X-Ray Production and Properties

• Wilhelm Conrad Roentgen discovered x-rays on November 8th, 1895.
• Roentgen was experimenting with a Crookes Tube, a glass low vacuum tube.

X-Ray Production and Properties

• The first x-ray was produced using paper covered with barium platinocyanide.
• Fluorescence is the instant production of light from the interaction of energy (x-rays) with an element (barium platinocyanide).
• The first x-ray exposure was of his wife's hand and lasted 15 minutes.
• Roentgenology is the branch of medicine concerned with the use of x-rays.
• The unit of radiation exposure is the Roentgen.
• Roentgen received the first Nobel Prize in physics in 1901.
• The letter "X" in x-ray represents the unknown.
• Erythema is the reddening and burning of the skin.
• Electromagnetic radiation is energy that travels in waves with electric and magnetic fields.
• X-rays are invisible, electrically neutral, massless, and travel at the speed of light in a vacuum.
• X-rays cannot be focused by a lens.
• X-rays form a polyenergetic beam, are produced in a range of energies and travel in straight lines.
• X-rays can cause substances to fluoresce.
• X-rays can penetrate the human body, and be absorbed or scattered.
• X-rays can produce secondary radiation if absorbed, and cause damage to living tissue.
• The speed of light is 3 x 10^8 m/sec or 186,000 miles.
• X-rays possess kinetic energy.
• Electrical energy applied to the tube is converted to heat and x-rays.
• The maximum energy of an x-ray photon is expressed as Kilovoltage Peak (kVp).
• The medically useful diagnostic range of x-ray energies is 30kVp to 150kVp.
• X-rays have a dual nature, behaving like waves and particles.
• Wavelength is the distance between two crests or troughs.
• Wavelength is measured in Angstroms (Å) and nanometers (nm).
• One Angstrom (Å) equals one ten-billionth of a meter, or 10^-10 m.
• The range of wavelengths for x-rays is 0.1 to 1.0 Å.
• Lambda (λ) represents wavelength in formulas.
• Frequency is the number of waves (cycles) that pass through a point per unit of time (second).
• Frequency is measured in Hertz (Hz).
• One Hertz equals one cycle per second.
• Nu (v) represents frequency in formulas.
• Wavelength and frequency have an inverse relationship.
• Frequency increases when wavelength decreases, and vice versa.
• Amplitude is the height of a wave.
• A photon or quantum is a small, discrete bundle of energy.
• The energy of an individual photon is measured in electronvolts (eV).

Radiation Exposure and Safety

• Radiation exposure is quantified using the Standard (British) and International System (SI).
• The SI system is more widely adopted.
• Radiation is quantified to understand radiation exposure, dose, and biologic effects.
• Equivalent dose is calculated as Absorbed dose * Wr.
• Effective dose is calculated as Absorbed dose * Wr * Wt.
• ALARA stands for As Low As Reasonably Achievable.
• ORP stands for Optimization for Radiological Protection.
• The cardinal principles for minimizing radiation dose are time, distance, and shielding.
• A radiation weighting factor is a quality factor that accounts for the biologic effects produced by a type of radiation.
• Radiation weighting factor is expressed as Wr
• The weight factor for x-rays and gamma rays is 1.
• A tissue weighting factor is a correcting factor that accounts for the radiosensitivity of different tissues, and is expressed as Wt

Wilhelm Conrad Roentgen discovered x-rays in 1895 while experimenting with a Crookes Tube. The first x-ray was produced using barium platinocyanide. Roentgenology is the branch of medicine using x-rays, and the unit of radiation exposure is the Roentgen.