*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
- Acne vulgaris
- Chronic wounds (UVC)
- Psoriasis (UVA or UVB with psoralan medication)
Indications for UV
- Photosensivity (condition, drug or food induced)
- Overdosed (UV) patient
- precancerous skin lesions
- Recent x-ray therapy
- No dose of UV radiation should be repeated until previous dose effects have disappeared
Precautions for UV
- irradiation of the eyes
- Acute pulmonary TB
- Skin Cancer
- Systemic Lupus erthematosus
- Fever
- Patients receiving radiation therapy
- Cardiac, liver or kidney disease
Contraindications for UV
no change in skin within 24 hrs with this dosage
SED (Sub-erythemal dose) (for UV)
is the smallest dose required to produce erythema that appears within 8 hours, but is gone or barely visible at the end of 24 hours
MED (dose for UV)
MED Exposure Testing
Erythrometer
- Pre-treatment Assessment
- Modality Used
- Body part treated; patient positioning
- Treatment parameters (dosage, duration)
- Tolerance/reaction to treatment
- Post-treatment assessment
Documentation for UV
Light Amplification by Stimulated Emission of Radiation
L.A.S.E.R.
Amplifying chamber or resonating cavity
Lasing medium: gas, liquid, crystal, chemical or semiconductor-each with a different wavelength. (placed in chamber)
External source of energy (electrical chemical or optical)
Pair of mirrors/one which is half-slivered which allows ½ the light to reflect and ½ to pass through.
needed to make laser radiation
Laser light wavelengths have _____________: all the waves emitted by individual gas molecules have the same wavelength.
temporal coherence
Laser light wavelengths also have ______________: all the waves travel in the same direction.
spatial coherence
Monophasic – wave of = energy & 1 phase
Monochromatic- 1 frequency/1 color
Coherent –logically ordered
nondivergent
Laser light
Pain Management -Used in areas of low skin impedance; trigger points or acupuncture points -Intervention Dosage ~1-3 J J/cm2 Wound Healing/Tissue Repair -Intervention Dosage ~0.5 J/cm
Primary Indications for laser use
eyes, pregnancy, malignancies, hemorrhage, within 4-6 mo. After radiotherapy, over thyroid or endocrine glands
Contraindicated for laser use
LB or abdomen during pregnancy, epiphyseal plates in kids, impaired sensation, impaired cognition, photophobia or sensitivity to light, pretreatment with one or more photosensitizers.
Precautions for laser use
Diathermy is heat transfer via…
conversion
Higher frequency, lower wavelength
Higher absorption and more superficial penetration
Higher risk of burning superficial tissues
Microwave Diathermy
Falls within the radio wave frequencies
Lower frequency, higher wavelength
Less absorption, deeper penetration
Short Wave Diathermy
a swirling current that is created when a metal plate is forced through a magnetic field. Causes the movement of molecules which in turn creates heat.
This takes a while, therefore diathermy treatments are fairly long.
Eddy currents
means the energy source is interrupted on a regular basis, allowing for tissue cooling periods.
Pulse rate, pulse duration and intensity are all inter-related.
*Higher pulse length (width/duration) generates more energy to tissues (higher wattage output intensities)
*Higher pulse rates (more frequent sets of pulses, less “off” time) generate more energy to tissues (higher wattage output intensities)
Preset options on machine will calibrate accordingly. Decide whether you want high or low energy output and set pulses to desired amount. SEE DRAPER PG. 289
PULSED shortwave diathermy (PSWD)
Indicated for acute trauma, inflammation. Purpose is to reduce edema and repair cells.
Nonthermal (application of PSWD)
Indicated for subacute inflammation. Used to get nonthermal benefits with some thermal benefits.
Mild thermal (application of PSWD)
Indicated for pain, muscle spasm, chronic inflammation.
Moderate thermal (application of PSWD)
Indicated for stretching, elongating tissues.
Vigorous thermal (application of PSWD)
Pacemakers Implanted electrical devices Pregnancy Cancer Metal implants Over eyes, testes, growth plates Systemic fever Infection Joint Effusion Protruded nucleus pulposus
Contraindications to all Diathermy
