ULTRASOUND 1.pptx

ULTRASOUND
-JUHI NANAVATI
(MPT-ORTHOPEDICS)

SOUND
• DEFINITION: SOUND IS THE PERIODIC MECHANICAL
DISTURBANCE OF AN ELASTIC MEDIUM SUCH AS AIR.
• SOUND IS A MECHANICAL WAVE PRODUCED BY
VIBRATING BODIES.
• LONGITUDINAL WAVE, PROPAGATES IN MEDIUM BY
COMPRESSION AND RAREFACTION.
6.04 - 6.06 ULTRASOUND 2

• FREQUENCY OF THE SOUND WAVE IS THE SAME AS THE
RATE OF OSCILLATION OF SOURCE.
• FOR HUMAN BEING, AUDIBLE SOUND RANGES 20HZ -20KHZ.
• FREQUENCY INVOLVED IN SPEECH & MUSIC IS ABOUT 30HZ-4000HZ.
• HIGHER IN CHILDREN ABOUT 20KHZ.
• LOWER IN OLD AGE ABOUT 16HZ-20HZ.

•Require elastic
medium for
transmission
•Longitudinal waves.
•Propagates by
compression &
rarefaction.
•Can travel even in
vacuum
•Both longitudinal &
transverse wave.
•Particles go up &
down.

INFRASOUND
• VIBRATION BELOW 20HZ FREQUENCY IS CALLED INFRASOUND OR
INFRASONIC RADIATION.
• DURING EARTHQUAKES, INFRASOUND ARE PRODUCED, BUT IT IS
OUT OF AUDIBLE RANGE OF HUMAN.

ULTRASOUND
• ULTRASONIC ENERGY OR ULTRASOUND DESCRIBES ANY VIBRATION
AT A FREQUENCY ABOUT ABOVE THE SOUND RANGE.
I.E. >20KHZ.
• FREQUENCIES OF A FEW MEGAHERTZ THAT ARE TYPICALLY USED
THERAPEUTICALLY RANGES FROM 0.5MHZ TO 5MHZ.

NATURE OF SONIC WAVES.
• SONIC WAVES ARE A SERIES OF MECHANICAL
COMPRESSION & RAREFACTIONS IN THE DIRECTION
OF TRAVEL OF WAVE, HENCE THEY ARE CALLED
LONGITUDINAL WAVES.

• VELOCITY DEPENDS ON ELASTICITY(ABILITY TO DEFORM)
OF MEDIUM.
• SONIC WAVES PASS MORE RAPIDLY THROUGH MATERIAL
IN WHICH THE MOLECULES ARE CLOSE TOGETHER.
• SO, VELOCITY IS HIGHER IN SOLIDS AND LIQUIDS THAN
IN GASES.
• SONIC WAVES VELOCITY
1. IN AIR- 340M/S.
2.IN BONE 2800M/S.
3.IN STEEL 5850M/S.

• FOR WAVE EQUATION V=F.Λ
• WHERE F & Λ ARE INVERSELY RELATED. & V REMAINS
CONSTANT.

WAVE ABSORPTION.
• PROPAGATION OF SOUND WAVE DEPENDS UPON THE
TRANSMISSION OF ENERGY FROM PARTICLE TO
PARTICLE.
• SOMETIMES THE ENERGY IS ABSORBED RAPIDLY &
SOME PASSES WITHOUT LOSS.
• AS MOLECULES JOSTLE & COLLIDE WITH ONE ANOTHER
ENERGY WILL BE TRANSFERRED FROM ONE TO
ANOTHER.

TRANSMISSION.
• IT DEPENDS ON ELASTICITY .
• ELASTICITY IS THE ABILITY OF MATERIAL TO UNDERGO
DEFORMATION CALLED ACOUSTIC IMPEDANCE OF
MEDIUM.
• A.I.= (DENSITY OF MEDIUM)(VELOCITY OF SONIC WAVES)
• METAL HAVE VERY HIGH A.I.
• WATER HAVE LESSER A.I.
• AIR HAVE VERY LOW A.I.

• DURING TRANSMISSION OF SOUND WAVE
FROM ONE MEDIUM TO ANOTHER
MEDIUM, EITHER SOUND WAVE CAN BE
1.REFLECTED.
2.REFRACTED.
3.ABSORBED.

THE PRODUCTION
OF THERAPEUTIC
ULTRASOUND.

• TO PRODUCE THE HIGH FREQUENCY ULTRASOUND WAVES USED
THERAPEUTICALLY ,MECHANICAL OSCILLATION FREQUENCIES IN
THE RANGE FROM ABOUT 1-3MHZ ARE NEEDED.
• ULTRA SOUND CAN BE PRODUCED USING
PIEZOELECTRIC CRYSTALS.

• PIEZOELECTRIC CRYSTALS ARE CRYSTALLINE SOLIDS
WHICH HAVE AS A SPECIAL PROPERTY THAT THEY
CHANGES IN THICKNESS IN RESPONSE TO AN APPLIED
VOLTAGE.
• MANY TYPES OF CRYSTAL CAN BE USED TO PRODUCE
THERAPEUTIC SOUND BUT THE MOST FAVORED ARE
QUARTZ,
• SOME SYNTHETIC CERAMIC MATERIALS SUCH AS
BARIUM TITANATE AND LEAD ZIRCONATE TITANATE

• IF ALTERNATING VOLTAGE IS APPLIED TO A
PIEZOELECTRIC CRYSTAL, ITS THICKNESS WILL
CHANGE IN AN OSCILLATORY MANNER.
• THICKNESS OF CRYSTAL SHOULD BE SUITABLY
CUT SO THAT IT CAN RESONATE AT A CHOSEN
FREQUENCY.

• ALL THERAPEUTIC ULTRASOUND GENERATORS HAVE A
HAND-HELD PROBE WITH A TREATMENT HEAD, WITHIN
WHICH A PIEZOELECTRIC CRYSTAL IS MOUNTED.

• PIEZOELECTRIC EFFECT:
• THERE ARE TWO FORMS OF THE PIEZOELECTRIC EFFECT.
1.DIRECT.
2.REVERSE (INDIRECT).

•THE DIRECT PIEZOELECTRIC
EFFECT
• IS THE GENERATION OF AN ELECTRIC VOLTAGE ACROSS A CRYSTAL
WHEN THE CRYSTAL IS COMPRESSED.

• THE REVERSE PIEZOELECTRIC EFFECT
• IS THE CONTRACTION OR EXPANSION OF CRYSTAL IN
RESPONSE TO A VOLTAGE APPLIED ACROSS ITS FACE.
• A CHANGE IN THE POLARITY OF THE APPLIED VOLTAGE
CAUSE A CONTRACTED CRYSTAL TO EXPAND AND VICE
VERSA.

COMPONENTS OF ULTRASOUND
CIRCUIT
• MAIN SUPPLY: THIS IS THE A.C., NORMALLY OF 220 VOLT
HAVING FREQUENCY OF 50 HZ.
• TRANSFORMER: STEP UP TRANSFORMER IS USED TO INCREASE
THE VOLTAGE OF THE CURRENT.
• RECTIFIER: WHERE CURRENT IS CONVERTED FROM A.C. TO D.C.
• OSCILLATOR: THIS IS TO GIVE HIGH FREQUENCY OSCILLATING
CURRENT TO THE OUTPUT CIRCUIT.
• AMPLIFIER: THIS IS TO INCREASE THE MAGNITUDE OF CURRENT
.
• CO-AXIAL CABLE: IT IS A SIMPLE WIRE COVERED BY A METALLIC
PLATE AND SEPARATED BY INSULATING MATERIAL. IT TAKES
THE CURRENT TO THE TRANSDUCER.

• POWER SUPPLY ON
• ELECTRICAL ENERGY TO
OSCILLATOR CIRCUIT
• PRODUCE OSCILLATING
VOLTAGE TO DRIVE
TRANSDUCER

• TRANSMISSION OF SONIC WAVES:
• THE METAL PLATE OF THE TREATMENT HEAD MOVES BACKWARDS AND
FORWARDS TO GENERATE A STREAM OF COMPRESSION WAVES THAT FORMS
THE SONIC BEAM DUE TO THE FACT THAT THE WAVELENGTH OF THESE
WAVES IS MUCH SMALLER THAN THE TRANSDUCER FACE.
• THE SONIC BEAM IS ROUGHLY CYLINDRICAL AND OF THE SAME DIAMETER AS
THE TRANSDUCER HEAD.

• SOME WAVES CANCEL OUT, OTHERS REINFORCE SO THAT
THE NET RESULT IS A VERY IRREGULAR PATTERN OF SONIC
WAVES IN THE REGION CLOSE TO THE TRANSDUCER FACE,
CALLED THE NEAR FIELD OR FRESNEL ZONE.
• THE REGION BEYOND THIS, THE FAR FIELD OR FRAUNHOFER
ZONE.

• THE LENGTH OF NEAR FIELD WILL DEPEND :
1. DIRECTLY ON THE SQUARE OF THE FACE
2. INVERSELY ON THE WAVE LENGTH
SO, LENGTH OF FRESNEL ZONE =R2/Λ
THERAPEUTIC ULTRASOUND UTILIZES THE NEAR FIELD AND
HENCE IS IRREGULAR. THERE IS RELATIVELY MORE ENERGY.
CARRIED IN THE CENTRAL PART OF THE CROSS-SECTION OF THE
BEAM.

EFFECTIVE RADIATION AREA:
• AREA OF THE TRANSDUCER FROM WHICH ULTRASOUND TRAVELS.
• ERA IS SMALLER THAN THE TRANSDUCER HEAD – AS CRYSTAL DOESN’T VIBRATE
UNIFORMLY
• TAKEN CONSIDERABLE WHILE CALCULATING EXTENT OF NEAR FIELD.
• NEAR FIELD HAS GREATER VARIATION IN INTENSITY
• SO WHILE CONSIDERING TREATMENT OF DEEPER STRUCTURE – ESSENTIAL TO
SELECT DEFINITIVE RADIUS OF TRANSDUCER HEAD

ATTENUATION: PROGRESSIVE LOSS OF INTENSITY OF
ULTRASOUND AS IT IS TRAVEL THROUGH THE MEDIUM
ABROPTION SCATTER
• At molecular level
• As absorbed by tissue
– convert to heat
• Protein absorbs more
ultrasound
• In air 500 to 1000
times that in water
• Hence water is good
coupling medium
•
• Occurs when
cylindrical beam of
ultrasound deflected
from its path by
reflection interface,
bubbles or particle in
path
• Decrease in intensity
• Half value depth
( The distance from the
surface at which
intensity of the
ultrasound reduces to its
half value)

• DURING TRANSMISSION OF SOUND WAVE
FROM ONE MEDIUM TO ANOTHER
MEDIUM, EITHER SOUND WAVE CAN BE
1.REFLECTED.
2.REFRACTED.
3.ABSORBED.

REFLECTION :
• ULTRASONIC BEAM TRAVELLING THROUGH ONE MEDIUM TO ANOTHER – ACOUSTIC
MISMATCH BETWEEN 2 MEDIA AS EACH MEDIUM HAS DIFFERENT IMPEDANCE
• THE AMOUNT OF ENERGY REFLECTED IS PROPORTIONAL TO
THE DIFFERENCE IN A.I. BETWEEN 2 MEDIA
• REFLECTED POWER IS ALWAYS SMALLER THAN INCIDENT ONE
• AIR DOESN’T TRANSMIT THE ULTRASONIC WAVES BECAUSE OF THE REFLECTION
• SO, DURING THE TREATMENT GREAT CARE IS TAKEN TO AVOID THE AIR BETWEEN
THE TREATMENT HEAD AND TISSUE TO AVOID THE REFLECTION.

REFRACTION:
• DEVIATED FROM ORIGINAL PATH
• IF TRANSDUCER HEAD IS NOT HELD PERPENDICULAR TO THE TISSUES, AREA
NEEDED TO BE TREATED IS MISSED

MODES OF APPLICATION:
Continuous Pulsed
For producing thermal effect • Delivery of ultrasound during only a
portion of the treatment period
• Pulsed on and off – non thermal effect
1) Mark space ration : Ratio of on time to
off time.
Some machine
fixed – 2:8
2) Duty cycle : % of total period of time US
machine is on

INTENSITY :
• WATT/CM2
• WHO LIMITS THE AVERAGE INTENSITY – 3W/CM2
Spatial average Average intensity of US output over the area of
transducer head
In w/cm2
Spatial peak Peak intensity over the area of transducer head
Greatest in the centre and lowest at edge of
beam
Spatial Average Temporal Peak (SATP) Spatial Average intensity during pulse on time
Spatial Average Temporal Average (SATA) Average intensity over whole period of time
SATA = SATP * Duty cycle

• THE BEAM NON-UNIFORMITY RATIO (BNR) IS THE RATIO BETWEEN
PEAK INTENSITY AND AVERAGE INTENSITY IN THE BEAM. THE
LOWER THE BNR THE MORE UNIFORM THE BEAM.

COUPLING
MEDIA
• Ultrasound waves are not transmitted by air,
thus some couplant which does transmit
them must be interposed
• Unfortunately no couplant affords perfect
transmission & only a percentage of the
original intensity is transmitted to the patient.
Aquasonic gel 72.6%
Glycerol 67 %
Distal water 59 %
Petroleum jelly 0 %
Air 0 %

EFFECTS OF ULTRASONIC WAVES ON TISSUE :
THERMAL EFFECTS NON THERMAL EFFECTS BIOLOGICAL EFFECTS
• Travels through the tissue
Absorption Heating of
tissue
• Reduction of pain, spasm
associated with chronic
inflammation as increase
in blood flow
• Increase in ROM – as
heating cause elongation
of collagen fiber
• US produce biological
effects without producing
significant temperature
changes
• The physical mechanism
thought to be involved in
producing non thermal
effects are :
1. Cavitation
2. Acoustic streaming
3. Standing waves
4. Micro massage
In 3 phases:
1. Inflammation
2. Proliferation
3. Remodelling

NON THERMAL EFFECTS :
CAVITATION:
• CAVITATION IS A COMMON CONDITION IN WHICH A BUBBLE GAS IS PRODUCED
IN THE TISSUES AS A RESULT OF INSONATION.
• DEPENDING UPON THE PRESSURE AMPLITUDE OF ENERGY , EITHER ITS STABLE
CAVITATION OR UNSTABLE CAVITATION
Stable cavitation Unstable cavitation
Bubbles oscillate to and fro
throughout the cycles , but not
burst
Cell permeability changes
Occurs when bubble grow over a
number of cycles, increasing
volume and sudden collapse
causing high temperature changes
– damage to tissue

This effect produced by the ultrasonic beam
is unidirectional flow of tissue components
which occurs particularly at the cell
membrane.
Streaming has been shown to produce
changes in the rate of protein synthesis and
could thus have a role in the stimulation of
repair.
ACOUSTIC STREAMING

MICRO MASSAGE
• The micro massage effect of ultrasound occurs at a cellular
level where the cells are alternately compressed and then
pulled further apart. This effect on intracellular fluids and
thus to reduce oedema.
• Ultrasound has been found to be effective at reducing both
recent traumatic oedema and chronic induced oedema.

STANDING WAVES:
• OCCURS WHEN REFLECTED WAVE SUPERIMPOSED TO INCIDENT WAVE
• REFLECTED WAVE THAT INTERCONNECT WITH ONCOMING INCIDENT WAVES
FORMING STANDING WAVE FIELD
• SO, THE PEAK INTENSITYAND PRESSURE IS HIGHER THAN NORMAL INCIDENT
WAVE – DAMAGE TO THE TISSUE OCCURS

DOSAGE
• This is the most controversial area when discussing ultrasound. The argument
of whether pulsed or continuous modes should be used and the intensities of
ultrasound required to produced beneficial effects.
• While treating a patients with US it is worth remembering that intensity of US
leaving the treatment head is not the intensity being applied to the deep tissue,
it reduced by :
1. Absorption in coupling medium
2. Attenuation of the beam by absorption and scatter
3. Refraction of the beam at tissue interfaces

PARAMETERS OF ULTRASOUND:
Mode Frequency Intensity Duration
• Continuous mode
produces more
heat so it is used
for
musculoskeletal
conditions such as
muscular spasm,
joint
stiffness, pain,
etc.
• Pulsed mode
produces less heat
so it is used for
soft tissue repair,
e.g. tendinitis.
Attenuation increases
with increase in
frequency effectively
lower frequency
penetrate
further.
1. Ultrasonic 3 MHz—
superficial tissue
2. Ultrasonic 0.75 to
1 MHz—penetrate
deeply
For acute and
immediate post-
traumatic: 0.1 to 0.25
W/cm2
For chronic and scar
tissue: 0.25 to 1
W/cm2.
Size of area
determine the
treatment time
1–2 minutes for every
cm2
Minimum — 1–2
minutes
Maximum — 8
minutes
Average — 5 minutes
For chronic — Longer
treatment time
For acute — Lesser
treatment time

DOSAGEIN ACUTE
CONDITION
• As with any acute condition treatment is applied cautiously to prevent
exacerbation of symptoms. In initial stages a low dose (0.25 or 0.5
watt/cm²) is used for 2-3 times
• Progression of dosage is unnecessary if the condition improves.
• Aggravation of symptoms is not always a bad sign as it may indicate
that repair processes are taking place.

DOSAGEIN CHRONICCONDITION
• Chronic conditions can be treated with either a pulsed or a continuous beam.
• With a continuous beam, the maximum intensity which should be used is that
which produced a mildly perceptible warmth. This usually occurs around 2
watt/cm²
• A dose of 2 watts/cm² for 8 minutes is usually considered

TECHNIQUEOF
APPLICATION
1) DIRECT CONTACT
• If the surface to be treated is fairly regular then a coupling medium is applied to the
skin in order to eliminate air between the skin and the treatment head.
• The treatment head is moved in small concentric circles over the skin in order to
avoid concentration at any one point
• Preparation of patient
• Examination and testing
• Preparation and testing of apparatus
• Preparation of part to be treated
• Setting up
• Application
• Termination
• Doccumentation

2)WATERBATH:
• When direct contact is not possible because of irregular shape of part or because of
tenderness, a water bath may be used. As the part to be treated is immersed in
water this can only reasonably be applied to the hand, ankle and foot.
• A water bath filled with degassed water is used if possible. Ordinary tap water
presents the problem that gas bubbles dissociate out from the water, accumulate on
the patient skin and the treatment head, and reflect the US beam.
• The patient is seated and part is put in water of a comfortable temperature in such
a position that it is suitably supported
• The technique of application is that the treatment head is held 1 cm from the skin
and moved in small concentric circles.

3)WATER BAG METHOD:
• IRREGULAR SURFACE WHICH CANNOT CONVENTIONALLY BE PLACED IN A
WATER BATH IS TREATED WITH A PLASTIC OR RUBBER BAG FILLED WITH WATER
FORMING A WATER CUSHION BETWEEN THE TREATMENT HEAD AND THE SKIN.
• RUBBER BAG FILLED WITH DEGASSED WATER CAN BE USED. ALL VISIBLE AIR
BUBBLES SHOULD BE SQUEEZED OUT BEFORE KNOTTING THE NECK OF THE BAG
TO SEAL IT.
• A COUPLING MEDIUM HAS TO BE PLACED BOTH BETWEEN THE RUBBER BAG AND
SKIN AND BETWEEN THE RUBBER BAG AND THE TREATMENT HEAD TO
ELIMINATE ANY AIR.

TESTINGOFTHE
APPARATUS
• Testing should always be carried out prior to treatment
• The simplest way of finding out whether ultrasound is in fact
being produced is to use a water bath and to reflect an
ultrasonic beam up to the surface where it should produce
ripples

THERAPEUTICUSES OFUS
• Soft tissueshortening
• Paincontrol
• Surgicalskin incisions
• Tendoninjuries
• Resorption of calciumdeposits
• Bonefractures
• Carpaltunnel syndrome
• Plantarwarts

SOFTTISSUE
SHORTENING
• Soft tissue shortening can be the result of immobilization,
inactivity or scarring, and can cause joint Range-of-motion
(ROM) restrictions, pain, and functional limitations.
• Because ultrasound can penetrate to the depth of most joint
capsules, tendons, and ligaments, since these tissues have
high ultrasound absorption coefficients, ultrasound can be
an effective physical agent for heating these tissues prior to
stretching

SOFTTISSUE
SHORTENING
• The deep heating produced by 1 MHz continues
ultrasound at 1.0 to 2.5W cm² has been shown to be
more effective at increasing joint ROM than the
superficial heating produced by infrared.

PAIN
CONTROL
• Ultrasound may control pain by altering its transmission or perception or by modifying
the underlying condition causing the pain. These effects may be the result of stimulation
of the cutaneous thermal receptors or increased soft tissue extensibility due to increased
tissue temperature, the result of changes in nerve conduction due to increased tissue
temperature
or the non-thermal effects of ultrasound, or the result of modulation of inflammation due to
the non-thermal effects of ultrasound.

SURGICALSKIN
INCISIONS
• The effect of ultrasound on the healing of surgical skin incisions has been
studied in both animal and human subjects.
• Ultrasound has been shown to accelerate the evolution of angiogenesis a
vital component of early wound healing.
• Angiogenesis is the development of new blood vessels at an injury site
that serves to reestablish circulation and thus limits ischemic necrosis and
facilitate repair.

TENDON
INJURIES
• Ultrasound has been reported to assist in the healing of tendons after
surgical incision and repair Although some studies with both animal
and human subjects have reported treatment success others have failed
to support these findings.
• It is recommended that ultrasound be applied in a Pulsed mode at a low
intensity during the acute phase of tendon inflammation in order to
minimize the risk of aggravating the condition and to accelerate
recovery

RESORPTION OF CALCIUM
DEPOSITS
• Ultrasound may facilitate the resorption of calcium deposits.
• Although the mechanism underlying calcific deposits resorption is
not known, decrease in pain and improvements in function may be
due to the reduction in inflammation produced by ultrasound.

BONE
FRACTURES
• Although prior reports have recommended that ultrasound not
be applied over unhealed fracture because they have failed to
provide data to support this recommendation and because
recent studies have demonstrated that low-dose ultrasound can
reduce the fracture healing time in animals and humans, the use
of low-dose ultrasound to accelerate fracture healing is now
recommended.

CARPALTUNNEL
SYNDROME
• Continuous ultrasound has generally not been recommended for the
treatment of carpal tunnel syndrome because of the risk of
adversely impacting nerve conduction velocity by overheating.
However a resent study found that pulsed ultrasound produced
significantly greater improvement

CONTRAINDICATION:
1. Vascular conditions: Conditions such as thrombophlebitis, where insonation may
cause emboli to be broken off, are not treated with ultrasound.
2.Acute sespis: An area which presents acute sepsis should be treated cautiously with
ultrasound because of the danger of spreading the infection, or in some instances
breaking off septic emboli. If the treatment is passed over an infected area (as in the
treatment of herpes zoster) it must be sterilized with an appropriate solution before
treatment of the next patient.
3. Radiotherapy: Radiotherapy has a devitalizing effect on the tissue, therefore ultrasound
is not applied to a radiated area after six months of irradiation.

4. Tumors: Tumors are not insonated because they may be stimulated or
metastasize.
5. Pregnancy: A pregnant uterus is not treated as the insonation may cause
damage to the fetus. Consequently during pregnancy the back and abdomen
should not be treated.

6. Cardiac disease: Patients who have had cardiac disease are treated with low
intensities in order to avoid sudden pain, and area such as cervical ganglion and the
vagus nerve are avoided because of the risk of cardiac stimulation. Patients fitted
with cardiac pacemakers are not usually treated with ultrasound in the area of the
chest, as the ultrasound generator may have an effect on the pacemakers rate of
stimulation.
7. Hemorrhage: When bleeding is still occurring or has only recently been controlled,
such as an enlarging hemarthrosis or hematoma or uncontrolled hemophilia, ultrasound is
contraindicated.

8. Severely ischemic tissue: Because of the poor heat transfer and possibly greater
risk of arterial thrombosis due to statistics and endothelial damage, ultrasound is
contraindicated.
9. Nervous system: Normal doses of ultrasound have been applied for many years to
the tissues around the spinal cord without any ill effects. Infact treatment of the spinal
nerve roots and over the apophyseal joints is particularly common. Since the CNS is
deeply buried beneath the thick muscles and more importantly bone tissue, it seems
reasonable to suppose that only trivial amounts of energy could reach it. Where the
nerve tissue is exposed, e.g. over a spina bifida or after laminectomy, ultrasound is
avoided.

10. Specialized tissue: The fluid filled eye offer a exceptionally good
ultrasound transmission and retinal damage could occur. Treatment over the
gonads, i.e. testes and ovary are also not recommended.
11. Joint cement: Methylmethacrylate – Rapidly heat by US, result in
loosening of the procedure

REFRENCES:
1. CLAYTON’S ELECTROTHERAPY: THEORY AND PRACTICE - FORSTER &
PALASTANGA
2. ELECTROTHERAPY EXPLAINED – JOHN LOW & ANN REED
3. ELECTROTHERAPY SIMPLIFIED – BASANTA KUMAR NANDA
4. TEXTBOOK OF ELECTROTHERAPY – JAGMOHAN SINGH

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