Magnetically powered probe and method of use thereof

Abstract

A magnetically kinetic imaging probe device and method are described. The probe device includes a housing having an outer surface and an inner cavity, a magnet, and a sensing device configured to detect distance, motion, or magnetic material. The magnet is disposed within the inner cavity of the housing, and the sensing device is disposed on the outer surface of the housing, with the magnet positioned to generate a time-varying magnetic field in an imaging plane of the sensing device. The magnet is intended to move magnetic nanoparticles in tissue so that the motion can be detected by the sensing device (ultrasound, optical, or other). Detected motion is indicative of the presence of magnetic material (nanoparticles).

Description

[Technical Field]

[0001] The present invention relates generally to the field of magnetic force imaging. More particularly, the present invention relates to a magnetic force imaging probe device that is designed to be placed within an animal or human cavity, such as for transrectal or transvaginal use, although the device may also be designed or available for external use. [Background technology]

[0002] Magnetokinetic imaging is an imaging technique in which superparamagnetic iron oxide nanoparticles can be used as ultrasound contrast agents. The key idea of ​​this imaging technique is to apply a time-varying magnetic field (pulsed or sinusoidal) to a volume in which the nanoparticles are deposited. The magnetic field induces movement of the particles, which in turn induces movement of the surrounding tissue, which is detected by ultrasound. In early implementations, such as those disclosed in Evertsson, M. et al., IEEE Transactions on Ultrasonic, Ferroelectrics, and Frequency Control, Vol. 60, No. 3, March 1, 2013, pp. 481-491, an electromagnet was used to generate the time-varying magnetic field, consisting of a coil around a conical iron core (see Figure 1). When a current is applied, a magnetic field is generated from the tip of the iron core. The force acting on the particles depends on the field strength and the field gradient.

[0003] The electromagnet approach presents several problems in that the magnets tend to be heavy and require large currents to generate a sufficient magnetic field, the latter fact causing considerable heat. These facts make it difficult to produce magnetically powered systems that can be used clinically, especially in systems intended for endoscopic applications. A magnetic field generator is proposed in EP 2 801 323 A1, in which a permanent magnet is instead used, which is rotated so that its north and south poles alternately point towards the area where the superparamagnetic nanoparticles are concentrated, with the effect of exerting a varying magnetic force on the particles and alternately attracting them to the magnet.

[0004] This solution, a rotating permanent magnet, was proposed as a magnetic field generator, separate from the standard ultrasound transducer connected to the ultrasound scanner. This device is limited by its design and can only be used with a limited range of magnetic forces.

[0005] Therefore, easier to use, more compact, and more versatile magnetically powered imaging probe devices, methods, and / or systems that can be used in more locations in humans and / or animals would be advantageous. Further improved sensitivity of magnetic nanoparticle detection would also be an advantage, along with improved patient safety and the most cost-effective diagnostics. Summary of the Invention [Problem to be solved by the invention]

[0006] Accordingly, embodiments of the present invention seek to mitigate, alleviate or eliminate one or more of the deficiencies, disadvantages or problems in the art as identified above, singly or in any combination, by providing a magnetic force imaging probe assembly, and a method of magnetic force imaging using the probe assembly, preferably according to the appended claims. [Means for solving the problem]

[0007] According to a first aspect of the present disclosure, there is provided a magnetic kinetic imaging probe system. The magnetic kinetic imaging probe system can include a housing having an exterior surface and an interior cavity, a magnet, and a sensing device configured to detect distance, motion, or magnetic material. The magnet can be disposed in the interior cavity of the housing, and the sensing device can be disposed on the exterior surface of the housing. The magnet can be positioned to generate a time-varying magnetic field in an imaging plane of the sensing device.

[0008] In some embodiments of the magnetically powered imaging probe, the sensing device may be an ultrasound transducer.

[0009] In some embodiments of the magnetically powered imaging probe, the magnet may be a cylindrically shaped permanent magnet, and the time-varying magnetic field may be obtained by rotating the magnet.

[0010] In some embodiments of the magnetically powered imaging probe, the magnet may be a radially magnetized magnet.

[0011] In some embodiments of the magnetically powered imaging probe, the ultrasound transducer may be positioned along the length of the magnet, preferably such that the length of the cylindrically shaped magnet exceeds the width of the ultrasound transducer.

[0012] In some embodiments of a magnetically powered imaging probe, the distance between the magnet and the sensing device may be defined primarily by the thickness of the housing at the location of the sensing device and / or the distance between the inner surface of the housing and the magnet.

[0013] In some embodiments of a magnetically powered imaging probe, the magnet may be rotated using a motor.

[0014] In some embodiments of the magnetically powered imaging probe, the housing may have an elongated shape for positioning in a cavity of an animal, such as a human. The device may be configured for transrectal or transvaginal use.

[0015] In some embodiments of the magnetically powered imaging probe, the housing may be made of a non-conductive material.

[0016] In some embodiments of the magnetically powered imaging probe, the ultrasound transducers may be an array, such as a one-dimensional array or a 2D array.

[0017] In some embodiments of a magnetically powered imaging probe, the array may be positioned concentrically with the magnet.

[0018] In some embodiments of the magnetically powered imaging probe, the housing may have a tip portion and a handle portion. The magnet and sensing device may be disposed in a distal portion of the tip portion. The motor may be disposed within the handle portion and may rotate the magnet via a shaft extending therebetween.

[0019] In some embodiments of the magnetically kinetic imaging probe, sensors can be used to track the position of the magnet during rotation. Other examples of sensors that can be used are sensors for detecting probe position, temperature, acceleration, or other physical parameters.

[0020] In some embodiments of the magnetically powered imaging probe, a disk may be positioned on each side of the magnet, each disk may have a peg positioned at the center of each disk for holding the magnet, and one of the pegs may be configured to connect to a motor or to a shaft connected to a motor.

[0021] In some embodiments of the magnetically powered imaging probe, packing such as O-rings may be placed on each side of the magnet to center the magnet through the use of the pegs described above.

[0022] According to another aspect of the present disclosure, a method of magnetic force imaging is described. The method can include introducing magnetic particles into tissue of a subject to be examined. The method can further include obtaining a time-varying magnetic field using a magnet disposed within a cavity of a housing of the probe, the time-varying magnetic field causing the magnetic particles to vibrate and / or move in an imaging plane of a sensing device disposed on an outer surface of the housing. The method can also include imaging the vibration and / or movement of the particles using the sensing device. The method can also include analyzing the vibration and / or movement of the particles to determine a distribution of the magnetic particles.

[0023] In some embodiments of the method, steps are described that use the determined distribution to provide assistance in diagnosing a subject.

[0024] In some embodiments of the method, a step of analyzing the distribution of magnetic particles in the lymph nodes to assess whether the lymph nodes are cancer-free is described.

[0025] In some embodiments of the method, the step of rotating a permanent magnet to obtain a time-varying magnetic field is described.

[0026] In some embodiments of the method, a step of inserting a probe into an orifice of a subject to be diagnosed is described.

[0027] In some embodiments of the method, the opening is the rectum.

[0028] Some advantages of the above device are that it allows imaging and analysis of human and large animal tissues in more locations than the prior art, without the most prohibitive drawback of the prior art, which is the loss of beneficial magnetic field strength close to the ultrasound transducer due to its separation from the magnet, which improves the sensitivity of magnetic nanoparticle detection.

[0029] Further embodiments of the invention are specified in the dependent claims, in which the features of the second and subsequent aspects of the invention are as for the first aspect mutatis mutandis.

[0030] It should be emphasized that the term "comprises / comprising", when used in this specification, is understood to specify the presence of stated features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0031] These and other aspects, features, and advantages enabled by embodiments of the present invention will be apparent and made clear from the following description of embodiments of the invention, taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0032] [Figure 1A] FIG. 1 illustrates a schematic magnetically powered imaging probe assembly according to an embodiment of the present disclosure. [Figure 1B] FIG. 1 illustrates a schematic magnetically powered imaging probe assembly according to an embodiment of the present disclosure. [Figure 1C] FIG. 1 illustrates a schematic magnetically powered imaging probe assembly according to an embodiment of the present disclosure. [Figure 2A] 1A-1C are schematic diagrams of various exemplary configurations of ultrasound transducers in a distal portion of a probe. [Figure 2B] 1A-1C are schematic diagrams of various exemplary configurations of ultrasound transducers in a distal portion of a probe. [Figure 2C] 1A-1C are schematic diagrams of various exemplary configurations of ultrasound transducers in a distal portion of a probe. [Figure 2D] 1A-1C are schematic diagrams of various exemplary configurations of ultrasound transducers in a distal portion of a probe. [Figure 2E] 1A-1C are schematic diagrams of various exemplary configurations of ultrasound transducers in a distal portion of a probe. [Figure 2F]1A-1C are schematic diagrams of various exemplary configurations of ultrasound transducers in a distal portion of a probe. [Figure 3] 1A and 1B show schematic examples of the outer housing of a probe according to the present disclosure. [Figure 4] FIG. 4 is a diagram showing a schematic example of a cross section of the probe shown in FIG. 3. [Figure 5A] 1A-1C show schematic examples of magnet and ultrasound arrangements according to the present disclosure. [Figure 5B] 1A-1C show schematic examples of magnet and ultrasound arrangements according to the present disclosure. [Figure 5C] 1A-1C show schematic examples of magnet and ultrasound arrangements according to the present disclosure. [Figure 6] FIG. 1 illustrates a flowchart of an exemplary method according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0033] Specific examples of the present disclosure will now be described with reference to the accompanying drawings. However, the present disclosure may be embodied in many different forms and should not be construed as limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. The terminology used in the detailed description of the examples shown in the accompanying drawings is not intended to limit the disclosure. In the drawings, like numbers refer to like elements.

[0034] The following description focuses on embodiments of the present disclosure applicable to probe assemblies for magnetic force imaging, but it will be recognized that the present disclosure is not limited to this application and is applicable to many other fields and applications.

[0035] In magnetic force imaging, magnets are used to generate a nonuniform magnetic field. The nonuniform magnetic field can be a time-varying field at the same location as the imaging plane of an ultrasound transducer, regardless of where the probe is spatially positioned relative to the subject being imaged. Magnetic nanoparticles, typically made from magnetite (Fe3O4), maghemite, or zinc-doped magnetite, with sizes (including coatings) in the 10-100 nm range, are positioned at target locations within the imaging plane.

[0036] A time-varying magnetic field (T) is applied to a target location in the imaging plane of the ultrasound transducer. Magnetic nanoparticles positioned at the target location in the imaging plane therefore exhibit spatial variations in the time-varying magnetic field (T) and therefore translate, displace, and / or rotate under the influence of the magnetic field (T). Due to the generation of time-varying magnetic field components in the axial direction of the imaging plane, the displacement amplitude of the nanoparticles and their surroundings can be detected by the ultrasound transducer. The time-varying magnetic field may have a gradient that can cause the nanoparticles to translate, displace, and / or rotate under the influence of the magnetic field (T). Therefore, the temporal or displacement motion of the particles can oscillate due to the time variation of the magnetic field.

[0037] The shape of the particle can further enhance or suppress the effects of translation, displacement, and / or rotation. For example, particles with an oval / ellipsoidal shape produce rotational motion, which, along with translational motion, can be detected by an ultrasound transducer and used to improve detection. Spherical particles can rotate due to the gradient of a time-varying magnetic field. Furthermore, other shapes, such as rod-shaped, octagonal, or star-shaped particles, can also produce motion that can be used to improve detection.

[0038] By observing the movement and displacement of nanoparticles in the imaging plane, a precise concentration profile can be obtained, which can be used to delineate objects in magnetic force images or delineate multiple spots in tissue due to enhanced concentration of nanoparticles.

[0039] The displacement of the nanoparticles may also depend on the distance between the magnet and where the nanoparticles are positioned in the imaging plane.

[0040] FIG. 1A shows a schematic magnetic-power imaging probe device 100. The device includes a housing 101 having an outer surface and an internal cavity 107. The device may further include a magnet 102 disposed within the internal cavity 107 of the housing 101. The magnet 102 is configured to generate a time-varying magnetic field. The magnet 102 may be a cylindrically shaped permanent magnet, preferably a radially magnetized magnet. Such a radially magnetized magnet is a cylindrically shaped magnet with a rotation axis extending laterally. This type of magnet generates a magnetic field perpendicular to the axis. In one embodiment, the shape of the magnet may be a rectangular parallelepiped, such as a cube, that rotates about its axis, generating a magnetic field perpendicular to the axis, similar to that for a radially magnetized magnet. The magnet has opposing magnetic poles (N, S) separated radially (r) along the diameter of the magnet, such that rotation of the magnet generates a time-varying magnetic field (T) at the target location. It is conceivable that other shapes of the magnet 102 can achieve the same effect.

[0041] A time-varying magnetic field can be obtained by rotating the magnet 102 using a motor 104. The magnet 102 may be rotated by the motor 104 via a shaft 105.

[0042] Alternatively, in some embodiments, an electromagnet may be used and a time-varying magnetic field may be obtained by switching poles and driving a sinusoidal current, or any time-varying current that results in the desired magnetic field.

[0043] To detect the translation, displacement, and / or rotation of the particle, a distance-sensing, motion-sensing, or magnetic material sensing device 103 can be used, such as an ultrasonic transducer such as an ultrasonic array, an optical sensor (e.g., laser Doppler), a susceptometer, or other means known to those skilled in the art for detecting distance, motion, or magnetic materials. For the remainder of this application, an ultrasonic transducer will be used as an example of a sensing device. However, as will be described, other types of sensing devices can be used instead.

[0044] The ultrasound transducer can be disposed on the outer surface of the housing 101 such that the imaging surface of the ultrasound transducer 103 is within the time-varying magnetic field. In particular, this may be achieved by disposing the ultrasound transducer 103 on the outer surface of the housing 101 such that the ultrasound transducer 103 is disposed along the length of the magnet 102. Preferably, the length of the cylindrically shaped magnet 102 exceeds the width of the ultrasound transducer 103. The ultrasound transducer 103 is then disposed with the imaging surface of the ultrasound transducer 103 within the time-varying magnetic field. This arrangement can increase the sensitivity of detection of magnetic nanoparticles within the magnetic field volume that move due to changes in the magnetic field.

[0045] Typically, geometrically beam-shaped ultrasound pulses are emitted using multiple elements in an array, thereby achieving a focused beam by delaying the transmission of specific elements so that the sounds actively interfere at the focal point. Similarly, returning echoes can be detected at multiple elements, and a reconstructed signal can be achieved with the same delay as the transmission, with echoes along the transmit beam being amplified. Although magnetic particles are typically much smaller than the resolution cell of ultrasound, their displacement due to the magnetic field can induce detectable motion in their immediate vicinity, allowing this motion to be detected by ultrasound. This can be achieved by covering the imaging surface with an imaging beam at a rate exceeding that of the magnetic field frequency. Theoretically, the imaging (probing) speed at a single location should be at least twice the speed of the nanoparticle's induced motion, but in practice it can be much higher, e.g., 4-10 times faster. Other imaging schemes, such as illuminating a large portion of the area to be imaged with a plane wave, are possible.

[0046] Sensitivity can be further increased by positioning the magnet 102 and ultrasonic transducer 103 such that the active ultrasonic element is located as close as practical to the magnet 102. When the ultrasonic transducer is positioned on the housing, as shown in Figures 1A-1C, the distance between the magnet 102 and the ultrasonic transducer 103 can be defined primarily by the material thickness of the housing 101 at the location of the ultrasonic transducer and / or the distance between the inner surface of the housing and the magnet 102.

[0047] 1A shows a rotating permanent magnet 102 that is diametrically magnetized, thereby arranging multiple ultrasound elements in an arc concentric with the axis of rotation of the magnet 102. This concentric arrangement is also shown in FIG. 1B. As the magnet 102 rotates, the magnetic field at a point some distance from the probe 100 can rotate and induce rotational motion in magnetic particles located at that point. In FIGS. 1A and 1B, the imaging plane is perpendicular to the axis of rotation 108 of the magnet 102.

[0048] The probe 100 may further include a connector 106, such as a cable, for controlling the probe and for transmitting recorded data, such as imaging data, from the ultrasound transducer 103 to a computer or control unit including a processor. Additionally and / or alternatively, the probe may be controlled and data may be transmitted wirelessly, such as by Wi-Fi or other types of wireless protocols, such as Bluetooth.

[0049] Additionally and / or alternatively, the cable 106 may be used to provide power to the probe. Alternatively, power to the probe may be provided using a battery located in the probe.

[0050] The motor 104 of the magnetic-powered imaging probe apparatus 100 may be controlled by a control unit (not shown). As described above, the motor 104 may be coupled to the control unit via the connector 106 or via a wireless protocol. The power of the magnet 102's motion may then be controlled. The control unit may be configured to vary the speed of the magnet 102's motion (w) according to a predetermined pattern, thereby varying the frequency of the time-varying magnetic field (T) as a predetermined impulse to generate an impulse response of the magnetic nanoparticles at the target location. This results in determining an impulse response from the nanoparticles, which may indicate material properties such as viscosity and density. Thus, the nanoparticles may be displaced by the magnetic impulse, and material properties affect how the displacement changes over time, such as the dominant frequency, maximum amplitude, and the rate of decay, which may indicate material density, elasticity, and viscosity.

[0051] The control unit may be configured to vary the speed of the movement (w) of the magnet 102, such as by linearly increasing the speed up to a certain maximum speed and then decreasing the speed, to produce a sweep (chirp) across all frequencies and detect the resulting displacement amplitude of the nanoparticles. Thus, the control unit may be configured to vary the speed of the movement (w) of the magnet 102 according to such a predetermined pattern to produce detection of the frequency impulse response. The control unit may also be configured to set a constant speed of the movement (w) of the magnet 102. Depending on the position of the south pole relative to the north pole during rotation of the magnet, the rotational force may change, e.g., due to the influence of the earth's magnetic field or nearby iron structures, and therefore may be compensated for by the control unit.

[0052] The control unit can be further configured to synchronize the frequency or speed of the motion (w) of the magnet 102 with the ultrasound imaging to provide ultrasound detection at the magnetic field frequency (that of the time variation of the magnetic field) and further enable detection at the phase of the magnetic field relative to the ultrasound imaging.

[0053] The ultrasound transducer 103 may have an ultrasound control unit (not shown) that provides the necessary control and analysis associated with the ultrasound equipment.

[0054] The device can include various sensors, for example, a sensor for tracking the position of the magnet during rotation. This can be an encoder for detecting pulses during each rotation. This can be useful for synchronizing the frequency or speed of the motion (w) of the magnet 102 with ultrasound imaging, or when having a gearbox such as a reduction gear.

[0055] Other sensors that can be used are an accelerometer to detect whether the device is stationary or moving, a gyroscope, a thermometer, a pH sensor, and a sensor to detect disturbances to a magnetic field.

[0056] To avoid eddy currents that can reduce the transmitted magnetic field, the housing should be made of a non-conductive material. One such material is polyetheretherketone (PEEK). Other materials could be polyphenylene sulfide (PPS) or polysulfone.

[0057] FIG. 1C shows another magnet design 100b compared to the designs shown in FIGS. 1A and 1B. Instead of a magnet having a cylindrical shape with a constant diameter along its length, the magnet may have a cylindrical shape with at least two different diameters. For example, the magnet may be composed of two portions, such as a first portion 102b positioned as shown in FIGS. 1A-1B, and second portions 102a, 102c positioned to the sides of the first portion 102b. The second portions 102a, 102c may thereby be positioned adjacent to but to the sides of the array 103. The second portions 102a, 102c may have a different diameter than the first portion 102b, such that the diameters of the second portions 102a, 102c are larger than the diameter of the first portion 102b.

[0058] In some embodiments, the magnet may have three portions 102a, 102b, and 102c as shown in Figure 1C. The second portion 102a and the third portion 102c may have different diameters than the first portion 102b, e.g., the diameters of the second portion 102a and the third portion 102c may be larger than the diameter of the first portion 102b. In some embodiments, the magnet may have the second and third portions 102a, 102c with equal diameters.

[0059] Additionally and / or alternatively, in some embodiments of the magnet design, the magnet may consist of only one or two lateral portions 102a, 102c adjacent to but positioned to the sides of the array 103.

[0060] The range of magnetic force can be increased by adding cylindrical sections 102a, 102c with larger diameters to the magnets, and with cylindrical sections 102a, 102c positioned to the sides of array 103. The larger magnetic volume of magnets 102a and 102c results in a larger force at a given distance compared to a single magnet with the diameter of magnet 102b.

[0061] Since the effect of the magnetic field on particles depends on the angle and distance, in an embodiment where the magnet is positioned only to the side of the array 103, such as where the magnet has at least only elements 102a and 102c, it will affect particles located closer to the array 103 but at a distance of a few centimeters from the array 103, with relatively little difference, compared to magnets positioned below or above the array 103.

[0062] The cavity in the probe body that can be provided between the smaller diameter magnet 102b and the housing can be used for interface electronics or acoustic backing material. The magnet 102 can be manufactured as a single solid structure or by placing separate pieces of the magnet side by side. When the magnet is made in separate pieces, adhesive can be used to secure the pieces together. Alternatively, the magnetic force can be strong enough to hold the pieces together.

[0063] The diameters mentioned above can be varied, as can the number of cylindrical elements and their polarity.

[0064] 2A-2F are schematic diagrams of various exemplary configurations of ultrasound transducers relative to a magnet in a distal portion of a probe apparatus. The transducers in these examples are arrays of different types. The array can be a single array having multiple ultrasound elements located along a line, such as a single one-dimensional array. The number of elements can be, for example, between 128 and 256, depending on the size of the elements and the length of the array. Fewer or more elements may also be used.

[0065] FIG. 2A schematically illustrates an ultrasound array 103 arranged similarly to FIGS. 1A-1C, where the ultrasound array 103 is arranged concentrically with the axis of the magnet 102. By way of example, for an array 103 having between 128 and 256 elements and a center frequency, such as 10 MHz, in the range of 5-25 MHz, such as 7-15 MHz, such as 5-20 MHz, this arrangement can cover a field of view of approximately 160-230 degrees. As a further example, if the array 103 has 192 elements, assuming an ultrasound center frequency in the range of 7-15 MHz, such as 7-8 MHz, in the range of 5-25 MHz, such as 5-20 MHz, this arrangement can cover a field of view of approximately 180 degrees. The field of view may depend on the dimensions of the probe, as described above. The evaluations given are for probes to be used for transrectal or transvaginal applications.

[0066] 2B schematically shows the ultrasound array 103 positioned orthogonally to the configuration shown in FIG. 2A, meaning that the length of the array 103 is aligned along the length of the magnet 102.

[0067] FIG. 2C shows a schematic representation of a combination of at least two arrays, where a first ultrasonic array 103a is positioned as in FIG. 2A and a second ultrasonic array 103b is positioned as in FIG. 2B.

[0068] FIG. 2D shows a schematic diagram of a 2D array. The 2D array 103 is arranged concentrically with the axis of the magnet 102, but records an image in two dimensions in a manner similar to the use of two arrays 103a and 103b shown in FIG. 2C. As an alternative to a single 2D array 103, the array 103 may comprise multiple single arrays, such as multiple single 1D arrays. Such an arrangement is sometimes referred to as a 1.5D array. A 1.5D array is used to provide improved focusing in the elevation direction (i.e., the plane thickness) of the imaging plane. Improved focusing may be achieved by gradually increasing the difference in transmit (or receive) delays between different rows of arrays adjacent to the central array, for example, along the .5-direction, using multiple rows (e.g., 3 to 7) of arrays, so that the beam can be focused in the elevation direction. By varying these delays, the focal spot can be placed at different depths along the beam axis, and multiple transmits achieve an overall thinner imaging plane by using only data from the focused portion of the beam. Similar delays can be applied on receive to achieve improved elevation focusing on receive as well.

[0069] 2F schematically illustrates a combination of at least two arrays 103a, 103b, with a first array 103a disposed on one side of the probe housing and a second array 103b disposed on the opposite side of the probe housing. Each of the at least two arrays 103a, 103b can provide an imaging plane extending from the respective array. The arrays 103a, 103b can be orthogonally oriented on the probe support, as in FIG. 2F, to provide one plane that includes the magnet's axis of rotation or any parallel line, and another plane that is orthogonal or angled to the axis. Thus, multiple orthogonal planes of the same target can be examined by simply rotating the probe, providing a more complete understanding of tissue morphology.

[0070] Figure 2E shows the distal end of a different type of probe. While Figures 1A-1C, like Figures 2A-2D and 2F, show elongated devices usable primarily in animal or human cavities, such as for transrectal or transvaginal use, the illustrated devices may be improved for external use, such as for transcutaneous ultrasound examinations, such as in skin examinations. The ultrasound array 103 may be positioned relative to the magnet 102 as shown in any of Figures 2A-2D and 2F.

[0071] FIG. 3 shows a schematic example of an outer housing 300 of a probe according to an embodiment of the present disclosure. The probe includes a distal portion 109 and a handle portion 110. The ultrasound transducer 102 is disposed in the distal portion 109. The probe 300 may further include at least one connector 106 and / or a power cord. The distal portion 109 and the handle portion 110 may be connected via a neck portion 111. The neck portion 111 may have a smaller diameter than the distal portion 109. The probe 300 shown in FIG. 3 is elongated and sleek as well as sized for insertion into a human or animal cavity, such as transrectally or transvaginally. The device is not limited to use in a cavity and can also be used externally.

[0072] To make the device comfortable, distal portion 109 and neck portion 111 should be "slim." Slimness depends on the cavity, but for transrectal and transvaginal use, the diameter should preferably be less than 30 mm, such as about 15 mm, such as less than 20 mm, such as 25 mm.

[0073] To further improve positioning of the device within the cavity, a disposable sleeve can be placed over distal portion 109 and neck portion 111 before insertion into the cavity.

[0074] Alternatively, the distal portion can have a different shape for external use, such as having a wider tip to improve handling of the device, see, for example, Figure 2E.

[0075] Figure 4 shows a schematic example of a cross section 400 of the probe shown in Figure 3. As shown, the magnet 102 and also the ultrasonic transducer 109 are positioned as close to the distal end of the distal portion 109 as possible. The motor 104 is positioned within the handle portion 110, and the shaft 105 connecting the magnet 102 and the motor 104 is positioned through the neck portion 111. A printed circuit board 112 extends across the device to connect and control the ultrasonic transducer 102.

[0076] Figures 5A-5C show schematic example magnet and ultrasound arrangements 500, 500b according to the present disclosure. Figures 5A and 5B show cross-sectional views of example ultrasound and magnet configurations.

[0077] The magnet 102 is disposed within a cavity 107 in the distal portion of the probe device. In the illustrated example, the cavity 107 is a lumen extending through the housing 101. Disks 113a, 113b are disposed on each side of the magnet 102. The disks are preferably magnetically permeable. Each disk 113a, 113b has a peg 114a, 114b. The disks 113a, 113b and pegs 114a, 114b are used to hold the device. The pegs 114a, 114b extend through a central lumen 119 of the magnet 102. To minimize vibration, the lumen 119 should extend directly through the exact center of the magnet 102. One way to achieve this with low tolerances may be to place the disks 113a, 113b on the magnet by pegs 114a, 114b before the magnet 102 is lathed to its shape. By holding the magnet by the disks 113a, 113b and pegs 114a, 114b during lathing, high precision can be achieved.

[0078] To further minimize any vibration when the magnet 102 is rotated, packings 115a, 115b, such as O-rings, can be placed on each side of the magnet 102 to center the magnet 102 in the bore 107 with the pegs 114a, 114b. The proximal peg 114b can be connected to the motor via the shaft 105, while the distal-most peg 114a can be placed in a holder 118.

[0079] The ultrasonic transducer 103 is disposed on the outer surface of the housing 101. In this way, the distance between the ultrasonic transducer 102 and the magnet 102 is minimized, which is mainly composed of the thickness of the wall of the housing at the location between the magnet 102 and the ultrasonic transducer 103. This distance can also be determined by the space between the magnet 102 and the inner surface of the housing 101. This distance can also be determined by the tolerance required to rotate the magnet 102.

[0080] Because the ultrasonic transducer 103 requires control, such as synchronization with the magnet and data transfer to a control unit such as a computer, a printed circuit board (PCB) 112 may need to be connected to the ultrasonic transducer 103. The ultrasonic transducer is also placed on a plate used to hold the transducer in the housing. Therefore, a cutout 117 may be provided on the outer surface of the housing 101 to surround the magnet 102. Components used to hold the ultrasonic transducer 103 as well as connections to the PCB may be placed within the cutout 117, and therefore some of these components located below the transducer, such as between the ultrasonic transducer 103 and the magnet 102, may constitute part of the thickness of the housing 101 at the location of the ultrasonic transducer. Therefore, the cutout may assist in minimizing the distance between the ultrasonic transducer 103 and the magnet 102.

[0081] In total, the distance between the ultrasonic transducer 103 and the magnet 102 may be less than 2 mm, such as less than 1.5 mm, such as 1 mm.

[0082] Additionally, the ultrasonic transducer 116 may have a lens placed on top to focus the waves.

[0083] FIG. 5C shows a schematic example 500b of a magnet and ultrasound arrangement similar to the arrangements in FIGS. 5A and 5B. The difference is that the magnet 102 is solid in FIG. 5C and does not include a bore extending directly through the center of the magnet 102 as shown in FIG. 5A. Instead of the disks 113a, 113b located on each side of the magnet, one protruding into the bore to connect the disks 113a, 113b to the magnet 102 and the other protruding outward to connect the magnet to the shaft 105 and holder 108 as shown in FIG. 5A, the disks 113a, 113b may be connected to the magnet 102 through other means. For example, the disks 113a, 113b may be adhered to the magnet using an adhesive or other sticky material. Alternatively and / or additionally, in some embodiments, the disks 113a, 113b may be secured to the magnet using bolts or screws. In other embodiments, the discs 113a, 113b may be connected to the magnet 102 by friction obtained through pressure applied by the shaft. Depending on the material of the discs 113a, 113b, the discs 113a, 113b may be connected by adhesive forces, such as intermolecular forces.

[0084] An advantage of using a solid magnet is that the magnetic force can be stronger compared to a magnet of the same size that has a bore through its center. This can be due to the increased volume of material.

[0085] Magnetic force also depends on material properties, with some materials providing stronger magnetic forces than others. An example of a material is NdFeB (Neodymium-Iron-Boron) that is either sintered or bonded with a standard value of N42 or greater, such as N45, N48, N50, or N52. Another material with strong magnetic force may be iron nitride (FeN).

[0086] Additionally, a static magnetic field may be applied simultaneously to vary the magnetic field alone over time. Because the magnetic force acting on a particle is proportional to both the field strength and the field gradient, a second, non-varying magnetic field can enhance the magnetic force. The field strength of the second magnetic field may be below the magnetic saturation of the particle. The second magnetic field may be applied using an electromagnet. The electromagnet may be a plurality of fixed coils that generate a field that can pre-magnetize the particles to enhance the vibrational force after applying a DC current to them.

[0087] Alternatively, instead of a static second magnetic field, the magnetic field may be time-varying in relation to a time-varying field provided by a magnet on the probe. For example, the variation of the second magnetic field provided by the additional magnet may be associated with the rotation of the magnet inside the probe. For example, the variation of the second magnetic field provided by the additional magnet may be synchronized with the time variation of the magnet inside the probe, such as by synchronizing with the rotation of the magnet inside the probe. Synchronization may involve a difference in phase and / or amplitude between these two time-varying fields. If the magnet inside the probe is a rotating permanent magnet, a sensor for tracking the position of the magnet may be used to control the time variation of the second magnetic field. The time variation of the second magnetic field may be obtained by varying a DC current or applying an AC current to a stationary coil.

[0088] In some embodiments, a second magnet may be used to provide a counteracting force to the Earth's magnetic field. This can be done with a static magnetic field. In embodiments where a varying current is applied to the second magnet, a static component can be applied simultaneously.

[0089] The additional magnet may be part of the probe or may be part of a system in which an additional second magnet may be placed on the examination table as a separate unit, such as located in the examination room.

[0090] 6 shows a flowchart of an exemplary method 200. The method can be used to examine or diagnose a subject. Method 200 can include step 201 of introducing magnetic particles into tissue of the subject. The particles can be introduced intravenously or subcutaneously.

[0091] The method 200 may also include generating 202 a time-varying magnetic field (T) in an imaging plane of a sensing device 103, such as an ultrasound transducer.

[0092] The method 200 may further include detecting or imaging 203 the movement of the magnetic nanoparticles in the imaging plane in response to the time-varying magnetic field by the sensing device 103. This may include detecting or imaging the vibration and / or movement of the particles using the sensing device.

[0093] As described above, step 204 of analyzing the vibration and / or movement of particles to determine the distribution and / or concentration of magnetic particles can result in an accurate determination of the concentration and / or distribution of nanoparticles and further improved analysis of the material being examined.

[0094] Determining the concentration and / or distribution of the particles described above can help practitioners assess the state of tissue, such as when assessing whether the tissue is free of tumors, cancer, and / or metastases. One such area is determining whether cancer is free of lymph nodes.

[0095] The method 200 can further include rotating the cylindrical permanent magnet 102 according to a predetermined pattern, thereby varying the frequency of the time-varying magnetic field (T) as a predetermined frequency impulse to generate a frequency impulse response of the magnetic nanoparticles. Thus, the properties of the analyzed material can be determined. The predetermined pattern can include, for example, rotating the magnet a certain number of revolutions or a fractional number of revolutions, such as a half revolution, for a certain number of seconds or minutes, or a fractional number of seconds or minutes, to subsequently detect a response from the nanoparticles.

[0096] The method 200 may alternatively and / or additionally include rotating the cylindrically shaped permanent magnet 102 at a constant rotational speed.

[0097] The method 200 may alternatively and / or additionally include rotating the cylindrically shaped permanent magnet 102 at varying rotational speeds.

[0098] As will be appreciated by one skilled in the art, the present invention may be embodied as an apparatus, system or method.

[0099] The present disclosure has been described above with reference to specific embodiments. However, other implementations than those described above are equally possible within the scope of the present invention. Method steps other than those described above may be provided within the scope of the present invention. Different features and steps of the present invention may be combined in other combinations than those described. The scope of the present disclosure is limited only by the appended claims.

[0100] More generally, those skilled in the art will readily recognize that all parameters, dimensions, materials, and configurations described herein are intended to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application or applications in which the teachings of the present invention are used.

Claims

1. 1. A magnetic force imaging probe device, comprising: a housing having an exterior surface and an interior cavity; A magnet and a sensing device configured to detect distance, motion, or magnetic material; Equipped with the distance between the magnet and the detector is defined by the thickness of the housing at the location of the detector and the distance between the inner surface of the housing and the magnet; the magnet is disposed in the interior cavity of the housing, the sensing device is disposed on the exterior surface of the housing, the magnet is arranged to generate a time-varying magnetic field in an imaging plane of the sensing device; the imaging surface is external to the housing; Magnetically powered imaging probe device.

2. 2. The magnetic kinetic imaging probe apparatus of claim 1, wherein said sensing device is an ultrasonic transducer.

3. 3. The magnetic kinetic imaging probe apparatus of claim 2, wherein the magnet is a cylindrical permanent magnet having at least one diameter, and the time-varying magnetic field is obtained by rotating the magnet.

4. 4. The magnetic kinetic imaging probe apparatus of claim 3, wherein the magnet has at least two portions having different diameters.

5. 5. A magnetic dynamic imaging probe apparatus according to claim 3, wherein said magnet is a radially magnetized magnet.

6. 6. The magnetic-powered imaging probe apparatus of claim 2, wherein the ultrasonic transducer is disposed along the length of the magnet, and the length of the cylindrical magnet exceeds the width of the ultrasonic transducer.

7. A magnetically powered imaging probe apparatus according to any one of claims 3 to 6, wherein the magnet is rotated using a motor.

8. 8. The magnetic kinetic imaging probe device of claim 1, wherein the housing has an elongated shape for positioning in a cavity of an animal, including a human, wherein the device is configured for transrectal or transvaginal use.

9. A magnetic kinetic imaging probe apparatus according to any preceding claim, wherein the housing is made of a non-conductive material.

10. The magnetic kinetic imaging probe apparatus according to any one of claims 2 to 9, wherein the ultrasonic transducer is a one-dimensional array, at least two one-dimensional arrays, a 1.5D array, or a 2D array.

11. The magnetic kinetic imaging probe apparatus of claim 10 , wherein the array is disposed concentrically with the magnet.

12. The housing has a probe portion and a handle portion, the magnet and the sensing device are disposed in a distal portion of the probe; The motor is disposed within the handle portion and rotates the magnet via a shaft. A magnetic force imaging probe apparatus according to any one of claims 7 to 11.

13. A magnetic kinetic imaging probe apparatus according to any one of claims 2 to 12, wherein sensors are used to track the position of the north and south poles of the magnet during rotation.

14. 14. A magnetic kinetic imaging probe apparatus according to claim 2, wherein a disk is positioned on each side of the magnet, each disk having a peg positioned at the center of each disk for holding the magnet.

15. 15. The magnetic kinetic imaging probe apparatus of claim 14, wherein a packing is placed on each side of the magnet to center the magnet by using the pegs.

16. A magnetic kinetic imaging probe apparatus according to any one of claims 2 to 13, wherein a disk is positioned on each side of the magnet and fastened or glued to the magnet, the magnet being solid.

17. A magnetic force imaging probe apparatus according to any one of claims 1 to 16; a second magnet; and A system comprising:

18. 20. The system of claim 17, wherein the second magnet is an electromagnet that provides a static magnetic field.

19. 1. A method of magnetic dynamic imaging, comprising: introducing magnetic particles into the tissue of the subject to be examined; obtaining a time-varying magnetic field using a magnet disposed in a cavity of a housing of a magnetically kinetic imaging probe device, the time-varying magnetic field causing the magnetic particles to vibrate and / or move in an imaging plane of a sensing device disposed on an outer surface of the housing; imaging the vibration and / or movement of the particle using the sensing device; analyzing the vibration and / or movement of the particles to determine the distribution of the magnetic particles; Including, the distance between the magnet and the detector is defined by the thickness of the housing at the location of the detector and the distance between the inner surface of the housing and the magnet; the imaging surface is external to the housing; method.

20. 20. The method of claim 19, wherein the determined distribution is used to provide assistance in diagnosing the subject.

21. 21. The method of claim 19 or 20, wherein the distribution of the magnetic particles in a lymph node is analyzed to assess whether the lymph node is cancer-free.

22. A method according to any one of claims 19 to 21, comprising the step of rotating a permanent magnet to obtain the time-varying magnetic field.

23. The method according to any one of claims 19 to 22, wherein the magnetically powered imaging probe device is inserted into an opening in the object to be diagnosed.

24. 24. The method of claim 23, wherein the opening is the rectum.

25. A method according to any one of claims 19 to 24, wherein the second magnetic field is obtained using an external magnet.

26. 26. The method of claim 25, wherein the magnetic field of the second magnet is static or time-varying.

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