basics of ultrasoud and its uses in rehabilitaion medicin

1. ULTRASONIC
THERAPY

2. Def.: high freq. sound more than the power of human ear capacity (>20000 Hz)
NB: 17 – 20000 Hz human ear capacity sound wave.
infra sound wave 17 sound wave 20000 ultra sound wave
Components of apparatus of US & how it works:
1) Source of high freq. current ( base oscillating circuit).
2) Connected to co-axial cable.
3) Connected to transducer circuit
( treating head):
electrodes
crystals
metal plate.
Used in high freq. current
Electrical freq.
0.7-1 MHz

3. 4) Linking electrodes inside the transducer circuit convert the high freq.
current to crystal  quartz or Ba tetanate. ( peizo-electric effect).
5) Change in shape of crystals when subjected to varying potential diff. 
peizo-electric effect  movement of metal front plate  production of
US waves.
6) Coupling media  water, gel, paraffin oil or glycerol.(different efficiency)
if absent coupling media  reflection of US waves to the apparatus
destructing the crystals. Air doesn’t transmit US waves.
7) Application of ttt:
1) Test apparatus.
2) Determine duration  5 – 10 min
3) Determine intensity  0.1 – 3 watt / cm2 .
4) Determine freq.  1 – 3 MHz
5) Type  continuous or pulsed.
Waves travel in longitudinal way ( compression & rarefaction)

4. Uses (of ultrasound):
1. Diagnostic uses of US wave: echo & Doppler
2. Uses in surgery: focused therapy  ESWL ( extracorporeal
shock wave lithotripsy(,
3. in urology  ttt of benign prostate hyperplasia.
4. Physiotherapy.

5. Therapeutic effect of US wave on tissues:
• Thermal effect:
when US is absorbed it is transformed into
thermal energy ( heat). Depth of penetration
( 3 – 5 cm ).
Best produced by continuous waves,
Pulsed US has less thermal effect  used in
acute conditions (no need for heat) ↗Bl. Flow 
↗absorption of infl. Exudate. Relief pain,
relaxation of muscles spasm.

6. Cont ..
• Mechanical effect:
caused by pressure changes applied to the tissues by
sound waves, is best produced by using pulsed waves.
Include:
 cavitation “large dose”: condition in which bubbles
of gases is produced in tissue due to insonation;
• stable  harmless or,
• transient dangerous» avoided by average
intensity ≤ 3watt/cm2, pulsed US and circular mvt.)
 micro massage “ small dose “  at cellular level
↘both recent traumatic edema & chronic
indurated edema..

7. cont.:
pain relief ( pain gat theory) through stimulation of
mechano-R  S.C. cells  ↘ perception of peripheral pain.
Chemical and biological effects:
improvement of tissue repair, e.g. bed sores “ by under
water therapy.
Acoustic streaming, unidirectional flow of tissue
component which occur at cell memb. ↗proteins
syntheses rate  ++ tissue repair.
( can be used in phonophoresis)

8. Indication :
o Musculo-skeletal disorders:
articular & extra articular, Acute, subacute or chronic
e.g.:sprain – myalgia and Brachialgia – lumbago –
periarthritis – capsulitis – tendinitis.
o Localized conditions:
Tennis elbow – C.T.S – Achilles tendinitis – spondylosis
and disc prolapse – trigger finger.
o Chronic indurated oedema.
o Scar tissue & keloid + contracture after burns: break
fibrous tissues through thermal, mechanical, chemical
And biological effects.

9. Dosage:
 Intensity of US wave is measured in watts / cm2.
therapeutic doses vary between 0.25 to 3 w/cm2.
Lawer intensity below 0.5/cm2 are used for diagnostic
proposes
High intensity from 4 – 13 w/cm2 are used for destructive
purposes
Therapeutic intensities vary according to the part treated
whether thin or thick, acute or chronic.
 Duration: between 3 – 15 min, acute cases & small
area take short time for ttt while chronic cases & large
areas take a long time.
ttt can be given daily , EOD or even twice weekly.
The ttt should start with low doses & increased gradually in
accordance with the effect produced.

10. Preparation for ttt:
 Eliminate any contraindications.
 Skin sensation for heat tested before starting ttt.
 The pt. is informed that he will have a feeling of gentle
warmth or no thing at all.
 We must report any discomfort or pain especially deep
scatted pain e.g. periosteal pain to reduce dosage.
Application of ttt:
 US waves require a material medium
 Good contact & continuous mvt. Are necessary to
prevent over heating & burns.
 Methods of application: direct contact ( stroking or
circular mvt.)
 In water bath.

11. Methods of application:
1) Direct contact : perpendicular head &circular
movement. When the treated surface is regular.
2) Under water bath: (degased water)
3) Water bag therapy :
• uneven surface
• skin lesion
• traumatic conditions e.g. sprain & strains of
the lig. Tend. or ms. Usually start 24 – 48hs
after occurrence, to allows time for healing
injured capillaries.
Rubber bag filled with water is put between skin
& ttt head.
Bag & ttt head are moved on pt. skin with
coupling medium between bag & head + skin &
bag.

12. Hazards:
• Over dosage
• Burns
• Cavitation
• Damage to crystals when switch on air.
Intensity of US wave depends on:
absorption & reflection
If ↗ absorption & ↘reflection  ↗intensity
 hazards ( burns , cavitation)

13. precautions:
Over dosage of US has a reverse effect, so the ttt should start
with low doses & ↗ gradually.
Burns: can be avoided if the doses used within the therapeutic
range & proper technique.
Cavitation: US with high doses can disrupt the tissues & produce
cavitation of tissues.
Damage to the crystal: if The apparatus is turned to the “ ON “
position while the treating head is in air. The wave are reflected
back to the crystals, this may break the crystal.

14. contraindication:
 Absolute:
1. Brain tissue.
2. Spinal cord.  laminectomy ( only paraspinal application)
3. Ovary and testes.
4. Vascular dis. ( ischemia - DVT)
5. Pace maker ( cardiac pt.)
6. Prosthesis ( artificial knee)
7. Pregnancy (therapeutic not diag. US)
8. Radiotherapy  never applied on
immediate area for at least 6ms.
9. Tumors  US ++ growth & metastases.
10. Acute sepsis.
 relative:
1. Hypothesia  pulsed.
2. Subacute & chronic ischemia.
3. skin lesions Not infected.
4. children (risk to growing epiphysis) 
0.1 – 0.5 watt/cm2 , pulsed.
NB: avoide on bony prominence 
periosteal pain due to reflection of US wave
over periosteal  double intensity.