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Shortwave
Definition
Shortwave means the application of high
frequency electrical energy to the body
tissues in order to bring physiological and
therapeutic effects, these effects can be
achieved by thermal or non thermal
effect.
 Shortwave is one of the diathermy family.
 Other modalities that can also heat the tissues
are microwave and ultra sound.
 Shortwave, microwave and ultrasound can
heat the tissues up to a very deep layer.
 The electromagnetic spectrum has a wild
range of shortwave.
Shortwave Has Three Main
Frequencies:
 27.12 MHz, wavelength 11 M (most common
used one).
 13.56 MHz wavelength 22 M.
 40.68 MHz 7.5 M.
Shortwave Diathermy Machine
 Picture is on page 279 of Low and Reed book.
 First we have the power supply.
 Inside the machine there is a high frequency
generator + an amplifier + oscillator coil + resonator
coil + variable capacitor.
 Outside the machine we have two electrodes + the
part being treated
There Are Two Circuits
Here:
1) Machine circuit : composed of a high
frequency generator, amplifier, oscillator
coil.
2) Patient circuit: composed of a resonator
coil, variable capacitor, electrodes and the
treated tissue.
 Shortwave produces both electric and
magnetic fields.
The amount of electric field to magnetic
field is dependent on:
1) The characteristic of the machine itself
(dependent on the manufacturer).
2) The type of electrodes that we use.
Shortwave Can Be Used in Two
Modes:
1)
Continuous (energy is emitted all the time).
2)
Pulsed (energy is emitted part of the time).
When using the pulsed shortwave, there are certain
parameters that we need to know:

Pulse width: measured by micro seconds.

Pulse frequency: how many pulses we have per second
measured by Hz or pulses per second (PPS)
 Peak power output: usually is a set value that is determined by
the manufacturer.
 Mean power output: is variable and is determined by factors
such as the pulse width and the pulse frequency.
How could we produce energy into
the body without causing heat
production?
 The off time with pulsed shortwave is longer than the
on time which allows the dissipation of heat.
 The interpulse period gives time for the heat to
dissipate.
 If the interpulse is short heat will develop, because
there is no time for the effect to dissipate within the
body.
 Continuous shortwave is always thermal.
 Pulsed shortwave can be thermal or non thermal.
 High parameters usually gives thermal effect.
 If we use long pulse duration, high pulse frequency,
heat will develop.
 The mean power is affected by the parameters chosen
and the time of treatment.
 Pulsed shortwave can only be non thermal if
short pulses, low pulse repetition rate and
short treatment duration is being used.
Wrong Terminologies Used For
Pulsed Shortwave
1) Pulsed electromagnetic energy (PEME)
2) Pulsed electromagnetic energy treatment
(PEMET)
3) Pulsed electromagnetic field (PEMF)
4) Pulsed electromagnetic therapy (PEMT)
Do Not Use Them!
 Recent attention has been paid to the
shortwave in the last 5-7 years.
 More studies has been one to establish its
efficiency.
 Equipments now are safer than before.
 User friendly.
Advantages of Shortwave
 The deep penetration, it goes deep to 5cm.
 You can use it while attending to another
patient, which allows you to manage your time
in the clinic.
 It covers large areas.
 It can heat the deeper tissue without heating
the superficial tissue
 It can be used with sensitive tissues because it
doesn’t need to be in contact with the treated
tissue.
Types of Electrodes:
1)
2)
3)
4)
5)
6)
Flexible plates
Space electrode
Monode
Minod
Diplode
Coil
Minode and monode are called “drums”
Shortwave Can Be Applied In Two
Ways:
1) Capacitance (the electric field is more than the
magnetic field) :
Can be achieved by using two space plates together,
or one space plate and a flexible ,or diplodes.
2) Inductance (the magnetic field is more than the
electric field) :
Can be achieved by using the coil or the drums.
Effects of Shortwave on The
Molecules and Ions of Tissues:
 If it is charged  there will be vibration.
 If it is dipole  it will rotate.
 If it is not charged  it won’t be affected.
Air Space Electrodes
 They come in different sizes.
 Can be used in almost every part of the body, but
because they are rigid they will not fit every contour.
 It can be put on either side of the limb, or can be
used in the same side.
 If the electrodes are placed on the same side there
should be a distance between the electrodes, because
if there is no distance there would be a shock, so we
need to put a distance equal the diameter of the
electrode.
 Skin-electrode distance: is the distance
between the electrode and the skin.
 If we place to electrodes at the same distance
there will be even heating.
 If we placed one electrode closer to the skin
than the other, the heating won’t be even, it
will be more near the closer electrode.
 If we used a large electrode and a small one
the heating will be more near the small.
Flexible Electrodes
 When using them you should insure it is in full
contact.
 We have to rap it in towel that is 2 cm thick, less than
that could cause a burn, more than that will affect the
amount of heating created in the body.
 Distance between the electrodes should be equal the
diameter of the electrode, if it is less than that there
will be a shock.
Coil
 Usually used for limbs
 Used in two ways:
1) wrapped around the part being treated.
2) Pancake (usually used on the back).
 When wrapping, the space between one turn and the
other should be 5 to 10cm and it is insure by felt
spacers (comes from the manufacturer).
 It is known to heat the deeper tissue without heating
the superficial tissue.
Drum Electrodes
 It is known to heat the deeper tissue without heating
the superficial tissue.
 Penetration to 3cm.
 Make sure that the fat layer of the patient is not more
than 2cm, because the penetration will be limited and
the absorption of heat will accumulate in the fat layer
which might cause a burn.
 The tissues that are heated are blood vessels, muscles
and sweat.
Methods of Applying The Electrodes
1) Contraplanar electrodes are placed on opposite sides of the
part, to treat deeply placed structures.
2) Coplanar: electrodes are placed on the same side of the part to
treat more superficial structures.
3) Cross-fire: half the treatment is given with the electrodes in a
diagonal way, the other half of the treatment is put on the
opposite way. This method is usually used for sinuses and
body cavities such as the uterus.
4) Longitudinal: one flexible electrode is used with a space
electrode.
Factors Influencing The Field
 Spacing between the electrodes.
 Electrode size.
 The technique applied.
 Metal (If the patient has a metal implants, or if
the bed is metal).
Spacing The Electrodes
 When using flexible electrodes a 2cm thick towel
ensures the spacing between the electrode and the
body part.
 When using coil electrode “felt spacers” ensures the
distance between the turns.
 When using space electrodes the space between the
electrode and the body part is 2-2.5cm.
The Size
 If electrodes are smaller than the diameter of the part
treated there will be superficial heating.
 If the electrode is larger than the part being treated
there will be wasted energy.
 When using unequal electrodes size concentrates the
field on the small electrode side.
Spacing more than 2.5cm should be used on the
side where no concentration of the field is
required.
When Choosing The Size of
Electrode We Should Consider:
1)
2)
3)
4)
5)
The size of the area treated.
Location of the area to be treated.
The depth of the targeting tissue.
Treatment goals.
The contraindications.
Modes of Heat Transfer In
Shortwave
1) Conduction (with the capacitance)
2) Conversion (with the inductance)
Heat production depends on the amount of
resistance present inside the tissue.
Physiological Effects of Shortwave
(Thermal)
 Increase of tissue temperature by 1 degree 
increase metabolism (good for healing).
 Increase of tissue temperature by 2-3
degrees effective for pain and muscle
spasm.
 Increase of tissue temperature by 3-4
degrees good for tissue extensibility (when
we need to do stretching).
Patient’s Feeling
 Continuous (Thermal) shortwave  Tell the
patient that they will feel mild gentle warmth.
 Pulsed, Non thermal shortwave  the patient
will feel nothing.
 Pulsed, Thermal shortwave  Tell the patient
that they will feel mild gentle warmth.
Important Rule
 Chronic cases  you can treat it with thermal
or non thermal shortwave.
 Acute  only use non thermal shortwave
Contraindications
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Metal implants
Pregnancy
During menses
Cardiac pacemaker
Radiation therapy
Malignant tissue
After analgesic therapy
Blood pressure
abnormalities
 Vascular diseases
 Hemorrhage
 Fever
 Inflammation
 Wet dressing
 Tuberculoses
 Impaired thermal
sensation
Indications
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Sprain
Strain
Muscle and tendon tear
Capsule lesion
Degenerative joint disease
Joint stiffness
Hematoma
Synovitis
Bursitis
Abscess
Effects of Thermal Shortwave
Increase blood flow
Promote tissue healing
Decrease inflammation
Decrease pain
Increase tissue extensibility
decrease muscle spasm
Control infection
Dosage with the shortwave
Includes:
1) Time of application.
2) Parameters chosen (mode, frequency, type of
electrodes, etc…).
3) How much do we apply the treatment.
Duration
 Average of 15 minutes depending on the site
of the area and the patient’s response
 Can increase to 30 minutes.
 Longer treatment duration may result in
reflect vasoconstriction noticed clearly in the
toes and fingers
 When increasing the intensity wait 2-3
minutes to allow the temperature to build in
the tissue before moving to the next stage.
How To Set The Parameters When
Using Pulsed Shortwave
If we want to set the pulsed shortwave:
 In acute conditions, the mean power output should be
3 and the treatment time is 10 minutes.
 In sub acute, the mean power output should be 2-5
and the treatment time 10 to 15 minutes.
 In chronic conditions, the mean power output is from
5-7 and the treatment can go up to 30 minutes.
Mean power output = peak pulse power /
percentage of on time
On time = pulse duration / pulse period
Pulse period = peak pulse power / pulse repetition
rate
When Using Thermal Shortwave
1)
2)
3)
4)
Adjust the machine.
Ask the patient.
If the temperature is too hot decrease it.
The patient is not feeling heat increase it.
5) Dosage with the continuous shortwave depending
on the thermal sensation reported from the patient.
6) Use your clinical judgment in administering the
dosage .
Frequency of The treatment
 Daily or every other day.
 Depends on the patient’s response.
 If the condition is very acute, daily treatment will
give better results.
 Chronic condition, every other day treatment.
 If it didn’t improve  do it everyday.
 I Wish You All The Best of Luck 