Physical Properties Of Radiation Flashcards
Explain the concept of ionization
-when ionizing radiation causes an electron to be ejected from an atom
Explain the concept of excitation
-when ionizing radiation causes an electron to reach a higher energy state, but it remains with the same atom
Determine if the following types of radiations are ionizing or non ionizing A) x rays B) microwaves C) heat D) beta particles E) neutron radiation
A) x-rays: ionizing B) microwaves: non ionizing C) heat: non ionizing D) beta particles: ionizing E) neutron radiation: ionizing
Which of the following is the best description of radiation?
A) acts as a particle
B) acts as a wave
C) may act as either a particle or a wave
C! May act as either a particle or a wave
What is the traditional unit of occupational exposure?
Rem!
What is the international unit of occupational exposure?
Sievert!
Define the term wavelength
- Distance between any two successive points on a wave
- measured crest-crest or trough-trough
- represented by greek letter lambda
What unit is used to measure wavelength?
The meter is used to measure wavelength
Define the term frequency
The number of waves that pass a particular point during a given time frame, or the number of cycles per second
What unit is used to measure frequency?
Frequency is measured in hertz or cycles per second
What is hertz equal to?
1 hertz= 1 cycle/second
Explain the relationship between frequency, wavelength and velocity of a wave
- frequency and wavelength are inversely proportional (the wavelength decreases, frequency increases and vice versa)
- product of frequency and wavelength of electromagnetic radiation always equals the velocity of the speed of light (3X10 to the 8 m/s)
Describe the wavelength of x-radiation
-x-radiation has a short wavelength compared to lower-energy electromagnetic radiation like visible light
How does radiation differ within the electromagnetic spectrum?
- as the energy level rises, wavelength decreases and frequency increases
- radiation varies depending on the energy level
- low energy levels are at the bottom end of the spectrum with radio waves and microwaves
- visible light is at the centre of the spectrum
- high energy levels contain gamma and x-rays
What is the speed of light?
3x10 to the 8 m/s (186,000 miles per second)
What is the wave equation?
Velocity= frequency x wavelength
Which source of radiation gives the largest radiation exposure to the population?
Natural background radiation gives the largest radiation dose to the population more than medical and man-made sources combined
Which source gives its radiation exposure to the lungs only?
Radon gas exposure occurs only to the lungs
Where does cosmic radiation come from?
From the sun, space and stars
Does cosmic radiation increase or decrease at higher altitudes?
It increases at higher altitudes
What man-made source gives the highest population dose?
Highest population dose from man-made sources is from medical procedures that involve radiation
1) of 14 properties of x-rays
X-rays are invisible, cannot be seen, felt, smelt or heard
2) of 14 properties of x-rays
X-rays are electrically neutral
- neither + or - charge
- cannot be accelerated
- magnets or electrical fields cannot change the photons direction
3) of 14 properties of x-rays
X-rays have no mass
- create no resistance to being put into motion
- cannot produce force
4) of 14 properties of x-rays
X-rays travel at the speed of light in a vacuum
-moving at a constant velocity of 3x10 to the 8 m/s
5) of 14 properties of x-rays
X-rays cannot be optically focused
-optical lenses have no ability to focus or refract photons
6) of 14 properties of x-rays
X-rays form a poly energetic or heterogenous beam
- x-ray beam used in diagnostic radiography is composed of photons that have many different energies
- maximum energy of a photon is expressed by the kilovoltage peak (kVp) set on the control panel by the radiographer
7) of 14 properties of x-rays
X-rays can be produced in a range of energies
- useful for different purposes
- medically useful diagnostic range is from 30-150 kVp
8) of 14 properties of x-rays
X-rays travel in straight lines
- each individual photon travels in a straight line
- forms a divergent beam
9) of 14 properties of x-rays
X-rays can cause some substances to fluoresce
- when x-rays strike some phosphors producing light
- phosphors are used in image intensifiers in fluoroscopy
10) of 14 properties of x-rays
X-rays cause chemical changes to occur in radiographic and photographic film
-capable of creating images or fogging any type of photographic film
11) of 14 properties of x-rays
X-rays can penetrate the human body
- passes through the anatomy based on the beam energy
- determined by the composition, thickness of the anatomy exposed
12) of 14 properties of x-rays
X-rays can be absorbed or scattered by the anatomy
-depends on the energy of the individual x-ray photon
-photons may be:
🔹absorbed- in the anatomy (dose)
🔹scattered- moving in another direction
🔹transmitted- to the IR
13) of 14 properties of x-rays
X-rays can produce secondary radiation
-x-rays introduction causes a specific type of interaction with matter producing:
🔹secondary photon
🔹characteristic photon
14) of 14 properties of x-rays
X-rays can cause chemical and biologic damage to living tissue
- excitation and ionization of atoms comprises cells
- damage to cells can occur
Both light and x-rays are electromagnetic radiation but can x-rays be reflected like light?
- no, photons have no mass or charge
- photons travel in straight lines
- travel through matter instead of being reflected
- important property for creating diagnostic images
Can x-radiation remove and electron from its orbit?
Yes, photons can ionize matter, so they are capable of removing an electron from its orbit
At what speed does x-radiation travel?
Ionizing radiation travels at the speed of light in a vacuum (3x10 to the 8 m/s)
