Download 1. Selection of the treatment head (Director)

Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
1






1.
2.
3.
4.
5.
6.
Define microwave current
Review the physics of the current
Effects of application
Indications
Contra-indications
Procedure of application
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
2

Microwaves are a form of electromagnetic
radiation, lying between the shortwaves and
infrared waves. Their frequencies ranges between
300 and 30 000 MHz with wavelengths of 10mm to
1 meter.
Electrotherapy Prof. Khaled
Mamdouh, Ms. I. Devreux
3
Microwave diathermy is a deep heating modality,
similar to short wave diathermy but differs in its
physics and mechanical properties.
Physics:
The clinical microthermy frequency is limited to
2.450 Mc range (10-12 cm wavelength), which is
shorter than short wave diathermy.
Electrotherapy Prof. Khaled
Mamdouh, Ms. I. Devreux
4



The
high
frequencies
of
microthermy are obtained from a
unique
device
called
the
magnetron, which is perforated
with tiny holes, through which the
electrons flow into the treatment
heads.
The
special
design
of
the
treatment
heads
shapes
and
focuses the field directly at the
target area.
The whole device is used to direct
the waves onto the tissues.
Electrotherapy Prof. Khaled
Mamdouh, Ms. I. Devreux
5
Transducer

Power
supply
Timing
 circuit

Magnetron
Antenna
Electrotherapy Prof. Khaled
Mamdouh, Ms. I. Devreux
Reflector
6
This device is sometimes termed *the emitter, *the
director or *the applicator.
In this kind of treatment, the patient does not form
a part of the circuit, so no tuning is necessary as in
short wave application.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
7


The heat produced by microthermal radiation is
known to be more concentrated than that produced
by short wave diathermy.
Although penetration is theoretically increased with
higher frequencies, absorption still depends on the
target density and the intervening tissues.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
8



According to the differences in
absorbability of tissues, the clinical effect of
microwave radiation depends on the type of
tissue involved.
Tissues with low water content are penetrated
to a greater depth.
Tissues with a high water content are
penetrated to a lesser depth.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
9
Absorption of the waves results in production of heat
in the tissues, but differs from other heat
treatment methods in the distribution of heat.
Electromagnetic energy is transformed into heat
energy.
Microwave is
structures.
not
suitable
for
deeply
placed
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
10



The effective depth of microwave penetration is
about 3 cm, so the depth of heating is
intermediate between that of infrared radiation
and short wave diathermy.
As the
water,
heated
tissues
microwaves are strongly absorbed by
tissues with high fluid content are
most, while less heat is produced for
with low fluid content as fat or bones.
Moreover, there is an appreciable heating of
tissues having good blood supply such as
muscles.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
11


The proportion of waves reaching the deeper
layers of the tissues depends also on the
amount of energy reflected at the air/skin
surface.
As much as 50% of the energy can be
reflected.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
12
The clinical indications for microthermy are, more
or less, similar to those for short wave diathermy.
Microthermy may be preferable to short wave when
more concentrated or localize heating is needed.


Traumatic and inflammatory lesions, in which
increase of blood supply and relief of pain and
muscle spasm are required.
Lesions in the superficial regions and those of
high fluid content.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
13

Traumatic and rheumatic conditions
affecting soft tissues and small superficial
joints.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
14





Superficial infections such as
septic fingers,
carbuncles and
other superficial abscesses.
It heals by increased circulation with
increased white blood cells and
antibodies
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
15


Pain relief ( muscular origin)
Healing of the skin ( by direct application on
the wound or by reflex vasodilatation to a
proximal level of the wound)
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
16


Burns: As water is heated rapidly by
microwaves, burning of wet skin
may occur.
Eyes: Irradiation to the eyes may
develop opacities.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
17

Circulatory defects: Such as hemorrhage,
thrombosis, phlebitis and other vascular
lesions.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
18

Malignancy: Microwave diathermy should not

Cardiac pacemakers.



be applied to regions of malignant
growth or tubercular infections
(tuberculosis).
Genital area ( sterility).
Pregnancy (miscarriage , hemorrhage)
Obesity, unreliable patients, metallic
implants, hypersensitivity to heat, impaired
sensation
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
19
1. Selection of the treatment head (Director):
Generally, two designs of directors are found:
- Circular: In which heat is denser at the periphery more
than at the center.
Two sizes of circular directors are available:
Small: for small areas.
Large: for large areas.
- Rectangular: for elongated areas.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
20



The director selection depends on the
shape and the anatomical configuration
of the treated area.
The actual distance from the director
to the skin will determine the extent of
the treatment zone.
It can be detected by passing an
ordinary fluorescent lamp between the
treatment head and the patient’s skin.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
21




The target area should be bare skin.
Clean the skin thoroughly to avoid
refraction or burn if the skin is wet.
Choose the comfortable position for
the patien on a wooden stool.
No towel is needed.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
22




The target distance will determine the
power levels, as the closer the director to
the skin, the lower the power levels and
vice-versa.
A warm-up period must be allowed to
permit the magnetron to develop enough
efficiency (+-4 minutes).
The desired sensation of the patient is
gentle warmth.
Reports of hot spots should be attended
immediately either by reducing the power
or increasing the distance.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
23


Treatment by microthermy requires between 10
and 20 minutes.
Generally, smaller target areas need less time,
while larger ones need more.


Treatment may be applied daily or every other day.
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
24




Operation of the machine is simple
Comfortable for the patient
Localised heat to small surfaces
No overheating if precautions are followed
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
25




Not for deep structures
Heats only one aspect of the joint
No accurate measurement of the energy given
and the heat received by the patient
Risk of burn
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
26
Electrotherapy Prof. Khaled Mamdouh, Ms. I. Devreux
27