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Physical Agents > EMR Lecture > Flashcards

EMR Lecture Flashcards

1
Q

What is EMR?

A

EMR= Electromagnetic Radiation
- composed of electric and magnetic fields that vary over time and are oriented perpendicular to each other
- radiation waves propagate without a medium
- all living organisms are exposed to natural and manufactured EMR
(Principle 1!)

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2
Q

What is the relationship between frequency and wavelength ? (Principle 2)

A

EMR is categorized according to its frequency and wavelength and travels through space at speed of light
- Velocity of light = frequency x wavelength
INVERSE RELATIONSHIP

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3
Q

Difference between non ionizing and ionizing?

A

Non ionizing = cannot break molecular bonds and therefore often used in medicinal applications (where PT sits)
Ionizing = can break molecular bonds and therefor can inhibit cell division and may be destructive in nature

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4
Q

What are thermal vs. Non thermal physiologic effects of EMR?

A

Thermal - same as superficial and deep heating agents
Non thermal - changes at cellular level by altering cell membrane function and permeability

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5
Q

What is definition of diathermy?

A

Literally means heat through
- use of electromagnetic energy with a frequency greater than 1 million cycles per second to generate heat and other physiological changes within tissues
- form of deep heat that can be pulsed or continuous.

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6
Q

Advantages of diathermy?

A
  1. Can heat deeper than superficial thermal agents
  2. Can heat larger areas than ultrasound
  3. There is a decreased risk of soft tissue burns
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7
Q

Application of diathermy is?

A

Shortwave or microwave electromagnetic energy to produce heat in tissues

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8
Q

Difference between shortwave diathermy and microwave diathermy?

A

SWD - waves are in a lower frequency range and much safer to use. Penetration is 3-5cm in depth.
- SWD is typically 27.12 MHz frequency and 11m wavelength
- SWD waves pass through the body with relative ease
MWD - more concentrated in one spot, used infrequently in USA

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9
Q

What mode is used for most diathermy applications?

A
  • pulsed
  • shortwave
    = Pulsed Shortwave Diathermy = PSWD
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10
Q

What are the parameters for PSWD?

A

Peak pulse power = 100-1000 Watts
Pulse Frequency = 1-1000 pulse/second
Pulse Duration = 40-400 microseconds
PWSD has non thermal and thermal effects but most of the time if you are using SWD you are going for the thermal results
If average power is set to less than 38 W then treatment should be non thermal but have to check with patient response and manufacturer!

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11
Q

What are the 2 methods of application for SWD?

A
  1. Inductive Method - most common used
  2. Capacitive Method
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12
Q

Describe the Inductive method of application for SWD?

A
  1. Patient placed within EM field
  2. Alternating current flows within the inductive coil/drum
  3. A magnetic field is produced within the conductive tissues perpendicular to the coil or drum inducing “eddy” currents.
  4. Eddy currents produce oscillating particles that increase tissue temperature due to the friction of oscillation
  5. Heats both deep and superficial structure — really good for heating muscle
    deep heating by conduction through muscle layers
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13
Q

What are the applicators for inductive SWD?

A

Coils — not really used in states
Hinge drums — most common. Typically hovering over the skin with some space between the drum and the skin or a small towel placed in between
More recently seen garments as well.

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14
Q

Describe the Capacitive method for SWD?

A
  1. Air spaced plates
  2. Patient is part of the electrical circuit with alternating current flowing from one plate to the other plate THRU the patient
  3. As current flows through the tissue, it causes oscillation of charged particles and thus an increase in tissue temp
    heat is more superficial than inductive coil or drum because the absorption rate of capacitive SWD is higher for adipose tissue than muscle
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15
Q

What are the thermal effects of diathermy?

A

same as superficial heat and US
- increased tissue temp
- increased nerve conduction velocity
- acceleration of enzymatic activity
- increased soft tissue extensibility

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16
Q

What are the non thermal effects of diathermy?

A
  • increased microvascular perfusion
  • altered cell membrane function
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17
Q

What are the clinical indications fro PSWD?

A
  • pain control
  • warm tissue prior to stretching for increased extensibility
  • non thermal —> edema control and wound healing
    Diathermy has been used on the following musculoskeletal conditions:
    muscle strains, contusions, ligament sprains, tendonitis, tenosynovitis,
    bursitis, joint contractures, myofascial trigger points, and OA.
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18
Q

Contraindications for PSWD?

A
  • metal implants or pacemakers
  • malignancy
  • pregnancy
  • eyes
  • testes
  • growing epiphysis
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19
Q

Precautions for PSWD?

A
  • electronic or magnetic equipment in vicinity
  • obesity — esp for capacitive method since it will be heating more superficial and thats where we have the fat tissue
  • copper bearing intrauterine contraceptive devices
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20
Q

What is the main disadvantage for diathermy?

A

COST

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21
Q

What is the dosage for PWSD?

A
  • Intensity: For thermal, gentle heat felt by patient
  • Duration: Usually 20 to 30 minutes (10 to 15 for subacute inflammatory conditions)
  • Frequency: Daily or twice daily for subacute conditions and less often for chronic conditions
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22
Q

What two heating methods will be getting down to MUSCLE really well?

A
  • Inductive coil for SWD
  • Ultrasound
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23
Q

What is laser light?

A
  • produced when an electron of an active medium undergoes a stimulated quantum jump from a higher to a lower energy state causing the emission of photons
  • the photons collide with one another causing a chain reaction that produces light with a frequency characteristic of the active medium.
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24
Q

What is laser light wavelengths?

A

Anywhere between 600 and 1300nm

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25
Q

What is relationship of wavelength and penetration?

A

THE LONGER THE WAVELENGTH THE GREATER THE PENETRATION !!!

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26
Q

What are the 3 things important about laser light? (Principle 3)

A

Laser light is
1. Monochromatic
2. Coherent - peak to peak distance of the waves is the same
3. Directional - when you focus a laser across the room the dot is going to stay really small and minima divergence

27
Q

Laser light impacts what on the body?

A

Chromophores — photo sensitive molecules in cells and molescules that are sensitive to light and undergo chemical reactions to cause changes

28
Q

How are lasers classified?

A
  • according to the nature of the material placed between the 2 reflecting surfaces
29
Q

What are the 2 popular lasers used in PT?

A
  • HeNE - Helium-Neon
    -GaAs- Gallium-Arsenide
30
Q

Describe HeNe…

A
  • Wavelength is 633nm
  • Emites red light
  • Delivered in a continuous wave
  • Stays pretty superficial so hitting the skin, mucosal membranes, wounds.
  • Direct effect: 2-5mm depth
  • Indirect effect: 8-10 nm depth
31
Q

Describe GaAs…

A
  • Wavelength 904 nm
  • Closer to infrared light so can’t see it
  • Delivered in a pulse mode
  • Gets to deeper structures so back, neck, shoulders, knees, hips, thigh
  • Direct effect: 1-2cm depth
  • Indirect effect: up to 5cm depth
32
Q

What is HILT?

A

High Intensity Laser Therapy
- considered a class 4 laser with power of >500mW
- mainly used in surgery
- generates heat and can destroy tissue
- NOT typically used in rehab however there has been new technology recently for PTs for thermal properities from HILT to treat MSK conditions at a power of 10-15mW

33
Q

What is LLLT?

A

Low Level Laser Therapy
- “cold lasers”
- Class 3 lasers with power of 5-500mW
- These DO NOT generate heat only non thermal effects
- Biostimulative and facilitate healing
- Common in PT
- Usually have an energy density of less than 35 J/cm2
-Causes photochemical effects rather than thermal

34
Q

What are the photochemical effects from LLLT?

A
  • Increased ATP
  • Increased RNA
  • Decrease in nociceptor activity
    all 3 aid in enhancement of tissue healing
35
Q

What is energy density equation?

A
  • Units = J/cm2
    Power (W) x Time (s) / Area of irradiation (cm2)
  • this is the total treatment dose. You can just plug it into the machine and the machine will spit out your time for the treatment.
36
Q

What is power density equation?

A
  • similar to US
  • This one you have to calculate time
  • Units = (W/cm2)
    Power (W) / Area of irradiation (cm2)
37
Q

What is the relationship between power and area of radiation?

A

Decreasing the area will increase the power density
Increasing the are will decrease the power density
Increasing the power will increase the power density
DIRECT relationship between power and power density
INDIRECT relationship between power density and area of irradiation

38
Q

What is the timing for treatment of lasers?

A
  • typically short but depends on the type of laser you are using and the condition you are treating
  • usually a few seconds to a few minutes
39
Q

What are the 3 ways for laser applications?

A
  1. Direct contact — thin film placed over the are and laser is right on the film
  2. Hovering/stationary — holding laser just above area you are working on typically 1cm away from skin
  3. Sweeping — gently back and forth but not actually touching the skin
40
Q

Laser precautions?

A
  • impaired sensation - for high intensity lasers
  • indirect eye exposure — patient and PT needs to wear goggles to minimize risk of retinal damage
  • skin color — tissue characteristics of darker skin may lead to greater laser energy absorption superficially and therefore produce heat
41
Q

Laser contraindications

A
  • Direct eye exposure
  • Preganncy
  • Active Malignancy
  • Active hemorrhage - laser will cause more vasodilation so more bleeding
  • Open growth plates
  • Endocrines system - specifically over the thyroid gland or anterior neck region due to increased circulation of hormone release.
42
Q

What is MIRE?

A

Monochromatic Infrared Radiation Energy
- Process of delivering photo energy directly to the skin via light emitting diodes.
- simulates the release of nitric oxide from hemoglobin which causes vasodilation and increased micro circulation
- this helps for cell receptors for growth factors and angiogenesis
- Finally augments collagen formation in healing wounds
really good for diabetic neuropathy, wounds, altered sensation

43
Q

Characteristics of MIRE

A
  • Similar wavelengths as laser
  • Most units at at a wavelength of 890 nm
  • Each rubber pad with the SLEDs have 60 little lights
  • Average power density of diode array over the MIRE pad = 9mW/cm2
  • Energy density of each pad = 43.2 J/cm2 per 30 minute treatments
  • need barrier between diodes and skin so often delivered in large pads
  • You will see burns from improper use and malfunction
44
Q

Dosage for MIRE?

A

30-40 minutes per treatment session 1-2x/day
For wounds 3-7 days for treatment

45
Q

Indications and contraindications for MIRE?

A

INDICATIONS
- Increase circulation for wound care
- Reducing pain
CONTRA
- cancerous lesions
- Active malignancy
- Pregnancy

46
Q

What is Ultraviolet light in therapy?

A

• DO NOT PRODUCE HEAT
• Most UV is absorbed within the first 1-2mm of skin
• Physiological effects by non thermal mechanism s
• Photochemical effect alters protein and enzyme production
• Histamine release results in dilation of superficial blood vessels
• End result — acute inflammatory response beings 8-10 hours following exposure
• UV rays A,B,C
◦ C does not make it past the ozone

47
Q

What are the types of UV rays?

A
  • UVA
  • UVB
  • UVC
48
Q

Describe UVA

A
  • Longest wavelength within UV portion of the spectrum at 320-400nm
  • Hypodermal penetration
  • associated with tanning booths and skin cancer
49
Q

Describe UVB

A
  • Lies in the middle of the UV spectrum with wavelength of 290-320 nm
  • Dermal penetration
  • Associated with sunburn and premature aging of skin
50
Q

Describe UVC

A
  • Shortest wavelength in UV spectrum ast 180-290 wavelengths
  • Epidermal penetration only
  • can kill bacteria and viruses
  • Provides least amount of pigment change
51
Q

What are the biophysical effects of UV?

A
  • Primary effect is production of an erythemal response
  • Thickening of pigment and epidermis
  • Vitamin D production is enhanced
52
Q

UV radiation is used for what effects?

A
  • Increase Vitamin D production
  • Stimulation of the skin
  • Sterilization
  • Tanning
  • Hyperplasia
  • Exfoliation (peeling)
53
Q

What are the common dermatological conditions that UVR is used for?

A
  • Psoriasis
  • Vitiligo — patchy loss of skin pigment that may be autoimmune
  • Acne
  • Hard to cure infectious skin conditions
54
Q

What are the common effects of erythema from UVR?

A
  • Redness of skin resulting from dilation of superficial blood vessels which is caused by release of histamines
  • Primarily produced in response to UVB
55
Q

What is the MED?

A

MINIMAL ERYTHEMAL DOSE
- patient’s vary in their degree of erythemal response so the MED needs to be determined FIRST before treating with UV light
- It is representative of the individual patient’s sensitivity to UVR
- SMALLEST DOSE PRODUCING ERYTHEMA WITHIN 8 HOURS AFTER EXPOSURE THAT DISAPPEARS WTIHIN 24 HOURS AFTER EXPOSURE

56
Q

What is suberythemal dose?

A

SED
- no change in skin redness after 24 hours following UV exposure

57
Q

What is First degree erythemal dose?

A

E1
- redness within 6 hours of exposure lasting up to 1-3 days.
- this dose is usually 2.5 times the MED

58
Q

What is Second degree erythemal dose?

A

E2
- intense erythema with edema
- Pigmentation appears within 2 hours or less after exposure and is like severe sunburn.
- Peeling of dead tissue is likely to occur
- This dose is usually 5 times the MED

59
Q

What is Third degree erythemal dose?

A

E3
- erythema with severe blistering, peeling, exudarían.
- this dose is usually 10 times the MED

60
Q

How do you determine the MED of UV for a patient?

A
  • cut four little squares and place on patient’s body — can be anterior forearm for example
    1. Set UV machine at specific distance and keep distance the same
    2. Cover 3 of the 4 squares and expose the UVR to the first square for 120 seconds
    3. Expose the second square for 60 seconds
    4. Expose the third square for 30 seconds
    5. Expose the fourth square for 30 seconds
    the final time exposed for each square is Square 1 at 240 seconds, square 2 at 120 seconds, square 3 at 60 seconds, square 4 at 30 seconds.
    6. Patient goes home and monitors the squares for when they see redness and how long it takes to go away
    7. THE AREA THAT SHOWS MILD REDDENING OF THE SKIN WITHIN 8 HOURS AFTER EXPOSURE THAT DISAPPEARS WITHIN 24 HOURS AFTER EXPOSURE WAS TREATED WITH THE MED.
61
Q

How do you increase dose for UVR?

A

2 ways — increase exposure time or decrease lamp distance
— Increase dose/exposure time by 25-35% per treatment/day to maintain MED
— If you move the lamp closer (to 50 cm), you need to decrease exposure time based on law of inverse square

62
Q

How do you increase dose for E1, E2, E3?

A

No dose of UVR should be repeated until the erythema from previous dose has disappeared.
E1 - increase dose by 50% every other day
E2 and E3 - increase does by 75% every 2 to 4 days
this progression is usually continued until exposure times reach 5 minutes, at which time and the distance between the UV lamp and patient is decreased to reduce treatment time.

63
Q

What has come out in the literature recently regarding UVR?

A

COVID
— can disinfect surfaces really well.

Physical Agents (3 decks)

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