Micromotor and optical system for high speed circular scanning of a light beam in a small diameter flexible catheter

Abstract

This disclosure provides a shaftless, brushless motor for rotating any optical or sensing element (e.g., a lens or mirror) at the distal end of a waveguide that also outputs electromagnetic waves (e.g., light). The waveguide itself serves as the axis for rotating the rotating component, thereby avoiding blind spots and overcoming limitations imposed by existing "micromotors." This distally driven shaftless motor significantly reduces motor size while simultaneously minimizing inertial load and bearing size, enabling high-pitch cylindrical scanning with uniform longitudinal velocity.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is based on and claims priority to U.S. Provisional Application No. 63 / 376,423 (filed September 20, 2022), the entire contents of which are incorporated herein by reference.

[0002] <Statement regarding federally sponsored research> This invention was made with government support under P41EB015903 awarded by NIH / NIBIB. The U.S. Government has certain rights in this invention. [Background technology]

[0003] Considerable effort has been devoted to developing miniaturized, high-speed scanning elements (e.g., optical mirrors, sensors, etc.) for imaging and sensing in catheters and endoscopes. For example, rotating optical elements, when placed at the tip of a light-transmitting optical fiber, enable radial rotational scanning and sampling, which may be required for biomedical imaging or other general testing and measurement. To improve sampling speed, it is desirable for the motors mentioned above to rotate as uniformly as possible and as fast as possible while maintaining the functional integrity of the overall system.

[0004] Existing motor drive units place conventional motors proximal and external to the device, rotating components along the entire length of the catheter sheath. The optical rotary connection transmits signals through the rotary interface to the outside, up to several meters away from the desired field of view at the distal end of the catheter. Because all components rotate within a non-rotating sheath, friction between rotating and non-rotating components severely limits the maximum rotational speed to 100 Hz while simultaneously introducing undesirable, non-uniform rotational distortion.

[0005] One solution utilizes a miniaturized brushless motor with a shaft at its very distal end. The motor faces the rearward-facing waveguide, allowing the rotating components to directly interact with the incident electromagnetic waves without having to rotate the waveguide itself across the entire length of the device. This avoids the significant limitations caused by friction between the rotating components and the sheath and allows for rotational speeds up to 2 kHz. However, to power the rearward-facing motor, wires must pass through the field of view, creating an unavoidable blind spot in the rotating field of view. Previous motor architectures are difficult to further miniaturize, and implementing them in disposable medical devices (e.g., intravascular imaging catheters) is prohibitively expensive.

[0006] Therefore, there is a need to overcome one or more of the above deficiencies. Summary of the Invention

[0007] The present disclosure provides a system and method that overcomes one or more of the above drawbacks by using a shaftless, brushless synchronous motor configured to rotate an optical element (e.g., a lens or mirror) at the distal end of a waveguide that outputs electromagnetic waves (e.g., light). For imaging applications, the fiber tip and / or subsequent optical elements relative to the fiber tip are configured to provide precise focusing of the emitted light. The waveguide also serves as a bearing support for the motor's rotor.

[0008] In one aspect, an imaging system is disclosed. The imaging system includes a power source, a catheter having a proximal end and a distal end, the catheter having a lumen between the proximal end and the distal end, and an imaging assembly having a proximal portion and a distal portion disposed within the lumen adjacent the distal end of the catheter. The imaging assembly further includes a waveguide disposed centered within the imaging assembly and extending the length of the catheter, at least one permanent magnet disposed in the proximal portion of the imaging assembly radially disposed around the waveguide, and an optical element coupled to an outer surface of the at least one permanent magnet. The optical element is disposed to extend beyond the distal portion of the imaging assembly and penetrate the distal end of the catheter. The imaging assembly further includes one or more electromagnetic coils disposed in the proximal portion of the imaging system radially outward from the at least one permanent magnet. The electromagnetic coils are in electrical communication with the power source.

[0009] In certain embodiments of the imaging system, the at least one permanent magnet may include a ring magnet.

[0010] In certain embodiments of the imaging system, the waveguide can be one or more optical fibers and can include one or more radial protrusions. In one embodiment of the imaging system, the one or more radial protrusions can be formed on the waveguide. In another embodiment of the imaging system, the radial protrusions can include bearing portions positioned radially on the waveguide.

[0011] In certain embodiments of the imaging system, the one or more radial protrusions may abut the at least one permanent magnet.

[0012] In certain embodiments of the imaging system, the distal tip of the waveguide may comprise a lens.

[0013] In certain embodiments of the imaging system, the optical element may include one or more mirrors or lenses.

[0014] In certain embodiments of the imaging system, an extension can couple the optical element to an outer surface of the one or more permanent magnets. In one aspect, the extension can be a tube. At least a portion of the extension can have an opening. In one embodiment of the imaging system, the waveguide can be configured to transmit light toward the one or more mirrors, where the light reflects off the one or more mirrors and passes through the opening in the extension.

[0015] In certain embodiments of the imaging system, the electromagnetic coils can be in electrical communication with the power source via one or more wires. In other embodiments of the imaging system, the electromagnetic coils can generate a magnetic field when supplied with an electrical current from the power source. In another embodiment of the imaging system, a yoke can be disposed in the proximal portion of the imaging assembly radially between the one or more electromagnetic coils and an inner surface of the catheter.

[0016] In certain embodiments of the imaging system, the at least one permanent magnet and the optical element can rotate based on the strength and frequency of the magnetic field.

[0017] In certain embodiments of the imaging system, a support bearing portion can be coupled to the extension, and the support bearing portion can abut a distal end of the one or more electromagnetic coils.

[0018] In certain embodiments of the imaging system, the spring can be positioned in the imaging assembly proximal to the at least one permanent magnet, and the spring can be oriented such that the waveguide passes through the spring.

[0019] In certain embodiments of the imaging system, an ultrasound transducer can be coupled to the extension.

[0020] In another aspect, an imaging assembly is disclosed that includes a proximal portion and a distal portion that is disposed with the distal end of a catheter. The imaging assembly includes a waveguide that is centered within the imaging assembly and extends the length of the catheter, at least one permanent magnet disposed in the proximal portion of the imaging assembly so as to be radially disposed around the waveguide, and an optical element coupled to an outer surface of the at least one permanent magnet. The optical element is disposed so as to extend beyond the distal portion of the imaging assembly and penetrate into the distal end of the catheter. The imaging assembly further includes one or more electromagnetic coils disposed in the proximal portion of the imaging assembly so as to be radially outward from the at least one permanent magnet.

[0021] In certain embodiments of the imaging assembly, the at least one permanent magnet may include a ring magnet.

[0022] In certain embodiments of the imaging assembly, the waveguide can be one or more optical fibers, and the waveguide can include one or more radial protrusions. In one embodiment of the imaging assembly, the one or more radial protrusions can be formed on the waveguide. In another embodiment of the imaging assembly, the radial protrusions can include bearing portions positioned radially on the waveguide.

[0023] In certain embodiments of the imaging assembly, the one or more radial protrusions may abut the at least one permanent magnet.

[0024] In certain embodiments of the imaging assembly, the distal tip of the waveguide may comprise a lens.

[0025] In certain embodiments of the imaging assembly, the optical element may include one or more mirrors or lenses.

[0026] In certain embodiments of the imaging assembly, an extension can couple the optical element to an outer surface of the one or more permanent magnets. In one aspect, the extension is a tube. An aperture can be provided in at least a portion of the extension. In one embodiment of the imaging assembly, the waveguide can be configured to transmit light toward the one or more mirrors, where the light reflects off the one or more mirrors and passes through the aperture in the extension.

[0027] In certain embodiments of the imaging assembly, the electromagnetic coils can generate a magnetic field when supplied with current from the power source. In another embodiment of the imaging assembly, a yoke can be disposed in the proximal portion of the imaging assembly radially between the one or more electromagnetic coils and an inner surface of the catheter.

[0028] In certain embodiments of the imaging assembly, the at least one permanent magnet and the optical element can rotate based on the strength and frequency of the magnetic field.

[0029] In certain embodiments of the imaging assembly, a support bearing portion can be coupled to the extension, and the support bearing portion can abut a distal end of the one or more electromagnetic coils.

[0030] In certain embodiments of the imaging assembly, the spring can be positioned in the imaging assembly proximal to the at least one permanent magnet, and the spring can be oriented such that the waveguide passes through the spring.

[0031] In certain embodiments of the imaging assembly, an ultrasound transducer can be coupled to the extension.

[0032] In another aspect, a method of imaging is disclosed. The method includes providing an imaging system including a waveguide centered within the imaging assembly and extending the length of the catheter, at least one permanent magnet disposed in the proximal portion of the imaging assembly radially surrounding the waveguide, and an optical element coupled to an outer surface of the at least one permanent magnet. The optical element is positioned to extend beyond the distal portion of the imaging assembly and penetrate the distal end of the catheter. The imaging assembly further includes one or more electromagnetic coils disposed in the proximal portion of the imaging assembly radially outward from the at least one permanent magnet. The method further includes supplying current to the one or more electromagnetic coils to generate a magnetic field, sending one or more beams of light through the waveguide toward the optical element, receiving one or more beams reflected from the optical element, and generating an image from the reflected one or more beams using a processor.

[0033] In certain embodiments of the imaging method, the optical element may include one or more mirrors or lenses.

[0034] In certain embodiments of the imaging method, an extension can couple the optical element to an outer surface of the one or more permanent magnets. In one aspect, the extension can be a tube. At least a portion of the extension can have an aperture. In some embodiments of the imaging method, the waveguide can be used to direct light toward the one or more mirrors so as to reflect the light through the aperture in the extension.

[0035] In certain embodiments of the imaging method, the electromagnetic coil can be electrically connected to the power source via one or more wires. In certain embodiments of the imaging method, the electromagnetic coil can be used to generate a magnetic field by sending a current from the power source. In some embodiments of the imaging method, the at least one permanent magnet and the optical element can be rotated based on the strength and frequency of the magnetic field.

[0036] Certain embodiments of the imaging method may include a yoke disposed in the proximal portion of the imaging assembly, the yoke being radially disposed between the one or more electromagnetic coils and the inner surface of the catheter.

[0037] Certain embodiments of the imaging method may include providing a support bearing portion coupled to the extension portion and abutting a distal end of the one or more electromagnetic coils.

[0038] In certain embodiments of the imaging method, a spring may be provided, the spring being positioned in the imaging assembly proximal to the at least one permanent magnet and the waveguide being oriented to pass through the spring.

[0039] In certain embodiments of the imaging method, ultrasound energy can be transmitted using an ultrasound transducer coupled to the extension. The above aspects are not intended to be limiting. Other aspects and configurations of the systems and methods described herein are described below.

[0040] The above configurations of each embodiment will be more easily understood by reading the following detailed description with reference to the accompanying drawings. [Brief explanation of the drawings]

[0041] [Figure 1] 1 is a schematic diagram of an imaging system according to various aspects of the present disclosure; [Figure 2A] 1 is a schematic diagram of a catheter and imaging assembly according to various aspects of the present disclosure; [Figure 2B] FIG. 2B is a front view of the imaging assembly shown in FIG. 2A. [Figures 2C-2D] 2C and 2D are schematic diagrams of a multi-sided radial scanning imaging assembly of the present disclosure and a multi-sided forward scanning imaging assembly of the present disclosure, respectively. [Figure 3] 1A-1C are schematic diagrams of multiple sided flexible circuit electromagnetic coils of the present disclosure. [Figure 4A-4B] Figure 4A is a schematic diagram of an imaging assembly according to one aspect of the present disclosure, in which the electromagnetic coil is offset from the magnetic field of the magnet. Figure 4B is a schematic diagram of the imaging assembly of Figure 4A according to various aspects of the present disclosure, in which the imaging assembly is recentered in the magnetic field of the magnet. [Figures 5A-5E] Figure 5A is one embodiment of a bulge bearing for a waveguide according to one aspect of the present disclosure. Figure 5B is another embodiment of a bulge bearing for a waveguide according to one aspect of the present disclosure. Figure 5C is another embodiment of a bulge bearing for a waveguide according to one aspect of the present disclosure. Figure 5D is another embodiment of a bearing for a waveguide according to one aspect of the present disclosure. Figure 5E is another embodiment of a bearing for a waveguide according to one aspect of the present disclosure. [Figures 6A-6C]Figures 6A, 6B, and 6C are schematic diagrams of a tube supporting multiple, lateral, ultrasonic transducers, two side-by-side optical elements, and two side-by-side optical elements for transmitting two light beams, respectively, according to the present disclosure. [Figure 7] FIG. 1 is a schematic diagram of an imaging assembly configured for multiple sided pullback scanning of the present disclosure. [Figure 8] 1 is a flowchart of an imaging method according to various aspects of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0042] Disclosed is a shaftless, brushless motor for rotating an optical or sensing element (e.g., a mirror, lens, prism, second waveguide, etc.) immediately adjacent to (e.g., distal to or forward of) the tip of a waveguide that outputs electromagnetic (e.g., light), acoustic, or ultrasonic energy. The waveguide itself serves as the axis for rotating the motor's rotating components. This unique feature contrasts with conventional designs in which the motor is positioned distal to the waveguide tip and generally facing rearward. Such conventional designs require electrical wires to pass through the beam emitted from the waveguide, resulting in blind spots. In addition to overcoming the blind spot limitations in the imaging or sensing capabilities of conventional devices, the present invention also enables further reductions in motor size (e.g., diameter and / or length) and significantly smaller inertial loads and bearing sizes, thereby enabling operating speeds beyond those of catheters of conventional designs. Specifically, operating speeds exceeding 100 revolutions per second (rps) can be provided. For imaging applications requiring motion artifact reduction or where monitoring of fast dynamic processes is of interest, the motors of the present invention may operate at speeds exceeding 3,000 revolutions per second. In one embodiment, the disclosed motors operate at speeds between 3,000 revolutions per second and 6,000,000 revolutions per second. Another advantage of the present invention is that it is inexpensive and relatively uncomplicated to manufacture, which facilitates the use of the device in disposable catheters and provides better reliability and / or improved sterility.

[0043] The unique configuration of the present invention allows for the fabrication of motors with outer diameters between 0.15 mm and 3.00 mm. In one embodiment, the motor outer diameter is less than 1 mm. The present invention allows for the fabrication of motors with outer diameters less than 0.7 mm for intravascular imaging and motors with diameters less than 0.5 mm for neurovascular imaging.

[0044] By way of non-limiting example, Figure 1 illustrates an imaging system 100 in accordance with a specific embodiment. The imaging system 100 includes a power supply 102. In one non-limiting example, the power supply 102 can be at least one direct current (DC) voltage source (e.g., a battery) or an alternating current (AC) voltage source (e.g., a wall socket or other time-varying power source). The system 100 further includes a catheter 104 having a proximal end 106 and a distal end 108. In one non-limiting example, the catheter 104 is made from a flexible polymeric material such as polyamide, polyurethane, or polytetrafluoroethylene. Alternatively, the catheter can be made from a braided copper wire tube. The catheter 104 further includes a lumen between the proximal end 106 and the distal end 108.

[0045] In one non-limiting example, the catheter includes an imaging assembly 110 disposed within the lumen adjacent the distal end 108. In one example, the imaging assembly 110 includes a micromotor 114. Details of the micromotor 114 are described with reference to FIGS. 2A-2D . In one non-limiting example, the micromotor 114 is in electrical communication with the power supply 102. In one non-limiting example, the electrical communication can be a wired connection. Alternatively, the electrical communication can be a wireless connection between the micromotor 114 and the power supply 102. In other embodiments, other forms of energy, such as optical energy, can be used to deliver power, which can then be converted to electricity.

[0046] In one non-limiting example, imaging system 100 further comprises an optical unit 116, which comprises one or more light sources and a light source detector. For example, the light source can be or include one or more of an optical coherence tomography (OCT) light source, an ultrasound imaging light source, and / or a fluorescence imaging light source.

[0047] In one non-limiting example, the imaging system 100 includes a pullback device 118 for pulling the catheter 104 back through the blood vessel during imaging.

[0048] In one non-limiting example, the power supply 102, the light unit 116, and the pull-back device 118 can be separate units or can be integrated into one control unit 120. For example, the control unit 120 can be a processor.

[0049] 2A-2D, the distal end of catheter 104 is shown, showing details of imaging assembly 200 and the micromotor. In one non-limiting example, imaging assembly 200 is positioned within catheter sheath 202 adjacent distal end 108.

[0050] In one non-limiting example, the imaging assembly 200 has a proximal section 204 and a distal section 206. In this non-limiting example, the imaging assembly 200 includes a waveguide 208 centered within the catheter sheath 202. For example, the waveguide 208 can be one or more optical fibers. The waveguide 208 further includes a distal tip 210. The distal tip 210 can be or can include a lens for focusing a light beam 212 transmitted through the waveguide 208.

[0051] In one non-limiting example, the waveguide 208 further includes one or more protrusions or bearing bulges 214 that extend radially from the waveguide to maintain separation between the waveguide 208 and the magnet 216 and / or facilitate rotation between the waveguide 208 and the magnet 216. In one example, the bearing bulges 214 may be formed directly into the waveguide itself by splicing or thermoforming an optical fiber to create a relatively larger diameter region in two or more locations. Alternatively, the bearing bulges 214 may be a bearing disposed around the waveguide 208, made from a material separate from the waveguide 208, such as ruby, rubber, or epoxy.

[0052] In one non-limiting example, the rotor of the micromotor 114 can be supported by the waveguide itself. To reduce friction between the rotating components and the waveguide, bearing bulges 214 can provide smaller surface area contact points at the periphery. In this way, the motor rotor slides over the "bulge," but only contacts the waveguide through these two or more contact points, thereby reducing friction. Alternatively, forming a textured, matte surface on the outer diameter of the waveguide can also reduce the surface area of ​​contact between the waveguide and the adjacent rotating element.

[0053] In one non-limiting example, the rotor of the micromotor 114 is or includes at least one permanent magnet 216. The permanent magnet can be a ring magnet, as shown in FIGS. 2A-2D, but any shape and / or number of permanent magnets can be used, as long as a central opening is provided for the waveguide 112. In one example, the magnet 216 is a radially magnetized permanent magnet with one or more pole pairs, where the use of multiple poles can improve motor speed, torque, and / or efficiency. The magnet 216 can be fabricated, for example, by sintering, electro-discharge machining, or metal 3D printing. The material of the magnet 216 can be neodymium iron, but can also be some other magnetic material, such as iron, nickel, or cobalt. In one non-limiting example, the motor rotor must also be balanced radially and axially to prevent undesired whirring or wobbling and enable high-speed rotation.

[0054] Magnet 216 is located in the proximal portion 204 of imaging assembly 200 and is radially disposed around waveguide 208. The bulges 214 or bearings in any of the above embodiments may be fully contained within the hollow rotating element, or may be raised out of the rotating element at each end to prevent axial movement, or some combination of both may be implemented.

[0055] In one embodiment, the magnetic rotor can be attached to a distal optical component operable to redirect a beam emitted from an axially disposed waveguide. In this embodiment, it may be desirable to balance the combined rotor, optical component, and any associated mechanical mounting elements radially and axially. In such an embodiment, it may be preferable to configure the center of mass of one component to offset any non-axial portions of the center of mass of one or more components. As shown in FIG. 2A , a proximal end of an extension 218 is attached to the outer radial surface of the magnet 216, and the distal end of the extension 218 includes an optical element 220 coupled thereto. In one non-limiting example, the extension 218 is a tube arm or bracket. In embodiments where the extension 218 is a tube (such as the embodiment of FIGS. 2A-2D ), the cross section can be circular. In another example, the cross section of the tube extension 218 can be any shape that fits the outer surface of the at least one permanent magnet. In one example, the tube 218 may be transparent to the spectrum of the beam emitted from the waveguide 208. There are many possible transparent materials, but in the case of an optical beam, the transparent material may include polyimide, acrylic, glass, crystal material, or any suitable plastic.

[0056] In embodiments of the invention, the permanent magnet 216 can be connected to additional elements 220 that interact with the light beam 212 transmitted through and emitted from the waveguide 208. Such elements can be configured to produce a uniformly circular focus or any other arbitrarily designed beam profile or profiles. In certain embodiments, elements of structure can be provided that compensate for certain aberrations in the emitted beam or (pre-)compensate for aberrations caused by the beam being subsequently transmitted through additional elements, structures or samples.

[0057] In one non-limiting example, optical element 220 at the other end of tube 218 may include one or more prisms, multiple mirrors, partially reflecting mirrors, any diffractive and / or refractive optical elements, such as lenses, or other conventional components used in imaging or sensing, such as ultrasound transducers. Components for lateral and forward or backward conical scanning, such as mirrors, may also be mounted at any angle to avoid Fresnel reflections due to encapsulating materials, structures, or samples. All such elements may support multiple beams, such as in fluorescence imaging, which requires at least one illumination beam and one detection beam, or in photoacoustic imaging, which transmits optical energy to and collects ultrasound energy from a sample.

[0058] In one example, the mirror(s) are configured to deflect the path of the output light beam 212 based on the relative angular position of the mirror's surface with respect to the light beam. Alternatively, the angle of the mirror 220 provides astigmatism correction 222. In the example described above, the imaging assembly 200 is used to perform a radial scan (FIG. 2C) while rotating 221 the optical element 220 about a rotation axis 223. In one non-limiting example, the tube 218 has at least one subaperture 224 adjacent the optical element 220, which is configured to transmit the reflected beam(s) 226 directly from the rotating element to a location radially offset from the axis of the waveguide (FIG. 2A). In one embodiment, the tube 218 can support a mirror that simply redirects and focuses the emitted light for imaging.

[0059] Alternatively, one or more diffractive or refractive optical elements 220, such as lenses, can be rotated about rotation axis 223 while the beam passes through the optical elements for forward scanning (FIG. 2D). In one non-limiting example for forward scanning, tube 218 does not have at least a partial aperture in a longitudinal surface of tube 218, since light beam 212 enters and exits diffractive or refractive optical element 220 in the same manner as diffracted or refracted light beam 227.

[0060] In one non-limiting example, the micromotor 114 further includes one or more electromagnetic coils 228 disposed in the proximal portion 204 of the imaging assembly 200 and radially outward from a tube 218 coupled to the permanent magnet 216 ( FIG. 2A ). In one non-limiting example, the electromagnetic coils 228 are separated from the radially inner tube 218 by an air gap 230 to reduce friction and allow the rotor to rotate ( FIG. 2A ). Alternatively, the air gap may be filled with a lubricating and / or cooling liquid, such as saline or oil. The one or more electromagnetic coils 228 are configured to pass a time-varying current around the permanent magnet 216, thereby varying an external magnetic field and causing the permanent magnet 216 to rotate. In one non-limiting example, the one or more electromagnetic coils 228 are in electrical communication with the power source 102 via one or more wires 232 ( FIG. 2A ). Although coil 228 is generally shown here as generating an external magnetic field to rotate permanent magnet 216, in some non-limiting examples, the varying electromagnetic field that rotates the magnet can be generated outside the catheter or device, for example, outside the body in biomedical applications.

[0061] Optionally, in some non-limiting examples, a yoke 234 can surround the electromagnetic coil 228 to provide a more efficient return path for magnetic flux between the electromagnets in the rotor, thereby increasing motor torque (FIGS. 3A-2D, 4A, 4B). However, a yokeless configuration can also be used to allow for larger magnets, which also increases torque (e.g., FIG. 2A). A suitable ferrous material for the yoke 234 can be provided in the form of a sleeve surrounding the coil, or can be provided as a layer or coating on the inner or outer surface of the catheter sheath 202.

[0062] In another non-limiting example, the imaging assembly 200 includes one or more tube support bearings 236 between the outer surface of the tube 218 and the distal face of the electromagnetic coil 228 for radially and axially balancing the rotating elements, including one or more of the ring magnet 216, the tube 218, and / or the optical element 220.

[0063] Referring again to the one or more electromagnetic coils 228 described above, in one non-limiting example, the coils can be fabricated from a flat flexible printed circuit material 302 wound into a cylindrical shape, or in another non-limiting example, the coils can be printed directly onto the cylindrical circuit using photolithography (FIG. 3). A suitable circuit can include one or more layers, and each layer can have one or more turns 304. Each turn is bonded to a respective solder pad. While FIG. 3 shows an unfurled three-phase circuit electromagnetic coil (the motor's long axis is vertical in this figure), the number of phases can be fewer or more than three. Alternatively, in another non-limiting example, the electromagnetic coil 228 can be formed by simply winding a thin wire around a magnet. In other non-limiting examples, the coils can be fabricated by 3D printing metal or laser sintering onto a substrate such as glass.

[0064] The coils of any of the above embodiments can be wired in a three-phase delta, star, or wye configuration. For magnets with multiple pole pairs, the coils will have corresponding phases greater than three.

[0065] 4A-4B, in another alternative embodiment, the one or more electromagnetic coils 228 can be positioned offset relative to the axial and / or longitudinal center of the magnetic field of the permanent magnet 216 to generate a deliberate longitudinal force on the magnet. The magnet can be held in place by a spring 402 to allow movement in response to such forces and otherwise maintain its position. The strength of the magnetic field of the coil 228 can be varied by changing the amplitude of the current supplied to the coil. Increasing the current supplied to the coil 228 increases the magnetic field strength, thereby centering the permanent magnet 216 inside the coil 228 and causing the tube 218 to compress the spring 402. When the current supplied to the coil decreases, decreasing the magnetic field strength of the coil 228, the spring 402 pushes the tube 218 distally. This change in magnetic field strength creates longitudinal motion that can be used for a variety of purposes, including longitudinal scanning and refocusing (as it also changes the distance between the distal tip lens 210 and the optical element 220).

[0066] Alternatively, longitudinal motion of the micromotor and / or imaging assembly within the catheter sheath 202 can be provided by tensioning wires, which can be attached to the coils of the motor. In another example embodiment, the wires can be embedded within the lumen of thin-walled tubing, which may include additional layers between the waveguide and the catheter sheath. In this embodiment, tensioning or actuating the thin-walled tubing layer can provide longitudinal motion of the motor and / or corresponding beam delivery components.

[0067] 5A-5E show other configurations of bearing bulges between the waveguide and the ring magnet. In the non-limiting example of FIG. 5A, the waveguide 208 has two bearing bulges 214 formed thereon. While FIG. 5A shows two bearing bulges 214, any number of bearing bulges 214 may be provided. The two bearing bulges 214 abut the permanent magnet 216, preventing the entire surface of the permanent magnet 216 from contacting the surface of the waveguide 208 except for the contact points between the bearing bulges 214 and the permanent magnet 216.

[0068] In another non-limiting example, shown in FIG. 5B, the waveguide 208 has a single bearing bulge 214 to prevent contact between the waveguide 208 and the permanent magnet 216. Furthermore, in this configuration, the radius of the distal tip 210 of the waveguide 208 is greater than the length of the waveguide 208. This larger diameter distal tip 210 provides a distal contact point to prevent translational movement toward the distal end of the catheter. In another non-limiting example, the larger diameter distal tip 210 can also be included in the embodiment of FIG. 5A. Providing at least two contact points between the waveguide 208 and the permanent magnet 216 helps stabilize the components relative to one another.

[0069] In another non-limiting example shown in Figure 5C, the waveguide 208 includes at least two bulge bearings 214 that are used to both prevent axial translation of the permanent magnet 216 and limit the amount of contact between the permanent magnet 216 and the waveguide 208. In yet another non-limiting example, the above configuration can be applied to the embodiment of Figure 5B, where the permanent magnet 216 is positioned only between the bearing bulges 214 and the large diameter distal tip 210.

[0070] In other alternative embodiments, the bearing bulge 214 of the above embodiment can be replaced by a separate bearing material disposed radially around the waveguide 208 (as opposed to forming the bearing bulge 214 from the waveguide material itself). As noted above, the material of the applied bearing 502 can be, but is not limited to, ruby, rubber, or epoxy resin.

[0071] In one non-limiting example of FIG. 5D, one or more separate bearings 502 are positioned radially around the waveguide to provide contact points with the permanent magnets 216 and reduce friction.

[0072] In another non-limiting example shown in FIG. 5E, one or more separate bearings 504 are provided between the waveguide 208 and the tube 218, further providing a separation space between the permanent magnet 216 and the waveguide 208.

[0073] 6A-6C, there are shown several different non-limiting examples of configurations for the tube 218 and the optical element 220. For example, in FIG. 6A, in addition to the optical element 220, an ultrasonic transducer 602 is also supported on the tube 218 to reflect light for radial light scanning.

[0074] 6B, two optical elements 220 and 604 are arranged side by side within the tube 218. In such a configuration, the light beam 212 passes through the optical element 604, which may be a partially reflective mirror. The light beam 212 is split into a reflected portion for a radial scan and a straight beam that reaches the second optical element 220, which may further reflect the light beam for a further radial scan at a second point.

[0075] 6C, two light beams 604 and 606 from two waveguides are shown being directed toward an optical element 220. The angle of the reflecting surface causes the beams 604 and 606 to be reflected at two different points. The gap between these two points along the length of the tube 218 can be controlled by varying the radial distance between the parallel light beams 604 and 606.

[0076] 7 shows a non-limiting example of an imaging assembly 200 enclosed in an outer sheath 702. The imaging assembly 200 can be pulled back or retracted longitudinally within the outer sheath to perform 3D volumetric measurements while rotating via a micromotor. The catheter sheath 202 can also be a braided copper wire tube 704.

[0077] In other example embodiments of the present invention, the micromotor can be an electrostatic motor, which generates motion without the need for permanent magnets but based on the attraction and repulsion of electric charges. Importantly for the disclosed invention, the waveguide can also function as a shaft supporting the rotating components, while the rotor and stator components can be interchangeable. The motor can be pneumatically driven, like a dental drill, or hydraulically driven using a similar mechanism.

[0078] In general, any of the force-generating mechanisms described herein can be driven by closed-loop velocity control using multiple wavelength optical channels and narrowband reflective grids, or the force-generating mechanisms can be driven by open-loop velocity control provided by external driver electronics.

[0079] Referring to Figure 8, a non-limiting method 800 for imaging using any of the imaging systems and imaging assembly configurations described above is described. In step 802, an imaging system, such as the imaging system described in Figure 1, is provided. The imaging system includes an imaging assembly described in any of the embodiments of Figures 2-7. In step 804, an electric current is supplied to the imaging assembly. Specifically, a current is supplied to an electromagnetic coil to generate a magnetic field and rotate the magnet. As described above, the magnet can be coupled to the tube and a distal optical element that rotates with the magnet.

[0080] In step 806, an imaging assembly is used to send one or more beams of light through the waveguide. The light beams travel through the distal tip of the waveguide and may be reflected, diffracted, or refracted by optical elements to perform radial or forward scanning. In step 808, one or more reflected beams of light are received. For example, the light may be reflected from tissue surrounding the catheter. Finally, in step 810, one or more images are generated from the one or more reflected beams of light.

[0081] In one non-limiting example, steps 806-810 can use an ultrasonic waveguide instead of an optical waveguide to transmit and receive ultrasonic signals and generate images from the ultrasonic signals.

[0082] As used in this specification and claims, the singular forms "a", "an" and "the" include the plural forms unless the context clearly dictates otherwise.

[0083] Additionally, the terms "about," "approximately," "substantially," and "significantly" used herein are terms that would be understood by a person skilled in the art and may vary to some extent depending on the context. If a term is used that is not clear to a person skilled in the art in the context, the terms "about" and "approximately" will mean up to ±10% of the particular term, and "substantially" and "significantly" will mean more than ±10% of the particular term.

[0084] As used herein, the terms "include" and "including" are synonymous with the terms "comprise" and "comprising." The terms "comprise" and "comprising" are to be interpreted as "open" introductory terms that allow for the inclusion of additional elements in addition to the elements recited in the claims. The terms "consist" and "consisting of" are to be interpreted as "closed" introductory terms that do not allow for the inclusion of additional elements in addition to the elements recited in the claims. The phrase "consisting essentially of" is to be interpreted as part-closed, allowing for the inclusion of only additional elements that do not fundamentally change the nature of the claimed invention.

[0085] The phrase "such as" should be construed as "for example, including." Furthermore, all examples, including but not limited to, "such as," are intended solely to facilitate understanding of the present invention and do not limit the scope of the invention unless otherwise stated in the claims.

[0086] Furthermore, when idiomatic expressions such as "at least one of A, B, and C, etc." are used, they are generally intended to be interpreted as meaning that one of ordinary skill in the art would understand from the expression (e.g., "a system comprising at least one of A, B, and C" includes, but is not limited to, systems comprising only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and / or a combination of A, B, and C). Furthermore, those of ordinary skill in the art will recognize that virtually any disjunctive language indicating two or more alternative terms, whether in the specification or drawings, should be understood to be intended to include any one, any more, or all of the terms in question. For example, the phrase "A or B" should be understood to include the alternatives "A" or "B" or "A and B."

[0087] For example, terms such as "up to," "at least," "greater than," and "less than" all include the stated numerical value and any range that may be further divided into ranges or subranges. A range includes each individual numerical value. Thus, for example, a group containing 1 to 3 elements refers to groups containing 1, 2, or 3 elements. Similarly, a group containing 6 elements refers to groups containing 1, 2, 3, 4, or 6 elements, and so on.

[0088] The modal verb "may" refers to the advantageous use or selection of one or more options or choices from among the described embodiments or configurations within those embodiments. When no options or choices are disclosed with respect to a particular embodiment or configuration within that particular embodiment, the modal verb "may" refers to a positive statement about an aspect of the described embodiment or configuration within it, or to a definitive decision to use special capabilities with respect to the described embodiment or configuration within it. In the latter context, the modal verb "may" is synonymous with the modal verb "can" and has the same nuance.

Claims

1. Power supply and a catheter having a proximal end and a distal end, the catheter having a lumen between the proximal end and the distal end; an imaging assembly including a proximal portion and a distal portion disposed within the lumen adjacent the distal end of the catheter; An imaging system comprising: The imaging assembly includes: a waveguide centered within the imaging assembly and extending the length of the catheter; at least one permanent magnet disposed in the proximal portion of the imaging assembly so as to be radially arranged around the waveguide; an optical element coupled to an outer surface of the at least one permanent magnet, the optical element positioned to extend beyond the distal portion of the imaging assembly and penetrate into the distal end of the catheter; one or more electromagnetic coils disposed in the proximal portion of the imaging system radially outward from the at least one permanent magnet, the electromagnetic coils in electrical communication with the power source; An imaging system comprising:

2. the at least one permanent magnet comprises a ring magnet; The imaging system of claim 1 .

3. the waveguide comprises one or more optical fibers; The imaging system of claim 1 .

4. the waveguide comprises one or more radial protrusions; The imaging system of claim 1 .

5. the one or more radial protrusions are formed on the waveguide; 5. The imaging system of claim 4.

6. the one or more radial protrusions include bearing portions positioned radially on the waveguide; 5. The imaging system of claim 4.

7. the one or more radial protrusions abut the at least one permanent magnet; 5. The imaging system of claim 4.

8. the distal tip of the waveguide comprises a lens; The imaging system of claim 1 .

9. the optical element comprises one or more mirrors or lenses; The imaging system of claim 1 .

10. further comprising an extension coupling the optical element to an outer surface of the one or more permanent magnets. The imaging system of claim 1 .

11. An opening is provided in at least a portion of the extension.

11. The imaging system of claim 10.

12. the waveguide is configured to transmit light towards the one or more mirrors, the light reflecting off the one or more mirrors and passing through the opening in the extension.

12. The imaging system of claim 11.

13. a support bearing portion coupled to the extension portion and abutting a distal end of the one or more electromagnetic coils.

11. The imaging system of claim 10.

14. further comprising an ultrasonic transducer coupled to the extension.

11. The imaging system of claim 10.

15. the extension is a tube; 11. The imaging system of claim 10.

16. the electromagnetic coil is in electrical communication with the power source via one or more wires; The imaging system of claim 1 .

17. The electromagnetic coil generates a magnetic field when supplied with a current from the power source. The imaging system of claim 1 .

18. the at least one permanent magnet and the optical element rotate based on the strength and frequency of the magnetic field.

18. The imaging system of claim 17.

19. a yoke in the proximal portion of the imaging assembly radially disposed between the one or more electromagnetic coils and an inner surface of the catheter; The imaging system of claim 1 .

20. It also has a spring, the spring is disposed in the imaging assembly proximal to the at least one permanent magnet, and the waveguide is disposed in a direction passing through the spring; The imaging system of claim 1 .

21. an imaging assembly comprising a proximal portion and a distal portion disposed adjacent a distal end of the lumen catheter, The imaging assembly includes: a waveguide centered within the imaging assembly and extending the length of the catheter; at least one permanent magnet disposed in the proximal portion of the imaging assembly so as to be radially arranged around the waveguide; an optical element coupled to an outer surface of the at least one permanent magnet, the optical element positioned to extend beyond the distal portion of the imaging assembly and penetrate into the distal end of the catheter; one or more electromagnetic coils positioned in the proximal portion of the imaging assembly so as to be radially outward from the at least one permanent magnet; 12. The imaging assembly according to claim 11, further comprising:

22. the at least one permanent magnet comprises a ring magnet; 22. The imaging assembly of claim 21.

23. The waveguide is an optical fiber.

22. The imaging assembly of claim 21.

24. the waveguide comprises one or more radial protrusions; 22. The imaging assembly of claim 21.

25. the one or more radial protrusions are formed on the waveguide; 25. The imaging assembly of claim 24.

26. the one or more radial protrusions include bearing portions positioned radially on the waveguide; 25. The imaging assembly of claim 24.

27. the one or more radial protrusions abut the at least one permanent magnet; 25. The imaging assembly of claim 24.

28. the distal tip of the waveguide comprises a lens; 22. The imaging assembly of claim 21.

29. the optical element comprises one or more mirrors or lenses; 22. The imaging assembly of claim 21.

30. further comprising an extension coupling the optical element to an outer surface of the one or more permanent magnets.

22. The imaging assembly of claim 21.

31. An opening is provided in at least a portion of the extension.

31. The imaging assembly of claim 30.

32. the waveguide is configured to transmit light towards the one or more mirrors, the light reflecting off the one or more mirrors and passing through the opening in the extension.

32. The imaging assembly of claim 31.

33. a support bearing portion coupled to the extension portion and abutting a distal end of the one or more electromagnetic coils.

31. The imaging assembly of claim 30.

34. further comprising an ultrasonic transducer coupled to the extension.

31. The imaging assembly of claim 30.

35. the extension is a tube; 31. The imaging assembly of claim 30.

36. The electromagnetic coil generates a magnetic field when supplied with a current from a power source.

22. The imaging assembly of claim 21.

37. the at least one permanent magnet and the optical element rotate based on the strength and frequency of the magnetic field.

37. The imaging assembly of claim 36.

38. a yoke in the proximal portion of the imaging assembly radially disposed between the one or more electromagnetic coils and an inner surface of the catheter; 22. The imaging assembly of claim 21.

39. It also has a spring, the spring is disposed in the imaging assembly proximal to the at least one permanent magnet, and the waveguide is disposed in a direction passing through the spring; 22. The imaging assembly of claim 21.

40. 1. A method of imaging, comprising: Power supply and a catheter having a proximal end and a distal end, the catheter having a lumen between the proximal end and the distal end; an imaging assembly including a proximal portion and a distal portion disposed within the lumen adjacent the distal end of the catheter; providing an imaging system comprising: a waveguide centered within the imaging assembly and extending the length of the catheter; at least one permanent magnet disposed in the proximal portion of the imaging assembly so as to be radially arranged around the waveguide; an optical element coupled to an outer surface of the at least one permanent magnet, the optical element positioned to extend beyond the distal portion of the imaging assembly and penetrate into the distal end of the catheter; one or more electromagnetic coils disposed in the proximal portion of the imaging assembly radially outward from the at least one permanent magnet, the electromagnetic coils in electrical communication with the power source; It is equipped with supplying current to the one or more electromagnetic coils to generate a magnetic field; directing one or more beams of light through the waveguide towards the optical element; receiving one or more beams reflected from the optical element; generating an image from the reflected beam or beams with a processor; An imaging method comprising:

41. the optical element comprises one or more mirrors or lenses; 41. The imaging method of claim 40.

42. further comprising an extension coupling the optical element to an outer surface of the one or more permanent magnets.

41. The imaging method of claim 40.

43. An opening is provided in at least a portion of the extension.

43. The imaging method of claim 42.

44. and further comprising using the waveguide to direct light toward the one or more mirrors so as to reflect the light through the opening in the extension.

44. The imaging method of claim 43.

45. providing a support bearing portion coupled to the extension portion and abutting a distal end of the one or more electromagnetic coils.

43. The imaging method of claim 42.

46. further comprising transmitting ultrasonic energy using an ultrasonic transducer coupled to the extension.

43. The imaging method of claim 42.

47. the extension is a tube; 43. The imaging method of claim 42.

48. further comprising electrically connecting the electromagnetic coil to the power source via one or more wires.

41. The imaging method of claim 40.

49. generating a magnetic field using the electromagnetic coil by sending a current from the power supply; 49. The imaging method of claim 48.

50. further comprising rotating the at least one permanent magnet and the optical element based on the strength and frequency of the magnetic field.

50. The imaging method of claim 49.

51. and further comprising providing a yoke disposed in the proximal portion of the imaging assembly, the yoke being radially disposed between the one or more electromagnetic coils and an inner surface of the catheter.

41. The imaging method of claim 40.

52. further comprising providing a spring; the spring is disposed in the imaging assembly proximal to the at least one permanent magnet, and the waveguide is disposed in a direction passing through the spring; 41. The imaging method of claim 40.

Images