JP6305752B2 - Ultrasonic diagnostic apparatus and ultrasonic probe - Google Patents

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus and an ultrasonic probe.

  Conventionally, in an ultrasonic diagnostic apparatus, an ultrasonic focusing point is controlled by controlling a delay time of a drive signal supplied to each of a plurality of vibration elements incorporated in an ultrasonic probe and a reception signal obtained from each vibration element. (Focus) is controlled electronically. In recent years, the transition of ultrasonic probes from 1D array probes (one dimensional array probes) to 2D array probes (two dimensional array probes) has progressed. When the ultrasonic probe is a 1D array probe, vibration elements are arranged only in the lateral (lateral) direction, but in the case of a 2D array probe, arrangement in the longitudinal (elevation) direction is also added. For this reason, in the ultrasonic probe, the total number of vibration elements has increased dramatically.

  The distance between the focal point and each vibration element has a different value because the position of each vibration element is different. For this reason, it is necessary to calculate the delay time for focusing the ultrasonic wave on the focal point for each vibration element, and the amount of calculation of the delay time is increased as the total number of vibration elements is increased.

JP 2012-152432 A

  The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus and an ultrasonic probe that can easily calculate a delay time for each vibration element.

An ultrasonic diagnostic apparatus according to an embodiment includes an ultrasonic probe, a delay time calculation unit, a transmission / reception unit, and an image generation unit. In the ultrasonic probe, a plurality of vibration elements for transmitting and receiving ultrasonic waves to and from a subject are arranged. The delay time calculation unit calculates, for each of the plurality of subarrays obtained by dividing the array of the plurality of vibration elements, a delay time required for transmission / reception of the ultrasonic wave at a representative coordinate in or near the subarray, and the delay time Based on the difference between the vibration elements included in the sub-array with respect to the representative coordinates, the delay time in each vibration element is approximated and calculated. The transmission / reception unit performs transmission / reception of ultrasonic waves in the plurality of vibration elements of the ultrasonic probe with the delay time based on the delay time calculated for each of the vibration elements. An image generation part produces | generates the image data inside the said test object from the ultrasonic wave received from the said transmission / reception part. The delay time calculation unit includes a first delay time calculation unit, a second delay time calculation unit, a plurality of third delay time calculation units, and a plurality of fourth delay time calculation units. One first delay time calculation unit is provided for each of the plurality of subarrays, and calculates a delay time required for transmission of the ultrasonic wave at the representative coordinates for each of the subarrays. One second delay time calculation unit is provided for each of the plurality of subarrays, and calculates a delay time required for reception of the ultrasonic wave at the representative coordinates for each of the subarrays. The third delay time calculation unit is provided for the number of vibration elements included in one of the subarrays, and is based on the delay time calculated by the first delay time calculation unit and the difference between the corresponding vibration elements. Then, the delay time in the vibration element is approximated and calculated. The fourth delay time calculation unit is provided for the number of vibration elements included in one of the subarrays, and is based on the delay time calculated by the second delay time calculation unit and the difference between the corresponding vibration elements. Then, the delay time in the vibration element is approximated and calculated.

FIG. 1 is a block diagram illustrating the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a block diagram illustrating a detailed configuration of the transmission / reception unit. FIG. 3 is an explanatory diagram for explaining the arrangement of the vibration elements in the ultrasonic probe. FIG. 4 is an explanatory diagram for explaining the positional relationship among the representative coordinates of the subarray, the coordinates of the vibration elements included in the subarray, and the focus coordinates. FIG. 5 is a block diagram illustrating a calculation configuration of the delay calculation unit. FIG. 6 is an explanatory diagram for explaining the arrangement of the vibration elements in the 1D array probe. FIG. 7 is a block diagram illustrating a calculation configuration of the delay calculation unit according to the comparative example. FIG. 8 is a block diagram illustrating a calculation configuration of the delay calculation unit according to the comparative example. FIG. 9 is a block diagram illustrating the configuration of an ultrasonic probe according to the second embodiment. FIG. 10 is a flowchart illustrating an example of the operation of the ultrasonic diagnostic apparatus according to the modification.

  Hereinafter, an ultrasonic diagnostic apparatus and an ultrasonic probe according to embodiments will be described in detail with reference to the accompanying drawings. In the following description, common constituent elements are given common reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a block diagram illustrating the configuration of an ultrasonic diagnostic apparatus 100 according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus 100 includes an ultrasonic probe 1, a monitor 2, an input apparatus 3, and an apparatus main body 10.

  The ultrasonic probe 1 is communicably connected to the apparatus main body 10 via a probe cable 4 or the like. Note that the ultrasonic probe 1 may be configured to be communicably connected to the apparatus main body 10 not only by wired connection via the probe cable 4 but also by wireless or the like.

  In the ultrasonic probe 1, a plurality of vibration elements for transmitting and receiving ultrasonic waves to and from the subject P are arranged (see FIG. 3). The plurality of vibration elements may be piezoelectric vibrators that generate ultrasonic waves by vibrating based on a drive signal supplied from a transmission / reception unit 11 included in the apparatus main body 10 to be described later. In addition, the plurality of vibration elements of the ultrasonic probe 1 receives the reflected wave from the subject P and converts it into an electrical signal. The ultrasonic probe 1 includes a matching layer provided in the vibration element, a backing material that prevents propagation of ultrasonic waves from the vibration element to the rear, and the like. The ultrasonic probe 1 is detachably connected to the apparatus main body 10 via the probe cable 4.

  When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are reflected one after another at the discontinuous surface of the acoustic impedance in the body tissue of the subject P, and the ultrasonic probe is used as a reflected wave signal. 1 is received by a plurality of vibration elements of 1. The amplitude of the received reflected wave signal depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. Note that the reflected wave signal when the transmitted ultrasonic pulse is reflected on the moving blood flow or the surface of the heart wall depends on the velocity component of the moving body in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift.

  Here, the ultrasonic probe 1 according to the present embodiment can ultrasonically scan the subject P in three dimensions by arranging a plurality of vibration elements in a matrix in the lateral direction and the elevation direction. 2D array probe (see FIG. 3). The ultrasonic probe 1 transmits and receives ultrasonic waves to a predetermined position (focus) inside the subject P by transmitting and receiving ultrasonic waves for each vibration element with the delay time calculated by the delay calculation unit 18. It is possible to focus and scan.

  The ultrasonic probe 1 is provided with a temperature sensor 60 in the vicinity of the vibration element. The temperature of the ultrasonic probe 1 detected by the temperature sensor 60 is notified to the control unit 17 of the apparatus main body 10 via the probe cable 4.

  The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus 100 to input various setting requests using the input apparatus 3, and displays an ultrasonic image generated in the apparatus main body 10. Or display. For example, the monitor 2 displays an ultrasonic image generated by the processing of the image generation unit 14 described later.

  The input device 3 includes a trackball, a switch, a dial, a touch command screen, and the like. The input device 3 receives various setting requests from an operator of the ultrasonic diagnostic apparatus 100 and transfers the received various setting requests to the apparatus main body 10. For example, the input device 3 receives an input operation for designating a predetermined position on the two-dimensional image.

  The apparatus main body 10 is an apparatus that generates an ultrasonic image based on the reflected wave received by the ultrasonic probe 1. Specifically, the apparatus body 10 is an apparatus that can generate a three-dimensional ultrasonic image (volume data) based on three-dimensional reflected wave data received by the ultrasonic probe 1. As shown in FIG. 1, the apparatus body 10 includes a transmission / reception unit 11, a B-mode processing unit 12, a Doppler processing unit 13, an image generation unit 14, an image memory 15, an internal storage unit 16, and a control unit 17. And a delay calculation unit 18.

  The transmission / reception unit 11 performs transmission / reception of ultrasonic waves with a delay time on the plurality of vibration elements of the ultrasonic probe 1 based on the delay time calculated for each vibration element of the ultrasonic probe 1 by the delay calculation unit 18. Make it.

  FIG. 2 is a block diagram illustrating a detailed configuration of the transmission / reception unit 11. As shown in FIG. 2, the transmission / reception unit 11 includes a transmission unit 21 that supplies a drive signal for focusing the emitted ultrasonic wave to the focal point to a plurality of vibration elements of the ultrasonic probe 1, and a plurality of transmission signals for each of these vibration elements. A receiving unit 22 for phasing and adding channel reception signals is provided. The transmission unit 21 includes a pulse generator 211, a transmission delay circuit 212, and a drive circuit 213.

  The pulse generator 211 generates a rate pulse for determining the repetition period of the transmission ultrasonic wave radiated into the body by dividing the reference signal supplied from the control unit 17, and delays the obtained rate pulse for transmission. Supply to circuit 212. The transmission delay circuit 212 is based on the delay time calculated for each vibration element of the ultrasonic probe 1 by the delay calculation unit 18 with respect to the rate pulse supplied from the pulse generator 211, and the vibration element of the ultrasonic probe 1. Give each delay time. The drive circuit 213 generates a drive signal for driving the plurality of vibration elements of the ultrasonic probe 1 based on the rate pulse to which the delay time is given for each vibration element of the ultrasonic probe 1 by the transmission delay circuit 212.

  The receiving unit 22 includes a preamplifier 221, an A / D converter 222, a reception delay circuit 223, and an adder 224. The preamplifier 221 performs gain correction processing by amplifying reception signals (reflected wave signals) obtained from a plurality of vibration elements of the ultrasonic probe 1 for each channel. The A / D converter 222 performs A / D conversion on the gain-corrected received signal. The reception delay circuit 223 performs, for each received signal channel (for example, vibration) on the basis of the delay time calculated for each vibration element of the ultrasonic probe 1 by the delay calculation unit 18 with respect to the A / D converted reception signal. A delay time is given to each element). The adder 224 performs addition processing on the reception signal output from the reception delay circuit 223 to generate reflected wave data. That is, the reception delay circuit 223 and the adder 224 perform phasing addition on the reception signals corresponding to the reception ultrasonic waves from the ultrasonic transmission / reception direction.

  The B-mode processing unit 12 receives the reflected wave data from the transmission / reception unit 11, performs logarithmic amplification, envelope detection processing, and the like, and generates data (B-mode data) in which the signal intensity is expressed by brightness. . Here, the B-mode processing unit 12 can change the frequency band to be visualized by changing the detection frequency. Further, the B-mode processing unit 12 can perform detection processing with two detection frequencies in parallel on one reflected wave data.

  The Doppler processing unit 13 performs frequency analysis on velocity information from the reflected wave data received from the transmission / reception unit 11, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and mobile body information such as average velocity, dispersion, and power. Is generated for multiple points (Doppler data).

  Note that the B-mode processing unit 12 and the Doppler processing unit 13 according to the present embodiment can process both two-dimensional reflected wave data and three-dimensional reflected wave data. That is, the B-mode processing unit 12 according to the present embodiment can generate three-dimensional B-mode data from the three-dimensional reflected wave data. Further, the Doppler processing unit 13 according to the present embodiment can generate three-dimensional Doppler data from the three-dimensional reflected wave data.

  The image generation unit 14 generates an ultrasound image from the data generated by the B mode processing unit 12 and the Doppler processing unit 13. That is, the image generation unit 14 generates a B-mode image in which the intensity of the reflected wave is represented by luminance from the B-mode data generated by the B-mode processing unit 12. Specifically, the image generation unit 14 generates a three-dimensional B-mode image from the three-dimensional B-mode data generated by the B-mode processing unit 12.

  In addition, the image generation unit 14 generates a color Doppler image as an average velocity image, a dispersed image, a power image, or a combination image representing moving body information from the Doppler data generated by the Doppler processing unit 13. Specifically, the image generation unit 14 generates a three-dimensional color Doppler image from the three-dimensional Doppler data generated by the Doppler processing unit 13. Hereinafter, ultrasonic images such as a three-dimensional B-mode image and a three-dimensional color Doppler image generated by the image generation unit 14 are collectively referred to as “volume data”.

  In addition, the image generation unit 14 can generate various images for displaying the generated volume data on the monitor 2. The image generation unit 14 can also generate a composite image in which character information, scales, body marks, and the like of various parameters are combined with the various images described above.

  The image memory 15 is a memory that stores volume data generated by the image generation unit 14. The image memory 15 can also store data generated by the B-mode processing unit 12 and the Doppler processing unit 13.

  The internal storage unit 16 stores a control program for performing ultrasonic transmission / reception, image processing and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), various data such as a diagnostic protocol and various body marks. To do. The internal storage unit 16 is also used for storing images (volume data) stored in the image memory 15 as necessary.

  The control unit 17 is a control processor (CPU: Central Processing Unit) that realizes a function as an information processing apparatus (computer), and controls the entire processing of the ultrasonic diagnostic apparatus 100. Specifically, the control unit 17 is based on various setting requests input from the operator via the input device 3 and various control programs and various data read from the internal storage unit 16. The processing of the processing unit 12, the Doppler processing unit 13, the image generation unit 14, and the delay calculation unit 18 is controlled. The control unit 17 also displays volume data stored in the image memory 15, various images stored in the internal storage unit 16, a GUI for performing processing by the image generation unit 14, processing results of the image generation unit 14, and the like. Control is performed to display on the monitor 2.

  The delay calculation unit 18 is an arithmetic circuit that calculates a delay time for each vibration element of the ultrasonic probe 1 for focusing the ultrasonic wave to a predetermined focal point under the control of the control unit 17. Specifically, the delay calculation unit 18 may be an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). In the present embodiment, an FPGA capable of dynamically switching a circuit configuration by dynamic reconfiguration is used for the delay calculation unit 18.

  The control unit 17 reads out the elements (such as the coordinates of the vibration element and the coordinates of the focal point) for calculating the delay time for each vibration element of the ultrasonic probe 1 stored in the internal storage unit 16 and the like to the delay calculation unit 18. input. The delay calculation unit 18 calculates a delay time for each vibration element based on the input element. Here, the details of the delay time for each vibration element calculated by the delay calculation unit 18 will be described.

  The delay time for each vibration element for focusing the ultrasonic wave on a predetermined focal point is obtained by calculating the distance from each vibration element to the set focal point and converting it from the speed of sound to time. Here, the distance from the focal point to each vibration element is unique because the position (coordinate in space) of each vibration element is different. Therefore, the delay time is also unique for each vibration element. That is, it is necessary to perform delay calculation for all the vibration elements.

  For example, when the ultrasonic probe is a 1D array probe, the vibration elements are arranged only in the lateral direction, but when the ultrasonic probe is a 2D array probe, an arrangement in the elevation direction is also added. As an example, in the case of a 2D array probe for a circulatory device having 48 elements in the lateral direction and 36 elements in the elevation direction, the total number of elements is 1728. Further, in the case of a 2D array probe for the abdomen, with 128 elements in the lateral direction and 36 elements in the elevation direction, the total number of elements is 4608. Thus, as the total number of vibration elements in the ultrasonic probe 1 increases, the amount of calculation of the delay time also increases.

  For this reason, in order to easily calculate the delay time in the delay calculation unit 18, for each subarray obtained by dividing the array of the plurality of vibration elements in the ultrasonic probe 1, the ultrasonic wave at the representative coordinates in or near the subarray is obtained. The delay time required for transmission / reception is calculated. Then, the delay calculation unit 18 approximates and calculates the delay time in each vibration element based on the calculated delay time of the representative coordinate and the difference of each vibration element included in the sub-array with respect to the representative coordinate.

  FIG. 3 is an explanatory diagram for explaining the arrangement of the vibration elements e1 to ei in the ultrasonic probe 1. FIG. As shown in FIG. 3, the vibration elements e1 to ei in the ultrasonic probe 1 are arranged in the lateral direction and the elevation direction. Here, all the vibration elements of the vibration elements e1 to ei are divided into groups of a predetermined number of vibration elements adjacent to each other in the lateral direction and the elevation direction. These groups are called subarrays a. In the example of FIG. 3, there are 4 elements in the lateral direction and 3 elements in the elevation direction, and 4 × 3 12 elements constitute one subarray a. However, the number of elements in the lateral direction and the elevation direction is the same. Is not limited to the illustrated example.

  Here, representative coordinates representing the vibration elements in the subarray a are set at one point on the spatial coordinates in or near the subarray a. For example, representative coordinates are set at the spatial midpoint of the vibration elements in the subarray a. The representative coordinates are preset in the internal storage unit 16 as values for each grouped subarray a, and the control unit 17 stores the internal coordinates in order to obtain the representative delay (delay time in the representative coordinates) of the subarray a. This is one of the elements that are input to the delay calculation unit 18 with reference to the unit 16.

  The delay calculation unit 18 calculates the delay time at the input representative coordinates as a representative delay. Further, the delay calculation unit 18 receives the coordinates of the vibration elements in the sub-array a from the control unit 17, and represents the coordinates of the vibration elements in the sub-array a by a difference (difference coordinates) from the representative coordinates. Then, the delay calculation unit 18 obtains an actually required delay time unique to each vibration element by approximating the above-described representative delay and difference coordinates.

  The representative coordinates may be set to the coordinates of one vibration element located closest to the spatial midpoint in the subarray a. In this case, the delay time of the other vibration elements in the sub-array a may be obtained by approximation from the delay time of the vibration element set as the representative coordinates and the difference coordinates, and the coordinates of one vibration element are not used as the representative coordinates. Since the delay time calculation can be reduced by one as compared with the case, the calculation can be reduced.

FIG. 4 is an explanatory diagram for explaining the positional relationship among the representative coordinates rep of the subarray a, the coordinates P of the vibration elements included in the subarray a, and the focus coordinates F. As shown in FIG. 4, the representative coordinate rep is (xr yr zr), and the representative delay from the focus coordinate F (xf yf zf) to the representative coordinate rep is dly _rep . The difference between each vibration element and the representative coordinate rep is represented by (dx _i dy _i dz _i ). Therefore, the coordinate P of each vibration element is represented by (xr + dx _i yr + dy _i zr + dz _i ). dlyi is the delay time of each vibration element that is actually desired.

In accordance with the coordinate setting shown in FIG. 4, the calculation formula of the delay time dly _i is expanded as the following formula (1). In equation (1), the division by the speed of sound for calculating the delay time is omitted. In the calculation of the delay time, since distance-time conversion can be included in the coordinate parameter, in the following description, the delay time is expressed in a form in which division by sound speed is omitted.

Here, the square of the last term and the difference coordinate in the route of the equation (1) is a small value of a relatively small value relative to | dly _i |, and is sufficiently small. As a result, the following equation (2) is obtained.

  It can be seen that the three forward terms in the route of equation (2) match the terms in the typical delay route shown in equation (3) below.

  Here, the following equation (4) is defined.

When Taylor expansion is performed on dly _i and the second and subsequent terms are ignored, the following equation (5) is obtained.

Equation (5) indicates that the delay time of each vibration element in the sub-array a can be obtained by calculating the representative delay (dly _rep ) and the calculated value (dlta _i ) of Equation (4). Show. In other words, it is only necessary for the representative coordinates to calculate the delay time according to the conventional theoretical formula (see formulas (6) and (7) described later). The delay time can be approximated by four arithmetic operations. The hardware scale and the amount of calculation are generally increased by the square root calculation part. Therefore, in the calculation configuration calculated in accordance with the above equation (5), the number of vibration elements increases. However, it is possible to suppress an increase in hardware scale and calculation amount.

  The calculation configuration of the delay calculation unit 18 calculates the delay time of each vibration element in accordance with the above-described equation (5). FIG. 5 is a block diagram illustrating a calculation configuration of the delay calculation unit 18.

As shown in FIG. 5, the operation configuration of the delay calculation unit 18 includes a part for obtaining a representative delay (dly _rep ) by an adder 101 to 105, a multiplier 111 to 113, and a square root circuit 120, and a representative delay. , And a delay calculation unit 140 that obtains a delay for each vibration element in the subarray a by approximating the difference coordinate.

Here, the delay calculation unit 140 is prepared for the number of vibration elements in the subarray a (for example, 3 × 4 12 elements). Thereby, the delay time in all the vibration elements in the subarray a can be obtained by one calculation. The delay calculation unit 140 also multiplies the part for obtaining the calculated value (dlta _i ) of Expression (4) by the multipliers 141 to 143 and the adders 145 and 146 and the output from the reciprocal calculation circuit 130. 144 and an adder 147 that adds a representative delay (dly _rep ) and outputs the delay time (dly _i ) of the vibration element.

  In the delay calculation unit 18 having the above-described calculation configuration, the time required for calculating the delay with respect to the total number of vibration elements of, for example, 4608 (the number of vibration elements in the subarray 12) is 0.025 us x when the clock frequency is 40 MHz. 4608/12 = 9.6 us. Assuming that the calculation time is within 10 us, the calculation configuration of the delay calculation unit 18 described above is sufficient. In order to calculate both the transmission and reception delays, one set of the calculation configuration of the delay calculation unit 18 described above is insufficient, but in that case, there is a method of increasing one more set or increasing the clock frequency to 80 MHz. In the method of increasing one set and the method of increasing the clock frequency, the former is an option in consideration of reducing the amount of heat generation and minimizing power consumption.

  Here, unlike the above-described calculation configuration in which the delay time in each vibration element is approximated and calculated for each subarray a, a comparative example in which the delay time is calculated for each vibration element in the 1D array probe and the 2D array probe will be described. To do.

FIG. 6 is an explanatory diagram for explaining the arrangement of the vibration elements e1 to ei in the 1D array probe. As shown in FIG. 6, in the 1D array probe, the vibration elements e1 to ei are arranged in one direction (X direction). Here, of the Y and Z directions orthogonal to the X direction, the irradiation direction for irradiating ultrasonic waves is defined as the Z direction. When the coordinates of the focal point are (x _f z _f ) and the coordinates of the vibration element ei are (xe _i ze _i ), the calculation formula of the delay time dly _i is the following formula (6), similar to the formula (1): It can be expanded as follows.

  FIG. 7 is a block diagram illustrating a calculation configuration according to a comparative example. Specifically, FIG. 7 is a diagram illustrating a calculation configuration for calculating the delay time of each vibration element of the 1D array probe according to the above-described formula (6). It is. As shown in FIG. 7, in the calculation configuration for calculating the delay time of each vibration element according to the equation (6), a part for obtaining the inside of the route by the adders 1001, 1002, 1021 and the multipliers 1011, 1012, A square root circuit 1031.

  Since the square root circuit 1031 is a relatively large circuit, the degree of influence on the cost / power of the system is determined depending on how many sets of the arithmetic configuration in FIG. 7 are required. When the delay time for all the vibration elements is required at one time, assuming that the number of vibration elements is 128, 128 sets of the operation configuration of FIG. However, in practice, after a certain transmission / reception process is completed, there is a preparation period (10 to 20 us) for the next process, so it is only necessary to be able to calculate the delay time during the preparation period. In addition, the calculation configuration of FIG. 7 is shared between the vibration elements, and the respective delay times are calculated in order. For example, if the arithmetic configuration is operated at 40 MHz, the time required for executing 128 calculations is 0.025 us × 128 = 3.2 us, and 6.4 us is sufficient even if both transmission and reception delays are calculated. Computation amount that ends within the preparation period. That is, for the focus of the 1D array probe having 128 vibrating elements, only one calculation configuration in FIG. 7 is required, and the influence of cost / power on the system is small.

  Similarly, in the comparative example of the 2D array probe, since a vibration element in the elevation direction (Y direction in the coordinate system) is added, the calculation formula of the delay time is the following formula (7).

  FIG. 8 is a block diagram illustrating a calculation configuration according to a comparative example. Specifically, FIG. 8 is a diagram illustrating a calculation configuration for calculating the delay time of each vibration element of the 2D array probe according to the above-described equation (7). It is. As shown in FIG. 8, in the calculation configuration for calculating the delay time of each vibration element of the 2D array probe according to the equation (7), the adder 1003 is compared with the case of the equation (6) (see FIG. 7). 1022 and a multiplier 1013 are further added.

Here, when the number of vibration elements is 4608, the necessary time when executing with one set of calculation configuration is 0.025 us x 4608 = 115.2 us. In this case, it cannot be finished during the preparation period. Therefore, the calculation configuration of the comparative example has the following countermeasures.
a) Increase the operating speed (increase the clock frequency).
b) Having multiple sets of circuits.

  For a), the required clock frequency is about 930 MHz when executed with only one arithmetic configuration. Currently, there is no FPGA that can operate with this clock. Even if a dedicated integrated circuit (ASIC) that is highly circuit-optimized is used, power consumption increases with high-speed operation, and it becomes difficult to satisfy the system requirements in that respect.

  As for b), assuming that the total number of vibrating elements is 4608, the clock frequency is 40 MHz, and the allowable calculation time is 10 us, the number of circuit sets necessary for calculating the transmission / reception delay is estimated to be 24 sets as in the above-described conditions. . If 24 sets of the computation configuration of FIG. 8 are required, the cost impact on the system is enormous. In particular, when the algorithm for taking the square root is realized by hardware, the circuit scale is large. Therefore, when 24 are required, it is necessary to select a larger one if it is realized by, for example, FPGA. In the following (Table 1), assuming that the total number of vibrating elements is 4608, the clock frequency is 40 MHz, and the allowable calculation time is 10 us, the calculation configuration of FIG. A comparison of hardware elements with (2 sets) is shown.

  As is clear from Table 1, the effect of the comparative example having 24 square root circuits that have a large influence on the hardware scale is sharply reduced to 2 in the delay calculation unit 18 described above. In the delay calculation unit 18 described above, the number of multipliers increases. However, since recent FPGAs have a large number of multipliers as hard macros, this difference is not disadvantageous. In addition, although an inverse number calculation circuit is required, there is a method in which data necessary for inverse number calculation is stored in advance in a built-in memory in dynamic reconfiguration, and the data is obtained by referring to the data. Like the multiplier, even if the recent FPGA is small in scale, the built-in memory is prepared abundantly and only two sets are required, so it does not increase the cost. The effect of reducing the number of square root circuits is more than offset.

(Second Embodiment)
Next, a second embodiment in which the circuit configuration corresponding to the delay calculation unit 18 and the transmission / reception unit 11 is provided inside the ultrasonic probe 1 will be described. FIG. 9 is a block diagram illustrating the configuration of an ultrasonic probe 1a according to the second embodiment.

  The probe control unit 40 controls the delay calculation unit 18, the transmission unit 21, and the reception unit 22 based on a control signal transmitted from the control unit 17 of the apparatus body 10. The temperature sensor 60 is a thermistor that detects the temperature applied to the ultrasonic probe 1 a and outputs the detected temperature to the probe control unit 40. The temperature detected by the temperature sensor 60 is the temperature of the contact surface with the subject P that can be detected by being arranged in the vicinity of the vibration element of the acoustic module 50, as well as the transmission / reception unit 11, the delay calculation unit 18, and probe control. It may be the internal temperature of the ultrasonic probe 1a such as the section 40.

  As in the ultrasonic probe 1a described above, a circuit configuration corresponding to the delay calculation unit 18 and the transmission / reception unit 11 may be provided inside the probe. As for the ultrasonic probe 1a, the hardware mounting area is naturally within a limited volume, and heat is trapped, so that there is a restriction that power consumption must be suppressed as much as possible. However, by adopting the delay calculation unit 18 described above, these restrictions can be easily cleared.

(Modification)
In the first and second embodiments described above, each subarray a operates only in an operation mode (hereinafter referred to as a power saving mode) in which the delay time in each vibration element is approximated and calculated. On the other hand, in the modified example, in addition to the power saving mode described above, as shown in the comparative example, an operation mode (hereinafter referred to as normal mode) that calculates a delay time in each vibration element based on the position of each vibration element. Mode) is prepared, and the configuration for switching between the two operation modes is illustrated. In order to correspond to the power saving mode and the normal mode described above, a plurality of delay calculation units 18 having an arithmetic configuration corresponding to each may be prepared. However, in a modified example, control as a switching unit is performed by dynamic reconfiguration. It is assumed that the circuit configuration of the delay calculation unit 18 is switched under the control of the unit 17.

  FIG. 10 is a flowchart showing an example of the operation of the ultrasonic diagnostic apparatus 100 according to the modification. As shown in FIG. 10, when the processing is started, the control unit 17 of the ultrasonic diagnostic apparatus 100 performs initial setting of each unit (S10). Specifically, the control unit 17 calculates by dynamic reconfiguration so as to start the operation in the operation mode (power saving mode / normal mode) according to the initial setting condition stored in the internal storage unit 16. Write the configuration to the delay calculator 18.

  For example, when the power saving mode is set as the initial setting condition, the control unit 17 uses the calculation configuration illustrated in FIG. 5 that approximates and calculates the delay time in each vibration element for each subarray a as the delay calculation unit. 18 is written. In addition, when the normal mode is set as the initial setting condition, the control unit 17 has a predetermined calculation configuration illustrated in FIG. 8 for calculating the delay time in each vibration element based on the position of each vibration element. The set is written in the delay calculation unit 18.

  This setting condition is set in advance by the operator via the input device 3 or the like. For example, when using the abdominal ultrasonic probe 1 having a large number of vibration elements, the power saving mode is set as an initial setting condition. When the circulatory ultrasonic probe 1 having a relatively small number of vibration elements is used, the normal mode is set as an initial setting condition.

  The operation status in the normal mode and the power saving mode described above may be displayed on the display screen of the monitor 2 under the control of the control unit 17. In this case, the operator can recognize whether the operation is performed in the normal mode or the power saving mode by checking the display on the monitor 2.

  Next, the control unit 17 acquires the temperature of the ultrasonic probe 1 or 1a using the temperature sensor 60 or the like, and determines whether or not the acquired temperature is equal to or higher than a preset temperature (S11). When the temperature of the ultrasonic probe 1 or 1a is higher than a preset temperature, the control unit 17 sets the operation mode to a power saving mode that can reduce power generation while suppressing power consumption ( S14).

  When the temperature of the ultrasound probe 1 or 1a is lower than a preset temperature, the control unit 17 determines whether or not the focus position of the ultrasound is a deeper position than the preset position. (S12). When the ultrasonic focus position is deeper than a preset position, an error that occurs when the delay time is approximated and calculated is smaller, so the control unit 17 sets the operation mode to the power saving mode. Set (S14).

  When the ultrasonic focus position is a shallow position that is less than a preset position, the control unit 17 sets the operation mode to the normal mode (S13), and it is clearer without calculating the approximate delay time. An ultrasound image is obtained.

  Following S13 and S14, the control unit 17 compares the operation mode set in S13 and S14 with the operation mode set before that, and determines whether or not there is a mode change (S15). Here, when there is no change in the operation mode, the control unit 17 advances the processing to S17. When there is a change in the operation mode, the control unit 17 writes the operation configuration according to the normal mode set in S13 or the power saving mode set in S14 to the delay calculation unit 18 by dynamic reconfiguration (S16). ), The process proceeds to S17.

  In S <b> 17, the control unit 17 determines the presence / absence of the process based on the presence / absence of an end instruction from the input device 3. Here, when the process is continued (S17: NO), the control unit 17 returns the process to S11.

  The above-described flowchart switches the operation mode according to the temperature of the ultrasonic probe, and is suitable for the second embodiment including the delay calculation unit 18 in the probe. About 1st Embodiment, since the delay calculation part 18 is provided in the apparatus main body 10 side, it is not necessary to switch an operation mode according to the temperature of an ultrasonic probe, and the process of S11 may be abbreviate | omitted. Further, in place of S11, a process for determining whether or not the setting for reducing the power consumption is performed by the input device 3 or the like is added, and the control unit 17 performs the setting for reducing the power consumption. The power saving mode may be set when it is present.

  According to at least one embodiment described above, the delay time for each vibration element can be easily calculated.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. For example, the second embodiment shown in FIG. 9 has a transmission / reception circuit on the probe side, but it is rare that the A / D converter is currently built in. In many cases, the main beam forming is performed after A / D conversion. Even in this case, the present invention is effective. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 100 ... Ultrasonic diagnostic apparatus 1, 1a ... Ultrasonic probe, 2 ... Monitor, 3 ... Input device, 4 ... Probe cable, 10 ... Apparatus main body, 11 ... Transmission / reception part, 12 ... B-mode process part, 13 ... Doppler process , 14 ... Image generation unit, 15 ... Image memory, 16 ... Internal storage unit, 17 ... Control unit, 18 ... Delay calculation unit, 21 ... Transmission unit, 22 ... Reception unit, 40 ... Probe control unit, 50 ... Acoustic module , 60 ... temperature sensor, 213 ... drive circuit, 212 ... transmission delay circuit, 211 ... pulse generator, 221 ... preamplifier, 222 ... A / D converter, 223 ... reception delay circuit, 224 ... adder, a ... subarray, e1-ei ... vibration element, P ... subject

Claims (8)

An ultrasonic probe in which a plurality of vibration elements for transmitting and receiving ultrasonic waves to and from a subject are arranged;
For each of the plurality of sub-arrays obtained by dividing the array of the plurality of vibration elements, a delay time required for transmission / reception of the ultrasonic waves at the representative coordinates in or near the sub-array is calculated, and the delay time and the representative coordinates are calculated. Based on the difference between each vibration element included in the sub-array, a delay time calculation unit that approximates and calculates a delay time in each vibration element;
Based on the delay time calculated for each vibration element, a transmission / reception unit that performs transmission and reception of ultrasonic waves in the plurality of vibration elements of the ultrasonic probe with the delay time,
An image generation unit that generates image data inside the subject from the ultrasonic waves received from the transmission / reception unit;
Equipped with a,
The delay time calculation unit
A first delay time calculation unit that is provided for each of the plurality of subarrays, and calculates a delay time for transmission of the ultrasonic wave at the representative coordinates for each of the subarrays;
A second delay time calculation unit that is provided for each of the plurality of subarrays, and calculates a delay time required to receive the ultrasonic wave at the representative coordinates for each of the subarrays;
Based on the delay time calculated by the first delay time calculation unit and the difference between the corresponding vibration elements, the delay time of the vibration elements is provided for the number of vibration elements included in one subarray. A plurality of third delay time calculation units to calculate by approximation;
Based on the delay time calculated by the second delay time calculation unit and the difference between the corresponding vibration elements, the delay time in the vibration element is provided by the number of vibration elements included in one subarray. A plurality of fourth delay time calculating units to calculate by approximation;
Having
Ultrasonic diagnostic equipment. An ultrasonic probe in which a plurality of vibration elements for transmitting and receiving ultrasonic waves to and from a subject are arranged;
For each subarray in which the array of the plurality of vibration elements is divided, a delay time required for transmission / reception of the ultrasonic wave at representative coordinates in or near the subarray is calculated, and the delay time and the subarray for the representative coordinates are calculated. A delay time calculation unit that approximates and calculates a delay time in each vibration element based on the difference between each vibration element included;
Based on the delay time calculated for each vibration element, a transmission / reception unit that performs transmission and reception of ultrasonic waves in the plurality of vibration elements of the ultrasonic probe with the delay time,
An image generation unit that generates image data inside the subject from the ultrasonic waves received from the transmission / reception unit;
With
The delay time calculation unit is configured to calculate a position of the vibration element for each of the plurality of vibration elements in a first calculation mode in which the delay time in each vibration element included in the subarray is approximated and calculated for each subarray. The delay time is calculated in the second calculation mode for calculating the delay time in the vibration element,
A switching unit for switching between the first calculation mode and the second calculation mode based on a preset condition;
The switching unit switches to the first calculation mode when the ultrasonic focus position is deeper than a predetermined value, and switches to the second calculation mode when the ultrasonic focus position is shallower than the predetermined value.
Ultrasonic diagnostic equipment. The delay time calculation unit is configured to calculate a position of the vibration element for each of the plurality of vibration elements in a first calculation mode in which the delay time in each vibration element included in the subarray is approximated and calculated for each subarray. The delay time is calculated in the second calculation mode for calculating the delay time in the vibration element,
A switching unit that switches between the first calculation mode and the second calculation mode based on a preset condition;
The ultrasonic diagnostic apparatus according to claim 1. A temperature detector for detecting the temperature applied to the ultrasonic probe;
The switching unit switches to the first calculation mode when the detected temperature is equal to or higher than a predetermined value, and switches to the second calculation mode when the detected temperature is lower than the predetermined value.
The ultrasonic diagnostic apparatus according to claim 3 . The switching unit switches to the first calculation mode when the ultrasonic focus position is deeper than a predetermined value, and switches to the second calculation mode when the ultrasonic focus position is shallower than the predetermined value.
The ultrasonic diagnostic apparatus according to claim 3 . The delay time calculation unit calculates a delay time of the one vibration element using the coordinates of one vibration element included in the subarray as a representative coordinate, and based on the delay time and a difference between the other vibration elements. Approximating the delay time in the other vibration element,
The ultrasonic diagnostic apparatus as described in any one of Claims 1 thru | or 5 . The ultrasonic probe is a 2D (two dimensional) array probe in which the vibration elements are arranged in a lateral direction and an elevation direction,
The delay time calculation unit approximates and calculates a delay time in each vibration element included in the subarray for each of the subarrays in which a predetermined number of the vibration elements are arranged in the lateral direction and the elevation direction.
The ultrasonic diagnostic apparatus as described in any one of Claims 1 thru | or 6 . An acoustic module in which a plurality of vibration elements for transmitting and receiving ultrasonic waves to and from a subject are arranged;
For each of the plurality of sub-arrays obtained by dividing the array of the plurality of vibration elements, a delay time required for transmission / reception of the ultrasonic waves at the representative coordinates in or near the sub-array is calculated, and the delay time and the representative coordinates are calculated. Based on the difference between each vibration element included in the sub-array, a delay time calculation unit that approximates and calculates a delay time in each vibration element;
Based on the delay time calculated for each vibration element, a transmission / reception unit for performing transmission and reception of ultrasonic waves in the plurality of vibration elements of the acoustic module with the delay time;
Equipped with a,
The delay time calculation unit
A first delay time calculation unit that is provided for each of the plurality of subarrays, and calculates a delay time for transmission of the ultrasonic wave at the representative coordinates for each of the subarrays;
A second delay time calculation unit that is provided for each of the plurality of subarrays, and calculates a delay time required to receive the ultrasonic wave at the representative coordinates for each of the subarrays;
Based on the delay time calculated by the first delay time calculation unit and the difference between the corresponding vibration elements, the delay time of the vibration elements is provided for the number of vibration elements included in one subarray. A plurality of third delay time calculation units to calculate by approximation;
Based on the delay time calculated by the second delay time calculation unit and the difference between the corresponding vibration elements, the delay time in the vibration element is provided by the number of vibration elements included in one subarray. A plurality of fourth delay time calculating units to calculate by approximation;
Having
Ultrasonic probe.

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