U.S. patent application number 10/055764 was filed with the patent office on 2003-07-31 for apparatus and method for substantially stationary transducer therapeutic ultrasound treatment.
Invention is credited to Coffey, Kenneth W., Dorholt, Gregory F..
Application Number | 20030144611 10/055764 |
Document ID | / |
Family ID | 27609220 |
Filed Date | 2003-07-31 |
United States Patent
Application |
20030144611 |
Kind Code |
A1 |
Coffey, Kenneth W. ; et
al. |
July 31, 2003 |
APPARATUS AND METHOD FOR SUBSTANTIALLY STATIONARY TRANSDUCER
THERAPEUTIC ULTRASOUND TREATMENT
Abstract
An apparatus and method for therapeutic ultrasound treatment
using a plurality of spaced apart piezoelectric crystals
sequentially activated for a preselected time, thereby allowing the
transducer containing the piezoelectric crystals to be used
substantially stationary relative to the area being treated.
Inventors: |
Coffey, Kenneth W.; (Tulsa,
OK) ; Dorholt, Gregory F.; (Tulsa, OK) |
Correspondence
Address: |
Frank L. Hart
Attorney at Law
8911 S. 73rd East Ave.
Tulsa
OK
74133
US
|
Family ID: |
27609220 |
Appl. No.: |
10/055764 |
Filed: |
January 25, 2002 |
Current U.S.
Class: |
601/2 |
Current CPC
Class: |
A61N 2007/0078 20130101;
A61N 7/00 20130101 |
Class at
Publication: |
601/2 |
International
Class: |
A61H 001/00 |
Claims
What is claimed is:
1. A therapeutic ultrasound system adapted to substantially
stationary transducer application, comprising: first means for
generating a pulsed digital signal at a frequency in the range of
greater than about 800 kHz to less than about 3.0 MHz and a spatial
average intensity in the range of about 0.1 watt per square
centimeter to about 3.0 watt per square centimeter; a sine wave
filter connected to the first means and adapted to receive the
signal from the first means and converting it to a second signal; a
programmable controlling element connected to the sine wave filter
and being adapted to deliver said second signal to a plurality of
separate locations in a preselected sequence, each for a
preselected period of time; a transducer having a plurality of
spaced apart piezoelectric crystals each operatively connected to
the programmable controlling element for sequentially receiving the
second signal and delivering a pulsed ultrasound energy outwardly
therefrom; and means for maintaining the transducer substantially
stationary during operation thereof.
2. A system, as set forth in claim 1, wherein the first means
includes an oscillator connected to a variable gain transformer,
said oscillator being controllably interrupted to produce a signal
having a preselected duty cycle.
3. A system, as set forth in claim 2, wherein said oscillator is
controllable to maintain the duty cycle of the pulsed signal in the
range of about 5 percent to about 50 percent.
4. A system, as set forth in claim 1, wherein the piezoelectric
crystals of the transducer are each connected to the programmable
controlling element via a respective coaxial cable.
5. A system, as set forth in claim 1, wherein the spatial average
intensity of system is maintainable at about 1 watt per square
centimeter.
6. A system, as set forth in claim 1, wherein there are at least 4
piezoelectric crystals each being actuateable only one preselected
time period during a sequencing cycle of the programmable
controlling element.
7. A system, as set forth in claim 1, wherein there are a plurality
of groups of piezoelectric crystals with each piezoelectric group
comprising a plurality of separate piezoelectric crystals.
8. A system, as set forth in claim 7, wherein each piezoelectric
crystal group is independently and separately controlled relative
to other piezoelectric crystal groups of the system.
9. A system, as set forth in claim 1, including means for
maintaining the transducer substantially stationary relative to a
preselected location on a user.
10. A system, as set forth in claim 9, wherein the maintaining
means is at least one Velcro strap, said strap having a length
sufficient to encircle a portion of a user's body.
11. A system, as set forth in claim 9, wherein the maintaining
means are a plurality of Velcro straps.
12. A system, as set forth in claim 1, including a plurality of
separate transducers each having a plurality of spaced apart
piezoelectric crystals each operatively connected to the
programmable controlling element for sequentially receiving the
second signal therefrom.
13. A system, as set forth in claim 12, wherein the piezoelectric
crystals of one of the separate transducers are independently
sequenced relative to the sequence of operation of the
piezoelectric crystals of the other transducer.
14. A system, as set forth in claim 13, wherein each of the
transducers are operational during the same period.
15. A method of therapeutic ultrasound treatment, comprising:
generating a pulsed digital signal at a frequency in the range of
greater than about 800 kHz to less than about 3.0 MHz; and a
spatial average intensity in the range of about 0.1 watt per square
centimeter to about 3.0 watt per square centimeter; converting the
pulsed digital signal to a pulsed sine wave signal; delivering the
pulsed sine wave signal to a first plurality of separate locations
in a preselected sequence, each for a preselected period of time;
and receiving the pulsed sine wave signal at said first plurality
of separate locations and delivering ultrasound energy outwardly
from each of said separate locations while maintaining the first
plurality of separate locations substantially stationary relative
to a first area being treated.
16. A method, as set forth in claim 15, including a second
plurality of separate locations operatively separate and spaced
from said first plurality of separate locations and adapted to
deliver ultrasound energy outwardly therefrom while maintaining the
second plurality of separate locations substantially stationary
relative to a different second area being treated.
Description
TECHNICAL FIELD
[0001] The subject invention relates to apparatus and the method of
using same for therapeutic ultrasound treatment. More particularly,
the subject invention is directed to an apparatus and method of
using same for the therapeutic ultrasound treatment during which
the transducer is maintained substantially stationary relative to
the area being treated.
BACKGROUND ART
[0002] Ultrasound has been employed in medicine for more than 50
years. The application of ultrasound for medical treatment was
introduced in Germany in the late 1930s, and in the United States
in the late 1940s.
[0003] Sound with a frequency greater than 20,000 Hz is called
ultrasound. For a given sound source, the higher the frequency, the
less the emerging sound beam diverges. Sound at audible frequencies
appears to spread out in all directions, whereas ultrasound beams
are well collimated, similar to a light beam leaving a flashlight.
Ultrasound beams at frequencies greater than 800 kHz are
sufficiently collimated to selectively expose a limited target area
for physical therapy treatment. At frequencies less than about 800
kHz the ultrasound beards intensity is sufficiently low as to be
outside the range for physical therapy treatment, but has been used
at these low intensity levels for diagnostic procedures.
[0004] Absorption of sound, and therefore attenuation, increases as
the frequency increases. Absorption occurs in part because of the
internal friction in tissue that needs to be overcome in the
passage of sound. The higher the frequency, the more rapidly the
molecules are forced to move against this friction. As the
absorption increases, there is less sound energy available to
propagate through the tissue. At frequencies greater than 20 MHz,
superficial absorption becomes so great that less than 1 percent of
the sound penetrates beyond the first centimeter.
[0005] Therefore, for physical therapy applications, the frequency
range is generally considered to be limited to frequencies within
the range of about 800 kHz to about 3.3 MHz. Frequently most often
used for physical therapy application is a frequency of about 1.0
MHz or 3.0 MHz because they offer a good compromises between
sufficiently deep penetration and adequate heating under customary
exposure levels.
[0006] Sound waves can be produced as continuous wave or as pulsed
wave. A pulsed wave is intermittently interrupted. Pulsed waves are
further characterized by specifying the fraction of time the sound
is present over one pulse period. This fraction is called the duty
cycle and is calculated by dividing the pulse time on by the total
time of a pulse period; e.g. time on plus time off. Duty cycles for
therapy machines, when in the pulsed mode, range from about 5
percent to about 50 percent.
[0007] The strength of an ultrasound beam is determined by its
intensity. Intensity is the rate at which energy is delivered per
unit area. It is expressed in units of watts per square centimeter.
Intensities employed in physical therapy are limited to the range
of about 0.25 to about 3.00 watts per square centimeter.
[0008] Where sound beams are pulsed, the intensity of the beam will
be zero when the sound beam is off and at its maximum during the
pulse. The temporal average intensity of a beam is obtained by
averaging the intensity over both the on and off periods. The
amount of heating depends on the temporal average intensity. The
temporal average intensity is decreased proportionally to the
amount of time the sound is off. Thus less heating will occur even
though the temporal peak intensity is unchanged.
[0009] Because the ultrasound beam is not uniform, some regions of
the beam will be more intense than other regions. The measurement
of intensity gives an average intensity and is referred to as the
spatial average intensity. The World Health Organization limits the
spatial average intensity to a maximum of 3 watt per square
centimeter. Intensities greater than 10 watt per square centimeter
are used to destroy tissue surgically and intensities (temporal
average) below 0.21 watt per square centimeter are used for
diagnostic purposes.
[0010] Therapeutic ultrasound treatment is customarily performed
using a moving transducer technique with a small layer of gel or
lotion between the transducer and the tissue. This movement is to
avoid damage caused by beam "hot spots" as is known in the industry
and in general to treat areas which are typically larger than the
area of the transducer.
[0011] Ultrasound treatment is an attended therapy that requires a
clinician to be present to move the sound head over the treatment
area. This movement of the transducer over the gel covering the
treatment area causes the gel to be displaced and therefore
requires constant attended application of the gel.
[0012] Movement speed rate of the transducer during treatment vary
widely from one clinician to another. Therefore, there often is
misuse of the treating machine, by the clinician which is caused by
moving the transducer too fast, not using enough coupling medium,
not moving the transducer, trying to treat too large and area, not
keeping the transducer in contact with the patient and other
faults.
[0013] Since treatments must be supervised by a clinician, the
patient is often limited to specific treatment times with greater
repetitions. It has been found that often it would be more
beneficial to the patient to have fewer treatments each of longer
duration.
[0014] The present invention is directed to over come one or more
of the heretofore problems, as set forth above.
DISCLOSURE OF THE INVENTION
[0015] In one aspect of the invention, a therapeutic ultrasound
system is adapted to substantially stationary transducer
application during use. The system has a first means for generating
a pulsed digital signal at a frequency in the range of greater than
about 800 kHz to less than about 3.0 MHz and a spatial average
intensity in the range of about 0.1 watt per square centimeter to
about 3.0 watt per square centimeter.
[0016] A sine wave filter is connected to the first means and is
adapted to receive the signal form the first means and convert it
to a second signal. A programmable controlling element is connected
to the sine wave filter and is adapted to deliver said second
signal to a plurality of separate locations in a preselected
sequence, each for a preselected period of time.
[0017] A transducer has a plurality of spaced apart piezoelectric
crystals each operatively connected to the programmable controlling
element for sequentially receiving the second signal and delivering
a pulsed sound beam therefrom. Means is provided for maintaining
the transducer substantially stationary during operation
thereof.
[0018] In another aspect of the invention, a method of therapeutic
ultrasound treatment is provided. A pulsed digital signal is
generated at a frequency in the range of greater than about 800 kHz
to less than about 3.0 MHz and a spatial average intensity in the
range of about 0.1 watt per square centimeter to about 3.0 watt per
square centimeter. The signal is converted to a pulsed sine wave
signal. The pulsed sine wave signal is delivered to a first
plurality of separate locations in a preselected sequence, each for
a preselected time period. The pulsed sine wave signal is received
at said first plurality of separate locations and ultrasound energy
is delivered outwardly from each of said separate locations while
maintaining the first plurality of separate locations substantially
stationary relative to a first area being treated. Means is
provided for maintaining the transducer substantially stationary
during operation thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a diagrammatic view of the apparatus of this
invention; and
[0020] FIG. 2 is a diagrammatic view of the apparatus of this
invention which has a second transducer.
BEST MODE FOR CARRYING OUT THE INVENTION
[0021] Referring to FIG. 1, a Therapeutic ultrasound system 2 is
shown. The ultrasound system 2 has an oscillator 4 connected to a
variable gain transformer 6 which is connected to a sine wave
filter 8 for converting a pulsed digital signal to a pulsed sine
wave signal. The pulsed sine wave signal is delivered by line 10 to
a programmable controlling element 12.
[0022] The oscillator 4 and variable gain transformer 6 are adapted
to generating a pulsed digital signal at a frequency in the range
of greater than about 800 kHz to less than about 3.0 MHz and a
spatial average intensity in the range of about 0.1 watt per square
centimeter to about 3.0 watt per square centimeter, preferably
about 1.0 watt per square centimeter. At these values, the
therapeutic ultrasound system 2 intensity is limited to the values
used for therapeutic treatment.
[0023] The programmable controlling element 12 receives the pulsed
sine wave signal via line 10 and delivers said signal to a
plurality of separate locations 13-16 within a transducer 11, each
location 13-16 which is occupied by a separate piezoelectric
crystals 17-20, via respective lines 21-24. The piezoelectric
crystals 17-20 receives the pulsed sine wave signal in a
preselected sequence, each for a preselected time period as
delivered from the controlling element 12.
[0024] In response to pulsed actuation, each piezoelectric crystal
17-20 delivers ultrasound energy outwardly from the transducer 11.
Since each individual piezoelectric crystal 17-20 is actuated to
deliver ultrasound energy during only a fraction of the total time
of one complete cycle of operation of the transducer 11 and since
the individual piezoelectric crystals 17-20 are spaced one from the
other, the transducer 11 can remain stationary relative to the area
being treated without the development of undesirable "hot spots" as
described above. For this reason, the transducer 13 can be strapped
to an individual by, for example by a Velcro strap 26, Velcro
straps 26,27, or any other means for maintaining the transducer 11
stationary relative to the area being ultrasonically treated.
[0025] The oscillator is controllable to maintain the duty cycle of
the pulsed signal in the range of about 5 percent to about 50
percent. Preferably the duty cycle is maintained at about 20
percent. Maintaining a low duty cycle percentage coupled with
sequencing of multiple piezoelectric elements assures against the
avoidance of "hot spots" in an immobile transducer.
[0026] The lines 21-24 which connect the transducer 11 to the
controlling element are preferably coaxial cables. The purpose of
the coaxial cable is to maximize transmission of the electrical
energy and to minimize frequency distortion and interference with
the external environment.
[0027] Referring to FIG. 2, another embodiment of the invention is
shown, which has a plurality of transducers 11, 28, each having a
plurality of separate piezoelectric crystals 17-20, 30-33. In this
embodiment each transducer has a separate group of piezoelectric
crystals with each crystal group 17-20,30-33 connected to the
controlling element 12 and each crystal group is independently
sequenced relative to the other crystal group.
[0028] Each of the transducers 11,28 are operational during the
same period. FIG. 2 shows such a use where a separate transducer
11,28 is treating a respective opposed side of a patients knee.
[0029] The ultrasound generator preferred in this invention is part
No. 0185, available from Rich-Mar Corporation, PO Box 879, Inola,
Okla. 74036, Phone 918-543-2222. The transducer 11 or 28 will also
be available as an off-the-shelf item from Rich-Mar Corporation, as
will be the programmable controlling element 12. However, it is
urged that one skilled in the art, after reading this specification
can easily build the apparatus of this invention without employing
actions of an inventive nature.
[0030] Industrial Applicability
[0031] In the method of using the apparatus of this invention, a
pulsed digital signal is generated at a frequency in the range of
greater than about 800 kHz to less than about 3.0 MHz and a spatial
average intensity in the range of about 0.1 watt per square
centimeter to about 3.0 watt per square centimeter. This generated
signal is then converted to a pulsed sign wave signal which is
delivered to a first plurality of separate locations in a
preselected sequence, each for a preselected period of time. The
signal is received sequentially at each of said first plurality of
separate locations and result in the delivery of ultrasound energy
outwardly from each of said separate locations while maintaining
the first plurality of separate locations substantially stationary
relative to a first area being treated.
[0032] FIG. 2 shows another method having two transducers 11,28
connected to the controlling element 12, each transducer 11,28
being functionally similar. The second transducer 28 has a second
plurality of separate locations operatively separate and spaced
from said first plurality of separate locations and adapted to
deliver ultrasound energy outwardly therefrom while maintaining the
second plurality of separate locations substantially stationary
relative to a different second area being treated. This other
embodiment of the invention is most useful in treating a joint of
an individual which sustained damage to opposed sides of the
joint.
[0033] Other aspects, objects and advantages of this invention can
be obtained from a study of the drawings, the disclosure and the
appended claims.
* * * * *