Diathermy Flashcards
Speed of Light
3x10^8
Wavelength, Frequency, Relationship
The longer the wavelength, the lower the frequency and energy
Non-ionizing
Radio
Microwave
Infrared
Visible
Ultraviolet
< or equal to 10 eV
Ionizing
Ultraviolet
X-Ray
Gamma Rays
> or equal to 10 eV
Optimum radiation occurs when the source is
perpendicular to the center of the surface to be radiated.
LAMBERT’S COSINE LAW / RIGHT
ANGLE LAW
Use the head perpendicularly
LAMBERT’S COSINE LAW / RIGHT
ANGLE LAW
Intensity of radiation is inversely proportional to the distance squared.
I = 1/d^2
INVERSE SQUARE LAW
Appropriate distance of the machine for treatment
INVERSE SQUARE LAW
Waves must be absorbed to be beneficial (induce chemical processes).
LAW OF GROTHUS-DRAPER / DRAPER
LAW / PRINCIPLE OF CHEMICAL
ACTIVATION
Ensure proper absorption of radiation
LAW OF GROTHUS-DRAPER / DRAPER
LAW / PRINCIPLE OF CHEMICAL
ACTIVATION
There is an optimal amount of energy absorption
per unit time for beneficial results to be expected.
ARNDT-SCHULTZ PRINCIPLE
Dosage determination (Intensity = warmth)
ARNDT-SCHULTZ PRINCIPLE
Intensity and duration of the dose of radiant energy
is inversely proportional.
BUNSEN-ROSCOE LAW OF
RECIPROCITY
Adjustment of parameters in treatment
BUNSEN-ROSCOE LAW OF
RECIPROCITY
“to heat through” or “through heating
dia & thermia
Diathermy first used in __ by __
1892, Jacques Arsene d’Arsonval
application of _____ electromagnetic
energy to produce heat and
other physiological changes
within tissues.
Shortwave & microwave
Wavelength LWD
300-30m
LWD Penetration Depth
Deep
LWD Therapeutic Use
No longer used
SWD Wavelength
200-3 m
SWD Frequency
1.8-30 MHz
SWD Frequency Bands
13.56 MHz (22 m)
27.12 MHz (11 m)–
40.68 MHz (7.5 m)
SWD Penetration Depth
Deeper
SWD Therapeutic Use
For rehabilitation
MWD Wavelength
(1m – 1mm)
MWD Frequency
300 MHz – 300 GHz
MWD Frequency Bands
433.9 MHz (69 cm)
915 MHz (33 cm)
2,450 MHz (12 cm)
MWD Penetration Depth
Deepest
MWD Therapeutic Use
For rehabilitation
Factors of Tissue Absorption
Amount of energy
* Tissue type
Not reflected by bones & do
not concentrate on
periosteum (no periosteal
burning or pain)
SW Diathermy
Heats larger areas
SW Diathermy
Some energy is being
absorbed directly by
the fatty tissues
MWD
Some energy is being
reflected to the fatty
tissue at fat-muscle
interface
MWD
Thermal Effects of Diathermy
▪ Pain control
▪ Accelerated tissue healing
▪ inc blood flow (vasodilation)
▪ inc metabolism
▪ dec joint stiffness
▪ inc collagen extensibility
▪ Muscle relaxation
▪ In conjunction with
stretching to inc ROM
Achieved when using
continuous mode
Non Thermal Effects of Diathermy
inc microvascular perfusion
▪ Modulates cell growth &
division
▪ Accelerates process, if slow
▪ Inhibits process, if fast
▪ Accelerates Ca^2+ binding to
calmodulin
▪ inc rate of phagocytosis (SWD)
▪ inc ATP activity
Achieved when using both
modes
Made of metal encased in plastic housing or
transmissive carbon rubber electrodes
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
- Heating by electrical field method
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Techniques of Application:
Contra-planar / Transverse
Positioning
Co-planar Positioning
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Plates in series on each side
of body part
Contra-planar / Transverse
Positioning
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Plates in parallel on same
body surface
Co-planar Positioning
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Types of Electrodes/Condenser:
Plates:
Capacitor / Condenser Electrodes
Pads:
Flexible / Condenser Pads
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Distance between condenser & skin
1-3 inches (2-10 cm)
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Most heating
occurs on tissues
with
highest
conductivity
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Produces more
heat on
superficial tissues
CAPACITIVE PLATES / ELECTRIC FIELD METHOD
Do not penetrate as effectively to deeper tissues if less
conductive tissues
Muscle
0.7-0.9
Kidney
0.83
Liver
0.48-0.54
Brain
0.46
Fat
0.04-0.06
Bone
0.01
Made up of a coil where AC flows
INDUCTIVE COILS / MAGNETIC FIELD METHOD
INDUCTIVE COILS / MAGNETIC FIELD METHOD
- AC produces magnetic
field → induces
electrical Eddy
currents in tissues →
oscillation of charged
particles → friction →
generates heat
INDUCTIVE COILS / MAGNETIC FIELD METHOD
Types of Electrodes/Condenser:
Drums:
❑ Diplode
❑ Monode
❑ Sleeves with
cables:
❑ Circumferential
effects on limbs
Heats tissues
closest to the
applicator
INDUCTIVE COILS / MAGNETIC FIELD METHOD
Most heating
occurs on tissues
with highest
conductivity
INDUCTIVE COILS / MAGNETIC FIELD METHOD
Distance
* Slight air gap
INDUCTIVE COILS / MAGNETIC FIELD METHOD
SHORTWAVE DIATHERMY (in general)
* Factors affecting field distribution:
Spacing: closer distance to tissue → more superficial
* Electrode size: smaller → more superficial
For Non-thermal Effect…
Pulsed SWD (PSWD) / Pulsed Electromagnetic Fields (PEMF) / Pulsed Electromagnetic Energy (PEME)
* With “on” and “off” cycles
- Produces high-frequency AC
in an antenna →
electromagnetic field - Used for smaller, defined
areas
MAGNETRON (CONDENSER)
Most heating
occurs on tissues
with highest
conductivity;
however, it
penetrates less
deeply than SWD.
MAGNETRON (CONDENSER)
- Distance
- Few inches
MAGNETRON (CONDENSER)
Magnetron Tissue Heating
Shallow depth of
penetration
Direct Absorption by
the fatty tissues
Reflection at tissue
interfaces
Inductive coil
Fat Muscle Bone
Minimum, Maximum, None
Capacitive Plate
Fat Muscle Bone
Maximum, Moderate, Low
Magnetron
Fat Muscle Bone
Maximum, Maximum, None
Ultrasound
Fat Muscle Bone
Slight, Maximum, None
Acute injuries (sprains, strains,
etc.)
Dose I Non-thermal
Subacute injuries
Dose II Mild heat sensation
Pain, muscle spasm, chronic
inflammation
Dose III Moderate heat
sensation
(comfortable)
Increase blood flow, heating of
collagen fibers for stretching of
soft tissues
Commonly used intensity: mild, comfortable,
Dose IV Vigorous heating
Indications for Diathermy
Thermal
▪ Pain control
▪ Accelerates tissue healing
▪ Decreases jointstiffness
▪ Increase soft tissue
extensibility
Indications for Diathermy
NonThermal
▪ Pain and Edema Control
▪ Soft tissues healing
▪ Nerve and bone healing on
animal studies*
Contraindications for Diathermy
▪ Pacemakers or electronic-implants
▪ Metal implants
▪ Malignancies
▪ Thrombophlebitis
▪ Over abdomen, low back or pelvis of pregnant women
Contraindications Specific for thermal
▪ Over the eyes or testes
▪ Over growing epiphyses of
children
▪ Hemorrhage
▪ Contact lenses
Contraindications Specific for Non thermal
Deep tissues (internal
organs)
Precautions
- External electronic medical devices nearby (EKG,
EEG, TENS, & computer-controlled devices) = 3-5 m
(10-16 ft) away from active diathermy devices - Copper-bearing intrauterine contraceptive devices
- Obesity (Capacitive SWD & MWD)
- Impaired sensation or circulation
- Decreased consciousness
- Over moist clothes or accumulated sweats
- Atrophic, infected or damaged skin
- Over growing epiphyses of children (PSWD)
- Excessive exposure of PT to radiation
- 1-2 m (Continuous SWD); 0.5-1 m (PSWD)
Adverse Effect
Burns
* Blistering
Documentation
- Continuous SWD or MWD x model/Machine x
< distance > x < treatment area >x position x 20
min to < rationale > - Pulsed distance > x < treatment area >x position
x 20 min to < rationale >
