Card Set Information
Radiation therapy physics rad science
Radiation Physics Test 10/29
Structures that absorb X-rays
Structures that transmit X-rays
(ie. soft tissue)
The Inverse Square Law can be applied to distances greater than _________ times the longest dimension of the source
The inverse square law can be applied to distances greater than
times the longest dimension of the source.
States that the intensity of radiation at a location is inversely proportional to the square of its distance from the source.
The Inverse Square Law
A discrete bundle of energy
the x-ray photon
Photon energy is
Photon energy is ____________ proportional to photon wavelength
Photon energy is
proportional to photon wavelength.
at the speed of light or not at all
Planck's Quantum Equation
The longer the wavelength, the _____________ the energy of each photon.
The law of conservation of mass & energy states:
Energy & Matter can neither be destroyed or created
The properties of elctromagnetic radiation include:
Electromagnetic energy exists over a wide range called:
an energy continuum
A continuum is an uninterrupted (continuous) ordered sequence.
An atom of light
The smallest quantity of any type of electromagnetic energy
A photon may be pictured as a small bundle of energy, sometimes called a
A quantum of electromagnetic energy
an x-ray photon
Energy disturbances that move through space at the speed of light
Mass of a photon
Photons have NO MASS
but they do have electric and magnetic fields
Speed of light
The speed of light (c)
The velocity of electromagnetic radiation
3 x 10
Variations of amplitude over time
One-half the range from crest to valley over which the sine wave varies
The number of wavelengths that pass a point of observation per second
measured in Hertz (Hz)
The rate of rise and fall
What is frequency measured in?
One hertz is equal to one cylce per second
ie. 20 cycles in 10 sec is 2 Hz
The distance from one crest to another, one valley to another or from any point on the sine wave to the next corresponding point
What are the 3 parameters needed to describe electromagnetic energy?
Velocity (v- measured in m/s)
Frequency (f- measured in Hz)
At a given velocity _______________ & ______________ are inversely proportional
wavelength & frequency
For electromagnetic energy, frequency and ____________ are inversely proportional
The deviation of course that occurs when photons of visible light traveling in straight lines pass from one transparent medium to another
________ light consists of photons with wavelengths longer than visible light but shorter than microwaves
___________ light is between visible light & ionizing radiation on the spectrum
An x-ray photon contains ___________ energy than a visible light photon or an RF photon
The frequency of x-radiation is much _________ and the wavelength is much _________ than for other types of electromagnetic energy
Where are x-rays produced?
Outside of the nucleus of excited atoms; emitted from the electron cloud
Where are gamma rays produced?
Inside the nucleus of the atom
A photon of x-radiation & a photon of visible light are fundamentally the same except that x-radiation has ________ frequency & hence a _________ wavelength
X-rays are identified by
Visible light tends to behave more like
X-ray photons tend to behave more like
The reduction in intesnsity that results from scattering and absorption
Transfer of energy from an electromagnetic field to matter.
Removal of x-rays from a beam via the photoelectric effect.
Return or re-entry of an x-ray
Passage of an x-ray beam through an anatomical part with no interaction with anatomical structures