Short Wave Diathermy SWD Flashcards
What does diathermy mean
Dia= through
Thermy = heat
What does short wave refer to
Shortwave electromagnetic band of the electromagnetic spectrum
What are two types of diathermy
Short wave
Microwave
Radiofrequency range of short wave
10-100 MHz
True or False
The SWD device itself does not generate heat
True
Heat results when electromagnetic waves come in contact with the body/tissues, causing a resistance that leads to movement of molecules; and thus heat is generated
Difference between SWD and US
SWD is DEEP
SWD covers large areas
Define short wave diathermy SWD
use of NON-ionizing high frequency electromagnetic energy to heat deep and large areas
(Ionizing energy is illegal and harmful, so make sure you know it’s NON-ionizing)
SWD has two modes of application
Continuous CSWD
Pulsed PSWD
What does PEME stand for
Pulsed electromagnetic energy
What does PEMET stand for
Pulsed electromagnetic energy treatment
What does PEMF stand for
Pulsed electromagnetic field
Electromagnetic spectrum is characterized based on 3 things
- frequency
- wavelength
- energy per photon
What is the relationship between frequency and wavelength
Inversely proportional
(As F increases = W decreases)
What is the relationship between frequency and energy per photon ?
Directly proportional
(As energy per photon increases = frequency increases)
What is electromagnetic wave ?
The interaction between an electric and magnetic fields
Energy in 1 photon is = ?
1 eV (electron volt)
Compare eV per photon found in diagnostic x-rays and SWD
eV per photon in diagnostic X-ray is GREATER than that found in SWD
(Which means SWD is not harmful)
Describe the wavelength and frequency of short wave
Long wavelength
Low frequency
Which part of the electromagnetic spectrum does shortwave sit within
Radio wave band
Read this and acknowledge
👍🏻
Read this
👍🏻
SWD uses _______________ to produce heat deep inside the targeted tissue
Electric current
How deep can SWD reach
Two inches deep (5 cm)
( just interesting fact: some studies have shows it may even reach 6-8 cm)
True or false
The diathermy applies heat DIRECTLY to the body
False
The current from the machine allows the body to generate heat from within the target tissue
Benefits of the heat that results from SWD
Promotes blood flow
Increases cell metabolism
Improve flexibility in stiff joints and connective tissue
Explain the principle of diathermy
Before the injury , tissue molecules are arranged based on POLARITY
(- - - + + +)
When tissue damage occurs, the distribution becomes IRREGULAR and deviates form polarity-based arrangements
(- + - - + + -)
Under the influence of an electric field (SWD), the molecules rotate according to the polarity of their charge, restoring previous stage of polarity
( - - - + + +)
What are some challenges of SWD
- A fatty subcutaneous layer can act as a barrier, preventing the direct delivery of heat to the deeper layers of tissue.
(So it doesn’t work on obese people and it may even burn them as fat has relatively good specific heat capacity)
- Short waves do not have excitatory effect on nerve and muscle
(This is because the voltage fees of SWD is less than 1/50 of μs while the nerve needs at least 0.1 ms to be stimulated; so there is not enough time for altering ionic balance across the membrane and muscle or nerve)
What is the method of heat transfer for SWD
Converting electromagnetic energy into thermal energy
The heat produced by SWD depends on two things:
- Water content in treated area
- Machine parameters
What mode of heat transfer is seen in SWD
Radiation
Why is edema a MAJOR contraindication for SWD
Due to its high water content
(Water has High specific heat capacity and high conductivity so there is a huge risk of burning the patient)
Why should there be a piece of fabric layer (i,e towel) between skin and electrodes
To prevent burn as the patient may sweat (water)
Read
👍🏻
We have two types of short wave diathermy : CSWD and PSWD.
Which is used for chronic and which for acute?
CSWD = chronic
PSWD = acute
How many fields does the SWD produce ? What are they?
Two
Electric (E) and magnetic (H) field
The ratio between electric and magnetic field (E:H) depends on what
Type of electrodes and manufacturing characteristics
Just in case we need to know this, read.
👍🏻
Two shapes of SWD devices and they are :
Cabinet device
Portable device
What are the different types of electrodes (hint: 5)
Important points when using pad electrodes
- made out of rubber
- uniform contact is needed
- several layers of toweling is needed
- distance between the electrodes should be at least the diameter of one pad
Which type of electrodes is this
Pad electrodes
What type of electrodes is this
Space electrodes
Where can space electrodes be applied
Almost all parts of the body
Application of space electrodes can be done in two ways :
- placed on either side of treated part (contraplanar)
- placed on the same side ( coplanar )
What type of electrode is this
Drum electrode
Properties of drum electrode
- does NOT follow skin contour
- penetrate up to 3-5 cm
- heat is generated in tissues of high conductivity such as blood and muscle
What type of electrode is this
Diplode electrode
Properties of diplode electrodes
- consists of flat coil electrode encased in Perspex cover with two wings
What type of electrode is this
Coil or cable electrode
Properties of coil or cable electrode
- consists of wire with plugs at either end , creating a magnetic field
- wrapped around the treated part with 5-10 cm between each turn OR in pancake shape
- Fat does NOT provide resistance = heats up deeper tissues
- towel must be placed (this is the case for all electrodes)
Factors that influence field distribution in SWD
Electrode spacing
Electrode size
Electrode positioning
Metal
Air cavities
Why is more heated required for air cavities (air sinuses) ?
Because the heat isn’t being absorbed by the air
Why is electrode spacing needed ?
- To allow lines of force in the electrostatic field to diverge before entering the tissue
- prevents concentration of heat in the superficial tissues and ensures more heating through the treated part
What provides spacing for electrodes
Provided by:
- flat felt spacers
- towels
- space palates
- air (when using space electrodes)
With space electrodes, spacing should be between
2-4 cm
Closer spacing leads to
Concentrate of the field = excessive heating and burn
Wide spacing (not more than 4 cm) leads to
Uniform heating
Regarding electrode placement, distance between electrodes should be …….?
At least equal to the diameter of the LARGEST electrode
True or false
Distance between the electrodes should be at least equal to the diameter of the smallest electrode
False
Largest
Electrode size : what happens if electrodes are smaller than the diameter of the part treated ?
Superficial heat
Electrode size: what happens if the electrodes are much larger than the diameter of the part treated ?
Line of force will travel in the air and will be lost = waste of energy
What should the size of the electrode being compared to the treated area ?
Electrodes should be SLIGHTLY LARGER than part treated
Uneven sized electrodes leads to ?
Field concentration under the SMALL electrode
What happens if electrodes are close to the body
More heat 
What happens if electrode is small
Less heat
What happens if we have normal spacing between electrodes ?
Even field distribution
What happens if we increase the spacing between electrodes
Deep field concentration
Heat developed depends on …………
Tissue conductivity
Tissue with high conductivity can absorb high energy levels and dissipated heat efficiently
Examples of tissue with high conductivity
Muscle
Blood
Why is it pointless for the treatment to exceed 20 minutes ?
Because tissue with high conductivity will absorb high energy levels and DISSIPATE heat efficiently
So as it absorbs heat, the absorption will plateau within 15-20 minutes into the treatment and then the heat will decrease as it dissipates after 20 minutes so no point in prolonging the treatment duration
Arrangement of electrodes could be :
What method of application is this
Co-planer
What method of application is this
Contra-planer
What method of application is this
Longitudinal
What method of application is this
Cross fire
What is the cross fire technique used for
Air cavities such as in case of SINUSITIS
Which method of application can be used for sinusitis
Cross fire
Electrode positioning: electrodes need to be ______________ to the skin
Parallel
The distance between the electrodes in coplanar arrangement needs to be …………………
Greater than the combined skin-electrode distance
What happens in the case of uneven spacing between coplanar electrodes ?
Concentrates the field near the closer electrode
Which provides superficial or deep heating ? Coplanar or contraplaner?
Coplanar : superficial
Contraplaner : deeper than coplaner
Which is co-planer vs contra-planer
A.. Electrodes placed on either side of the treated area
B. Concentrating on one side of the body
A. Contra-planer
B. Co-planer
How to increase the depth of penetration using coplanar arrangement
Increasing the spacing between electrodes 
In Contra-planer arrangement, how far should the electrodes be away from the treated area
2 to 4 cm
What are the two types of applicators
Capacitive applicators
Inductive applicators
What are capacitive applicators made of
Rubber or metallic material
What are inductive applicators made of
One or more flat spiral copper coils mounted and hidden in rigid hard plastic casing
Capacitance and inductance can be administered using which mode of application (continuous or pulsed)?
BOTH can be administered in continuous or pulsed mode
Capacitance has high proportion of which field ?
Electrical field
(Electrical field > magnetic field)
With capacitance , the part treated is ______________ of a circuit
a part
In capacitance, heat is generated in what type of tissues ?
Provide examples of these tissues
- low conductivity
- high resistance
Examples: fat, ligaments, tendons, cartilage
Electrodes used in capacitance
2 flexible pads
2 space plates
1 flexible pad + 1 space plate
1 diplode
Type of heating in capacitance
Superficial heating
Capacitance is recommended for treating areas with
LOW subcutaneous fat
Mode of heat transfer using capacitor method
Conduction
Tissues of __________ electric content are good conductors , such as tissue with high ___________ content.
High
Water
Inductance has high proportion of which field ?
Magnetic field
With inductance , the part treated is ______________ of a circuit
NOT a part
In inductance, heat is generated as ______________
Eddy current
Type of heating using inductance
Deep heating (deeper than capacitance)
NOTE: most of the heating occur in muscle but not in fat layer
Which method provides deeper heating ; inductance or capacitance
Inductance
In inductance, heat is generated in what type of tissue ?
Provide example of these tissues
- high conductivity
Examples: blood, muscle, sweat
What electrodes are used in inductance
Drum electrode
Cables (coils)
Inductance is recommended for treating __________ structures
Deep
While using inductance, area treated must be _________.
DRY
(Wet will cause burn)
Indications of continuous SWD
Chronic musculoskeletal disorders
Chronic inflammatory conditions
Infective conditions
Pain
(Know examples)
What are the general contraindications of SWD
(Hint: 9)
Impaired sensation
Cardiac pacemaker (any implanted devices)
Metal implants
Pregnancy (therapist or patient)
Malignancy (cancer)
Uncontrolled blood pressure (hypertension or hypertension)
Obese patients
Transthoracic application
Fever
(Hint: OPTIMUM F )
What are the local contraindications of SWD
Impaired thermal sensation
Peripheral vascular disorder
Menstruating uterus (when treating back, abdomen, pelvis)
Skeletal immaturity
Over the eye
Acute hemorrhage (around treated area)
Over external metallic objects
(Hint: I SAMPOO)
What are the therapeutic parameters with pulsed SWD
Pulse width ( μs)
Pulse frequency (Hz or pps)
Power ( Watt )
Production of pulsed PSWD
(Some numbers idk if we have to know)
Short wave frequency : 27.12 MHz
Output frequencies: 15 - 200 Hz
Power: up to 1000W
The mean power of PSWD is affected by two things :
Parameters
Treatment time
Pulsed SWD is thought to nonthermal (athermal).
When is this true?
When LOW pulse width and LOW pulse frequency is used (=LOW power)
True or false
Pulsed SWD can produce thermal and nonthermal effects depending on parameters?
True
Indications of pulsed SWD
(Hint: 6)
Physiological effects
Therapeutic effects of SWD
(Hint: 7)
Duration of treatment for SWD (continuous)
15 to 20 minutes
How long do we have to wait when increasing the intensity before moving to another setting and why
2 to 3 minutes
To allow the temperature to build up in the tissue
Longer duration of SWD treatment may result in
Reflex vasoconstriction which is seen clearly in toes and fingers
Frequency of SWD treatment
Daily or every other day based on patient response
Duration of treatment and dosage with pulsed SWD
Dosage and duration time for pulsed SWD in acute conditions
Mean power; less than 3W
Duration: 10 minutes 
Dosage and duration time for pulsed SWD in subacute conditions
Mean power: 2 to 5 W
Duration: 10 to 15 minutes
Dosage and duration time for pulsed SWD in chronic conditions
Mean power: more than 5 W
Duration: 15 to 20 minutes
Expected feeling/sensation with continuous SWD
Mild comfortable warmth
Expected feeling/sensation with pulsed SWD
Nothing or mild comfortable warmth if higher intensities are being used
Treatment considerations
Advantages of SWD
Deep penetration
Covers large body areas
Can heat deep tissue without heating superficial tissues
Allows time to attend another patient
Used when patient cannot tolerate the weight of hot pack
What to document for SWD
Safety considerations for SWD
