Exposure

• 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.