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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ultrasonic treating apparatus for
resecting the prostate or destroying a calculus of a subject.
2. Description of the Related Art
It has so far been common practice to, upon the resecting of an affected
living prostate, cauterize the prostate tissue with a high frequency
current.
In recent times, an ultrasonic treating apparatus has increasingly been
employed in that field of art.
The ultrasonic treating apparatus is adapted to cut an affected tissue of a
subject with ultrasonic vibrations and includes an ultrasonic vibration
element and a probe as an ultrasonic transmitter.
The probe of the ultrasonic treating apparatus is guided into the prostate
of a living subject with an endoscope and the prostate can be resected
with the ultrasonic vibrations with the probe being applied to that
prostate site.
It is also possible for the ultrasonic treating apparatus to destroy the
calculus of the subject.
In the above described ultrasonic treating apparatus, however, the
ultrasonic vibration element sometimes fails and there is a risk of its
being destroyed with a continuous use.
SUMMARY OF THE INVENTION
It is accordingly the object of the present invention to provide an
ultrasonic treating apparatus which can avoid a risk of being damaged even
when a defect occurs in the ultrasonic vibration element and assure added
safety during use.
According to the present invention, there is provided an ultrasonic
treating apparatus comprising an ultrasonic vibration element for
transmitting ultrasonic vibrations to a region of interest of a subject,
an impedance detection unit for detecting an impedance of the ultrasonic
vibration element, a determining unit for determining whether the
ultrasonic vibration element is good or not in accordance with the
impedance which is detected by the impedance detecting unit, and a control
unit which, when the ultrasonic vibration element is not good, inhibits
the generation of the ultrasonic vibrations from the ultrasonic vibration
element, in which, when the ultrasonic vibration element is not good, this
state is detected by the impedance detection of the impedance detection
unit and determination of the determining unit and the generation of the
ultrasonic vibrations from the ultrasonic vibration element is inhibited
by the operation of the control unit, thereby preventing the destruction,
etc., of the apparatus per se.
In another embodiment of the present invention, there is provided an
ultrasonic treating apparatus which comprises an ultrasonic vibration
element for transmitting ultrasonic vibrations to a region of interest of
a subject, a drive circuit for supplying an electric power to the
ultrasonic vibration element for drive, a burst drive control unit for
operating the drive circuit in ON-OFF fashion, an impedance detection unit
for detecting the impedance of the ultrasonic vibration element, a
determining unit for determining whether the ultrasonic vibration element
is good or not in accordance with the impedance which is detected by the
impedance detection unit and a control unit which, when the ultrasonic
vibration element is not good, inhibits the operation of the drive
circuit, in which, when the "not good" state occurs in the ultrasonic
vibration element, it is detected by the impedance detection of the
impedance detection unit and determination of the determining unit,
whereby the operation of the drive circuit is inhibited by the control
unit. By so doing, it is possible to inhibit the generation of ultrasonic
vibrations from the ultrasonic vibration element and hence to prevent the
destruction of the apparatus.
In still another embodiment of the present invention, there is provided an
ultrasonic treating apparatus which comprises an ultrasonic vibration
element including a plurality of layered piezoelectric elements and
adapted to transmit ultrasonic vibrations to a region of interest of a
subject, a drive circuit for supplying an electric power to the ultrasonic
vibration element for drive, an impedance detection unit for detecting an
impedance of respective piezoelectric elements, a determining unit for
determining whether respective piezoelectric elements of the ultrasonic
vibration element are good or not in accordance with the impedance which
is detected by the impedance detection unit, and a control unit which,
when a piezoelectric element is not good, inhibits the operation of the
drive unit. In this embodiment, if any of the respective piezoelectric
elements is defective, this state is detected by the impedance detection
of the impedance detection unit and determination of the determining unit
and the operation of the drive circuit is inhibited by the operation of
the control unit. It is, therefore, possible to inhibit the generation of
the ultrasonic vibration from the ultrasonic vibration element and to
prevent the destruction of the apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram showing an ultrasonic treating apparatus
according to a first embodiment of the present invention;
FIG. 2 is a flowchart for explaining the operation of the embodiment shown
in FIG. 1;
FIG. 3 is a circuit diagram showing an ultrasonic treating apparatus
according to a second embodiment of the present invention;
FIGS. 4A and 4B form a flowchart for explaining the operation of the
embodiment shown in FIG. 3;
FIG. 5 is a circuit diagram showing an ultrasonic treating apparatus
according to a third embodiment of the present invention;
FIGS. 6A and 6B form a flowchart for explaining the operation of the
embodiment shown in FIG. 5;
FIG. 7 is a circuit diagram showing an ultrasonic treating apparatus
according to a fourth embodiment of the present invention; and
FIGS. 8A and 8B form a flowchart for explaining the operation of the
embodiment shown in FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first embodiment of the present invention will be explained below in
conjunction with FIGS. 1 and 2.
In FIG. 1, a forward tip 1 of a handpiece comprises an ultrasonic vibration
element 2, horn 3 and probe 4.
The ultrasonic vibration element 2 transmits ultrasonic vibrations onto a
region of interest (ROI) of a subject. The ultrasonic vibrations which are
transmitted from the ultrasonic vibration element 2 are amplified by the
horn 3 and transmitted to the probe 4.
The probe 4 is formed of a transmitting element for transmitting the
ultrasonic vibrations to the ROI of the subject and adapted to be guided
there with the use of, for example, an endoscope.
A drive circuit 5 is operated in accordance with an instruction of a CPU 10
as will be set forth in more detail below and a driving electric power is
applied across output terminals 5a and 5b so that the ultrasonic vibration
element may be driven.
The output terminal 5a of the drive circuit 5 is connected to one terminal
of the ultrasonic vibration element 2 via a normally open contact of a
switch 7a.
The output terminal 5b of the drive circuit 5 is connected to the other
terminal of the ultrasonic vibration element 2 via a normally open contact
of a switch 7b in a changeover circuit 6.
The changeover circuit 6 comprises of the switches 7a, 7b and a switch
drive circuit 8. The switch drive circuit 8 drives the switches 7a, 7b in
accordance with an instruction of a CPU (central processing unit) 10 in a
good/not good determining circuit 9.
One end of the ultrasonic vibration element is connected to an output
terminal 11a of an impedance detection circuit 11 via the normally closed
contact of the switch 7a.
The other end of the ultrasonic vibration element 2 is connected to an
output terminal 11b of the impedance detection circuit 11 via the normally
closed contact of the switch 7b.
The impedance detection circuit 11 comprises the output terminals 11a, 11b,
an AC power source 12 for supplying an AC voltage to the output terminals
11a, 11b, a switch 13 provided on a current conduction path between the AC
power source 12 and the output terminals 11a, 11b, a current detector 14,
a current detector 14 provided between the AC power source 12 and the
output terminals 11a, 11b, a voltage detector 15 connected to the AC power
source 12 via the switch 13, a computing section 16 for computing an
impedance of the ultrasonic vibration element 2 on the basis of a
detection voltage of the voltage detector 15 and current detector 14, and
a switch drive circuit 17 for driving the switch 13.
Here, the computing section 16 divides a detection voltage V of the voltage
detection 15 by a detection current I of the current detection 14 to find
an impedance Z of the ultrasonic vibration element 2. The impedance Z thus
found is sent to a CPU 10 in the good/not good determining circuit 9.
The switch drive circuit 17 drives the switch 13 in accordance with an
instruction of the CPU 10.
The good/not good determining circuit 9 is mainly constructed of the CPU 10
and determines the good/not good state of the ultrasonic vibration element
2 in accordance with the impedance Z which is detected in the impedance
detection circuit 11.
The drive circuit 5, switch drive circuit 8, computing section 16, switch
drive circuit 17, display unit 18 and operating unit 19 are connected to
the CPU 10.
The display unit 18 displays, for example, a result of determination by the
CPU 10. The operation unit 19 gives an instruction to start and end the
treating operation on the ROI of the subject to be treated.
The CPU 10 has, means for determining the good/not good state of the
ultrasonic vibration element 2, a control function means for controlling
the drive circuit 5, switch drive circuit 8 and switch drive circuit 17 in
accordance with the instructions and so on of the operation unit 19 and
control function means for inhibiting the generation of the ultrasonic
vibrations by the ultrasonic vibration element 2 when the good/not good
state is determined in the good/not good state determining circuit.
The function of the ultrasonic treating apparatus thus constructed will be
explained below in more detail by referring to FIG. 2.
Suppose that the operation unit 19 outputs a start-to-treat instruction at
step S1. In this case, the CPU 10 issues an instruction to the switch
drive circuit 17 in the impedance detection circuit 11 to turn the switch
13 ON (step S2).
With the switch 13 turned ON, a voltage on the AC power source 12 is
created across the output terminals 11a, 11b via the current detector 14.
The voltage is applied to the ultrasonic vibration element 2 via the
normally closed contacts of the switches 7a, 7b in the changeover circuit
6.
As a result, a current I flows through the ultrasonic vibration element 2
and detected by the current detector 14. The result of detection is sent
to the computing section 16.
With the switch 13 turned ON, a voltage V on the AC power source 12 is
detected by the voltage detector 15 and a result of detection is sent to
the computing section 16.
The computing section 16 divides the voltage V by the current I to find an
impedance Z of the ultrasonic vibration element 2 at step S3. The
impedance Z thus found is fed to the CPU 10.
The CPU 10 ascertains whether the impedance Z is within a predetermined
range, such as Z.sub.1 .ltoreq.Z.ltoreq.Z.sub.2, at step S4. Here Z.sub.1
and Z.sub.2 denote the setting values. If the impedance Z is a proper
value, the CPU 10 determines that the ultrasonic vibration element 2 is
good at step 5.
If the CPU 10 determines that the ultrasonic vibration element 2 is good,
then the display 18 indicates "good" at step S6. The switch 13 is turned
OFF, stopping the operation of the impedance detection circuit 11 (step
7). The CPU 10 turns the switches 7a, 7b ON, connecting the ultrasonic
vibration element 2 to the drive circuit 5 (step S8). Then the drive
circuit 5 is operated at step S9.
A drive circuit 5 delivers a drive electric power from the drive circuit 5
to the ultrasonic vibration element 2 via the normally open contacts of
the switches 7a, 7b. By doing so, the ultrasonic vibration element 2 is
driven to generate ultrasonic vibrations from the ultrasonic vibration
element 2.
At the time of transmitting the ultrasonic vibrations, it is assumed that
an instruction for ending the treating procedure is given by the operation
unit 19 (step S10).
At this time, the CPU 10 ends a display "good" on the display unit 18 at
step S11. Further, the CPU 10 stops the operation of the drive circuit 5
at step S12 and the switches 7a, 7b are turned OFF at step S13. As a
result, the driving operation of the ultrasonic vibration element 2 is
ended, thus ending the generation of the ultrasonic vibrations from the
ultrasonic vibration element 2.
In step S4, if the impedance Z is not within the range of Z.sub.1
.ltoreq.Z.ltoreq.Z.sub.2, that is, within a proper value range, the CPU 10
determines that the ultrasonic vibration element 2 is not good (step S14).
If the CPU 10 makes such a determination, then the display unit 18 displays
"not good" at step S15. The switch 13 is turned OFF, stopping the
operation of the impedance detection circuit 11 (step S16). The CPU 10
inhibits the operation of the drive circuit 5 in spite of an instruction
of the operation unit 19 (step S17).
In this case, the ultrasonic vibration element 2 is not driven and
ultrasonic vibrations are not generated from the ultrasonic vibration
element 2. It is thus possible to avoid a risk of the apparatus being
destroyed, for example, thus obtaining an added safety.
Since the "not good" is displayed on the display unit 18, the user
immediately knows that the lack of ultrasonic vibrations is caused by the
"not good" state of the ultrasonic vibration element 2. Thus the user can
operate the apparatus with added safety.
A second embodiment of the present invention will be explained below with
reference to FIGS. 3, 4A and 4B. In FIG. 3, the same reference numerals
are employed to designate parts or elements corresponding to those shown
in FIG. 1. Further explanation is thus omitted.
In the embodiment, a burst drive control circuit 20 is connected to a CPU
10 and adapted to operate a drive circuit 5 in ON-OFF fashion.
The burst drive control circuit 20 has the function of outputting a signal
representing a burst drive control state. This signal is supplied to a
switch drive circuit 8 in a changeover circuit 6.
The CPU 10 has a function means for determining the good/not good state of
the ultrasonic vibration element 2 in accordance with an impedance Z
detected at an impedance detection circuit 11, a function means for
controlling a drive circuit 5, switch drive circuit 8, switch drive
circuit 17 and burst drive control circuit 20 and a control function means
for inhibiting the generation of ultrasonic vibrations by an ultrasonic
vibration element 2 when a "not good" state is determined by the
determining function means.
The function of the ultrasonic treating apparatus will be explained below
by referring to FIGS. 4A and 4B.
Assume that a start-to-treat instruction is issued from an operation unit
19 (step T1). Then the CPU 10 operates a burst drive control circuit 20 at
step T2. The CPU 10 allows the operation of the drive circuit 5 at step T3
and then allows switches 7a, 7b to be turned ON and OFF by the switch
drive circuit 8 at step T4.
Thus the drive circuit 5 is turned ON and OFF and the switches 7a, 7b are
turned ON in accordance with the ON operation of the drive circuit 5.
That is, a drive electric power is supplied from the drive circuit 5 to the
ultrasonic vibration element 2 via normally open contacts of switches the
burst drive of the ultrasonic vibration element 2.
The CPU 10 supplies an instruction to the switch drive circuit 17, turning
a switch 13 ON (step T5).
With the switch 13 ON, a voltage on an AC power source 12 emerges between
output terminals 11a and 11b via a current detector 14. With the switches
7a, 7b OFF, that voltage is applied to the ultrasonic vibration element 2
via normally closed contacts of the switches 7a, 7b.
The switches 7a, 7b are turned OFF at step T6 and a current I flows through
the ultrasonic vibration element 2. On the other hand, the current I is
detected by the current detector 14 and, at the same time, a voltage V on
the AC power source 12 is detected by the voltage detector 15. A computing
section 16 divides the voltage V by the current I to find an impedance Z
of the ultrasonic vibration element 2 (step T7).
The CPU 10 ascertains whether or not the impedance Z falls within a
predetermined impedance range, for example, within a range of Z.sub.1
.ltoreq.Z.ltoreq.Z.sub.2 (Z.sub.1 and Z.sub.2 : the setting values) at
step T8. If, here, the impedance Z is any proper value, the CPU 10
determines that the ultrasonic vibration element 2 is good (step T9).
If the "good" state is so determined by the CPU 10 a display "good" is made
on a display unit 18 at step T10. The burst drive operation and impedance
detection continue whereby ultrasonic vibrations are generated from the
ultrasonic vibration element 2.
It is assumed that, at the time of the generation of the ultrasonic
vibrations, a treatment procedure ending instruction is issued from the
operation unit 19 (step T11).
By the CPU 10, the display "good" is ended on the display unit 18 (step
T12). Then the CPU 10 stops the operation of the burst drive control
circuit 20 at step T13 and then that of the drive circuit 5 at step T14.
The switch 13 is turned OFF at step T15, stopping the operation of the
impedance detector 11. When this occurs, the burst drive operation of the
ultrasonic vibration element 2, as well as the detection of the impedance,
is ended, so that the generation of the ultrasonic vibrations by the
ultrasonic vibration element 2 is terminated.
If, at step T8, the impedance Z does not fall within a proper value range,
that is, within a range of Z.sub.1 .ltoreq.Z.ltoreq.Z.sub.2 (Z.sub.1 and
Z.sub.2 the setting values), the CPU 10 determines that a defect occurs in
the ultrasonic vibration element 2 at a step T16.
If the presence of such a defect is determined by the CPU 10, the display
"not good" is made on the display unit 18 at step T17 and the operation of
the burst drive control circuit 20 is stopped at step T18. The CPU 10
inhibits the operation of the drive control circuit 5 in spite of an
instruction from the operation unit 19 (step T19) and, at the same time,
the switch 13 is turned OFF, stopping the operation of the impedance
detector 11 (step T15).
In this case, the burst drive of the ultrasonic vibration element 2 is
immediately stopped, immediately stopping the generation of the ultrasonic
vibrations from the ultrasonic vibration element 2. It is thus possible to
avoid a risk of destruction, etc., of the apparatus and to ensure added
safety to the user.
Since the display "not good" is made on the display unit 18, the user
immediately finds the ultrasonic vibration element 2 defective and hence
the absence of ultrasonic vibrations. It is thus possible to offer added
safety to the user.
A third embodiment of the present invention will now be explained below by
referring to FIGS. 5, 6A and 6B. In FIG. 5, the same reference numerals
are employed to designate parts and elements corresponding to those shown
in FIGS. 1 and 3. Any further explanation is therefore omitted.
In this embodiment, an impedance is detected for a plurality of
piezoelectric elements 2a, 2b, 2c which constitute essential elements of
an ultrasonic vibration element 2.
As shown in FIG. 5, the ultrasonic vibration element 2 comprises a
plurality of layered piezoelectric elements 2a, 2b, 2c.
On end of the piezoelectric element 2a is connected to an output terminal
5b of a drive circuit 5 via a switch 31 in a changeover circuit 30. The
other end of the piezoelectric element 2a is connected to an output
terminal 5a of the drive circuit 5 via a switch 32 in the changeover
circuit 30. One end of the piezoelectric element 2b is connected via the
switch 32 to the output terminal 5 of the drive circuit 5. The other end
of the piezoelectric element 2b is connected to the output terminal 5b of
the drive circuit 5 via a switch 33 in the changeover circuit 30.
One end of the piezoelectric element 2C is connected to the output terminal
5b of the drive circuit 5 via the aforementioned switch 33. The other end
of the piezoelectric element 2c is connected to the output terminal 5a of
the drive circuit 5 via a switch 34 in the changeover circuit 30.
The changeover circuit 30 comprises the switches 31, 32, 33, 34, switches
35, 36, 37, 38 and switch drive circuit 39. The switch drive circuit 39
drives the switches 31, 32, 33, 34, 35, 36, 37 and 38 in accordance with
an instruction of the CPU 10.
The switches 35, 36, 37, 38 are of a two-way type having a neutral
position.
One end of the piezoelectric element 2a is connected to an output terminal
11a of an impedance detection circuit 11 via one contact of the switch 35.
The other end of the piezoelectric element 2a is connected to an output
terminal 11b of the impedance detector 11 via the other contact of the
switch 36.
One end of the piezoelectric element 2b is connected to the output terminal
11a of the impedance detection circuit 11 via one contact of the switch
36. The other end of the piezoelectric element 2b is connected to the
output terminal 11b of the impedance detection circuit 11 via the other
contact of the switch 37.
One end of the piezoelectric element 2c is connected to the output terminal
11a of the impedance detection circuit 11 via one contact of the switch
37. The other terminal of the piezoelectric element 2c is connected to the
output terminal 11b of the impedance detection circuit 11 via the other
contact of the switch 38.
The drive circuit 5, computing section 16, switch drive circuit 17, display
unit 18, operation unit 19 and switch drive circuit 39 are connected to a
CPU 10.
The CPU 10 has a function means for determining whether each piezoelectric
element of the ultrasonic vibration element 2 is good or not in accordance
with an impedance detected by the impedance detection circuit, function
means for controlling the drive circuit 5, switch drive circuit 17 and
switch drive circuit 39 in accordance with, for example, an instruction of
the operation unit 19, and control means for inhibiting the generation of
ultrasonic vibrations from the ultrasonic vibration element 2 when a
piezoelectric element is found defective.
The operation of the ultrasonic treating apparatus will be explained below
with reference to FIGS. 6A and 6B.
Now suppose that a start-to-treat instruction is issued from the operation
unit 19 (step U1). The CPU 10 supplies an instruction to the switch drive
circuit 17 in the impedance detection circuit 11, turning the switch 13 ON
(step U2).
With the switch 13 ON, a voltage on the AC power source 12 is created
across the output terminals 11a and 11b via the current detector 14.
The CPU 10 supplies an instruction to the switch drive circuit 39 in the
changeover circuit 30, turning one contact of the switch 35 ON and the
other contact of the switch 36 ON in which case the switches 37 and 38 are
set to a neutral position. That is, the piezoelectric element 2, of the
ultrasonic vibration element 2 is connected to the output terminals 11a
and 11b of the impedance detection circuit 11 at step U3.
A voltage which is developed between the output terminals 11a and 11b is
applied to the piezoelectric element 2a via the switches 35 and 36. As a
result, a current I flows through the piezoelectric element 2a and is
detected by the current detector 14. A result of detection is supplied to
the computing section 16.
With the switch 13 ON, a voltage V on the AC power supply 12 is detected by
the voltage detector 15. A result of detection is fed to the computing
section 16.
The computing section 16 divides the voltage V by the current I and finds
an impedance Z.sub.a at step U4. The impedance Z.sub.a thus found is sent
to the CPU 10.
The CPU 10 ascertains whether or not the impedance Z.sub.a falls within a
predetermined impedance range, for example, is a proper value of Z.sub.a1
.ltoreq.Z.sub.a .ltoreq.Z.sub.a2 range (Z.sub.a1, Z.sub.a2 the setting
values)-step U5.
If, at the ascertaining step, the impedance Z.sub.a is found to be a proper
value, then the piezoelectric element 2b is next selected.
That is, the CPU 10 turns one contact of the switch 36 ON and the other
contact of the switch 37 ON in which case the switches 35, 38 are set to a
neutral position. Thus the piezoelectric element 2b of the ultrasonic
vibration element 2 is connected to the output terminals 11a, 11b (step
U6).
A voltage which is developed across the output terminals 11a and 11b is
applied to the piezoelectric element 2b via the switches 36 and 37. At
this time, a current I flows through the piezoelectric element 2b and the
computing section 16 finds an impedance Z.sub.b of the piezoelectric
element 2b at step U7. The impedance Z.sub.b thus found is sent to the CPU
10.
The CPU 10 ascertains whether or not the impedance Z.sub.b falls within a
predetermined range, for example, within a Z.sub.b1 .ltoreq.Z.sub.b
.ltoreq.Z.sub.b2 range (Z.sub.b1, Z.sub.b2 the setting values) at step U8.
It, at this ascertaining step, the impedance Z.sub.b is a proper value,
then the piezoelectric element 2.sub.c is next selected.
The CPU 10 turns one contact of the switch 37 ON and the other contact of
the switch 38 ON. At this time, the switches 35 and 36 are set to the
neutral position. That is, the piezoelectric element 2.sub.c of the
ultrasonic vibration element 2 is connected to the output terminals 11a
and 11b at step U9.
A voltage which is induced between the output terminals 11a and 11b is
applied to the piezoelectric element 2c via the switches 37 and 38. In
consequence, a current I flows through the piezoelectric element 2c and
the impedance Z.sub.c of the piezoelectric element 2c is found by the
computing section 16 (at step U10). The impedance Z.sub.c thus found is
fed to the CPU 10.
The CPU 10 ascertians whether or not the impedance Z.sub.c falls within a
predetermined impedance range, for example, within a Z.sub.c1
.ltoreq.Z.sub.c .ltoreq.Z.sub.c2 range (Z.sub.c1, Z.sub.c2 : the setting
values)-step U11.
If, at the ascertaining step, the impedance Z.sub.c is a proper value, the
CPU 10 determines that the piezoelectric elements 2a, 2b, 2c are good
(step U12).
If the CPU 10 determines a piezoelectric element as being "good", the
display "good" is made on the display unit 18 at step U13.
The switch 13 is turned OFF, stopping the operation of the impedance
detection circuit 11 at step U14. The CPU 10 sets the switches 35, 36, 37,
38 to the neutral position at step U15 and the switches 31, 32, 33, 34 are
turned ON at step U16.
Upon the setting of the switches 35, 36, 37, 38 to the neutral position,
the piezoelectric elements 2a, 2b, 2c are separated from the impedance
detection circuit 11.
With the switches 31, 32, 33 and 34 ON, the piezoelectric elements 2a, 2b,
2c are connected to the drive circuit 5.
In that state, the CPU 10 operates the drive circuit 5 at step U17.
Thus a drive electric power is supplied from the drive circuit 5 to the
piezoelectric elements 2a, 2b, 2c via the switches 31, 32, 33, 34. As a
result, the ultrasonic vibration element 2 is driven and ultrasonic
vibrations are transmitted from the ultrasonic vibration element 2.
In the transmission of the ultrasonic vibrations as set forth above, it is
assumed that an instruction for ending a treatment procedure is issued
from the operation unit 19 at step U18.
At this time, the CPU 10 eliminates the display "good" from the surface of
the display 18 at step U19. The CPU 10 stops the operation of the drive
circuit 5 at step U20 and the switches 31, 32, 33, 34 are turned OFF at
step U21. When this occurs, the drive operation of the ultrasonic
vibration element 2 is terminated, st | | |
