Radiation Safety Penguin Facts/Terms

mass

quantity of matter as described by its energy equivalence

energy

ability to do work

radiation

transfer of energy

ionization

removal of an electron from an atom

mass-energy equation & meanings

E = mc²,

E=energy, m = mass, c = velocity (speed) of electromagnetic radiation in a vacuum

what is needed for a satisfactory x-ray beam?

x-ray tube must be supplied with a high voltage and electric current

how did radiology emerge as a medical speciality?

from the discovery and use of the snook transformer & Coolidge x-ray tube

why is radiology considered a safe occupation today?

effective radiation protection practices

ALARA

as low as reasonably achievable

unit of radiation exposure

air kerma (Gya)

unit of RAD (absorbed radiation dose)

Gray (Gyt)

unit of occupational radiation exposure & effective dose

sievert (Sv)

unit of radioactivity

becquerel (Bq)

how do x-rays behave and move?

as particles

how does visible light behave and move?

as a wave

attenuation

reduction in intensity that results from scattering and absorption

x-ray intensity is proportional to ____?

mAs - measure of total number of projectile electrons that travel from cathode to anode to produce x-rays

mAs = mA x s

= mC/s x s

= mC

C (coulomb) = measure of electrostatic charge

1 C = 6.25 × 10^18 electrons

kVp² = kilovolt peak

if kVp were doubled, the x-ray intensity would increase by a factor of 4

x-ray intensity is inversely proportional to ____?

square of the distance from the source (inverse square law)

in order to maintain constant exposure to the image receptor…?

when SID (source-to-image distance) is increased, mAs must be increased by SID²

x-ray photon

a quantum of electromagnetic energy/discrete bundle of energy

velocity of ALL electromagnetic radiation

speed of light - 3 × 10^8 m/s

amplitude

one half the range from crest to valley over which the sine wave varies

frequency

number of wavelengths that pass a point of observation per second

at a given velocity, wavelength & frequency are _____?

inversely proportional

the electromagnetic spectrum includes ___?

the entire range of electromagnetic energy

what is NOT a part of the electromagnetic spectrum?

diagnostic ultrasound/sound waves/acoustics

the energy of a photon is directly proportional to its ___?

frequency

difference between x-rays and gamma rays

where they originate from

visible light is identified by ___? RF is identified by ____> x-rays are identified by _____?

wavelength, frequency, energy p

photons interact with matter most easily when?

the matter is approximately the same size as the photon wavelength

inverse square law can be applied to distances greater than ___ times the longest dimension of the source

7

Planck’s Quantum Equation

E = hf

E = photon energy

h = Planck’s constant

f = photon frequency in Hz