ulTrasound modalITy InformaTIon
DYNATRON® 25 SERIES™ | OPERATOR’S MANUAL
54
The selection of the appropriate soundhead is key to the success of the treatment and is based on the size of the area to be
treated. Ultrasound treatments should be kept specific to the tissue involved in pathology. A good guideline is 2 to 4 times
the size of the soundhead. For example:
• A 2 cm
2
soundhead can deliver up to 4 Watts and is appropriate for small areas (i.e. hands, fingers, feet).
• A 5 cm
2
soundhead can deliver up to 10 Watts and is appropriate for medium sized areas (i.e. extremities such as
arms, legs, and cervical areas).
• A 10 cm
2
soundhead can deliver up to 20 Watts and is appropriate for large areas (i.e. torso and back).
Ultrasound is a directed beam of energy. Therefore, not only will the average spatial intensity be a factor in the dosage the
patient receives, but the time delivered and area covered will matter as well. For example, an area of 50 cm
2
is treated for 5
minutes. Then an area of 200 cm
2
is treated for 5 minutes. Both receive the same intensity. The 200 cm
2
area however does
not receive the same dosage (only ¼ ) because as the soundhead is moved around the area it has to cover represents 4 times
as much tissue.
The Soundhead area measurement is the ERA (effective radiating area). Each soundhead has an effective radiating area. It is
not necessarily the outside diameter of the soundhead, but the area of the crystal inside, therefore special care should be
taken in selecting the correct size soundhead for the area to be treated according to the diameter of the crystal.
Penetration of Ultrasound Waves
The correct frequency should be selected for the depth of penetration desired. The amount of penetration needed is
determined by the density of tissue and the depth of the site to be treated. Care should be taken to select a penetration level
that does not cause periosteal (bone) pain.
The frequency determines the depth of penetration of
the Ultrasonic wave.
• Select 1 MHz for deep lesions; provides a
Half-Value Distance (HVD) of about 5cm.
• Select 2 MHz for moderate depth lesions; about
2.6cm HVD.
• Select 3 MHz for superficial lesions; about
1.5cm HVD.
HVD is the approximate point at which the Ultrasound
energy is reduced to half in the average human tissue.
NOTE: If a patient experiences pain during a treatment, the size of the soundhead maybe inappropriate for the area
being treated, the intensity maybe too high, the treatment time maybe too long, or coupling maybe poor.
Multi-Frequency Ultrasound
