System for controlling shock wave irradiation in shock wave therapy apparatus

Abstract: In a shock wave therapy apparatus, shock wave irra­ diation conditions, such as the number of shock wave irradiations, a pulse rate, a driving voltage and the number of pause shots, are set by a setting unit (101) in accordance with the position and size of a calculus in a subject which are acquired by an ultrasonic tomogr­ aphic image. Irradiation of shock waves by a shock wave applicator (17) starts according to the set shock wave irradiation conditions, and the ultrasonic tomographic image and the corresponding irradiation condition data are displayed on a display unit (103) during shock wave irradiation. When the number of shock wave irradiations reaches the number of pause shots, the shock wave irra­ diation is temporarily stopped. Then, the focus point of a shock wave is moved on the basis of the ultrasonic tomographic image and irradiation condition data dis­ played on the display unit (103). When the shock wave irradiation is completed, a therapy record of the sub­ ject is printed out by an output unit (102).

Description: The present invention relates to a system for controlling a shock wave irradiation in a shock wave therapy apparatus. Recently, shock wave therapy apparatuses have been developed which irradiate a shock wave (ultrasonic wave) to a subject to be examined to disintegrate a calculus or the like in the subject. If a shock wave is irradiated to a normal tissue, not a calculus, it is inevitable to cause an adverse effect on the subject, such as damaging the normal tissue. In this respect, therefore, it is important to disintegrate a calculus with the minimum adverse effect on the subject. The prior art system as defined in DE-A-37 36 733 comprises a presetting circuit (first setting means) for setting a number of shock waves. The set number of shock waves is continuously irradiated to the subject. If a large abnormal portion such as a calculus exists in the subject, though its size varies depending on the subject, it is difficult to disintegrate the calculus. There is therefore a demand for a shock wave therapy apparatus capable of controlling the irradiation of a shock wave so as to disintegrate a calculus based on a therapy plan. It is the object of the present invention to provide a system for controlling shock wave irradiation in a shock wave therapy apparatus with which the disintegration of a calculus can be made based on a therapy plan. This is achieved in accordance with the wording of claim 1. According to the present invention, for example, when a maximum number of 3000 shots and a number of pause irradiations of 300 shots are set by using the first and the second setting means, respectively, shock wave irradiation is stopped every time the number of shock wave irradiations reaches 300, thereby ensuring the subject's safety even if a focus point of the shock wave is shifted from the location of calculus, since the shock waves of 3000 shots are not continuously irradiated to the subject. This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 is a block diagram illustrating the arrangement of a shock wave therapy system embodying the present invention; Fig. 2 is a diagram showing the structure of a shock wave applicator of the present system; Fig. 3 is a diagram presenting the layout of a console panel of a setting unit of the present system; Fig. 4 is a diagram showing a therapy record printed out by an output unit of the present system; Figs. 5A and 5B are diagrams showing an image displayed on a display unit of the present system; Fig. 6 is a diagram for explaining the movement of a focusing point of a shock wave to a subject under therapy; and Figs. 7A and 7B are flowcharts for shock wave irradiation control in the present system. A preferred embodiment of this invention will now be described referring to the accompanying drawings. A shock wave therapy system as illustrated in Fig. 1 comprises a shock wave applicator 17, a pulser 18, a transmitting/receiving (T/R) unit 19, a signal processor 20, a signal converter 21, a CPU (Central Processing Unit) 22, a controller 23, a switch 29, a position controller 30, a setting unit 101, an output unit 102 and a display unit 103. The shock wave applicator 17 includes a shock wave transducer 15 for irradiating a shock wave and an ultrasonic transducer 16 for transmitting and receiving an ultrasonic wave having a frequency range different that of the shock wave from the shock wave transducer 15. The pulser 18 supplies a pulse signal to the shock wave transducer 15. The T/R unit 19 outputs a pulse signal to the ultrasonic transducer 16 to execute sector scanning and receives a signal from the ultrasonic transducer 16 in the sector scanning. The signal processor 20 detects the amplitude of a signal from the T/R unit 19. The CPU 22 performs the control of the individual sections of the system. The controller 23 controls the signal transmission/reception timing for the pulser 18, the T/R unit 19 and the signal processor 20. The signal converter 21 constituted by, for example, a digital scan converter, performs signal conversion process for converting a signal from the signal processor 20 into a video signal. The display unit 103 constituted of, for example, a TV monitor, displays an ultrasonic tomographic image (sector scan image) including the surface of a subject, kidneys and a calculus, a shock wave focus point marker 26 indicating an irradiation region of a shock wave, etc., based on the video signal from the signal converter 21. As will be described later, the display unit 103 also displays data indicating the shock wave irradiation conditions according to the ultrasonic tomographic image displayed thereon. The switch 29 is used to set the timing for generating a pulse signal supplied to the shock wave transducer 15 from the pulser 18. The position controller 30 controls the relative position of the ultrasonic transducer 16 to the shock wave transducer 15. The setting unit 101 is used to set the shock wave irradiation conditions, such as the number of shock wave irradiations, the rate of shock wave irradiation (hereinafter referred to as pulse rate), a shock wave driving voltage and the number of pause shots. The number of shock wave irradiations represents the number of shock waves to be irradiated until a calculus disintegration is completed. The pulse rate is the number of shock wave irradiations per unit time; for example, when the pulse rate is 2 Hz, two shock waves per second are irradiated to the subject. The number of pause shots indicates one interval for calculus disintegration by shock waves; for example, shock wave irradiation is temporarily stopped when the number of pause shots is 300, that is, the number of shock waves reaches 300. In short, the shock wave irradiation is controlled on the basis of the shock wave irradiation conditions set by the setting unit 101. The output unit 102 outputs (e.g., prints out) record data of shock waves actually irradiated to the subject. The print out record data is used as a therapy record or history. The output unit 102 can also print out an image and the like displayed on the display unit 103 (described later). When a predetermined switch included in the switch 29 is on, the therapy record or the like is printed out. The shock wave applicator 17 will be described in detail below. Referring to Fig. 2, the shock wave applicator 17 comprises the shock wave transducer 15 and the ultrasonic transducer 16. The shock wave transducer 15 generates a shock wave, for example, a high-energy ultrasonic wave converging on a focus point 41a in a subject 32. The shock wave transducer 15 is a concave transducer having a predetermined curvature. The ultrasonic transducer 16 is disposed out of a shock wave irradiating region 41 extending from a shock wave irradiating surface 15a to the focus point 41a. When an ultrasonic transmitting/receiving face 16a of the ultrasound transducer 16 contacts with the surface 32a of the subject 32, an ultrasonic tomographic image (sector scanned image) in a sector scan region 42a including the focus point 41a is obtained. The ultrasound transducer 16 is attached to the center portion of the shock wave transducer 15 by using a transducer moving section 36, and is movable in the direction B in Fig. 2. The transducer moving section 36 moves the ultrasonic transducer 16 to a predetermined position in the direction B based on a control signal from the position controller 30. For instance, the relative position between the transducers 15 and 16 is controlled by adjusting the rotational angle of a motor (not shown) having its drive shaft connected to a pinion gear (not shown) that engages with a rack member (not shown) fixed to the side of the ultrasound transducer 16. A water tank 33 filled with water as a shock wave propagating liquid is provided in the shock wave transducer 15. The water tank 33 has a cylindrical or conical shape with a bottom whose size is substantially equal to the outer diameter of the shock wave transducer 15. The water tank 33 has a bellows 33a formed at its side; the bellows 33a can be stretched or shrunk in the direction B or in a direction having a predetermined angle to the direction B. A bottom 37 of the water tank 33 is formed by a thin film having an acoustic impedance nearly equal to that of water. The layout of a console panel (not shown) of the setting unit 101 will be described referring to Fig. 3. Shock wave irradiation conditions to be set include the number of shock wave irradiations, a shock wave driving voltage, a pulse rate and the number of pause shots, as mentioned above. The number of shock wave irradiations is set by using shock wave irradiation setting buttons, i.e., an UP button 201 and a DOWN button 202. Every time the UP button 201 or DOWN button 202 is pushed, the number of shock wave irradiations is increased or decreased by 100. When the number of shock wave irradiations is set to 3000, an indicator (Maximum Shot No.) 206 displays "3000". This figure remains on the indicator 206 until the number of shock wave irradiations is changed or cleared. The number of pause shots is set by pause setting buttons, i.e., an UP button 204 and a DOWN button 205. Each pushing of the button 204 or 205 increases or decreases the number of pause shots by 100. When the number of pause shots is set to 300, an indicator (Pause/Remaining Shot No.) 208 displays "300," which counts down by 1 upon each irradiation of a shock wave. That is, the indicator 208 shows the remaining number of pause shots during shock waves are irradiated. When the indicator 208 displays "0", the irradiation is stopped. The indicator 208 is set again to the set value "300" when the irradiation is temporarily stopped. The shock wave driving voltage is set by 1 kV by rotating a driving voltage setting dial 213. When the shock wave driving voltage is set to 15 kV, a driving voltage indicator (Driving Voltage) 211 displays "15.0". The pulse rate is set by the order of 0.5 Hz by rotating a pulse rate setting dial 214. If the pulse rate is 2 Hz, a pulse rate indicator 212 displays "002.0". An indictor 207 shows the actual number of shock wave irradiations, and this figure increases by 1 every time a shock wave is irradiated. Upon each shock wave irradiation, a SHOOT lamp 209 is turned on. When the shock wave therapy system is not ready to irradiate a shock wave, a PULSER READY lamp 210 is turned off. A CLEAR button 203 is used to clear the set values of the shock wave irradiation conditions. The output unit 102 will now be described. The output unit 102 can be a printer. This output unit 102 prints out a therapy record as shown in Fig. 4, for example. In the therapy record, the portion 1 ○ presents a graph showing the relation between the driving voltage and the number of shock wave irradiations from the first shot to the 1000th shot. Likewise, the portions 2 ○, 3 ○ and 4 ○ present graphs showing the relation between the driving voltage and the number of shock wave irradiations from the 1001th shot to the 2000th shot, from the 2001th shot to the 3000th shot, and from the 3001th shot to the 4000th shot. The vertical and horizontal scales can be changed in accordance with the shock wave irradiation conditions. The therapy record includes the shock wave irradiation conditions and patient information. For instance, the patient information (patient ID) has a patient name, the position of the patient's calculus, the size thereof, etc. The patient information is input from a keyboard (not shown). As can be seen from Fig. 4, the driving voltage is increased to a set value (15 kV) from 0 for every 300 shots of shock waves. This figure "300" is the number of pause shots and shock wave irradiation is temporarily stopped for every 300 shots. After shock wave irradiation is temporarily stopped and the focus point is moved (see Fig. 6), the driving voltage used in the next shock wave irradiation is gradually increased preferably from zero, to ensure the safety of the subject for the next irradiation. When the number of shock wave irradiations ranges from 1 to 4000, for example, the driving voltage is increased by 1 kV to a desired voltage every four shots. When the number of shock wave irradiations ranges from 4001 to 9000, for example, the driving voltage is increased by 1 kV to the desired voltage every eight shots. This method of irradiating shock waves can be set as an irradiation condition. The operation of the shock wave therapy system according to this embodiment will be described. When the shock wave applicator 17 is placed on the surface of a patient by an operator and the present shock wave therapy system is operated, an ultrasonic tomographic image, shock wave irradiating region 41 and focus point marker 26 are displayed by the display unit 103. Calculus probing is executed by moving the shock wave applicator 17 according to the displayed image. When a calculus is detected, the shock wave irradiation conditions are set by the setting unit 101 in accordance with the position and size of the calculus. For example, when the number of shock wave irradiations is 3000, the pulse rate is 2.0 Hz, the driving voltage is 15 kV and the number of pause shots is 300, irradiation condition data representing the shock wave irradiation conditions is displayed on the upper left of the screen of the display unit 103 (see Fig. 5A). In this diagram, N is the actual number of shock wave irradiations also shown on the indicator 207 of the setting unit 101; N = 0 because Fig. 5A shows an image on the display unit 103 before irradiation of shock waves. The pulse rate R is a constant value (for example, 2Hz) during shock wave irradiation. The driving voltage V varies during the shock wave irradiation; V = 0 because no shock waves have been irradiated yet. When a predetermined switch included in the switch 29 is on after the irradiation conditions are set, shock wave irradiation starts according to the set irradiation conditions. The irradiation condition data displayed on the display unit 103 frequently changes during shock wave irradiation. When the number of shock wave irradiations reaches the number of pause shots (300), the shock wave irradiation is temporarily stopped. In this time, the displayed image may be stored in memory by an image memory apparatus (not shown). The focus point of shock waves is moved while referring to the ultrasonic tomographic image and irradiation condition data displayed on the display unit 103. For instance, the focus point is moved to 2 ○ from 1 ○ in Fig. 6. After moving the focus point, the irradiation of shock waves restarts. By repetition of the above operation, for example, an image as shown in Fig. 5B is displayed on the display unit 103 during the operation. That is, in the irradiation condition data, the actual number of shock wave irradiations N is 1000, the pulse rate R is 2 Hz and the driving voltage for the 1000th shot is 15 kV. When the shock wave irradiation is completed (i.e., the number of shock wave irradiations reaches 3000 in this embodiment), by turning on a predetermined switch included in the switch 29 the aforementioned therapy record (see Fig. 4) is printed out. Referring to Figs. 7A and 7B, the shock wave irradiation control by the CPU 22 of the present shock wave therapy system will be described. In step S1, the total number of shock wave irradiations m, the maximum driving voltage W, pulse rate R and the number of pause shots P are set by the setting unit 101. The reference "n" in step S1 indicates the number of shock wave irradiations to be displayed as irradiation condition data on the display unit 103 and is initially set to 0. In step S2, it is determined whether or not m is equal to or greater than 4000. If m ≦ 4000, a constant i is set to "4" (step S3). That is, the driving voltage V is increased by, for example, 1 kV for every i shots of shock waves. In step S4, it is determined whether or not m is equal to or greater than 8000. If m ≦ 8000, the constant i is set to "8" (step S5). If m > 8000, the constant i is set to "10" (step S6). In step S7, the number of pause shots P is set to a variable q, and the driving voltage V and a variable j are set to 0. The variable q indicates the number of remaining shots until the next pause, and the variable j is used to increase the driving voltage V. It is determined in step S8 whether or not a shock wave irradiation start switch (not shown) included in the switch 29 is on. If the shock wave irradiation start switch is on, the actual number of shock wave irradiations n is compared with the total number of shock wave irradiations m in step S9. If n ≧ m in step S9, the shock wave irradiation is completed. If n < m, it is determined whether or not the variable q reaches 0 (step S10). If q = 0 in step S10, the shock wave irradiation is temporarily stopped and the processing of step S7 is repeated. If q > 0, variable q is compared with the number of pause shots P (step S11). If q = P in step S11, it is determined that the irradiation control has just started or it is the first irradiation control after pause. Accordingly, the driving voltage V is increased by 1 kV (step S12). In the step S13, the increased driving voltage V is compared with the maximum driving voltage W which has been set in advance. In other words, the driving voltage at the time of irradiating a shock wave is determined. If V > W in step S13, the driving voltage for irradiating a shock wave is set to the maximum driving voltage W in order to prevent a setting of the driving voltage larger than the maximum driving voltage W (step S14). If V ≦ W, the increased driving voltage V is set as the driving voltage for irradiating a shock wave (step S15). If q is not equal to P in step S11, the variable j is compared with the constant i (step S16). If j < i in step S16, the driving voltage V is set as the driving voltage for irradiating a shock wave (step S18). That is, the driving voltage is not increased. If j ≧ 0, j is set to 0 (step S17). As a result, the driving voltage V is increased by 1 kV (step S12) and the driving voltage for irradiating a shock wave is then determined as described above (step S13). After the driving voltage for irradiating a shock wave is determined in the above manner, n and j are increased by 1 and q is decremented by 1 (step S19). In step S20, a shock wave is irradiated once at the set driving voltage V and set pulse rate R. In other words, a command signal for shock wave irradiation is input to the controller 23 and a shock wave is irradiated once under the control of the controller 23. Data representing the driving voltage, the number of shock wave irradiations, etc. which are changed during shock wave irradiation is displayed on the display unit 103 upon each updating of data. As described above, by the use of the setting unit for setting shock wave irradiation conditions in the shock wave therapy apparatus according to the embodiment of the present invention, it is possible to make a long-term therapy plan and carry out a therapy based on the therapy plan, thus obtaining a high safety. Further, the therapy state can be accurately grasped and a more effective therapy plan can be made by referring to an ultrasonic tomographic image and data representing the shock wave irradiation state corresponding to this tomographic image, both displayed on the display unit, acquiring the displayed shock wave irradiation condition data by a video camera, and displaying and printing out a therapy record with additional patient information on the display unit and by the output unit. Furthermore, by gradually increasing the driving voltage for irradiating a shock wave, a therapy with high safety can be performed, and by setting the number of pause shots, excess irradiation of shock waves or unnecessary shock wave irradiation can prevented. The present invention is not limited to the above embodiment. For instance, the irradiation energy of a shock wave can be set as a shock wave irradiation condition or only some of the aforementioned conditions can be set. An ultrasonic tomographic image and data representing shock wave irradiation states corresponding to this image are displayed simultaneously at the display time lag within a range of several milliseconds.

Claims: A system for controlling a shock-wave irradiation in an shock wave therapy apparatus, comprising: acquiring means (16) for acquiring an ultrasound tomogram image of a subject; displaying means (103) for displaying the acquired ultrasound tomogram image (42) to detect a portion (26) to be irradiated within the subject; irradiating means (15) for irradiating shock-waves to the detected portion in accordance with a driving voltage; first setting means (201, 202) for setting the maximum number of irradiations of the shock-waves; second setting means (204, 205) for setting the number of pause irradiations of the shock-waves; indicating means (206, 208) for indicating at least one of the maximum number of irradiations of the shock waves set by said first setting means (201, 202) and the number of pause irradiations of the shock waves set by said second setting means (204, 205); and controlling means (22, 23) for controlling said irradiating means (15) in accordance with the maximum number (206) of irradiations of the shock-waves and the number of pause irradiations (208) of the shock-waves to irradiate the shock-wave to the detected portion during a plurality of irradiation periods determined by the maximum number of irradiations of the shock-waves and the number of pause irradiations of the shock-waves; wherein said driving voltage is gradually increased during each pause irradiation of the shock waves up to a set value. The system according to claim 1, characterized in that said displaying means (103) displays the maximum number of irradiations of the shock-waves and the number of pause irradiations of the shock-waves corresponding to the displayed ultrasound tomogram image during irradiation of the shock-waves. The system according to claim 2, characterized in that said displaying means (103) further displays the actual number of irradiations of the shock-waves (N). The system according to claim 1, characterized by further comprising means (102) for outputting an irradiation record (Fig. 4) representing an irradiation result after irradiation of the shock-waves to the detected portion is completed. The system according to claim 1, characterized by further comprising: third setting means (214) for setting a pulse rate of the shock-waves; and fourth setting means (213) for setting said driving voltage that generates the shock-waves. The system according to claim 5, characterized in that said displaying means (103) displays the pulse rate of the shock-waves set by said third means and the driving voltage set by said fourth setting means.

Inventors: OKAZAKI KIYOSHI, OKAZAKI, KIYOSHI, OKAZAKI, KIYOSHI, C/O INTELLECTUAL PROPERTY DIV.
Applicants: TOSHIBA KK, KABUSHIKI KAISHA TOSHIBA
Application year: 1990
Main classification: A61B17
IPC codes: A61B18, A61B17