Sound is a mechanical vibration. Audible sound frequencies for humans range from 20 to 20,000 Hz. Ultrasonic sound above 20,000 Hz is inaudible to humans. Its medical use began in the 1930s. It is applied for various purposes including diagnostics (e.g., examination of internal organs or blood vessels), kidney and gallstone lithotripsy, tissue "cutting" (as a surgical scalpel), dental tartar removal, and physiotherapy for treating musculoskeletal disorders.
Ultrasound therapy is used for musculoskeletal complaints (joint and tendon inflammation, muscle pain, contractures, etc.) as well as dermatological and cosmetic treatments.
For musculoskeletal issues, 1MHz ultrasound is commonly used because these waves can penetrate 10-15cm deep into the body. Conversely, 3MHz ultrasound penetrates maximally 2-3 cm deep, making it suitable primarily for skin treatments and superficial tendons and small joints (e.g., finger joints). For cavitation treatments, frequencies below 640kHz are most effective.
Consequently, a 3MHz device is not suitable for treating deep joints like the knee or hip, as the waves cannot reach sufficient depth. However, it is 100% effective on the surface. Meanwhile, 1MHz ultrasound has a significantly smaller effect on the skin and superficial structures while reaching the deeper areas. Both 1 and 3 MHz ultrasounds have minimal cavitation effect; frequencies below 640kHz have no significant therapeutic effect but are suitable for fat reduction.
Applications of ultrasound therapy
- pain relief: for muscle, joint, and tendon diseases, as well as reducing symptoms of back pain, lumbago, sciatica, and herniated discs
- inflammation reduction: relieving joint inflammation and effectively treating acne
- edema reduction: for example, reducing edema around nerve roots under pressure in lumbago or herniated disc cases
- cavitation: treating cellulite and removing unwanted fat deposits
- phonophoresis: delivering active substances into deeper layers of the skin
- wrinkle treatment: highly effective for wrinkle reduction
Beauty applications
- Enhances absorption of active ingredients on the face and body; recommended when using cosmetic products. Ultrasound helps absorb oils, fat-soluble vitamins, liposomal products, emulsions, and water-soluble substances.
- Increases cell permeability, reduces the skin's functional barrier layer, and enhances the activity of active ingredients. The substances penetrate deeper skin layers, making their effects stronger than topical application alone.
- Treatment of superficial wrinkles and sensitive skin. The treatment helps smooth and reduce expression lines. The thermal effect of ultrasound warms tissues and promotes cell building and biochemical processes.
- Treatment of acne and pimples on the face and body. Besides its anti-inflammatory effect, ultrasound activates fibroblast cells, essential for post-inflammatory regeneration. Collagen produced after ultrasound treatment increases tissue elasticity and reduces scar formation. It also aids absorption of anti-acne preparations, boosting their effectiveness.
- Anti-cellulite (cellulite removal) treatment.
- The thermal treatment mobilizes fat layers in treated areas, aiding fat metabolism and removal.
Effects of ultrasound treatment
The effects are largely due to heat generated by tissue-absorbed vibrations. Particles in tissues vibrate at the ultrasound frequency, creating micro-massage as cellular elements move relative to each other. This mechanical energy converts to heat, which warms tissues and provides tissue-loosening, pain-relieving, and vasodilating effects.
Main effects:
- Pain relief. Pain relief results from heat and ultrasound's direct effect on sensory nerve endings.
- Tissue "softening" effect (fibrolysis). Ultrasound vibration causes collagen fiber fragmentation in fibrotic tissues.
- Healing stimulation (trophic effect). Heat-induced vasodilation promotes healing and supplies tissues with nutrients and oxygen. Ultrasound enhances cell defense against bacterial and viral invasion, supports tissue repair, and accelerates recovery from inflammation.
Additionally:
- relaxes tight, stiff muscles,
- stimulates metabolism and removal of waste and toxins,
- beneficial for arthrosis and arthritis,
- aids in breaking down old hematomas and scar tissue,
- relieves tendon and tendon sheath inflammation and bone spur pain,
- reduces inflammation,
- alleviates pain caused by lumbago, herniated discs, and sciatica,
- treats nerve inflammations,
- improves lymphatic circulation,
- helps relax and soften stiff muscles and joint ligaments before therapeutic massage.
Ultrasound treatment modes: contact and underwater therapy
Therapeutic ultrasound is usually applied with a treatment head placed directly on the skin. Contact gel is used between the head and skin, essential for ultrasound waves to penetrate the body. Without gel, the treatment may be ineffective!
In some cases, such as severe rheumatic arthritis pain, pressure or contact from the treatment head causes unbearable pain. Then underwater (subaquatic) ultrasound therapy is used. The affected body part is immersed in water (e.g., basin or tub). The waterproof ultrasound head does not touch the painful area but directs waves from 1-2 cm distance. Vibrations travel undisturbed through water, allowing the therapy effect to persist.
Attention! MSonic 901, 950, Sonic 922 and 1032 devices are NOT suitable for underwater use! The MediSound 3000 has a waterproof treatment head!
Contraindications
Do not use ultrasound in the following cases:
- In cancer, especially not on or near tumors; ultrasound may stimulate tumor growth and metastasis formation.
- Fresh hematoma—may increase bleeding.
- Acute phlebitis (thrombophlebitis)—may spread inflammation.
- Acute deep vein thrombosis—ultrasound treatment could dislodge clots and cause embolism.
- Acute sepsis—on infected areas, ultrasound may spread infection.
- Areas recently irradiated; radiation therapy damages tissues, so ultrasound must be avoided in irradiated regions for at least 6 months. Non-irradiated areas can be treated.
- Severe osteoporosis—use with caution after thorough evaluation.
- Near joint growth plates during bone growth phases.
- On or near eyes.
- During pregnancy, on abdominal and lower back areas.
- Near thyroid and heart.
Ultrasound dosing – treatment dosage
Ultrasound treatment—like other procedures and medications—cannot be used without limits. It can be overdosed! Although not toxic, overdose may worsen symptoms and pain. If this occurs, stop treatment and assess the appropriate dosage. Reducing treatment frequency, duration, and/or intensity usually resolves such issues.
Proper ultrasound dosing requires attention. To learn more, read the expert article by Dr. Zsolt Zátrok in the Lifetime Health magazine.
