introduction microwave diathermy الميكروويف إنفاذ حراري (mwd), is a form of...

INTRODUCTIONMicrowave diathermy الميكروويف إنفاذ

is a form of electromagnetic ,(MWD)حراريradiations lying between shortwave and infrared waves.

Where energy is first absorbed at the surface of the body (skin) and a part of it penetrate and absorbed in deep tissues.

Microwave diathermy does not penetrate as deep as shortwave diathermy.

INTRODUCTIONMicrowave has a much higher frequency

and a shorter wavelength than shortwave diathermy.

Generates Strong Electrical Field and Relatively Little Magnetic Field

The general frequency of microwave is between 300 MHz to 300 GHz with wave length of 10mm to 1 meter.

INTRODUCTIONThe therapeutic microwave generators

used frequency of 2450MHz with wave length of 122.5mm.

Microwave radiation is radiated as a beam شعاع from an antenna هوائي and absorbed by water-rich tissues 7000 times more effectively than shortwave radio frequency energy.

INTRODUCTIONA microwave beam can be narrowed ضاقت

to allow small areas to be treated accurately, is highly directional  للغاية ,اتجاهيand can be aligned rapidly.

Microwave energy is generated ولدت by an electronic

device known as a MAGNETRON. المغنطرون

The applicators consist of an antenna element backed by a reflector عاكس and endorsed within a plastic case,  من حالة one face of which is transparent البالستيك.to microwave energy شفافة

PANNEL DIAGRAM OF MWD

MWD Applicators (Electrodes)1. Circular دائري

Shaped Applicators 4” or 6”

Maximum Temperature At

Periphery

2. Rectangular Shaped مستطيلةApplicators 4.5 x 5” or 5 x 21” Maximum Temperature At Center

METHODS OF APPLICATION1. DIRECT CONTACT  المباشر االتصال

APPLICATION less stray radiation produce a more uniform pattern of heating

deep inthe tissues.2. NON – CONTACT  -- بنا اتصل غير

APPLICATION Reflection at the air-skin interface occurs

frequentlyOccasionally generating unacceptably

intense stray radiation.

PHYSICAL BEHAVIOUR OF MWD1. REFLECTION

2. REFRACTION

3. ABSORPTION

4. PENETRATION

5. TRANSMISSION

THERMAL MECHANISM OF MWDMicrowaves with a frequency of 2450MHz penetrate 1.7اختراق cm in muscle and skin,

and 11.2cm in fat and bone.Superficial tissues moderately heated,

achieve a maximum temperature within five to ten

minutes, after which local vasodilatation prevents

further warming.

THERAPEUTIC EFFECTS OF MWD1. RELIEF OF PAIN BY PAIN GATE

MECHANISM

2. REDUCTION OF MUSCLE SPASM BY STIMULATION OF SECONDARY NERVE ENDINGS.

3. REDUCTION OF INFLAMMATION BY INCREASE IN BLOOD SUPPLY.

THERAPEUTIC EFFECTS OF MWD4. To promote healing of open skin by

increase in circulation

5. Control the chronic infection by increasing the circulation.

6. Fibrosis: heat increase the extensibility of fibrous tissues such as tendons, joint capsules and scars

INDICATIONS OF MWD1. Musculoskeletal disorders:Sprain- strain – muscle and tendon tear –

degenerative joint disease- joint stiffness in superficial joints- capsular lesions.

2. Superficial inflammatory or infective conditions :

Tenosynovitis – bursitis – Synovitis – infected surgical incisions – carbuncles – abscess.

CONTRAINDICATIONS OF MWDOver malignant tissues.

Over ischemic tissues.

Moderate and excessive edema.

Over wet dressings and adhesive tapes.

Metal implants.

Pacemaker.

Over growing bone.

CONTRAINDICATIONS OF MWDHemorrhage.

Tuberculosis joints.

Impaired thermal sensation.

Unreliable patients.

Recent radiotherapy.

Hypersensitivity to heat.

Acute infection or inflammation.

CONTRAINDICATIONS OF MWDVenous thrombosis or phlebitis.

Pregnancy: heat applied to pelvis or hip in pregnancy may cause hemorrhage or miscarriage.

Acute dermatological conditions.

Severe cardiac conditions.

Blood pressure abnormalities.

PRECAUTION & DANGERThe eyes: cause cataract.

Obesity: with 2450MHz microwave, there is danger of producing an excessive heat in the subcutaneous fat layer.

Dosage of MWDDuration of treatment 20 minutes is the optimum.

Intensity: the patient should feel mild and comfortable warmth.

Frequency: daily or on alternating day.