*4.PTA 200-Light Physical Agents Flashcards
basic unit of radiant energy
Photon
These have specific properties
Waves
The _________ of the wave is the amount of energy carried by the wave (intensity)
Amplitude
is the distance from a peak of one wave to the identical peak of the next wave. Wavelengths are measured in nanometers (nm =10-9m)
Wavelength
The ________ of the energy is measured by the number of cycles each second (Hertz = Hz)
Frequency
As wavelength increases, frequency decreases
As wavelength decreases, frequency increases
Higher frequency – Higher _________
Absorption
Higher frequency, shorter wave length=
light has a tendency to be absorbed at a more superficial level than light of longer wavelengths.
the angle of incidence (the direction of the light source in relation to the targeted tissue)
Cosine Law
a form of dry, superficial heat
Infrared (IR)
A repeated dosing of infrared may cause a mottled pigmentation called…
erythema ab igne
- Heat applied without touching
- Tissues easily observed
Advantages of Infrared
- Can’t treat small localized areas
- Must have accurate patient positioning
- Not as effective for pain control as moist heat
Disadvantages of Infrared
- Draper states, “None due to ease of burning the patient”
- Subacute and chronic traumatic and inflammatory conditions
- Painful conditions
- Circulatory disturbances
- Superficial skin infections
Indications for Infrared
Same as for therapeutic heating
-Unreliable judges (decreased cognition) and/or decreased sensation
Contraindications and Precautions for Infrared
a high frequency radiant energy used to create an sub-erythemal or erythemal response via photochemical reaction
Ultraviolet