Continuous emission EQultrasound hand probes (Flat Red Hand Probe and Concave Red Hand Probe) can produce a significant temperature increase in deep tissues, while avoiding excessive heating of overlying tissues. Therefore EQultrasound can be used to selectively heat specific equine structures (such as joints, tendons, ligaments and muscles), without overheating skin.
Factors affecting heat depth and diffusion are:
- ultrasound frequency
- intensity of ultrasound emission
- treatment duration
- size of the area to treat
- type of tissue to treat
The higher the frequency, the greater the amount of energy absorbed by superficial tissues and consequently the more superficial the thermal effects.
This is one of the major advantages offered by EQultrasound low-frequency / longwave treatment modality (38 kHz +/-2) versus traditional high frequency ultrasound devices (1-3 MHz): since EQultrasound operates at a much lower frequency than traditional high frequency devices, it can reach deeper equine tissues and structures with limited absorption by superficial tissues.
In fact ultrasound energy is attenuated when the wave propagates through biological tissues. Attenuation is the result of absorption and scattering effects. Absorption in tissue leads to the transformation of ultrasound energy into heat, and is the main component of attenuation.
The temperature induced in tissue is directly proportional to its absorption coefficient. Biological tissues with a high fluid content absorb ultrasound waves better than less hydrated tissues.
Ultrasound does not appreciably heat skin but can significantly heat deeper tissues such as joint structures, tendon, muscle, nerve, and bone. Continuous emission modality is usually employed for pathologies in the chronic phase or when heat is a desirable element (for example to increase soft tissue extensibility before active or passive stretching activities).
Heating biological tissues using EQultrasound continuous mode administration induces the following physiological effects:
- decrease of viscosity in fluid elements
- increase of vasodilation and blood flow (which convey more oxygen and nutrients to the injured area and assist in the reduction of swelling)
- increase in enzymatic activity
- increase in cellular metabolic activity, accelerating oxygen consumption and removal of waste substances generated by the injury (histamine, bradykinin and prostaglandins, which contribute to sensitization of nerve fibers and pain)
- stimulation of the immune system
- pain relief
- increase of soft tissue extensibility
Therapeutic continuous emission ultrasound is commonly used for:
- chronic inflammatory conditions
- pain control in chronic pain
- prior to stretching exercises of a tight structure (tendon, ligament, fascia, scar, capsule)
Deep heat induced by continuous emission ultrasound stimulates tissue repair in chronic inflammatory conditions and is a valuable tool for veterinarians and equine physical therapists, since it enables them to selectively treat specific areas most often affected in sports injuries, while avoiding excessive heating of overlying skin.
Continuous emission EQultrasound hand probes (red hand probes) are also used in the first minutes of sonophoresis treatments. In fact by minimally rising the skin surface temperature, EQultrasound red hand probes increase dermal capillary vasodilation and cell membrane permeability, therefore allowing transcutaneous absorption of the medication. The acoustic pressure generated by EQultrasound promotes deep drug diffusion and absorption, therefore optimizing both pharmacokinetics and drug action.