Note: Descriptions are shown in the official language in which they were submitted.
1 159904
This invention relates to high frequency electromagnetic
therapy apparatus and particularly to inductors for use with
such apparatus.
For over forty years, high radio frequency electromagnetic
radiation has been in regular use in the therapeutic treatment
of a number of medical conditions. Many pathological processes
have been successfully treated, by the direct application
to the area under consideration, of an induced electromagnetic
field in the VHF band. The Diapulse Corporation (New York,
U.S.A.) produces a pulsed VHF electromagnetic field generator
suitable for such medical use.
Present equipment is relatively high powered and
is consequently large. The Diapulse Corporation equipment,
for example, can produce a pulsed peak power of 900 watts
and an average power output of 1.5 to 38 watts. The inductor
which is placed adjacent the area to be treated is approximately
the size of a domestic kettle and consequently the patient
is somewhat restricted in movement during treating sessions.
I have recently discovered that the use of such
large amounts of power is in fact unnecessary for the treatment
of some conditions. I have therefore developed a smaller,
portable, high frequency, low energy, electromagnetic energy ther-
apy apparatus which employs a relatively small treatment inductor
to radiate a high frequency, low energy electromagnetic field
from the inductor into the area of the body to be treated
at a field strength which promotes healing of body tissue
but which is too small to significantly heat the body tissue.
This may be placed in position to leave the patient generally
mobile. Since the patient maintains mobility and can continue with
-- 1 --
1 1~990~
normal activities during treatment, beneficially longer
therapeutic treatment periods are possihle.
According to the present invention, then, there
is provided a high fre~uency electromagnetic therapy apparatus
comprising a low voltage power supply, a flexible inductor
of generally circular configuration forming an antenna which
is positionable on an area of a body to be treated, and a
high-frequency, low-energy signal generator circuit connectable
between the power supply and the inductor-antenna to radiate
1~ a high-frequency, low-energy electromagnetic field from the
inductor-antenna into the area of the body to be treated at
a field strength which promotes healing of body tissue, but
which is too small to significantly heat the body tissue,
the frequency of the field being controlled by an inductive-
capacitive tuned circuit, the inductor-antenna forming a part
of the tuned circuit, whereby signal strength of the radiated
field is independent of the differences in capacitive coupling
between the inductor-antenna and the body to be treated.
The inductor may be provided as a single flexible
loop of wire. In the alternative, the inductor elements may
be provided with a resilient covering material to form a flexible
body which may be conveniently attached to the patient by
means of surgical tape and will lie naturally against the
area to be treated.
An inductor so substratéd will be generally planar,
but for treatment of acutely curved areas of the body, it
may be more convenient to form the inductor as a complementary
curved surface.
The inductor may be part of a tuned circuit of the
-- 2
1 15990.~
high frequency electromagnetic therapy apparatus, in which
case the inductor elements will be wound, generally in a circle.
The number of turns provided, and any tapping points, will
need to be exactly determined to provide the appropriate resonating
frequency. In other words, the inductance of the treatment
inductor, which acts in this case as an antenna to receive
a low power radio frequency (r.f.) oscillating signal, is
utilized as a frequency determining component of the tuned
circuit including a VHF pulse generator.
The incorporation of the inductor in the tuned circuit
can be avoided by including a crystal oscillator in the pulse
generator. This arrangement may in some cases be preferred
since it provides more flexibility to the design of the inductor.
The inductor elements are generally electrically-
conductive wire, for example multifilament wire. Coaxial
cable has also proved to be useful. More than one inductor
element may be employed if desired.
To form the tr,eatment inductors, the inductor elements
can be laid in the pattern required and then provided with
a flexible cover, for example, of silicone rubber. Various
patterns may be provided for different areas of the body,
and if a generally-planar inductor is required then the product
will generally be a sheet-like body of resilient material
having the inductor elements embedded therein and having connector
leads extending from one edge, for connection to the high
frequency electromagnetic radiation generator. The latter
is generally a miniaturised VHF pulse generator. The power
generated by such apparatus (functioning from small batteries)
is in the milliwatt region and as such, thermal phenomena
1 1~990~
such as tissue heating are substantially avoided.
Preferred features of the invention will now be
described with reference to the accompanying drawings,
wherein:
Figure 1 is a schematic plan view in cross-section
of a treatment inductor according to the invention,
Figure 2 is a view similar to Figure 1 of a further
inductor according to the invention, and
Figure 3 is a circuit diagram of a miniature VHF
pulse generator for use with a treatment inductor of the invention.
Figure 1 illustrates a treatment inductor which
is to form part of a tuned circuit with a VHF pulse generator.
The inductor comprises a spirally-wound, sheathed multi-filament
electrically-conductive wire 2 havin~ a centre-tapping 4.
This provides a three-pin connection 6 from the two ends and
the centre of the wire. The wire is embedded in silicone
rubber 8 and the whole inductor is of generally planar appearance.
Figure 2 illustrates a treatment inductor for use
with a self-oscillating VHF pulse generator. Since the inductor
does not need to form part of a tuned circuit (as with the
Figure 1 inductor), the number of turns of inductor element
wire and other parameters are not so critical. The inductor
comprises a small coaxial cable 10 providing a two-pin connection
12, one of the connections being to the coaxial cable screen
14 and the other to central conductor 16. The cable is embedded
in silicone rubber 8 and the inductor is of generally-planar
appearance. It is also elongated for use with the treatment
of elongated areas of the body, e.g. along the length of a
limb or a digit.
-- 4
~'
~ 159gO~
Figure 3 is a circuit diagram of a self-oscillating
VHF pulse generator for use with a three-pin treatment inductor
of the invention. The latter consists of a spirally-wound
coaxial cable, similar to the inductor shown in Figure 1,
but with the centre-tapping of the cable being taken to the
screen and the outer and inner connections being made to the
central conductor o~ the cable. The inductor winding connections
are shown to the right of Figure 3.
The pulse generator includes a timing-unit 18 (Type
555 available from Radio Spares, London, U.K.) feeding a power
amplifier output stage which itself provides outputs for connection
to the three pins of the treatment inductor already mentioned.
The circuit illustrated provides 12 volt output pulses from
pin 3 of the oscillator, 100 ~sec. in width and at intervals
of 1 msec. The inductor coil was formed of coaxial cable
with cable lengths; outer connection to screen connection
79 cm, screen connection to inner connection 57 cm. The generally
circular electrode produced was approximately 10 cm in diameter
and produced a power output in the milliwatt range.
