Microwave diathermy

• MWD-lies between radio waves and infrared
waves :1m to 1 cm
• 300MHz to 30GHz
Frequency(MHz) Wavelength(cm)
2450 12.245
915 32.79
433.9 69.14.

Behaviour of Microwaves
• Like electromagnetic radiation,
• reflection and refraction at interfaces,
• absorption and penetration depends on the nature of material.

Production of microwaves
• High frequency oscillating currents-
magnetron
• Physiologic effects of Microwaves-
• Raised metabolic rate,increased blood flow, decrease blood and tissue viscosity,collagen extensibility,pain relief.
• Fat is less heated,muscle is more heated and bone is least heated

• Distribution:ring pattern or oval pattern
• Therapeutic uses:
• 1.Pain relief-pain gate mechanism,increase
blood flow,decrease muscle spasm and sedative effect.
• 2.muscle spasm
• 3.accelerated healing:increase metabolic activity
• 4.softening of scar tissues
• 5.heating of muscle tissue.

Principles of application
• Preparation of patient
• Preparation of apparatus
• Small area-2-5 cm,large area-10 cm.

Dosage
• Time duration-20 minutes
• 200mW/cm2
• Dangers:Metals reflection ,concentration;
cardiac pacemakers,eyes,testes,.

Contraindications
• defective thermal sensation,
• defective blood supply,
• acute inflammation,
• recent haemorrhage,
• metal in the tissues,
• malignancy,
• cardiac pacemakers,
• intrauterine devices,
• eyes and testes. Indication of microwave diathermy. *Disorders of musculoskeletal condition. -Strains. – sprains. -capsular lesion. – degenerative joint disease. – Hematoma. – rheumatoid arthritis

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