deep heating by short wave diathermy

2.  Def.: SWD is a modality that produces deep heating via
conversion of electromagnetic energy to thermal energy.
The pattern of heat produced depend on:
ᴥFreq. used.
ᴥ type of SWD unit.
ᴥwater content of the tissues.
 Shortwave diathermy current freq. 10 – 100 MHz
(The shortest radiofrequency wave is used in therapeutic diathermy.)
the commonly used in medical work having freq.
of 27.12 MHz with wavelength of 11 meters
 Modalities:
 ether continuous or pulsed (PSWD).
o PSWD: application of series of short pulses of SWD so that short periods of SWD interrupted by gaps
where there is no SWD. The pt. receives lower dose of SWD energy if compared with continuous SWD
applied of the same time. The tissues will receive lower thermal load.
o SWD: produce both deep and sup. Tissue heating, under certain controlled conditions it’s applied for
20 min at the max tolerable dose.
SWD produced by an oscillating electric
current of extremely high frequency.

3.  Therapeutic effect:
1. Increase blood flow.
2. Help resolution of inflammation.
3. accelerate wound healing.
4. ↗ extensibility of deep collagen tissues.
5. ↘ joint stiffness.
6. Relief deep mus. Pain & spasm. ( via muscle spindle & Golgi
tendon organ stimulation)

4.  Clinical indications:
1. Resent burns.
2. Recent injuries.
3. Plastic surgery.
4. Postoperative
5. Post laminectomy pain.
6. Sinusitis
7. TMJ disorders.
8. Bell’s palsy.
9. Sub deltoid bursitis ass. With calcification.
10. Chronic arthritis
11. Degenerative complaints.
12. PID (pelvic infla. Dis.)
13. ↘pain ass. With herpes zoster.

5. Exp. Of SWD application in various cond.:
Soft tissues healing:
SWD ++ earlier maturation of collagen fibers.
raped regeneration of damaged ms. fibers.
PSWD more raped activity in collagen formation.
enhance rate of skin healing.
Resolution of haematoma:
enhance rapid resolution.
Recent ankle injuries
PSWD  more effective
improve: pain, swelling, disability.
Pain:
relief pain ass. With various cond. E.g.: back pain.
PSWD relief pain ass. With acute injuries.
Nerve regeneration:
PSWD accelerate recovery of nerve conduction.
O.A:
SWD & PSWD forming part of physiotherapeutic modalities used in OA ttt.

6.  contraindications:
1) Implanted pacemaker.
2) Metal in the tissues or ext. fixators.
3) Impaired thermal sensation.
4) Over pregnant uterus & intrauterine devises.
5) Hemorrhagic areas ( menses ).
6) Ischemic tissues.
7) Recent thrombosis.
8) Mlg. Tumors  ↗proliferation.
9) Active TB.
10) Pt. pyrexia.
11) Areas of skin affected by courses of x-ray.
12) Uncooperative pt.

7. Application of SWD:
pt. is connected to the electrode
circuit of the high freq. Generator by:
A) capacitive applicator
or
B) inductive coil

8. A) capacitive applicator:
2 diff. types of electrodes for applying the
capacitive method:
Flexible metal plate  malleable electrodes
Rigid metal discs  disc electrode (more commonly used method.
Uses the patient’s tissues as a part of the circuit
The tissues’ electrical resistance produces heat
Selectively heats skin
Muscle is heated via conduction from the
adipose
Also referred to as “condenser field diathermy”

9. capacitive applicator .. Cont
The pt. is placed between 2 metal condenser plates.
Achieve higher temperature in water-poor tissues, (like:
sub. Cut. Adipose tissue, lig, tendons, joint capsule, Bone.)
Guid lines for electrode selection & placement:
1. Electrode should be of equal size
2. Electrode should be slightly larger than the body part
 electric field is less uniform at the edge of the plate.
3. Electrode should be equidistant & at right angles to the
skin surface.
Electrodes arrangement
1. contraplanar application ( transverse): an electrode
is placed on either side of the limb.
2. Coplanar application: both electrodes are placed on
the same side of the limb.
3. Longitudinal application:  one electrode is placed at
each end of the limb.

10. B) Inductive application
Based on ( electromagnetic induction)
Use induction coils that apply a magnetic field to
induce circular electrical field in the tissue.
They achieve higher temperature in water-rich
tissues. (Like: ms. Skin. Blood ..etc.) Current flowing within the coil
produces a rotating magnetic field
Which produces eddy currents in the
tissues
Eddy currents cause friction that
produce heat

11. Inductive application… cont.
Induction SWD method  using
magnetic induction to produce
small eddy current in the tissues
which ↗↗ tissue temp.
2 diff. applicators are used in this
method:
1) most commonly used  an
inductive coil applicator
2)Wrapping insulated cable around
the limb to be ttt.

12. Dose determination using thermal sensation
Pt. pain perception used to monitor heat intensity that is being
produced. (inaccurate method )
Therapist must be aware of the potential risk of causing tissue damage
& ensure that the max dose that a pt. receives cause only a mild
sensation of warmth. Towels are sometime placed to spacing &
absorb sweet, which is highly conductive and could result in
potentially sever focal heating.
Typical ttt time is 20 to 30 minutes
Acute cond. Should be ttt with low dose PSWD
And chronic conditions should be ttt with high dose SWD.

13. TTT procedures
Prepare the pt.:
1. Exclude any C.I.
2. Examine thermal & pain sensitivity of the pt.
3. Ensure removal of any metal object (ring jewelry ..) from the ttt area.
4. Ensure removal of any hearing aid. Contact lenses.
5. Removal of all bandages & clothes from the ttt area.
6. Ensure dryness of skin.
7. Ask the pt. to report immediately any abnormal sensation felt during ttt.
8. Ensure that the gonads aren’t subjected to irradiation.

14. TTT procedures … cont
Prepare the machine:
1. Ensure correct connection of cables.
2. Ensure that cables & applicators aren’t placed
on metal surfaces.
3. Ensure appropriate alignment of the applicator
for max energy transfer.
4. Ensure that cables aren’t close to untreated
tissues.
5. Ensure that pt. support isn’t metallic & all metal
objects are kept at least 3ms. Away from the
applicators & cables.
Correct wrong

15. TTT procedures … cont.
Once the unit activated the operator
should:
1.Remain at least 1m from the cables
2.Ensure that the pt. maintain correct
position.
3.Ensure that the pt. not left alone during
ttt unless supplied with reliable cut-off
switch.
4.Ensure the pt. not touch the machine.
5.Ensure that no other person is in the
vicinity of the machine.

16. Dangers of SWD.
1) Burns.
2) Scalads.
3) Faintness  due to ↘ BP.
4) Ppt. of gangrene  if area of ↘blood supply
5) Sparking  if one electrodes touched while application of current
6) Electric shock.
7) Over dose … ↗ pain.