Midterms | Unit 3.1 EM Spectrum Flashcards
A continuum of electromagnetic energy
Electromagnetic Spectrum
Energy of Electromagnetic Spectrum
10^(-12) — 10^(10) eV
Frequency of Electromagnetic Spectrum
10^(2) — 10^(24) Hz
Wavelength of Electromagnetic Spectrum
10^(7) — 10^(-16) m
Properties of radiofrequency
Range: 0.3 kHz — 300 GHz
Range in M.R.I.: 1—100 mHz
Low energy & long wavelength
Properties of microwaves
Very-short wavelength R.F.
Higher than broadcast R.F.
Lower than infrared
Measured in centimeter
Interacts with hotdogs & hamburgers
Properties of infrared
Longer λ than visible light
Shorter λ than microwaves
It heats any substance on which it shines (radiant heat)
Properties of visible light
o Occupies the smallest segment of the EM spectrum
o Described in terms of wavelength
o Behaves like a wave
o Measured in nanometer
o Interacts with rods & cones of the eye
o Range: 400 nm (violet) to 700 nm (red)
Properties of ultraviolet
o Wave of moving molecules
o Requires matter
o Cannot exist in a vacuum
o U.V. Light is an example
o Causes sunburn
o Lies between visible light & ionizing radiation
o Interacts with molecules
- “Diagnostic ultrasound is not part of the electromagnetic spectrum”
Properties of x-ray
o Used in medical imaging, radiation therapy, airport security scanners, and material characterization.
o Emitted from the electron cloud
o Produced in diagnostic imaging systems
o Interacts with electrons
o Behave as though they are particles
Properties of gamma
o Produced by the decay from high energy states of atomic nuclei
o Comes from inside the nucleus of a radioactive atom
o Emitted spontaneously from radioactive material
o Sources: gamma decay from naturally occurring radioisotopes, secondary
radiation from atmosphere interactions with cosmic ray particles; lightning strikes and gamma-ray flashes
3 Regions Important to Radiologic Science
o Visible Light Region
o X-Ray Region
o Radiofrequency Region
o Others
▪ U.V. light, infrared light, & microwave radiation
Viewing condition of radiographic & fluoroscopic images are critical to diagnosis
Visible Light Region
Fundamental to producing a high-quality radiograph, mammographic images, C.T. Scan images, D.S.A. & IVR images, and Fluoroscopic images
X-Ray Region
With the introduction of M.R.I., become more important in medical imaging
Radiofrequency Region
The only difference between x-rays & gamma rays is their —
origin
Visible light is identified by (1),
R.F. is identified by (2), & x-rays are identified by (3)
- wavelength
- frequency
- energy
EM energy is directly propertional to (1) and inversely proportional to (2)
- Frequency
- Wavelength
Occupies the smallest segment of the electromagnetic spectrum
Visible Light
It cannot exist in a vacuum
Ultraviolet
Wave of moving molecules
Ultraviolet
Lies between visible light & ionizing radiation
Ultraviolet
Where are x-rays used?
medical imaging
radiation therapy
airport security scanners
material characterization
It is emitted from the electron cloud
X-rays
It is produced in diagnostic imaging systems
X-rays
It is produced by the decay from high energy states of atomic nuclei
Gamma
It comes from inside the nucleus of a radioactive atom
Gamma
It is emitted spontaneously from radioactive material
Gamma
Sources of gamma
- gamma decay from naturally occurring radioisotopes
- secondary radiation from atmosphere interactions with cosmic ray particles
- lightning strikes and gamma-ray flashes
Arrange EM spectrum in increasing frequency and decreasing wavelength
RF
Microwaves
Infrared
Visible light
UV
X-rays
Gamma rays
