RU2765605C1 - Tomography device using a ring antenna array - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: tomography device using a ring antenna array contains a metal base of a circular ultrasonic antenna array with alternately alternating emitting and receiving antenna elements, phase shifters in the emitter channels, an adder of signals from all receiving elements, a monochromatic wave source feeding all emitting antenna elements through phase shifters, a phase shifter control device coupled with an electronic computer. In this case, the base of the ultrasonic antenna array is made of N-metal ring segments with the ability to connect into a ring to form a regular circle. On the inner side of the segments, a damper layer is applied, in which emitting and receiving antenna elements are arranged alternately with recessed into the damper by the thickness of the antenna element. Each segment of the ring is placed in an elastic applicator filled with immersion liquid with the possibility of adjusting its amount.

EFFECT: use of this invention will expand the area of ​​operation of the device due to the provision of tight ultrasonic contact of the annular antenna array with the surface of the neck, sternum or lumbar regions of the patient.

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Description

The present invention relates to the field of near location on acoustic waves with sounding of the surrounding space with a monochromatic signal. Information about the distance to the reflective points of the object is extracted using controlled focus. This proposal can be used in medicine for tomography of the internal structure of an object, as well as for delivering ultrasonic energy to a given area of the patient's body for therapeutic purposes, for example, for crushing kidney stones.

An analogue of the proposed device is a well-known device [patent No. US 2014/0316269 A1] (FIG.1), containing a flat antenna array (FIG.61 J.), or an antenna array in the form of a parabola sector (FIG.61 A.), or in in the form of a paraboloid (FIG.61 B.) with mechanical displacement of the focus of the emitted ultrasonic energy, by changing the position of the antenna array inside the applicator (FIG.1.), generator of probing pulses FIG.1., several receiving piezoelectric elements, computer control unit with focusing with using a beacon to deliver ultrasonic energy to the area indicated by the beacon. (the indicated numbering of the figures refers to the description of the patent US 2014/0316269 A1).

This device, containing a flat antenna array or a paraboloid-shaped array, does not allow tomography of the patient's cervical region due to the inappropriate shape of the antenna array, which does not allow reaching the desired contact with the neck surface, and also does not allow delivering ultrasonic energy to the desired region of the cervical region.

Also widely known are ultrasonic pulsed Doppler tomographs with a shallow penetration of the probing signal for visualization of the carotid artery of the cervical region. [Osipov L.V. - Ultrasonic diagnostic devices. Practical guide for users Moscow VIDAR 1999, https://studizba.com/files/show/djvu/1786-1-osipov-l-v--ul-trazvukovye.html]. The main feature of this tomograph is shallow probing, which allows you to view in detail the carotid artery, located close to the surface of the neck.

Known ultrasonic Doppler device with a pulsed principle of action is designed for shallow probing of the carotid artery does not allow you to get a complete, deep picture of the cervical section.

Device according to [Osipov L.V. - Ultrasonic diagnostic devices. Practical guide for users Moscow VIDAR 1999] differs from the device according to [patent No. US 2014/0316269 A1] only in the design of the ultrasonic sensor (antenna array) and the parameters of the probing signal.

A common disadvantage of both devices is the impossibility of obtaining a complete picture of the section of the patient's body. They allow you to visualize a small sector, that is, a section of an object in the form of a sector.

в каналах излучателей, сумматор

5 сигналов со всех принимающих элементов, источник монохроматической волны 6, запитывающий все излучающие антенные элементы через фазовращатели, устройство управления фазовращателями

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……… 7 сопряжённое с электронно-вычислительным устройством. Данное устройство с помощью фазовращателей позволяет сфокусировать ультразвуковую энергию внутри кольца. Фазовращатели позволяют управлять положением фокуса внутри кольца. Это позволяет доставлять ультразвуковую энергию в нужную область пациента, находящегося внутри кольца. Если связать дискретные положения фокуса с дискретными элементами матрицы изображения, то можно просканировать фокусом внутренние области шейного отдела и построить изображение шейного отдела в сечении. Разрешающая способность отражающих точек внутри кольца Δ соответствует пределу Релея, определяется формулой Δ=λ/5, где λ – длина ультразвуковой волны.As a prototype, a tomography device using a ring antenna array [patent RU2728512]. The prototype device is shown in Fig. 1. It contains a metal base of an ultrasonic antenna array in the form of a ring 1 with alternating emitting 2 and receiving 3 antenna elements made of piezoceramic strips based on lithium niabate or barium titanate, phase shifters 4

in emitter channels, adder

5 signals from all receiving elements, monochromatic wave source 6 feeding all radiating antenna elements through phase shifters, phase shifter control device

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……… 7 interfaced with an electronic computing device. This device with the help of phase shifters allows you to focus ultrasonic energy inside the ring. Phase shifters allow you to control the position of the focus inside the ring. This allows you to deliver ultrasonic energy to the desired area of the patient inside the ring. If we associate discrete focus positions with discrete elements of the image matrix, then it is possible to scan the internal regions of the cervical region with focus and construct an image of the cervical region in section. The resolution of the reflecting points inside the ring Δ corresponds to the Rayleigh limit, is determined by the formula Δ=λ/5, where λ is the ultrasonic wavelength.

The method of tomography based on controlled focus provides for probing the patient with an ultrasonic monochromatic wave, eliminates dispersion distortions and makes it possible to obtain a better image than with pulsed ultrasonic tomography.

However, this device in the form of a ring does not allow tomography of the patient's cervical region. If the diameter of the annular array is chosen according to the condition of the passage of the patient's head, then there will be a large air gap in the neck area, which will not ensure tight contact of the annular antenna array with the neck surface. The specified air gap prevents the passage of the ultrasonic wave into the patient's body and makes it impossible to deliver focused ultrasonic energy to the desired area of the patient. This, in turn, does not allow scanning the internal regions of the neck with controlled focus and constructing an image of the internal structure in section.

The same problem occurs when tomography of the thoracic or lumbar region.

The objective (technical result) of the invention is to expand the area of operation of a tomography device based on a ring antenna array by expanding the functionality of the ring due to the variation of its geometry for tight contact of the emitting and receiving antenna elements of the ring array with the surface of the neck, chest or lumbar region. The positive effect expected from the use will ensure tight contact of the annular antenna array with the indicated surfaces and will allow delivering ultrasonic energy to the desired area of the patient's body, and will also make it possible to scan the internal area of the patient's body with focus and build its image in section.

The task is achieved by the fact that in a known device containing a metal base of an annular ultrasonic antenna array with alternately alternating emitting and receiving antenna elements, phase shifters in the channels of the emitters, an adder of signals from all receiving elements, a source of a monochromatic wave that feeds all emitting antenna elements through phase shifters, a phase shifter control device coupled to an electronic computer, in order to obtain a tight contact of the antenna array elements with the patient's body to ensure the delivery of focused ultrasonic energy to a given area of the neck, as well as the thoracic and lumbar region and to enable tomography of these departments, a technological change in geometry is provided ring during its installation on the patient for this, while the base of the ultrasonic antenna array is made of N-metal segments of the ring with the possibility of connecting into a ring with formed The inner side of the segments is covered with a damper layer, in which the radiating and receiving antenna elements are alternately located with recession into the damper for the thickness of the antenna element, each segment of the ring is placed in an elastic applicator filled with immersion liquid with the possibility of adjusting its amount. Technological change in the geometry of the ring during
the time of its installation on the patient provides for a different possible N-number of segments of the ring of the base of the ultrasonic antenna array. For example, when N=2, the base is two half rings. The emitting and receiving antenna elements can be made, for example, in the form of strips of piezoelectric elements. The connection of the segments, and in particular the semi-rings, into a ring can be carried out, for example, by means of end magnets. As an electronic computer (computer) can be used, for example, a personal computer.

Figure 1 shows a device taken as a prototype. On FIG. 2 shows the proposed device for tomography using a ring antenna array with N=2. Figure 3 shows an example of the location of the segments (half rings) of the ultrasonic antenna array on the patient's neck. On FIG. 4 shows the design of a semi-circular antenna array.

The tomography device using an annular antenna array (Fig.1, Fig.2, Fig.4) contains 1 - metal base of the ultrasonic annular antenna array, 2 - emitting elements of the antenna array, 3 - receiving elements of the antenna array, 4 - phase shifters, 5 - adder of received coherent signals, 6 – monochromatic wave source, 7 – phase shifter control device interfaced with a computer, 8 – metal base of an ultrasonic annular antenna array of segments (with N = 2 metal base in the form of a half ring), 9 – end face of connecting segments into a ring , for example, magnetic, 10 - damper, 11 - elastic applicator, 12 - immersion liquid.

The proposed device for N=2 (figure 2) is a two-ring ultrasonic antenna array. The specific device of one of the semirings is shown in Fig.4. Semirings are made of metal and are semicircles. After connecting the half rings, they should form a regular circle, with a known radius. The radius of a circle made up of semirings is necessary when calculating the initial phases, which are set by phase shifters. Locks are provided at the ends of the half-rings, for example, in the form of magnets 9, allowing you to connect two half-rings into a ring, covering the neck or torso of the patient in Fig.3. A layer of damper 10 made of sound-absorbing material is applied on the metal base in the form of a half-ring 8 on the inside. In the damper layer 10, with a slight recession, there are emitting 2 and receiving 3 antenna elements, made, for example, in the form of strips of piezoelectric elements that perform the functions of emitting and receiving ultrasonic waves. Due to the damper 10, the antenna elements 2 radiate ultrasonic energy in a directed manner only into the interior of the ring. The receiving antenna elements 3 also have a directional reception of ultrasonic energy coming from the inner region of the ring. Receiving 3 and emitting 2 elements alternate. The damper 11 makes it possible to form the radiation patterns of individual antenna elements, and also allows you to decouple the receiving elements 3 from the emitting elements 2. All elements are placed inside the applicator 11 filled with immersion liquid 12. Pumping the immersion liquid into the inside of the applicator allows you to select the sizes of the half rings for the individual dimensions of the patient and provide good ultrasonic contact with the patient's body. Such a device of an annular antenna array will ensure a coordinated exchange of ultrasonic energy with the patient's body with low losses and small reflections of the wave from the interface between two media.

Device tomography using a ring antenna array works as follows. The generated ultrasonic energy by the source 6 in the form of a monochromatic wave is supplied to the radiating elements 2 of the segments of the annular antenna array through the phase shifters 4. The phase shifters are controlled by voltages U _y coming from the control device 7 associated with the electronic computing device. The part of the device described above makes it possible to focus the ultrasonic energy and furthermore allows to control the position of the focus within the ring where the patient is located. The reflected signals from the points of the object that are in focus arrive at the receiving piezoelectric elements 3 on the segments of the annular antenna array. The reflected signals coming from the focus inside the ring are added in phase in the adder 5 and give a burst of ultrasonic energy at the output of the adder. The reflected signals from points outside the focus are added out of phase in the adder and therefore do not give a power surge at its output.

The problem of good contact with the patient's body and delivery of ultrasonic energy to the desired area of the patient's body, without losses and reflections from the boundary of two media, is solved by the design features of the annular antenna array. The emitting and receiving antenna elements are located on the damper with some recession for the thickness of the element. This allows you to get rid of the omnidirectional radiation of the antenna elements and limit the radiation in the desired direction. Thus, the radiation pattern of the antenna element (ultrasonic sensor) is formed. In addition, the damper provides decoupling between the radiating and receiving elements.

The elastic applicator filled with immersion liquid adapts the circular ring of the antenna array to the non-circular perimeter of the patient, ensuring close ultrasonic contact with the patient's body. The circular nature of the antenna ring needs to be made unchanged. Otherwise, it will be impossible to calculate the initial phase of the emitted signals by each antenna element. Therefore, an elastic applicator filled with immersion liquid is required to align the antenna ring formed by the N-segment rings with the patient's non-annular perimeter.

The technical result of the invention is to expand the area of operation of the device by providing a tight ultrasonic contact of the annular antenna array with the surface of the neck, sternal or lumbar regions of the patient. A positive result is achieved by the fact that the annular antenna array is replaced by N detachable ring segments with the possibility of connecting into a ring, for example, by means of end magnets. This, in turn, will allow focused delivery of ultrasound energy to the desired area of the patient's body, and eventually obtain a tomogram of the neck, sternal or lumbar region.

The antenna elements of the segments of the rings of the annular antenna array are placed inside an elastic applicator filled with an immersion ultrasound liquid. The technical result of this is to ensure close contact with the patient's body and unhindered penetration of the diagnostic ultrasonic wave into the patient's body without reflections at the interface of two media,

The location of the piezoelectric elements on the damper with a recession to the thickness of the piezoelectric plate gives a positive technical result, consisting in decoupling the emitting and receiving elements of the antenna array and allows you to form the required radiation and reception pattern for each antenna element.

The regulation of the amount of immersion liquid inside the applicator by, for example, pumping makes it possible to ensure good ultrasonic contact of the antenna elements with a large scatter in the sizes of the tomographed areas associated with the individual characteristics of patients.

Claims (6)

1. A tomography device using a ring antenna array, containing a metal base of an annular ultrasonic antenna array with alternately alternating emitting and receiving antenna elements, phase shifters in the channels of the emitters, an adder of signals from all receiving elements, a monochromatic wave source that feeds all emitting antenna elements through phase shifters, a phase shifter control device coupled to an electronic computer, characterized in that the base of the ultrasonic antenna array is made of N-metal ring segments with the possibility of connecting into a ring with the formation of a regular circle, a damper layer is applied to the segments on the inner side, in which emitting and receiving antenna elements recessed into the damper for the thickness of the antenna element, each segment of the ring is placed in an elastic applicator filled with immersion liquid with the possibility of adjusting its amount. 2. The device according to claim 1, characterized in that the basis of the ultrasonic antenna array is two half rings. 3. The device according to claim 1, characterized in that the base of the ultrasonic antenna array consists of three ring segments. 4. The device according to claim 1, characterized in that the emitting and receiving antenna elements are made in the form of strips of piezoelectric elements. 5. The device according to claim 1, characterized in that the connection of the ring segments into the ring is carried out by means of end magnets. 6. The device according to claim 1, characterized in that a personal computer is used as an electronic computer.

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