have factor / Wr of 20
    • Effective dose = absorbed dose x Wr x Wt
    • ALARA = as low as reasonably achievable
    • x-rays are both electric and magnetic ( electromagnetism ).
    • x-rays act as both particles and waves
    • Time , distance and shielding is considered to be the principles of safety
    • Half life is the time it takes for an activity to reduce its radioactivity by half.
    • Units of Exposure
      The traditional unit is Radian (R), but Sievert (Sv) is the SI unit, equivalent to Rem (R).
    • Rem vs Sievert
      Rem is a traditional unit, specifically for X-rays, while Sievert (Sv) is the SI unit for all types of ionizing radiation.
    • Rem and X-rays
      Rem is a unit specifically designed for X-rays, introduced in the 1940s as a simplification for medical and diagnostic applications.