Deep Heat
Ultrasound & Diathermy
Frequency
• 3MHz 0-1cm
• 2 MHz 1-2 cm
• 1 MHz 2-3 cm
3 MHz 2 MHz
1MHz
.5 cm
1.0 cm
1.5 cm
2.0 cm
Bone
Transducer:
• Choose an area that is an appropriate size
– no greater than 1.5 to 2 times the ERA
• Speed of rotation will vary the heat
Therapeutic Applications
Effect
Non
Thermal
Mild
Thermal
Moderate
Thermal
Vigorous
Temp.
Increase
None
Application
2 C
Acute, Injury,
Edema, Healing
Sub Acute Injury
Hematoma
Trigger points
3 C
Stretch Collagen
1 C
US Application Time
• Continuous: A duty factor of 100% is
needed to elevate tissue temperature to
physiologically significant temperature
(104-112 degrees F)
– This results in a reduction of pain and muscle
spasm as well as an increase in tissue
extensibility and increase blood flow.
• Pulsing: the sound wave will decrease the
depth of US delivery
– Current machines have % pulsed, thus you can
modify depth of delivery
Application Techniques
• Coupling Medium: US
energy will not pass
through the air or skin
without the presence
of a coupling medium.
The ideal coupling
medium should have
the following
qualities:
– High transmission and
low absorption of US
energy
– Exclude air, minimal
air entrapment
– good impedance
– low drag coefficient
– good viscosity
– low salt content
– economical cost
– easy to use
Coupling Agents
•
•
•
•
Gel
Water Immersion
Bladder Method (water filled balloon)
Phonophoresis
Application Techniques
• The best medium is aqueous gel (different
from electrical stim. gel)
• Water meets all of the criteria, good for
irregular or small body parts (aqueous gels
are mainly water)
• Biofreeze or Flex-all does not allow as
great a healing effect
• Phonophoresis “jury still out”
Water Immersion Bath
– Use room temperature degassed water in a
plastic treatment tub
• Do not use in a metal tank!
– The transducer should be applied in a moving
technique as close as possible, but still
remaining perpendicular to the treatment area.
– Precaution is advised when immersing the
clinician’s hand into the water bath during
treatment or when removing bubbles from the
transducer's face since the dangers of long term
exposure to US are not known at this time.
Stretching
• Stretching window is 3 minutes
– After 3 minutes the tissues temperature drops
past tissue extensibility
PreHeating
• Preheating should be a decision based on
patient comfort
• Research indicates that pre heating (HP,
emersion) increased superficial heat
temperatures significantly
– Deep tissues are unaffected
PreCooling
• Research has indicated that precooling
retard increase of heat in the tissue
• Cooling may also anesthetize the area
limiting sensation
Diathermy
Diathermy
• Uses energy similar to broadcast radio
waves with shorter wavelength.
• Energy is alternating current lacking
properties to depolarize motor sensory
nerves
• Fiction caused by the movement6 of ions
from the High Frequency electromagnetic
energy causes heating
Diathermy
• Tissues with high water content (Fat, blood
and muscle) are selectively heated at depth
of 2-5cm.
• Local tissue temp. may reach 107ºF, but fat
layer dissipated heat secondarily heating
muscles
• Deep heating effects last longer than US
due to large area heated
Delivery of Diathermy
• Pulsed
– Acute and subacute
conditions
– heating related to
rations of time “on”
and “off”
– Heating occurs when
total amount of energy
delivered is greater
than 38 watts, below
this receive nonthermal effects
• Continuous
– Mainly used
– For chronic injuries
Effect on Injury Response
• Response similar to effects of heat
–
–
–
–
Skin temp raises 4.3ºF
Intra-articular temp raises 2.5 ºF
Blood flow increases
fibroblastic activity, collage deposition and new
capillary growth stimulated
– muscle spasm is resuced by sedation of sensory
and motor nerves
– local increase in cellular metabolic rate
Set-up and Application of
Diathermy
• Condenser and Induction Method will be
demonstrated in lab
• General Prep.
– No metal (including removal of all rings,
watches, hairpins etc.)
– Cover area with terrycloth towel to eliminate
sweat
– Explain to patient warmth should be felt, but no
unusual sensations
Diathermy Set-up
• Duration of Tx
– 20-30 minutes
– 2 weeks
– when using higher tx
temp, decrease the
duration of tx and
apply on alternate days
• Indications
–
–
–
–
–
Joint Inflammation
Larger areas than US
Fibrosis
Myositis
Subactue and Chronic
Inflam.
– Oasteoarthritis
Diathermy Precautions
•
•
•
•
•
•
•
Physician's Prescription (some states)
Never allow cables to touch (short circuit)
Do not allow for perspiration
Never allow direct contact with skin
Excessive fat in area may overheat area
Difficult to tx localized areas
Overheating tissues may cause damage
– deep acing
– fat neurosis
– burning
Diathermy Contraindications
• Ischemic Areas
• Peripheral vascular
disease
• Metal Implants
• Perspiration
• Tendency to
hemorrage including
menstration
• Cancer
• Fever
•
•
•
•
Sensory loss
Pregnancy
Cardiac pacemakers
Areas of particular
sensitivity
–
–
–
–
–
epiphyseal plates
genitals
infection
abdomen
eyes and face
Dosage Parameters
Dose
NT
1
2
3
Temp.
Indications
Sensation
NO
Acute trauma,
detectable inflam, edema
warmth
reduction
Mild
Subacute
Warmth
inflamation
Moderate Pain, muscle
warmth spasm, Chronic
inflam, inc.
blood flow
Vigorous
Stretching
heating collagen tissues
Pulse
Pulse
Width
Rate
65sec 100-200
pps
100sec 800pps
200sec 800pps
400sec 800pps