Focused ultrasound irradiation system and control method for focused ultrasound irradiation system

Abstract

A focused ultrasound irradiation system includes: an ultrasound device (11) that irradiates a to-be-irradiated target, such as a cranial nerve, with focused ultrasound from a therapeutic ultrasound probe (12); a position sensor (16) that measures the position of the therapeutic ultrasound probe (12); an initial position setting unit (18) that sets, on the basis of the position of the therapeutic ultrasound probe (12) and an image of the to-be-irradiated target, the initial position of the therapeutic ultrasound probe (12) for irradiating the to-be-irradiated target with focused ultrasound; a blood flow sensor (19) that detects blood flow at a position different from the to-be-irradiated target; a determination unit (20) that determines an increase in blood flow detected when focused ultrasound is irradiated into a skull; and a resetting unit (21) that resets the position of the therapeutic ultrasound probe (12) on the basis of the determination result.

Description

Focused Ultrasound Irradiation System and Control Method for Focused Ultrasound Irradiation System

[0001] The present invention relates to a focused ultrasound irradiation system that irradiates focused ultrasound into the skull of a subject and a control method for the focused ultrasound irradiation system.

[0002] Conventionally, as a method for non-invasively treating mental and neurological diseases, for example, as disclosed in Patent Document 1, a method of stimulating cranial nerves by irradiating low-intensity focused ultrasound (LIFU: Low Intensity Focused Ultrasound) into the skull from the outer surface of the skull of a subject is known. This method is promising because it is non-invasive and applicable to many diseases.

[0003] In order to obtain a therapeutic effect by this method, for example, as disclosed in Non-Patent Document 1, it is necessary to accurately irradiate the focused ultrasound to the target irradiation object. Therefore, for example, technologies such as those disclosed in Patent Documents 2 to 4 and Non-Patent Document 2 have been developed. Patent Document 2 discloses a technique for imaging the state of a subject's brain by so-called fMRI (functional Magnetic Resonance Imaging), VEEG (long-term Video EEG monitoring), or PET (Positron Emission Tomography). In this regard, Non-Patent Document 2 discloses a technique for imaging the state of a subject's brain almost in real time using fMRI. Further, Patent Documents 3 and 4 disclose techniques for accurately irradiating focused ultrasound to a target irradiation object by guiding the operation of an ultrasonic probe to a user using a pre-acquired MRI image and a magnetic sensor or automatically controlling the position of the ultrasonic probe.

[0004] International Publication No. 2010 / 009141, U.S. Patent No. 8086296, Japanese Unexamined Patent Application Publication No. 2011-513033, U.S. Patent No.9061133

[0005] Rios, et al, “Optimal deep brain stimulation sites and networks for stimulation of the fornix in Alzheimer's disease”, Nature communications, 13, 7707, 2022, Doi: https: / / doi.org / 10.1038 / s41467-022-34510-3. Nikolaus Weiskopf, “Real-time fMRI and its application to neurofeedback”, NeuroImage, Vol. 62, Issue 2, 15 August 2012, Pages 682-692Real-time fMRI and its application to neurofeedback-ScienceDirect.

[0006] However, large-scale devices such as the fMRI disclosed in Patent Documents 2 and 3 are often not installed in typical hospital facilities due to their high cost and other reasons. Furthermore, because MRI uses a strong magnetic field, it cannot usually be used on subjects with pacemakers, and when an ultrasound probe is used simultaneously for focused ultrasound irradiation, there are limitations on the material of the ultrasound probe. Methods that determine the irradiation position of focused ultrasound within the skull using magnetic sensors, as described in Patent Documents 3 and 4, can only achieve positional accuracy of a few millimeters, so it was sometimes impossible to accurately irradiate irradiation targets with a size of a few millimeters or less, such as areas deep in the brain involved in cognitive function.

[0007] This invention was made to solve the problems of the conventional invention, and aims to provide a focused ultrasonic irradiation system and a control method for the focused ultrasonic irradiation system that can accurately irradiate a target with focused ultrasound while having a simple system configuration.

[0008] The above objective can be achieved with the following configuration: [1] A focused ultrasound irradiation system comprising: an ultrasound device for irradiating a target of cranial nerves within the skull from a therapeutic ultrasound probe placed on the outer surface of the skull of a subject; a position sensor for measuring the position of the therapeutic ultrasound probe on the outer surface of the skull; an initial position setting unit for setting the initial position of the therapeutic ultrasound probe on the outer surface of the skull for irradiating a target of cranial nerves, based on the position of the therapeutic ultrasound probe measured by the position sensor and a pre-taken image of the target of cranial nerves, including the target of irradiation; a blood flow sensor for detecting blood flow in a blood flow observation site within the skull that is located at a different position from the target of irradiation; a determination unit for determining whether or not there is an increase in blood flow in the blood flow observation site based on the blood flow detected by the blood flow sensor when focused ultrasound for blood flow observation is irradiated into the skull from the therapeutic ultrasound probe; and a resetting unit for resetting the position of the therapeutic ultrasound probe on the outer surface of the skull based on the determination result by the determination unit. [2] The focused ultrasound irradiation system according to [1], further comprising a monitor and a guide unit that displays on the monitor the current position of the therapeutic ultrasound probe measured by a position sensor and the initial position of the therapeutic ultrasound probe set by an initial position setting unit, or the current position of the therapeutic ultrasound probe measured by a position sensor and the position of the therapeutic ultrasound probe set by a reset unit. [3] The focused ultrasound irradiation system according to [2], wherein when the position of the therapeutic ultrasound probe is reset by the reset unit, the guide unit displays on the monitor the position of the therapeutic ultrasound probe reset by the reset unit instead of the initial position set by the initial position setting unit. [4] The focused ultrasound irradiation system according to [1], further comprising a monitor and a guide unit that displays on the monitor the predicted position of the irradiation target corresponding to the initial position set by the initial position setting unit and the position of the center line of the focused ultrasound that is predicted to be irradiated from the current position of the therapeutic ultrasound probe measured by the position sensor, or the predicted position of the irradiation target corresponding to the position of the therapeutic ultrasound probe after it has been reset by the reset unit and the position of the center line of the focused ultrasound that is predicted to be irradiated from the current position of the therapeutic ultrasound probe measured by the position sensor.[5] The focused ultrasound irradiation system according to [4], wherein when the position of the therapeutic ultrasound probe is reset by the resetting unit, the guide unit displays on the monitor the position of the irradiation target predicted to correspond to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit, instead of the position of the irradiation target predicted to correspond to the initial position set by the initial position setting unit. [6] The focused ultrasound irradiation system according to [4] or [5], wherein when the determination unit determines that there is an increase in blood flow due to focused ultrasound irradiation into the cranial cavity from multiple positions of the therapeutic ultrasound probe on the outer surface of the skull, the guide unit displays on the monitor the region including the multiple positions for which the determination unit has determined there is an increase in blood flow. [7] The focused ultrasound irradiation system according to any one of [4] to [6], wherein the ultrasound device irradiates the irradiation target from the therapeutic ultrasound probe when the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe measured by the position sensor overlaps with the position of the irradiation target predicted to correspond to the position of the irradiation target after it has been reset by the resetting unit. [8] The focused ultrasound irradiation system according to [7], wherein the ultrasound device determines that the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe, as measured by the position sensor, has moved away from the position of the target to be irradiated, which corresponds to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit. [9] The focused ultrasound irradiation system according to any one of [4] to [6], wherein the ultrasound device determines that a defined first range centered on the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe, as measured by the position sensor, overlaps with a defined second range centered on the position of the target to be irradiated, which corresponds to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit, by a range threshold or more.

[10] The focused ultrasound irradiation system according to [9], wherein the ultrasound device determines that the portion where the first range and the second range overlap is less than a range threshold during irradiation of focused ultrasound for treatment.

[11] A focused ultrasound irradiation system according to any one of [1] to

[10] , wherein the ultrasound device automatically stops the irradiation of focused ultrasound for treatment when it has irradiated focused ultrasound for treatment for a predetermined irradiation time or when it has irradiated focused ultrasound for treatment for a predetermined amount of energy.

[12] A focused ultrasound irradiation system according to any one of [2] to

[11] , wherein the guide unit displays on a monitor the positions of the blood flow sensor and the therapeutic ultrasound probe, which are each placed on the outer surface of the skull, for past irradiation of focused ultrasound for treatment to the subject.

[13] A focused ultrasound irradiation system according to any one of [2] to

[12] , wherein the guide unit displays on the monitor a plurality of candidate positions for the blood flow sensor.

[14] A focused ultrasound irradiation system according to any one of [1] to

[13] , wherein the blood flow sensor detects blood flow in the blood flow observation site by transmitting and receiving near-infrared light to and from the blood flow observation site.

[15] A focused ultrasound irradiation system according to any one of [1] to

[13] , wherein the blood flow sensor has an ultrasonic probe for detecting blood flow, and detects blood flow in the blood flow observation site by transmitting and receiving ultrasound from the ultrasonic probe for detecting blood flow to the blood flow observation site.

[16] A focused ultrasound irradiation system according to any one of [1] to

[15] , wherein the blood flow observation site is set at a shallower position than the irradiation target.

[17] A control method for a focused ultrasound irradiation system, comprising: measuring the position of a therapeutic ultrasound probe on the outer surface of the subject's skull; setting the initial position of the therapeutic ultrasound probe on the outer surface of the skull for irradiating the target with focused ultrasound based on the measured position of the therapeutic ultrasound probe and pre-taken images of cranial nerves including the target to be irradiated; detecting blood flow in a blood flow observation site within the skull located at a position different from the target to be irradiated; determining whether there is an increase in blood flow in the blood flow observation site based on the blood flow detected when focused ultrasound for blood flow observation is irradiated into the skull from the therapeutic ultrasound probe; and resetting the position of the therapeutic ultrasound probe on the outer surface of the skull based on the determination result of the increase in blood flow.

[0009] According to the present invention, the focused ultrasound irradiation system comprises an ultrasound device for irradiating a target of cranial nerves within the skull from a therapeutic ultrasound probe placed on the outer surface of the skull of a subject; a position sensor for measuring the position of the therapeutic ultrasound probe on the outer surface of the skull; an initial position setting unit for setting the initial position of the therapeutic ultrasound probe on the outer surface of the skull for irradiating the target of irradiation based on the position of the therapeutic ultrasound probe measured by the position sensor and a pre-captured image of the cranial nerves including the target of irradiation; a blood flow sensor for detecting blood flow in a blood flow observation site within the skull that is located at a different position from the target of irradiation; a determination unit for determining whether or not there is an increase in blood flow in the blood flow observation site based on the blood flow detected by the blood flow sensor when focused ultrasound for blood flow observation is irradiated into the skull from the therapeutic ultrasound probe; and a resetting unit for resetting the position of the therapeutic ultrasound probe on the outer surface of the skull based on the determination result from the determination unit. As such, the system has a simple system configuration while accurately irradiating the target of irradiation with focused ultrasound.

[0010] This is a block diagram showing the configuration of a focused ultrasound irradiation system according to Embodiment 1 of the present invention. This is a schematic diagram showing an example of the appearance of a therapeutic ultrasound probe. This is a schematic diagram showing an example of an ultrasonic transducer included in a therapeutic ultrasound probe. This is a schematic diagram showing another example of an ultrasonic transducer included in a therapeutic ultrasound probe. This is a schematic diagram showing a therapeutic ultrasound probe and blood flow sensor attached to the head of a subject. This is a schematic diagram showing a method of transmitting focused ultrasound. This is a schematic diagram showing the position of the irradiation target inside the subject's skull, predicted in accordance with the initial position of the therapeutic ultrasound probe set by the initial setting unit, and the position of the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe. This is a diagram showing an example of displaying the initial position of the therapeutic ultrasound probe and the current position of the therapeutic ultrasound probe. This is a schematic diagram showing an example of multiple blood flow sensors being attached to the head of a subject. This is a diagram showing an example of displaying the reset position of the therapeutic ultrasound probe and the current position of the therapeutic ultrasound probe. This is a diagram showing an example of spatial distribution at the focal point of focused ultrasound. This is a flowchart showing the operation of the focused ultrasound irradiation system according to Embodiment 1 of the present invention. This is a flowchart showing the operation of determining the position of a therapeutic ultrasound probe for accurately irradiating a target with focused ultrasound in Embodiment 1 of the present invention. This is a flowchart showing the operation of irradiating a target with focused ultrasound for therapy in Embodiment 1 of the present invention. This is a schematic diagram showing an example of a therapeutic ultrasound probe having a planar radiating surface. This is a schematic diagram showing multiple positions of a therapeutic ultrasound probe for irradiating focused ultrasound for blood flow observation and the area of ​​the target to be irradiated. This is a diagram showing an example of a first range centered on the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe, and a second range centered on the position of the target to be irradiated inside the skull of the subject, which is predicted to correspond to the reset position of the therapeutic ultrasound probe. This is a diagram showing an example of displaying the reset position of the therapeutic ultrasound probe and the current position of the therapeutic ultrasound probe in three dimensions. This is a block diagram showing the configuration of a focused ultrasound irradiation system according to Embodiment 2 of the present invention. This is a diagram showing an example of displaying the position of the blood flow sensor and the position of the therapeutic ultrasound probe on the outer surface of the skull of the subject.This figure shows an example of a graph representing the time-series changes in oxyhemoglobin and deoxyhemoglobin concentrations detected by a blood flow sensor. This figure schematically shows an example of a color Doppler image representing intracranial blood flow in a subject, generated by a blood flow sensor. This is a flowchart showing the operation of a focused ultrasound irradiation system according to Embodiment 2 of the present invention. This is a flowchart showing the operation of position determination of a therapeutic ultrasound probe in Embodiment 2 of the present invention. This figure shows an example of a dialog box used for selecting position candidates for the blood flow sensor.

[0011] Embodiments of this invention will be described below with reference to the accompanying drawings. The following description of the constituent elements will be based on a typical embodiment of the present invention, but the present invention is not limited to such embodiments. In this specification, numerical ranges expressed using "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits. In this specification, "identical" and "same" include a range of error that is generally accepted in the art.

[0012] Embodiment 1 Figure 1 shows the configuration of a focused ultrasound irradiation system according to Embodiment 1 of the present invention. The focused ultrasound irradiation system includes an ultrasound device 11. The ultrasound device 11 is a device for irradiating focused ultrasound onto the target area of ​​the cranial nerves within the skull of a subject from a therapeutic ultrasound probe 12 positioned on the outer surface of the subject's skull. The therapeutic ultrasound probe 12 has an ultrasonic transducer 13 containing one or more elements. A transmitting circuit 14 and a transmitting control unit 15 are sequentially connected to the ultrasonic transducer 13. The ultrasound device 11 is composed of the therapeutic ultrasound probe 12, the transmitting circuit 14 and the transmitting control unit 15. A position sensor 16 is also attached to the therapeutic ultrasound probe 12.

[0013] A position detection unit 17 is connected to a position sensor 16. An initial position setting unit 18 is connected to the position detection unit 17. The focused ultrasound irradiation system also includes a blood flow sensor 19. A determination unit 20 is connected to the blood flow sensor 19. A reset unit 21 is connected to the position detection unit 17, the initial position setting unit 18, and the determination unit 20. A guide unit 22 is connected to the initial position setting unit 18, the determination unit 20, and the reset unit 21. A display control unit 23 and a monitor 24 are sequentially connected to the guide unit 22. A system control unit 25 is connected to the transmission control unit 15, the position detection unit 17, the initial position setting unit 18, the determination unit 20, the reset unit 21, the guide unit 22, and the display control unit 23. An input device 26 is connected to the system control unit 25.

[0014] Furthermore, the processor 27 for the focused ultrasonic irradiation system is comprised of a transmission control unit 15, a position detection unit 17, an initial position setting unit 18, a determination unit 20, a reset unit 21, a guidance unit 22, a display control unit 23, and a system control unit 25.

[0015] The therapeutic ultrasound probe 12 has a concave radiating surface A1, as shown in Figure 2. When the ultrasonic transducer 13 is composed of a single element, for example, as shown in Figure 3, one element 13A can be arranged along the shape of the radiating surface A1. Also, when the ultrasonic transducer 13 is composed of multiple elements, for example, as shown in Figure 4, multiple elements 13B can be arranged in a three-dimensional arrangement along the shape of the radiating surface A1. The therapeutic ultrasound probe 12 is placed on the head H of the subject, as shown in Figure 5, and focuses ultrasound waves are irradiated from the radiating surface A1 towards the inside of the subject's skull.

[0016] One element 13A or more elements 13B constituting the ultrasonic transducer 13 are formed by forming electrodes on both ends of a piezoelectric body, such as a piezoelectric ceramic represented by PZT (Lead Zirconate Titanate), a polymer piezoelectric element represented by PVDF (Poly Vinylidene Di Fluoride), a piezoelectric single crystal represented by PMN-PT (Lead Magnesium Niobate-Lead Titanate), a composite material of a single crystal and resin, CMUT (Capacitive Micromachined Ultrasound Transducers), or PMUT (Piezo Micromachined Ultrasound Transducers).

[0017] The transmitting circuit 14 transmits focused ultrasound from the ultrasonic transducer 13 under the control of the transmitting control unit 15. The transmitting circuit 14 includes, for example, a plurality of pulse generators, and based on a transmission delay pattern selected in accordance with the control signal from the transmitting control unit 15, supplies each drive signal to the elements of the ultrasonic transducer 13 with an adjusted delay amount so that the ultrasound transmitted from the elements of the ultrasonic transducer 13 forms focused ultrasound. In this way, when a pulsed or continuous wave voltage is applied to the electrodes of the elements of the ultrasonic transducer 13, the piezoelectric material expands and contracts, generating pulsed or continuous wave ultrasound from each element, and focused ultrasound is formed by the composite wave of these ultrasounds.

[0018] The transmission control unit 15 controls the transmission circuit 14 to transmit focused ultrasound according to preset transmission conditions such as the transmission frequency of the focused ultrasound pulse, the focal position of the focused ultrasound, the sound pressure at the focal point of the focused ultrasound, the pulse duration of the focused ultrasound, the pulse repetition frequency of the focused ultrasound, the burst duration of the focused ultrasound, the burst rest time, and the total irradiation time.

[0019] As shown in Figure 6, the sound pressure at the focus of focused ultrasound refers to the amplitude AP (single amplitude) at the focus of focused ultrasound. Focused ultrasound is transmitted in pulses into the skull of the subject, and transmission is repeated for a set pulse duration PT1 followed by a pulse rest period PT2. The pulse repetition frequency of focused ultrasound is defined by the reciprocal of the sum of the pulse duration PT1 and the pulse rest period PT2, i.e., 1 / (PT1 + PT2).

[0020] Furthermore, multiple pulse transmissions during burst duration BT1 are treated as a single burst of focused ultrasound transmission, resulting in the transmission of multiple bursts of focused ultrasound within the total irradiation time TT. During this process, the transmission of focused ultrasound is repeatedly paused for a burst rest period BT2 after the transmission of a single burst of focused ultrasound.

[0021] In this invention, as described later, two types of focused ultrasound transmission are performed: focused ultrasound for blood flow observation and focused ultrasound for treatment. The intensity of these focused ultrasound transmissions is set to a level that does not cause degeneration of intracranial tissues. The focused ultrasound transmission for blood flow observation is set to have a lower cumulative energy amount in focused ultrasound irradiation than the focused ultrasound transmission for treatment.

[0022] For focused ultrasound transmission for blood flow observation, for example, the transmission frequency of the focused ultrasound pulse can be set to 0.3 to 1.5 MHz, the sound pressure at the focus of the focused ultrasound can be set so that the MI (Mechanical Index) value is less than 1.9, the pulse duration PT1 of the focused ultrasound can be set to 0.1 to 1000 milliseconds, the pulse repetition frequency of the focused ultrasound can be set to 1 to 1 kHz, the burst duration BT1 can be set to 0.1 to 10.0 seconds, and the burst rest time BT2 can be set to 30 seconds or more.

[0023] Furthermore, the pulse transmission frequency of the focused ultrasound, the sound pressure at the focal point of the focused ultrasound, the pulse duration PT1 of the focused ultrasound, the pulse repetition frequency of the focused ultrasound, and the burst duration BT1 of the focused ultrasound are set so that the ISPPA (Spatial Peak Pulse Average Intensity) is below the standard value set by IEC 60601-2-37, an international standard related to the safety of ultrasound diagnostic equipment, or by the US FDA (Food and Drug Administration), etc. In addition, the burst rest time BT2 is set so that the ISPTA (Spatial Average Temporal Average Intensity) is below the standard value set by IEC 60601-2-37 or the US FDA, etc.

[0024] The transmission conditions for focused ultrasound can be set, for example, based on the sound pressure at the focal point of the focused ultrasound within the skull, which has been estimated in advance. The sound pressure at the focal point of the focused ultrasound within the skull can be estimated, for example, by setting the attenuation rates of the focused ultrasound in the scalp, skull, and brain for the beam profile of the focused ultrasound measured in advance by transmitting focused ultrasound from the therapeutic ultrasound probe 12 in water, or for the beam profile of the focused ultrasound transmitted from the therapeutic ultrasound probe 12 calculated in advance by simulation.

[0025] For focused ultrasound transmission for therapeutic purposes, in addition to the transmission conditions for focused ultrasound for blood flow observation described above, the number of burst pulses is set so that the cumulative time or cumulative energy of focused ultrasound irradiation is within a specified value. The number of burst pulses refers to the number of burst transmissions of focused ultrasound during the total irradiation time TT. The cumulative time can be calculated by multiplying the duty cycle [PT1 / (PT1+PT2)], which is calculated by dividing the pulse duration PT1 by the pulse repetition period, i.e., the sum of the pulse duration PT1 and the pulse rest time PT2, the burst duration BT1, and the number of burst repetitions. The cumulative energy can be calculated by summing the irradiation energy of focused ultrasound within the total irradiation time TT.

[0026] The position sensor 16 is a sensor device that measures the position of the therapeutic ultrasound probe 12 on the outer surface of the subject's skull. The position of the therapeutic ultrasound probe 12 measured by the position sensor 16 includes the placement position and orientation of the therapeutic ultrasound probe 12 in three-dimensional space. As the position sensor 16, for example, a magnetic sensor, acceleration sensor, or gyro sensor attached to the therapeutic ultrasound probe 12 can be used. Alternatively, an infrared sensor or optical camera positioned outside the therapeutic ultrasound probe 12 can also be used as the position sensor 16.

[0027] The position detection unit 17 generates position and orientation information representing the placement position and orientation of the therapeutic ultrasound probe 12 in three-dimensional space by analyzing information regarding the position of the therapeutic ultrasound probe 12 measured by the position sensor 16. For example, the position detection unit 17 can calculate the position coordinates of the therapeutic ultrasound probe 12 in three-dimensional space as information representing the position of the therapeutic ultrasound probe 12 in three-dimensional space. Furthermore, information representing the orientation of the therapeutic ultrasound probe 12 in three-dimensional space can be defined, for example, by the inclination angle of the therapeutic ultrasound probe 12 in three-dimensional space. For example, the position detection unit 17 can calculate the inclination angle of the therapeutic ultrasound probe 12 in three-dimensional space as the angle between the vertical direction and the orientation of the therapeutic ultrasound probe 12, i.e., the direction along the center line of the focused ultrasound being emitted.

[0028] The initial position setting unit 18 sets the initial position of the therapeutic ultrasound probe 12 on the outer surface of the subject's skull for irradiating the target with focused ultrasound, based on the position of the therapeutic ultrasound probe 12 measured by the position sensor 16 and a pre-acquired image of the subject's cranial nerves including the target for irradiation. As a pre-acquired image of the subject's cranial nerves including the target for irradiation, for example, a three-dimensional image such as an X-ray CT (Computed Tomography) image, an MRI (Magnetic Resonance Imaging) image, an fMRI (functional Magnetic Resonance Imaging) image, a PET (Positron Emission Tomography) image, a three-dimensional ultrasound image, or a three-dimensional photoacoustic image may be used. The initial position setting unit 18 can acquire these images of cranial nerves from an external device (not shown) or a memory (not shown).

[0029] The initial position setting unit 18 can, for example, calibrate the positional relationship between the position of the therapeutic ultrasound probe 12 measured by the position sensor 16 and at least one reference point on the outer surface of the subject's skull, calculate the positional relationship between the position of the therapeutic ultrasound probe 12 in a previously captured image of cranial nerves and the actual therapeutic ultrasound probe 12 on the outer surface of the subject's skull, and set the initial position of the therapeutic ultrasound probe 12 based on the calculated positional relationship and the position of the irradiation target in the image.

[0030] The initial position of the therapeutic ultrasound probe 12, set in this manner, is determined based on the therapeutic ultrasound probe 12 measured by the position sensor 16 and pre-captured images of the cranial nerves; therefore, its positional accuracy is only a few millimeters. The target of focused ultrasound irradiation is often a deep part of the brain involved in cognitive function, and its size is typically only a few millimeters. For this reason, even if the therapeutic ultrasound probe 12 is positioned in its initial location, it may not be possible to accurately irradiate the target with focused ultrasound.

[0031] The guide unit 22 displays the current position of the therapeutic ultrasound probe 12, measured by the position sensor 16 based on the position and orientation information of the therapeutic ultrasound probe 12 generated by the position detection unit 17, on the monitor 24. It also displays the initial position of the therapeutic ultrasound probe 12, set by the initial position setting unit 18, along with the current position of the therapeutic ultrasound probe 12, on the monitor 24. The guide unit 22 can schematically display the current position C and initial position T1 of the therapeutic ultrasound probe 12 on the monitor 24, for example, as shown in Figure 8.

[0032] The guide unit 22 further calculates the center line CL of the focused ultrasound that is predicted to be irradiated from the current position of the therapeutic ultrasound probe 12, and the position E1 of the intracranial target that is predicted to correspond to the initial position T1 of the therapeutic ultrasound probe 12, based on the position of the therapeutic ultrasound probe 12 measured by the position sensor 16, the initial position T1 of the therapeutic ultrasound probe 12 set by the initial position setting unit 18, and images of the cranial nerves to be irradiated that have been taken in advance, for example as schematically shown in Figure 7, and can display values ​​representing the positional relationship on the monitor 24. For example, at the current position of the therapeutic ultrasound probe 12, the guide unit 22 can calculate the center line CL of the focused ultrasound as a line extended from the tip of the therapeutic ultrasound probe 12 along the orientation of the therapeutic ultrasound probe 12. Furthermore, the guide unit 22 can, for example, receive information from the initial position setting unit 18 regarding the predicted position of the irradiation target corresponding to the initial position T1 of the therapeutic ultrasound probe 12, and calculate the shortest distance between the calculated center line CL of the focused ultrasound and the predicted position of the irradiation target corresponding to the initial position T1 as the positional relationship between the center line CL and the irradiation target.

[0033] Furthermore, the guidance unit 22 can also display on the monitor 24, for example, the current position C and initial position T1 of the therapeutic ultrasound probe 12 shown in Figure 8, based on the position of the therapeutic ultrasound probe 12 measured by the position sensor 16, the initial position T1 of the therapeutic ultrasound probe 12 set by the initial position setting unit 18, and a previously captured image of the brain nerve to be irradiated, the position of the center line CL of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe 12 on the same plane, and the position E1 of the target to be irradiated corresponding to the initial position T1 of the therapeutic ultrasound probe 12, in the same manner as the display method of the current position C and initial position T1 of the therapeutic ultrasound probe 12 shown in Figure 8. Note that the method of guiding the user by the guidance unit 22 is not limited to display on the monitor 24. The guidance unit 22 can also provide guidance to the user by voice via a speaker (not shown), for example.

[0034] In this way, the user of the focused ultrasound irradiation system can easily position the therapeutic ultrasound probe 12 at its initial position T1 by confirming the current position and initial position T1 of the therapeutic ultrasound probe 12 displayed on the monitor 24 by the guide unit 22.

[0035] The display control unit 23, under the control of the system control unit 25, performs predetermined processing on information representing guidance displays to the user by the guidance unit 22 and displays it on the monitor 24. The monitor 24 performs various displays under the control of the display control unit 23. The monitor 24 may include, for example, a display device such as an LCD (Liquid Crystal Display) or an organic EL display (Organic Electroluminescence Display).

[0036] As shown in Figure 5, the blood flow sensor 19 is positioned in a different location on the subject's head H from the therapeutic ultrasound probe 12, and detects blood flow in an intracranial blood flow observation site that is in a different location from the target of irradiation of cranial nerves. The blood flow sensor 19 can detect blood flow in the blood flow observation site by irradiating the subject's skull with near-infrared light using, for example, so-called NIRS (Near Infrared Spectroscopy). In this case, the blood flow sensor 19 can receive near-infrared light reflected from inside the skull and generate signals representing so-called oxyhemoglobin concentration and signals representing deoxyhemoglobin concentration.

[0037] When the blood flow sensor 19 detects blood flow using NIRS, it is preferable that the blood flow sensor 19 is composed of multiple near-infrared transceivers D, as schematically shown in Figure 9. By arranging multiple near-infrared transceivers D at multiple positions on the subject's head H, blood flow can be detected with high accuracy.

[0038] Incidentally, it is known that stimulating a specific cranial nerve can increase blood flow in a different part of the brain. For example, stimulating the nucleus basalis of Meynert may increase blood flow in the frontal lobe, which is the projection target corresponding to the nucleus basalis. Therefore, in this invention, the projection target corresponding to the target of focused ultrasound is selected as the blood flow observation site, and blood flow is detected in that blood flow observation site. If no significant change is observed in the detected blood flow, it can be determined that the target of the cranial nerve irradiation has not been irradiated with focused ultrasound. On the other hand, if the detected blood flow increases, it can be determined that the target of the cranial nerve irradiation has been stimulated by focused ultrasound.

[0039] Table 1 below shows examples of combinations of irradiation targets and corresponding projection sites. As shown in Table 1, for the nucleus basalis of Meinert, ventral tegmental area, nucleus accumbens, anterior cingulate gyrus, raphe nuclei, thalamic reticular formation, pedunculopontine tegmental nucleus, and amygdala, the blood flow observation site can be set to a shallower position than the irradiation target.

[0040] The determination unit 20 determines whether or not there is an increase in blood flow at the blood flow observation site based on the blood flow detected by the blood flow sensor 19 when focused ultrasound for blood flow observation is irradiated into the skull of the subject from the therapeutic ultrasound probe 12. When the blood flow sensor 19 detects blood flow by NIRS, the determination unit 20 can determine that there is an increase in blood flow at the blood flow observation site if, for example, the difference between the signal representing the oxyhemoglobin concentration and the signal representing the deoxyhemoglobin concentration generated by the blood flow sensor 19 has increased cumulatively for a certain period of time, such as 30 seconds, compared to before the irradiation of focused ultrasound.

[0041] The resetting unit 21 resets the position of the therapeutic ultrasound probe 12 on the outer surface of the subject's skull for irradiating the target with focused ultrasound, based on the determination result from the determination unit 20. For example, the resetting unit 21 can reset the position of the therapeutic ultrasound probe 12 on the outer surface of the subject's skull for irradiating the target with focused ultrasound if the determination unit 20 determines that there is an increase in blood flow in the blood flow observation site. The position of the therapeutic ultrasound probe 12 after being reset in this way is the position where it has been confirmed that blood flow increases in the blood flow observation site by irradiating with focused ultrasound, and is the position where focused ultrasound can be accurately irradiated to the target.

[0042] When the initial position T1 of the therapeutic ultrasound probe 12 for irradiating the target with focused ultrasound is reset by the resetting unit 21, the guide unit 22 displays the position T2 of the therapeutic ultrasound probe 12, which has been reset by the resetting unit 21, on the monitor 24 instead of the initial position T1 of the therapeutic ultrasound probe 12 set by the initial position setting unit 18.

[0043] At this time, the guide unit 22 further determines, based on the position T2 of the therapeutic ultrasonic probe 12 reset by the reset unit 21 and the image of the cranial nerve including the irradiation target taken in advance, the position E1 of the irradiation target predicted corresponding to the position T2 of the therapeutic ultrasonic probe 12 reset by the reset unit 21, and the positional relationship between the center line CL of the focused ultrasonic wave whose irradiation from the current position C of the therapeutic ultrasonic probe 12 measured by the position sensor 16 is predicted, and can display on the monitor 24 the shortest distance between the position of the irradiation target and the center line CL of the focused ultrasonic wave.

[0044] In addition, the guide unit 22 can display on the monitor 24 whether or not the therapeutic focused ultrasonic wave can be accurately irradiated to the irradiation target at the current position of the therapeutic ultrasonic probe 12 according to the positional relationship between the position of the irradiation target predicted corresponding to the reset position T2 of the therapeutic ultrasonic probe 12 and the center line CL of the focused ultrasonic wave whose irradiation from the current position C of the therapeutic ultrasonic probe 12 measured by the position sensor 16 is predicted. For example, as shown in FIG. 10, the guide unit 22 can display on the monitor 24 that the therapeutic focused ultrasonic wave can be irradiated to the irradiation target when the center line CL of the focused ultrasonic wave whose irradiation from the current position of the therapeutic ultrasonic probe 12 is predicted overlaps with the position of the irradiation target predicted corresponding to the position T2 of the therapeutic ultrasonic probe 12 after reset, and when it does not overlap, the guide unit 22 can display on the monitor 24 that the therapeutic focused ultrasonic wave cannot be accurately irradiated to the irradiation target at the current position C of the therapeutic ultrasonic probe 12.

[0045] The guide unit 22 can determine that when the position T2 of the therapeutic ultrasonic probe 12 after being reset is within a circular range having a predetermined size centered on the center line C, the center line C overlaps with the position of the irradiation target predicted corresponding to the position T2 of the therapeutic ultrasonic probe 12 after being reset. This circular range can be set as a range where the sound pressure is not less than half of the maximum sound pressure at the focus of the focused ultrasonic wave, as shown in FIG. 11, based on, for example, the beam profile of the focused ultrasonic wave measured by transmitting the focused ultrasonic wave from the therapeutic ultrasonic probe 12 in water in advance, or the beam profile of the focused ultrasonic wave transmitted from the therapeutic ultrasonic probe 12 calculated by simulation calculation in advance. In the example of FIG. 11, for example, a circular range with a diameter W within -6 dB from the maximum sound pressure can be set as the circular range.

[0046] Further, the guide unit 22 is based on the position C of the therapeutic ultrasonic probe 12 measured by the position sensor 16, the position T2 of the therapeutic ultrasonic probe 12 after being reset by the reset unit 21, and the image of the cranial nerve of the irradiation target taken in advance. The position of the center line CL of the focused ultrasonic wave whose irradiation from the current position C of the therapeutic ultrasonic probe 12 on the same plane is predicted, and the position E1 of the irradiation target predicted corresponding to the position T2 of the therapeutic ultrasonic probe 12 after being reset can be displayed on the monitor 24 in the same manner as the display method of the current position C and the position T2 of the therapeutic ultrasonic probe 12 shown in FIG. 10, for example.

[0047] The input device 26 receives an input operation by the user and sends the input information to the system control unit 25.

[0048] The system control unit 25 controls each part of the focused ultrasonic wave irradiation system according to a program recorded in advance and the like.

[0049] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor 27 as hardware, a program as software, or a combination thereof. In this case, the processor 27 is configured to cooperate with the program to execute the various processes in this embodiment, and can function as a unit or means in this embodiment. Also, the execution order of the processes by the processor 27 is not limited to the order described and may be changed as appropriate. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of executing each process.

[0050] The processor 27 may be composed of one or more hardware components, and the type of hardware is not limited. For example, the processor 27 may be composed of programmable logic devices such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), FPGA (Field Programmable Gate Array), dedicated circuits for executing specific processes such as an ASIC (Application Specific Integrated Circuit), and hardware such as a GPU (Graphic Processing Unit) or NPU (Neural Processing Unit). Furthermore, the type of hardware may be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of the processor 27, these components may reside in physically separate devices or in the same device. Furthermore, in any embodiment, the order of the processes performed by the processor 27 is not limited to the order described above and may be changed as appropriate. The hardware components are composed of electrical circuits (circuitries) and the like, which are combinations of circuit elements such as semiconductor elements.

[0051] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a set of program modules, each function of which may be implemented by a processor configured to perform its respective function. The program may be program code or multiple code segments stored on one or more non-temporary computer-readable media (e.g., storage media or other storage devices). The program may be divided and stored on multiple non-temporary computer-readable media located in physically separate devices. Program code or code segments may represent any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. Program code or code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0052] Next, an example of the operation of the focused ultrasonic irradiation system according to Embodiment 1 will be explained using the flowchart in Figure 12.

[0053] First, in step S1, the focused ultrasound irradiation system determines the position of the therapeutic ultrasound probe 12 to accurately irradiate the target area within the skull of the subject with focused ultrasound. This process will be explained using the flowchart in Figure 13. The process in step S1 consists of the processes in steps S11 to S18.

[0054] In step S11, the position sensor 16 measures the position of the therapeutic ultrasound probe 12 placed on the subject's head H. The position information of the therapeutic ultrasound probe 12 measured by the position sensor 16 is transmitted to the position detection unit 17. The position detection unit 17 analyzes the information received from the position sensor 16 to generate position and orientation information representing the placement position and orientation of the therapeutic ultrasound probe 12 in three-dimensional space.

[0055] In step S12, the initial position setting unit 18 sets the initial position T1 of the therapeutic ultrasound probe 12 for irradiating the target of the subject's cranial nerves with focused ultrasound, based on a pre-captured image of the cranial nerves including the target of irradiation of the subject's cranial nerves and the positional orientation information of the therapeutic ultrasound probe 12 generated in step S11. For example, the positional relationship between the position of the therapeutic ultrasound probe 12 measured in step S11 and at least one reference point on the outer surface of the subject's skull can be calibrated, the positional relationship between the position of the therapeutic ultrasound probe 12 in the pre-captured image of the cranial nerves and the actual therapeutic ultrasound probe 12 on the outer surface of the subject's skull can be calculated, and the initial position T1 of the therapeutic ultrasound probe 12 can be set based on the calculated positional relationship and the position of the target of irradiation in the image.

[0056] In step S13, the position sensor 16 measures the current position C of the therapeutic ultrasound probe 12 in the same manner as in step S11. The position detection unit 17 generates position and orientation information representing the current placement position and orientation of the therapeutic ultrasound probe 12 in three-dimensional space from the information received from the position sensor 16.

[0057] In step S14, as shown in Figure 8, the guide unit 22 displays the initial position T1 of the therapeutic ultrasound probe 12 set in step S12 and the current position C of the therapeutic ultrasound probe 12 measured in step S13 on the monitor 24. At this time, the guide unit 22 can also display on the monitor 24 a numerical value representing the positional relationship between the predicted intracranial irradiation target position E1 corresponding to the initial position T1 of the therapeutic ultrasound probe 12 and the center line CL of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12, for example, a numerical value representing the shortest distance between the irradiation target position E1 and the center line CL of the focused ultrasound.

[0058] Furthermore, the guide unit 22 can also display on the monitor 24 the positional relationship between the predicted position E1 of the irradiation target corresponding to the initial position T1 of the therapeutic ultrasound probe 12 on the same plane, and the position CL of the center line of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12, in the same manner as the display method of the initial position T1 and current position C of the therapeutic ultrasound probe 12 shown in Figure 8.

[0059] The user can adjust the position and tilt of the therapeutic ultrasound probe 12 so that its current position C1 coincides with its initial position T1, while checking the instructions displayed on the monitor 24.

[0060] In step S15, the system control unit 25 determines whether the user has given an instruction to irradiate the subject's skull with focused ultrasound for blood flow observation. The system control unit 25 can determine that no instruction has been given to irradiate focused ultrasound if no specific instruction is input from the user via the input device 26. In this case, the process returns to step S13. In this way, as long as the user is adjusting the position and tilt of the therapeutic ultrasound probe 12 and it is determined in step S15 that no instruction has been given to irradiate focused ultrasound, the process from steps S13 to S15 is repeated. The system control unit 25 can also determine that an instruction to irradiate focused ultrasound has been given if, for example, the user determines that the current position C of the therapeutic ultrasound probe 12 overlaps with the initial position T1 of the therapeutic ultrasound probe 12, and an instruction to irradiate the subject's skull with focused ultrasound for blood flow observation is input via the input device 26. In this case, the user fixes the position of the therapeutic ultrasound probe 12 and proceeds to step S16.

[0061] In step S16, the transmission control unit 15 controls the transmission circuit 14 to irradiate the intracranial region of the subject with focused ultrasound for blood flow observation from the ultrasonic transducer 13 of the therapeutic ultrasound probe 12. If the blood flow in the blood flow observation area increases, it can be determined that the focused ultrasound is accurately irradiating the target cranial nerve. On the other hand, if the blood flow in the blood flow observation area does not increase, it can be determined that the focused ultrasound is not accurately irradiating the target cranial nerve.

[0062] In step S17, the blood flow sensor 19 detects blood flow at a blood flow observation site located at a different position from the irradiation target. At this time, the blood flow sensor 19 can detect blood flow at the blood flow observation site by, for example, NIRS which transmits and receives near-infrared light to and from the inside of the subject's skull. Subsequently, the determination unit 20 determines whether or not there is an increase in blood flow at the blood flow observation site based on the information detected by the blood flow sensor 19.

[0063] The determination unit 20 can determine, for example, that there is an increase in blood flow at the blood flow observation site if the difference between the signal representing oxyhemoglobin concentration and the signal representing deoxyhemoglobin concentration generated by the blood flow sensor 19 has accumulated to increase for a certain period of time, such as 30 seconds, compared to before focused ultrasound irradiation. In this case, the determination unit 20 can determine that there is no increase in blood flow at the blood flow observation site if the difference between the signal representing oxyhemoglobin concentration and the signal representing deoxyhemoglobin concentration has not accumulated to increase for a certain period of time, compared to before focused ultrasound irradiation.

[0064] If it is determined in step S17 that there is no increase in blood flow at the blood flow observation site, the process returns to step S13. In step S13, the position of the therapeutic ultrasound probe 12 is measured, and in step S14, the initial position T1 of the therapeutic ultrasound probe 12 and the current position C of the therapeutic ultrasound probe 12 calculated in the previous step S14 are displayed on the monitor 24. In step S14, the guide unit 22 can display a message on the monitor 24 indicating, for example, that the therapeutic ultrasound probe 12 should be positioned at a location shifted from the initial position T1. The user adjusts the position and tilt of the therapeutic ultrasound probe 12 with the goal of positioning the therapeutic ultrasound probe 12 at a location where blood flow increases at the blood flow observation site.

[0065] Thus, steps S13 to S17 are repeated as long as it is determined in step S17 that there is no increase in blood flow at the blood flow observation site. During this time, if the user adjusts the position and tilt of the therapeutic ultrasound probe 12 and it is determined in step S17 that there is an increase in blood flow at the blood flow observation site, the process proceeds to step S18.

[0066] In step S18, the resetting unit 21 resets the initial position T1 of the therapeutic ultrasound probe 12, which was set in step S12, to the position of the therapeutic ultrasound probe 12 that was irradiated with focused ultrasound for blood flow observation in the preceding step S16. The reset position T2 of the therapeutic ultrasound probe 12 is a position that causes an increase in blood flow at the blood flow observation site and is a position in which focused ultrasound can be accurately irradiated onto the target.

[0067] Furthermore, the process of step S1, which consists of steps S11 to S18, allows for easy positioning of the therapeutic ultrasound probe 12 in a location where focused ultrasound can be accurately irradiated onto the target cranial nerve, using a simple system configuration that does not require large-scale equipment such as an X-ray CT scanner, MRI scanner, or PET scanner.

[0068] Once the process in step S18 is completed, the process in step S1, as shown in the flowchart in Figure 13, is completed.

[0069] In step S2, following step S1, the focused ultrasound irradiation system irradiates the subject's skull with focused ultrasound for treatment. The process in step S2 will be explained using the flowchart in Figure 14. The process in step S2 consists of the processes in steps S21 to S25.

[0070] In step S21, the transmission control unit 15 controls the transmission circuit 14 to irradiate the intracranial cavity of the subject with focused therapeutic ultrasound from the ultrasonic transducer 13 of the therapeutic ultrasound probe 12. At this time, the focused therapeutic ultrasound is irradiated from the position T2 of the therapeutic ultrasound probe 12, which was reset in step S19.

[0071] In step S22, the position sensor 16 measures the current position C of the therapeutic ultrasound probe 12 in the same manner as in steps S11 and S13. At this time, the position detection unit 17 generates position and orientation information of the therapeutic ultrasound probe 12 by analyzing the information regarding the position C of the therapeutic ultrasound probe 12 measured by the position sensor 16 in the same manner as in steps S11 and S13.

[0072] In step S23, the guide unit 22 displays the position T2 of the therapeutic ultrasound probe 12 after it was reset in step S18, and the current position C of the therapeutic ultrasound probe 12 measured in step S22, on the monitor 24, for example, as shown in Figure 10, in the same manner as in step S14.

[0073] The guide unit 22 can further display on the monitor 24 a numerical value representing the positional relationship between the predicted position E1 of the irradiation target corresponding to the reset position T2 of the therapeutic ultrasound probe 12 and the position of the center line CL of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12 as measured in step S22, and a message indicating whether or not the therapeutic focused ultrasound can be accurately irradiated to the target at the current position C of the therapeutic ultrasound probe 12. For example, the guide unit 22 can display "Irradiation Possible" on the monitor 24 if the position of the center line CL of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12 overlaps with the predicted position of the irradiation target corresponding to the reset position T2 of the therapeutic ultrasound probe 12, and display "Irradiation Impossible" on the monitor 24 otherwise.

[0074] Furthermore, the guide unit 22 can also display on the monitor 24, for example, the current position C and position T2 of the therapeutic ultrasound probe 12 shown in Figure 10, based on the position T2 of the therapeutic ultrasound probe 12 after being reset in step S18, the position C of the therapeutic ultrasound probe 12 measured in step S22, and a previously captured image of the cranial nerve to be irradiated, the position of the center line CL of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12 on the same plane, and the position of the target to be irradiated corresponding to the reset position T2 of the therapeutic ultrasound probe 12, in the same manner as the display method of the current position C and position T2 of the therapeutic ultrasound probe 12 shown in Figure 10.

[0075] By checking the information displayed on the monitor 24 in step S23, the user can confirm whether the position of the therapeutic ultrasound probe 12 has shifted from a position where focused ultrasound can be accurately directed onto the target, and thus maintain the position of the therapeutic ultrasound probe 12 in the appropriate location.

[0076] In step S24, the system control unit 25 determines whether a certain amount of focused therapeutic ultrasound has been irradiated into the skull of the subject. The system control unit 25 can determine, for example, that a certain amount of focused therapeutic ultrasound has been irradiated into the skull of the subject if the focused therapeutic ultrasound has been irradiated for a predetermined irradiation time (cumulative time) or if the focused therapeutic ultrasound has been irradiated for a predetermined amount of energy (cumulative energy).

[0077] The cumulative time can be calculated by multiplying the duty cycle (PT1 / (PT1+PT2)), which is obtained by dividing the pulse duration PT1 by the pulse repetition period, i.e., the sum of the pulse duration PT1 and the pulse rest time PT2, by the burst duration BT1 and the number of burst repetitions. The cumulative energy can be calculated by summing the irradiation energy of focused ultrasound within the total irradiation time TT.

[0078] If it is determined in step S24 that a certain amount of focused ultrasound has not been irradiated into the subject's skull, the process returns to step S22. In this way, the process from step S22 to step S24 is repeated until it is determined that a certain amount of focused ultrasound has been irradiated. If it is determined in step S24 that a certain amount of focused ultrasound has been irradiated into the subject's skull, the process proceeds to step S25.

[0079] In step S25, the transmission control unit 15 controls the transmission circuit 14 to terminate the transmission of focused ultrasound from the therapeutic ultrasound probe 12. In this way, the irradiation of focused ultrasound automatically ends when a certain amount of focused ultrasound has been irradiated into the skull of the subject, thus preventing the irradiation target from being exposed to more focused ultrasound than necessary.

[0080] Once the process in step S25 is completed, the process in step S2, as shown in the flowchart in Figure 14, is completed.

[0081] As described above, according to the focused ultrasound irradiation system of Embodiment 1 of the present invention, the initial position setting unit 18 sets the initial position T1 of the therapeutic ultrasound probe 12 on the outer surface of the skull for irradiating the target with focused ultrasound based on the position of the therapeutic ultrasound probe 12 measured by the position sensor 16 and a previously captured image of the cranial nerves including the target to be irradiated, the blood flow sensor 19 detects blood flow in a blood flow observation site inside the skull that is located at a different position from the target to be irradiated, the determination unit 20 determines whether or not there is an increase in blood flow in the blood flow observation site based on the blood flow detected when focused ultrasound for blood flow observation is irradiated inside the skull of the subject, and the resetting unit 21 resets the position of the therapeutic ultrasound probe 12 on the outer surface of the skull of the subject based on the determination result of the determination unit 20, so that focused ultrasound can be accurately irradiated onto the target to be irradiated despite having a simple system configuration.

[0082] Furthermore, although it has been explained that the therapeutic ultrasound probe 12 has a concave radiating surface A1 as shown in Figure 2, when focusing ultrasound waves into the skull by so-called electronic scanning, for example, the therapeutic ultrasound probe 12 can also have a planar radiating surface A2 as shown in Figure 15. Even in this case, for example, by performing electronic scanning, ultrasound waves can be focused to a desired position, similar to the case where the therapeutic ultrasound probe 12 has a concave radiating surface A1.

[0083] Incidentally, the nucleus basalis of Meinert, one of the targets of focused ultrasound irradiation in this invention, generally has a size of about 1 mm in width and 10.5 mm in length. Thus, the target of focused ultrasound irradiation may be too large to be covered by a single focused ultrasound irradiation, for example, on a circular area with a diameter of about 1 mm. Therefore, for example, by placing therapeutic ultrasound probes 12 at multiple positions and irradiating the inside of the skull with focused ultrasound for blood flow observation, and by determining the increase in blood flow at the blood flow observation site for each irradiation, it is possible to grasp the two-dimensional region in which the irradiation target exists.

[0084] In this case, for example as shown in Figure 16, focused ultrasound for blood flow observation is irradiated to multiple locations P on the outer surface of the subject's skull, and the blood flow sensor 19 detects the blood flow at each of the multiple locations P. The determination unit 20 determines the increase in blood flow at the blood flow observation site detected by the blood flow sensor 19 for each of the multiple locations P. The guide unit 22 can display on the monitor 24 the irradiation target area TR which includes the multiple locations P where the determination unit 20 has determined there is an increase in blood flow in response to the irradiation of focused ultrasound into the skull from multiple locations P of the therapeutic ultrasound probe 12 on the outer surface of the subject's skull.

[0085] The user can check the irradiation target area TR displayed on the monitor 24 and accurately irradiate the target area with focused ultrasound for treatment.

[0086] Furthermore, in step S2, the transmission control unit 15 can control the transmission circuit 14 to start or stop the irradiation of focused ultrasound for treatment depending on whether the center line CL of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12 coincides with the position of the irradiation target predicted to correspond to the position T2 of the therapeutic ultrasound probe 12 after it has been reset.

[0087] For example, if the transmission control unit 15 determines that the center line CL of the focused ultrasound predicted to be emitted from the current position C of the therapeutic ultrasound probe 12 coincides with the position of the target to be irradiated, corresponding to the position T2 of the therapeutic ultrasound probe 12 after it has been reset, it can automatically start irradiating the target with focused therapeutic ultrasound from the therapeutic ultrasound probe 12. Furthermore, if the transmission control unit 15 determines that the center line CL of the focused ultrasound predicted to be emitted from the current position C of the therapeutic ultrasound probe 12 has moved away from the position of the target to be irradiated, corresponding to the position T2 of the therapeutic ultrasound probe 12 after it has been reset, it can automatically stop irradiating the target with focused therapeutic ultrasound.

[0088] By controlling the start and stop of focused ultrasound irradiation in this way, it is possible to prevent focused ultrasound from being irradiated to areas other than the target area, and to irradiate only the target area.

[0089] The system control unit 25 can pre-set, for example as shown in Figure 17, a defined first range R1 centered on the center line CL of the focused ultrasound that is predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12, and a second range R2 centered on the position E2 of the irradiation target that is predicted to correspond to the position T2 of the therapeutic ultrasound probe 12 reset by the resetting unit 21. In the example in Figure 17, the position of the center line CL of the focused ultrasound is shown as a position E3 that lies on the same plane as the position E2 of the irradiation target.

[0090] The first range R1 and the second range R2 both represent the effective range at the focal point of the focused ultrasound. The transmission control unit 15 can automatically irradiate the target area with focused ultrasound from the therapeutic ultrasound probe 12 if it determines, for example, that the first range R1 overlaps the second range R2 by a range threshold (for example, more than half the area of ​​the first range R1 or the second range R2, or in another example, between 30% and 70% of the area of ​​the first range R1 or the second range R2). The range threshold represents, for example, the area threshold of the overlapping portion of the first range R1 and the second range R2. The transmission control unit 15 can also automatically stop irradiating the target area with focused ultrasound if it determines that the overlapping portion of the first range R1 and the second range R2 is less than the range threshold. In this case as well, it prevents focused ultrasound from being irradiated to areas other than the target area, and ensures that focused ultrasound is irradiated only to the target area.

[0091] The first range R1 and the second range R2 can be set, for example, based on the beam profile of the focused ultrasound measured in advance by transmitting focused ultrasound from the therapeutic ultrasound probe 12 in water, or the beam profile of the focused ultrasound transmitted from the therapeutic ultrasound probe 12 calculated in advance by simulation, as shown in Figure 11, to be at least half of the maximum sound pressure at the focal point of the focused ultrasound. In the example in Figure 11, for example, a circular range with a diameter W within -6 dB of the maximum sound pressure can be set as the first range R1 and the second range R2.

[0092] Furthermore, while it has been explained that the guide unit 22 displays the position of the therapeutic ultrasound probe 12 on the monitor 24 as shown in Figures 7 and 9, the manner in which the position of the therapeutic ultrasound probe 12 is displayed is not particularly limited. The guide unit 22 can also display on the monitor 24, for example, the position T2 of the therapeutic ultrasound probe 12 reset by the reset unit 21, the predicted position E1 of the irradiation target corresponding to this position T2, the current position C of the therapeutic ultrasound probe 12, the center line CL of the focused ultrasound predicted to be irradiated from the current position C of the therapeutic ultrasound probe 12, the position F of the focal point of the focused ultrasound on the center line CL, and the three-dimensional positional relationship of the subject's skull G. In addition, if the focused ultrasound irradiation system is equipped with a projection device (so-called projector) (not shown) that projects a figure onto the subject's head, the guide unit 22 can also project a figure onto the subject's head that represents the positional relationship between the position T2 of the therapeutic ultrasound probe 12 reset by the reset unit 21 and the current position C of the therapeutic ultrasound probe 12.

[0093] Furthermore, while an example is described in which the blood flow sensor 19 detects blood flow in a blood flow observation site by transmitting and receiving near-infrared light to and from the blood flow observation site using NIRS, the method by which the blood flow sensor 19 detects blood flow in a blood flow observation site is not particularly limited to this. For example, the blood flow sensor 19 may also have a blood flow detection ultrasound probe (not shown) different from the therapeutic ultrasound probe 12, and detect blood flow in a blood flow observation site by transmitting and receiving ultrasound from the blood flow detection ultrasound probe to and from the blood flow observation site.

[0094] In this case, the blood flow sensor 19 processes the ultrasound echo received by the blood flow detection ultrasound probe to generate a so-called B-mode image and a Doppler image of the blood flow observation site. The blood flow sensor 19 can generate Doppler images using known methods such as pulsed Doppler, continuous wave Doppler, color Doppler, or power Doppler. Based on the generated B-mode image and Doppler image of the blood flow observation site, the blood flow sensor 19 detects blood flow in the blood flow observation site. By using ultrasound, the blood flow sensor 19 can detect blood flow even in areas within the subject's skull G where near-infrared light cannot reach sufficiently.

[0095] Thus, even when the blood flow sensor 19 detects blood flow in the blood flow observation site by transmitting and receiving ultrasound, the determination unit 20 can determine whether or not there is an increase in blood flow in the blood flow observation site detected by the blood flow sensor 19, in the same manner as when the blood flow sensor 19 uses NIRS.

[0096] Incidentally, there are areas in the brain, such as the globus pallidus and striatum, where external stimulation is not recommended because it may cause cognitive decline. For example, when irradiating the nucleus basal ganglia of Meynert with focused ultrasound, it is preferable to avoid irradiating these areas. Specifically, it is preferable to place the therapeutic ultrasound probe 12 in the temporal region of the subject and irradiate the focused ultrasound in the coronal plane of the brain, including the nucleus basal ganglia of Meynert, so that the centerline of the sound axis of the focused ultrasound avoids the globus pallidus. Furthermore, it is preferable to adjust the sound pressure of the focused ultrasound so that the portion of the focused ultrasound passing through the globus pallidus is less than half the maximum sound pressure of the focused ultrasound at the centerline of the sound axis.

[0097] The system control unit 25 can also stop the operation of the focused ultrasound irradiation system at any timing in steps S11 to S18 of the flowchart shown in Figure 13, and steps S21 to S25 of the flowchart shown in Figure 14, based on user input via the input device 26. This allows the user to stop the operation of the focused ultrasound irradiation system and interrupt the treatment of the subject at their discretion, for example, if an increase in blood flow is not observed at the blood flow observation site, or if some urgent event occurs.

[0098] Embodiment 2 Treatment of the skull G of a subject using focused ultrasound is usually performed multiple times over several days, rather than just once. Therefore, when performing the second or subsequent treatments, the focused ultrasound irradiation system of the present invention can present the user with the positions of the blood flow sensor 19 and the therapeutic ultrasound probe 12 from previous treatments, so that the user can easily determine the positions of the blood flow sensor 19 and the therapeutic ultrasound probe 12 on the outer surface of the subject's skull G. Furthermore, depending on the subject or the timing of the subject's treatment, the position of the blood flow sensor 19, which can significantly measure the increase in blood flow due to irradiation with focused ultrasound for observation, may change. Therefore, the focused ultrasound irradiation system of the present invention can also present the user with multiple candidate positions for the blood flow sensor 19.

[0099] Figure 19 shows the configuration of a focused ultrasonic irradiation system according to Embodiment 2 of the present invention. The focused ultrasonic irradiation system of Embodiment 2 is the same as the focused ultrasonic irradiation system of Embodiment 1 shown in Figure 1, but with a guide unit 22A instead of a guide unit 22, a system control unit 25A instead of a system control unit 25, and further includes a detection result output unit 31 and a memory 32. The detection result output unit 31 is connected to the blood flow sensor 19. The detection result output unit 31 is connected to the display control unit 23 and the system control unit 25A. The memory 32 is connected to the initial position setting unit 18, the resetting unit 21, the guide unit 22A, and the system control unit 25A.

[0100] The processor 27A for the focused ultrasonic irradiation system is comprised of a transmission control unit 15, a position detection unit 17, an initial position setting unit 18, a determination unit 20, a reset unit 21, a guidance unit 22A, a display control unit 23, a system control unit 25A, and a detection result output unit 31.

[0101] Memory 32 stores, in relation to each other, information representing the type of focused ultrasound irradiation target, the position of the blood flow sensor 19 located on the outer surface of the skull G, and the position of the therapeutic ultrasound probe 12 located on the outer surface of the skull G, for past therapeutic focused ultrasound irradiation of the subject. Memory 32 further stores information representing multiple types of focused ultrasound irradiation targets and multiple candidate positions for the blood flow sensor 19 for each of the multiple irradiation targets. Here, multiple candidate positions for the blood flow sensor 19 refer to multiple positions of the blood flow sensor 19 corresponding to multiple projection targets measurable by NIRS as shown in Table 1, or multiple positions of the blood flow sensor 19 corresponding to multiple blood flow observation sites measurable by the blood flow detection ultrasound probe.

[0102] For memory 32, for example, recording media such as flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive), FD (Flexible Disk), MO disk (Magneto-Optical disk), MT (Magnetic Tape), RAM (Random Access Memory), CD (Compact Disc), DVD (Digital Versatile Disc), SD card (Secure Digital card), or USB memory (Universal Serial Bus memory) can be used.

[0103] Before the user places the blood flow sensor 19 and therapeutic ultrasound probe 12 on the outer surface of the subject's skull G, the guide unit 22A displays on the monitor 24, for example, the positions of the blood flow sensor 19 and therapeutic ultrasound probe 12 that were placed on the outer surface of the skull G in past focused ultrasound irradiations for therapeutic purposes on the subject, such as in past focused ultrasound irradiations performed on different days than the current focused ultrasound irradiation, as shown in Figure 20. The user places the blood flow sensor 19 and therapeutic ultrasound probe 12 on the outer surface of the subject's skull G while referring to the past positions of the blood flow sensor 19 and therapeutic ultrasound probe 12 displayed on the monitor 24. This makes it easier to place the blood flow sensor 19 in a position where blood flow can be accurately measured at the blood flow observation site by irradiation with focused ultrasound for confirmation, and the therapeutic ultrasound probe 12 in a position where focused ultrasound irradiation for therapeutic purposes can be accurately performed. The position of the therapeutic ultrasound probe 12 placed in this manner becomes the initial position of the therapeutic ultrasound probe 12.

[0104] In the example shown in Figure 20, a text group K1 indicating the date of past treatment, the subject's name, the location where therapeutic ultrasound was irradiated, and the location where increased blood flow was detected, along with Figure K2 showing the positions of the therapeutic ultrasound probe 12 and blood flow sensor 19 placed on the subject's head H during past treatment, are displayed. However, it is also possible to display only one of the text group K1 or Figure K2. Furthermore, the method for indicating the positions of the therapeutic ultrasound probe 12 and blood flow sensor 19 can be various, such as text, schematic diagrams, or numerical coordinates, and is not particularly limited.

[0105] The detection result output unit 31 outputs the blood flow detection results from the blood flow sensor 19 in a specific format such as a graph or figure. When the blood flow sensor 19 detects blood flow in the subject's skull G using NIRS, the detection result output unit 31 can output, for example, a graph M1 representing the time-series change in oxyhemoglobin concentration and a graph M2 representing the time-series change in deoxyhemoglobin concentration, as shown in Figure 21. In the example in Figure 21, at time Q1, focused ultrasound for observation is irradiated into the subject's skull G, and graph M1 representing the time-series change in oxyhemoglobin concentration is shown as a solid line, while graph M2 representing the time-series change in deoxyhemoglobin concentration is shown as a dotted line. When the blood flow sensor 19 detects blood flow inside the subject's skull G using ultrasound, the detection result output unit 31 can output, for example, a moving image representing a three-dimensional B-mode image J1 of the subject's skull G and a three-dimensional color Doppler image J2 superimposed on the three-dimensional B-mode image J1, as shown in Figure 22.

[0106] The blood flow detection results output in this manner are displayed on the monitor 24. By checking the blood flow detection results displayed on the monitor 24, the user can confirm whether or not an increase in blood flow is observed by the blood flow sensor 19 and determine whether or not the blood flow sensor 19 is positioned appropriately.

[0107] The guide unit 22A can also display multiple position candidates for the blood flow sensor 19 stored in the memory 32 on the monitor 24. If the user cannot observe an increase in blood flow at the current position of the blood flow sensor 19 even after irradiating the subject's skull G with focused ultrasound for observation, the user can select one of the multiple position candidates for the blood flow sensor 19 displayed on the monitor 24 by the guide unit 22A via the input device 26 and reposition the blood flow sensor 19 to the selected position candidate. After repositioning the blood flow sensor 19, focused ultrasound for observation is irradiated into the subject's skull G from the therapeutic ultrasound probe 12, blood flow is detected by the blood flow sensor 19, the determination unit 20 makes a determination, the detection result output unit 31 outputs the blood flow detection result, and the multiple position candidates for the blood flow sensor 19 are displayed. Subsequently, depending on the blood flow detection result, the position of the blood flow sensor 19 is determined or the blood flow sensor 19 is repositioned.

[0108] Thus, according to the guide unit 22A, even a user who is not familiar with the relationship between the target of focused ultrasound irradiation within the subject's skull G and the corresponding projection destination can easily position the blood flow sensor 19 at a location where an increase in blood flow can be clearly observed by irradiation with focused ultrasound for confirmation, by checking the multiple position candidates for the blood flow sensor 19 displayed on the monitor 24.

[0109] Next, the operation of the focused ultrasonic irradiation system of Embodiment 2 of the present invention will be explained using the flowchart in Figure 23.

[0110] First, in step S31, the system control unit 25A receives subject information input from the user via the input device 26. The subject information includes information that identifies the subject, such as a so-called subject-specific ID (Identifier), and information that indicates the type of target for focused ultrasound irradiation in this treatment.

[0111] In step S32, the guide unit 22A searches the memory 32 based on the subject information received in step S31 to determine whether or not focused ultrasound for therapeutic purposes has been irradiated to the target area of ​​the subject in the current treatment in the past. If it is determined that focused ultrasound for therapeutic purposes has been irradiated in the past, the process proceeds to step S33.

[0112] In step S33, the guide unit 22A reads the positions of the therapeutic ultrasound probe 12 and the blood flow sensor 19 in past treatments from the memory 32 and displays them on the monitor 24. The user places the therapeutic ultrasound probe 12 and the blood flow sensor 19 at the positions of the therapeutic ultrasound probe 12 and the blood flow sensor 19 in past treatments displayed on the monitor 24. The positions of the therapeutic ultrasound probe 12 and the blood flow sensor 19 in past treatments are positions where it is highly likely that an increase in blood flow caused by irradiation of focused ultrasound for observation into the skull G of the subject can be clearly observed.

[0113] If it is determined in step S32 that the subject has not been previously irradiated with focused ultrasound for therapeutic purposes, step S33 is skipped and the process proceeds to step S34. At this time, the user places the therapeutic ultrasound probe 12 at a predetermined position on the outer surface of the subject's skull G relative to the target of focused ultrasound irradiation, and places the blood flow sensor 19 at a predetermined position for observing the blood flow at the projection site corresponding to the target of focused ultrasound irradiation.

[0114] In step S34, the focused ultrasound irradiation system determines the position of the therapeutic ultrasound probe 12 to accurately irradiate the target area within the skull of the subject with focused ultrasound. This process will be explained using the flowchart in Figure 24. The process in step S34 consists of the processes in steps S11 to S18, S41 and S42. Steps S11 to S18 in the flowchart of Figure 24 are basically the same as steps S11 to S18 in the flowchart of Figure 13, so a detailed explanation will be omitted.

[0115] In step S11, the position sensor 16 measures the position of the therapeutic ultrasound probe 12 placed on the subject's head H. Furthermore, the position detection unit 17 analyzes the information received from the position sensor 16 to generate information on the placement position and orientation of the therapeutic ultrasound probe 12 in three-dimensional space.

[0116] In step S12, the initial position setting unit 18 sets the initial position T1 of the therapeutic ultrasound probe 12 for irradiating the target of the subject's cranial nerves with focused ultrasound, based on a previously captured image of the cranial nerves of the subject, including the target of irradiation, and the position and orientation information of the therapeutic ultrasound probe 12 generated in step S11. If it is determined in step S32 that the subject has been irradiated with focused ultrasound for treatment in the past, and the position of the therapeutic ultrasound probe 12 in the past treatment is displayed in step S33, the position of the therapeutic ultrasound probe 12 in the past treatment can be set as the initial position T1 of the therapeutic ultrasound probe 12. If it is determined in step S32 that the subject has not been irradiated with focused ultrasound for treatment in the past, the position of the therapeutic ultrasound probe 12 determined as the initial position T1 of the therapeutic ultrasound probe 12 is set.

[0117] In step S13, the position sensor 16 measures the current position C of the therapeutic ultrasound probe 12 in the same manner as in step S11, and the position detection unit 17 generates the current placement position and positional orientation information of the therapeutic ultrasound probe 12 in three-dimensional space from the information received from the position sensor 16.

[0118] In step S14, as shown in Figure 8, the guide unit 22 displays the initial position T1 of the therapeutic ultrasound probe 12 set in step S12 and the current position C of the therapeutic ultrasound probe 12 measured in step S13 on the monitor 24.

[0119] In step S15, the system control unit 25 determines whether the user has given an instruction to irradiate the subject's skull with focused ultrasound for blood flow observation. If it is determined that the user has not given an instruction to irradiate the subject's skull with focused ultrasound for blood flow observation, the system returns to step S13. If it is determined that the user has given an instruction to irradiate the subject's skull with focused ultrasound for blood flow observation, the system proceeds to step S16.

[0120] In step S16, the transmission control unit 15 controls the transmission circuit 14 to irradiate the intracranial region of the subject with focused ultrasound for blood flow observation from the ultrasonic transducer 13 of the therapeutic ultrasound probe 12.

[0121] In step S17, the blood flow sensor 19 detects blood flow at a blood flow observation site located at a different position from the irradiation target. Subsequently, the determination unit 20 determines whether or not there is an increase in blood flow at the blood flow observation site based on the information detected by the blood flow sensor 19. If an increase in blood flow is determined, in step S18, the current position of the therapeutic ultrasound probe 12 is reset as the position of the therapeutic ultrasound probe 12 for irradiating focused ultrasound for treatment, and the process in step S34 is completed. If no increase in blood flow is determined, the process proceeds to step S41.

[0122] In step S41, the detection result output unit 31 displays the blood flow detection results from step S17 on the monitor 24, for example, a graph showing the time-series changes in oxyhemoglobin concentration and deoxyhemoglobin concentration as shown in Figure 21, or a three-dimensional color Doppler image J2 as shown in Figure 22.

[0123] In step S42, the system control unit 25A determines whether to continue adjusting the position of the therapeutic ultrasound probe 12. The system control unit 25A can determine whether to continue adjusting the position of the therapeutic ultrasound probe 12 based, for example, on instructions from the user via the input device 26. In this case, the system control unit 25A can determine to continue adjusting the position of the therapeutic ultrasound probe 12 if the user inputs an instruction to continue adjusting the position of the therapeutic ultrasound probe 12, and to stop adjusting the position if the user inputs an instruction to stop adjusting the position of the therapeutic ultrasound probe 12. If it is determined to continue adjusting the position of the therapeutic ultrasound probe 12, the user adjusts the position of the therapeutic ultrasound probe 12, and the processes in steps S13 to S17 are performed again.

[0124] If the user adjusts the therapeutic ultrasound probe 12 and it is determined in step S17 that there is an increase in blood flow, the process proceeds to step S18, where the current position of the therapeutic ultrasound probe 12 is reset to the position for irradiating focused therapeutic ultrasound, and the process in step S34 is completed.

[0125] If it is determined in step S17 that no increase in blood flow is observed, steps S41 and S42 are performed sequentially. If it is determined in step S42 that the position adjustment of the therapeutic ultrasound probe 12 should be stopped, the therapeutic ultrasound probe 12 is returned to its initial position, and the process in step S34 is completed.

[0126] Once the processing in step S34 is completed as described above, the process proceeds to step S35. In step S35, the guide unit 22A displays multiple candidate positions for the blood flow sensor 19 stored in memory 32 on the monitor 24. The user can check the multiple candidate positions for the blood flow sensor 19 displayed on the monitor 24 and change the position of the blood flow sensor 19 to one of the candidate positions.

[0127] In step S36, the system control unit 25A determines whether the position of the blood flow sensor 19 has been changed. For example, the system control unit 25A can determine that the position of the blood flow sensor 19 has been changed if information indicating that the position of the blood flow sensor 19 has been changed by the user is input via the input device 26, and can determine that the position of the blood flow sensor 19 has not been changed if information indicating that the position of the blood flow sensor 19 has not been changed by the user is input via the input device 26.

[0128] In this case, the system control unit 25A can display a dialog box DB on the monitor 24, for example, as shown in Figure 25, and display, via the input device 26, a selection of position candidates different from the current position of the blood flow sensor 19 and the option to not change the position of the blood flow sensor 19. Furthermore, after selecting one of the position candidates, the system control unit 25A can display a selectable object on the monitor 24 indicating that the position change of the blood flow sensor 19 has been completed. When such a dialog box DB is displayed on the monitor 24, if the user selects one of the position candidates via the input device 26 and also selects that the position change of the blood flow sensor 19 has been completed, the system control unit 25A can determine that information indicating that the position of the blood flow sensor 19 has been changed has been input. Also, if the user selects not to change the position, the system control unit 25A can determine that information indicating that the position of the blood flow sensor 19 has not been changed has been input.

[0129] If it is determined in step S36 that the position of the blood flow sensor 19 has been changed, the process proceeds to step S37. In step S37, the transmission control unit 15 irradiates the intracranial region of the subject with focused ultrasound for blood flow observation from the ultrasonic transducer 13 of the therapeutic ultrasound probe 12, in the same manner as in step S16.

[0130] In step S38, the blood flow sensor 19 detects blood flow at the blood flow observation site at the new position changed by the user in step S36.

[0131] In step S39, the detection result output unit 31 displays the blood flow detection result from step S38 on the monitor 24 in the same manner as in step S41.

[0132] When step S39 is completed, the system returns to step S35, and the candidate positions of the blood flow sensor 19 are displayed on the monitor 24. At this time, the system control unit 25A can change the display manner of multiple position candidates compared to the previous step S35, for example, by darkening the display color of an already selected position candidate or displaying it in a different manner from the display manner of other position candidates, or by deleting an already selected position candidate and displaying only the remaining position candidates on the monitor 24.

[0133] Subsequently, for example, if an increase in blood flow is observed at the blood flow observation site in step S39 and it is determined that the position of the blood flow sensor 19 will not be changed in the following step S36, the system proceeds to step S40. In step S40, the system control unit 25A stores the current position of the therapeutic ultrasound probe 12 and the current position of the blood flow sensor 19 in the memory 32. The positions of the therapeutic ultrasound probe 12 and the blood flow sensor 19 stored here can be used, for example, as the initial positions of the therapeutic ultrasound probe 12 and the blood flow sensor 19 when starting treatment on the next patient.

[0134] In step S2, following step S40, focused ultrasound for treatment is irradiated onto the target area within the skull G of the subject. Once the process in step S40 is completed, the operation of the focused ultrasound irradiation system according to Figure 23 is completed.

[0135] As described above, according to the focused ultrasound irradiation system of Embodiment 2 of the present invention, the guide unit 22A displays on the monitor 24 the positions of the blood flow sensor 19 and the therapeutic ultrasound probe 12, respectively, which are located on the outer surface of the skull G during past focused ultrasound irradiation for therapeutic purposes to the subject. Therefore, the therapeutic ultrasound probe 12 and the blood flow sensor 19 can be easily positioned at locations where there is a high probability of accurately irradiating the target with focused ultrasound, and at locations where there is a high probability of clearly observing the increase in blood flow caused by focused ultrasound irradiation for observation into the subject's skull G.

[0136] Furthermore, since the guide unit 22A displays multiple candidate positions for the blood flow sensor 19 on the monitor 24, even users who are not familiar with the relationship between the target of focused ultrasound irradiation within the subject's skull G and the corresponding projection destination can easily position the blood flow sensor 19 in a location where an increase in blood flow can be clearly observed by irradiation with focused ultrasound for confirmation, by checking the multiple candidate positions of the blood flow sensor 19 displayed on the monitor 24.

[0137] In addition, regarding the processing in step S42 in the flowchart of Figure 24, it has been explained that the system control unit 25A determines whether or not to adjust the position of the therapeutic ultrasound probe 12 based on the user's input instructions. However, the system control unit 25A can also determine whether or not to adjust the position of the therapeutic ultrasound probe 12 based on the determination result of the determination unit 20 in step S17. For example, the system control unit 25A may determine in step S17 that it will continue adjusting the position of the therapeutic ultrasound probe 12 until it is determined that no increase in blood flow is observed a predetermined number of times, and then determine to stop adjusting the position of the therapeutic ultrasound probe 12 when it is determined in step S17 that no increase in blood flow is observed a predetermined number of times.

[0138] Incidentally, depending on the patient's disease, there may be projection areas where an increase in blood flow is particularly desirable through irradiation with focused ultrasound for observation. Therefore, the memory 32 can further store information about the patient's disease as patient information, and the guide unit 22A can display on the monitor 24, among multiple position candidates for the blood flow sensor 19, position candidates corresponding to projection areas where an increase in blood flow is particularly desirable for the patient's disease, in a different color than the other position candidates, or in a different display manner from the other position candidates. This allows the user to easily grasp the important position candidates for the blood flow sensor 19 and prioritize placing the blood flow sensor 19 in the important positions.

[0139] As a result of repeating the process from steps S35 to S39 in the flowchart of Figure 23, it is possible that no increase in blood flow due to focused ultrasound observation is observed at any of the candidate positions of the blood flow sensor 19. In this case, the user can decide based on the detection result of the blood flow sensor 19 displayed in step S39 and place the blood flow sensor 19 at one of the multiple candidate positions. At this time, the detection result output unit 31 can also display the blood flow detection results obtained by the blood flow sensor 19 at multiple candidate positions side by side on the monitor 24, for example, to make it easier for the user to compare and consider them.

[0140] The blood flow sensor 19 can employ any of several blood flow detection methods, such as using ultrasound in addition to NIRS. Therefore, the guide unit 22A can display multiple candidate locations for the blood flow sensor 19 on the monitor 24 in order for each blood flow detection method. For example, if no increase in blood flow is observed at multiple candidate locations corresponding to projection targets measurable by NIRS, the guide unit 22A can display multiple candidate locations for the blood flow sensor 19 corresponding to projection targets measurable by ultrasound on the monitor 24. This makes it possible to find a location of the blood flow sensor 19 where an increase in blood flow can be clearly confirmed using another detection method, even if an increase in blood flow cannot be confirmed using one blood flow detection method.

[0141] The explanation states that the guide unit 22A performs both the process of displaying the positions of the therapeutic ultrasound probe 12 and the blood flow sensor 19 in the patient's past treatments on the monitor 24, and the process of displaying multiple position candidates for the blood flow sensor 19 on the monitor 24. However, it is also possible to perform only one of these two processes.

[0142] The system control unit 25A can also stop the operation of the focused ultrasound irradiation system at any timing in steps S31 to S40 and S2 of the flowchart shown in Figure 23, or in steps S11 to S18, S41 and S42 of the flowchart shown in Figure 24, based on user input via the input device 26. This allows the user to stop the operation of the focused ultrasound irradiation system and interrupt the treatment of the subject at their discretion, for example, if an increase in blood flow is not observed at the blood flow observation site, or if some urgent event occurs.

[0143] 11 Ultrasound device, 12 Therapeutic ultrasound probe, 13 Ultrasound transducer, 13A, 13B Elements, 14 Transmitting circuit, 15 Transmitting control unit, 16 Position sensor, 17 Position detection unit, 18 Initial position setting unit, 19 Blood flow sensor, 20 Judgment unit, 21 Reset unit, 22, 22A Guidance unit, 23 Display control unit, 24 Monitor, 25, 25A System control unit, 26 Input device, 27, 27A Processor, 31 Detection result output unit, 32 Memory, A1, A2 Radiation surface, BT1 Burst duration, BT2 Burst rest time, C, P, T2 Position, CL Centerline, D Near-infrared transceiver, DB Dialog box, E1, E2 Position of irradiation target, E3 Position of centerline, F Position of focal point, G Skull, H Head, J1 3D B-mode image, J2 3D color Doppler image, K1 text group, K2 figure, M1, M2 graph, PT1 pulse duration, PT2 pulse rest time, Q1 time, R1 first range, R2 second range, T1 initial position, TR irradiation target area, W diameter.

Claims

1. A focused ultrasound irradiation system comprising: an ultrasound device for irradiating a target of cranial nerves within the skull from a therapeutic ultrasound probe positioned on the outer surface of the skull of a subject; a position sensor for measuring the position of the therapeutic ultrasound probe on the outer surface of the skull; an initial position setting unit for setting the initial position of the therapeutic ultrasound probe on the outer surface of the skull for irradiating the target of cranial nerves, based on the position of the therapeutic ultrasound probe measured by the position sensor and a previously captured image of the cranial nerves including the target of irradiation; a blood flow sensor for detecting blood flow in a blood flow observation site within the skull located at a position different from the target of irradiation; a determination unit for determining whether or not there is an increase in blood flow in the blood flow observation site based on the blood flow detected by the blood flow sensor when the focused ultrasound for blood flow observation is irradiated into the skull from the therapeutic ultrasound probe; and a resetting unit for resetting the position of the therapeutic ultrasound probe on the outer surface of the skull based on the determination result by the determination unit.

2. The focused ultrasound irradiation system according to claim 1, further comprising a monitor and a guide unit that displays on the monitor the current position of the therapeutic ultrasound probe measured by the position sensor and the initial position of the therapeutic ultrasound probe set by the initial position setting unit, or the current position of the therapeutic ultrasound probe measured by the position sensor and the position of the therapeutic ultrasound probe set by the resetting unit.

3. When the position of the therapeutic ultrasound probe is reset by the resetting unit, the guide unit displays the position of the therapeutic ultrasound probe reset by the resetting unit on the monitor instead of the initial position set by the initial position setting unit.

4. The focused ultrasound irradiation system according to claim 1, further comprising a monitor and a guide unit that displays on the monitor the position of the irradiation target predicted in correspondence with the initial position set by the initial position setting unit and the position of the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe measured by the position sensor, or the position of the irradiation target predicted in correspondence with the position of the therapeutic ultrasound probe after it has been reset by the reset unit and the position of the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe measured by the position sensor.

5. The focused ultrasound irradiation system according to claim 4, wherein when the position of the therapeutic ultrasound probe is reset by the resetting unit, the guide unit displays on the monitor the position of the irradiation target predicted to correspond to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit, instead of the position of the irradiation target predicted to correspond to the initial position set by the initial position setting unit.

6. The focused ultrasound irradiation system according to claim 4, wherein, when the determination unit determines that there is an increase in blood flow in response to the irradiation of focused ultrasound into the cranial cavity from a plurality of positions of the therapeutic ultrasound probe on the outer surface of the skull, the guide unit displays on the monitor the region including the plurality of positions where the determination unit has determined that there is an increase in blood flow.

7. The focused ultrasound irradiation system according to claim 4, wherein the ultrasound device irradiates the target with focused ultrasound for treatment from the therapeutic ultrasound probe when the center line of the focused ultrasound predicted to be irradiated from the current position of the therapeutic ultrasound probe, as measured by the position sensor, coincides with the position of the target to be irradiated, which is predicted to correspond to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit.

8. The focused ultrasound irradiation system according to claim 7, wherein the ultrasound device determines that the center line of the focused ultrasound, which is predicted to be irradiated from the current position of the therapeutic ultrasound probe measured by the position sensor, has moved away from the position of the irradiation target predicted to correspond to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit, and the ultrasound device automatically stops irradiating the focused ultrasound for treatment.

9. The focused ultrasound irradiation system according to claim 4, wherein the ultrasound device determines that a defined first range centered on the center line of the focused ultrasound, which is predicted to be irradiated from the current position of the therapeutic ultrasound probe as measured by the position sensor, overlaps with a defined second range centered on the position of the irradiation target, which is predicted to correspond to the position of the therapeutic ultrasound probe after it has been reset by the resetting unit, by a range threshold or more, and automatically irradiates the irradiation target with the focused ultrasound for treatment from the therapeutic ultrasound probe.

10. The focused ultrasound irradiation system according to claim 9, wherein the ultrasound device automatically stops the irradiation of the focused ultrasound for treatment when it determines that the portion where the first range and the second range overlap is less than the range threshold during irradiation of the focused ultrasound for treatment.

11. The focused ultrasound irradiation system according to claim 9, wherein the ultrasound device automatically stops the irradiation of the focused ultrasound for treatment when it has irradiated the focused ultrasound for treatment for a predetermined irradiation time or when it has irradiated the focused ultrasound for treatment for a predetermined amount of energy.

12. The focused ultrasound irradiation system according to any one of claims 2 to 11, wherein the guide unit displays on the monitor the position of the blood flow sensor and the position of the therapeutic ultrasound probe, which are located on the outer surface of the skull, respectively, in past irradiations of focused ultrasound for therapeutic purposes to the subject.

13. The focused ultrasonic irradiation system according to claim 12, wherein the guide unit displays a plurality of candidate positions for the blood flow sensor on the monitor.

14. The focused ultrasonic irradiation system according to any one of claims 1 to 11, wherein the blood flow sensor detects the blood flow in the blood flow observation site by transmitting and receiving near-infrared light to the blood flow observation site.

15. The focused ultrasound irradiation system according to any one of claims 1 to 11, wherein the blood flow sensor has an ultrasonic probe for detecting blood flow, and detects the blood flow in the blood flow observation site by transmitting and receiving ultrasound from the ultrasonic probe for detecting blood flow to the blood flow observation site.

16. The focused ultrasound irradiation system according to any one of claims 1 to 11, wherein the blood flow observation site is set at a shallower position than the irradiation target.

17. A control method for a focused ultrasound irradiation system, comprising: measuring the position of a therapeutic ultrasound probe on the outer surface of the skull of a subject; setting the initial position of the therapeutic ultrasound probe on the outer surface of the skull for irradiating the target with focused ultrasound based on the measured position of the therapeutic ultrasound probe and a pre-captured image of the cranial nerve including the target to be irradiated; detecting blood flow in a blood flow observation site within the skull located at a position different from the target to be irradiated; determining whether there is an increase in blood flow in the blood flow observation site based on the blood flow detected when the focused ultrasound for blood flow observation is irradiated into the skull from the therapeutic ultrasound probe; and resetting the position of the therapeutic ultrasound probe on the outer surface of the skull based on the determination result of the increase in blood flow.

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