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7.2.2 The contact medium
To ensure efficient transfer of energy, a contact medium is required between the ultrasound
applicator and the body. Air causes virtually total reflection of the ultrasound energy. The
best medium for the transfer of ultrasound energy is a gel.
The gel should be applied to the part of the body to be treated and then spread out
with the ultrasound applicator.
Never apply the gel to the ultrasound applicator. The applicator will register this as
acoustical contact and may emit ultrasound energy, which could damage the applica-
tor.
If the body surface is very irregular, making it difficult to obtain good contact between the
ultrasound applicator and the body, or if direct contact must be avoided (e.g. due to pain),
the affected area may be treated under water (subaqual method). The water should be
degassed (by previous boiling) in order to prevent air bubbles arising on the ultrasound
applicator and the body.
7.2.3 Before treatment
Check the patient for contra-indications. See section 4.2.2 for details.
Test the warmth sensibility of the treatment area.
To optimize ultrasound transmission, clean the skin of the treatment area with soap or
a 70% alcohol solution.
Strong hair growth has to be shaved.
7.2.4 During treatment
The ultrasound applicator has to be moved constantly, also with the semi-static
method. During treatment the displayed ultrasound Amplitude can vary around the set
value, caused by fluctuations in acoustical coupling.
Ask the patient regularly for his/her findings. If necessary the treatment will have to be
adapted. The Amplitude can be reduced or the continuous mode can be changed to
pulsed mode or vice versa.
When there are signs that the ultrasound transmission is bad, add more contact gel or
spread it with the applicator.
Rehab-Series
