Hanger ACP MEGAPULSE II, Руководство пользователя

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14 MEGAPULSE
®
II USER MANUAL
COPYRIGHT © 2017, ACCELERATED CARE PLUS CORP., ALL RIGHTS RESERVED
MODES OF OPERATION
Thermal Effect Variables
I. Tissue Energy Dissipation
The extent of the thermal effect in tissue is based on the tissue energy dissipation. The time average value of the
locally dissipated energy is given by the formula:
P = 0.5

E
2
(W/m
3
)

= specific electrical conductivity of the tissue
E = amplitude of the local electric field strength
At a frequency of 27 MHz, muscle has a resistance of 0.6 ohms / meter (10 times lower than fat) due to its high
electrolyte content . . . thus energy will be dissipated more rapidly in muscle tissue. The energy dissipation is often
expressed in W/kg, by standardization of the specific mass density p. The Specific Absorption Rate (SAR) is defined
as follows:
SAR = 0.5

E
2
/p (W/kg)
For muscle tissue p = 1070 kg/m
3
For Fat p = 940 kg/m
3
II.
Drum Inductive Applicator Design and Application Technique
The SAR is also controlled by the shape of the magnetic field, the drum inductive applicator design and the
positioning on the patient. Research by Lehman (Heating patterns produced by shortwave diathermy applicators,
Archives of Physical Med Rehabil 64:575 - 577, 1983) demonstrates a typical SAR of 0.39 to 2.67 for inductive
field applicators. Typical values for the Megapulse
®
II drum inductive applicator is 1.5 SAR. The higher the SAR
value, the greater the thermal effect in the tissue.
III. Treatment Time
In general treatment times for pulsed shortwave is 20 minutes. The dosage charts have been computed based on a 20
minute application time. The sensation of mild, moderate or vigorous warmth by the patient should be the final
indicator of obtaining the desired temperature in tissue. Start with the lowest dose capable of providing the desired
sensation of temperature to the patient. Increase the pulse rate and pulse duration to increase the dose as clinically
appropriate (assuming the patient has normal sensation). Preprogrammed doses may be selected on the front panel
for ease of operator selection.
IV. Safety
Due to the design of the drum inductive applicator, a strong magnetic field is produced with only a small incidental
amount of electrical field. As the distance away from the drum inductive applicator increases, the amount of energy
in the magnetic field drops rapidly and becomes equal to the energy in the electrical field. The nominal distance
where this occurs is called the boundary between near and far fields. This distance has been measured to be
approximately 5 feet. However, both the magnetic and electrical field intensities are well below all applicable RF
exposure standards at a distance of 2 feet from the drum inductive applicator.