Actuator for use with medical imaging modalities and system thereof

Abstract

An actuator for use with medical imaging modalities is provided. In one embodiment, said actuator comprises: (a) a shell comprising a first end with one or more first fluid port and a second end with one or more second fluid port; and (b) a concentric bellows comprising an outer bellows and an inner bellows; wherein an inner chamber is formed between said outer bellows and said inner bellows; wherein said inner chamber contains inner fluid and is connected to said one or more second fluid port; (c) an instrument adapter comprising a sealing part and a connection part; said sealing part forms an outer chamber with said shell at said first end; said outer chamber contains outer fluid; said connection part protrudes into said inner bellows for connection with an instrument inserted from said second end.

Description

ACTUATOR FOR USE WITH MEDICAL IMAGING MODALITIES AND SYSTEM THEREOFFIELD OF THE INVENTION

[0001] The present invention relates to magnetic resonance imaging (MRI)-safe actuators, particularly, for medical robotics and minimally invasive surgery.BACKGROUND OF THE INVENTION

[0002] Magnetic resonance imaging (MRI) has been increasingly used for needlebased clinical diagnosis (i.e. biopsy) and therapy (i.e. ablation and brachytherapy) in recent decades [1] due to its superior soft tissue imaging capabilities compared to computed tomography (CT) and ultrasound. With the small MR bore space and the high magnetic field restricting the regular interaction between the surgeon and the patient during a clinical procedure, robots present an attractive solution via MRLguided teleoperation [2], [3]. A needle driver thus becomes an essential part of these robotic systems to perform in-bore needle placement under continuous MR imaging. The most commonly used actuator in an MR-compatible needle driver is the linear piezoelectric actuator [4]-[6], which can generate highly accurate positioning. Rotary piezoelectric motors have also been used together with a lead screw mechanism to power a needle driver [7], [8]. Rotary ultrasonic motors have also been adopted with a crank-slider mechanism to insert and retract an MRI-conditional neurosurgical robot [9],

[0010] . Redundant ultrasonic motors were also used together with a differential mechanism to constrain the output to a linear region and therefore improve the performance of an MRI-compatible needle driver.

[0003] However, all these electric actuators have been shown to induce significant artifacts in the MR images due to the electromagnetic interference and potentially generating heat in the current-carrying material

[0011] ,

[0012] . Pneumatic actuation has been explored in different forms for MRI-compatible needle drivers.

[0004] First, pneumatic cylinder-based linear actuators custom-made of nonmagnetic materials have been adopted to perform needle insertion

[0013] ,

[0014] . They have high compactness and high output force but relatively low positioning accuracy.

[0005] Second, bidirectional rotary pneumatic stepper motors have been developed using different pneumatic components (e.g. diaphragm, piston-cylinder, etc.) and interacting mechanisms (meshing gears crank-shafts, etc.) to initiate sequential step motions and output a continuous rotary motion

[0015] ,

[0016] . Combined with a spindle or rack and pinion, they were used for linear needle driving

[0017] ,

[0018] . While these steppermotors can provide high control accuracy without any position sensor, most are complex to manufacture and take a relatively long time to move a significant distance due to the step motion

[0019] .

[0006] Third, inchworm motion-based pneumatic linear actuators, in combination with gripper pairs, have also been used as needle drivers, including the flexible fluidic actuators (FFAs) made of linear toroidal bellows and a multi-material 3D printed design with auxetic structure-based outer envelope

[0020] . The needle can be displaced by multiphase gripping and releasing actions with linear motion generated in between the phases. These actuators are highly compact but the motion speed is relatively slow due to their operation principle. The needle may also risk suffering from slippage from the grippers and its penetration force is limited by the gripping strength of the grippers instead of the output force of the linear actuator.

[0007] Hydrostatic linear actuation systems have been introduced to offer higher output force and fast motion compared with pneumatic actuation. They also feature minimal risk of leakage due to the closed fluid system. They adopt the master-follower transmission mechanism, whereby the master actuator is controlled with electric motors in the control room while the follower actuator is placed inside the MRI to interface with the robotic joint to ensure MR compatibility of the overall actuation system. Piston-cylinder hydraulic units were the earliest examples of hydrostatic linear actuation

[0021] but often present the issue of large sealing friction which is required to prevent fluid leakage.

[0008] Rolling diaphragms were proposed to replace the regular seal to minimize friction

[0022] , and have since been adopted as a linear actuator in several MRI-safe robotic systems, including a needle driver

[0023] ,

[0024] and intracardiac catheter

[0025] . However, rolling diaphragm-based actuators feature a short stroke-length ratio and require additional mechanisms

[0025] ,

[0026] such as gearboxes or crankshafts to increase the stroke length.

[0009] Considering the need for the needle driver to be operated under continuous MR imaging, it is more ideal to use an inherently safe actuation mechanism (e.g. pneumatic or hydrostatic) instead of electric actuators such as piezoelectric and ultrasonic motors. Hydrostatic actuation is explored in this work as opposed to pneumatic actuation due to its higher potential for large force output and high power transmission efficiency across long transmission lines.

[0010] Among the existing hydrostatic actuators, rolling diaphragm-based actuators arethe most promising but capable of only short strokes, which may not be sufficient for many needle procedures. Long stroke rolling diaphragms (LSDR) have recently been introduced to address this limitation

[0027] , but they are mostly single-acting actuators, which require additional mechanisms for effective bidirectional motion.

[0011] To sum it up, most actuator designs for MRI-compatible needle drivers are currently limited in different aspects and may not be able to contribute to the high performance required in a long-stroke needle procedure, such as high force output, long-stroke, high compactness, and high positioning accuracy.SUMMARY OF THE INVENTION

[0012] This invention provides an actuator for use with medical imaging modalities. In one embodiment, said actuator comprises: (a) a shell comprising a first end with one or more first fluid port and a second end with one or more second fluid port; and (b) a concentric bellows comprising an outer bellows and an inner bellows; wherein an inner chamber is formed between said outer bellows and said inner bellows; wherein said inner chamber contains inner fluid and is connected to said one or more second fluid port; (c) an instrument adapter comprising a sealing part and a connection part; said sealing part forms an outer chamber with said shell at said first end; said outer chamber contains outer fluid; said connection part protrudes into said inner bellows for connection with an instrument inserted from said second end; wherein said outer fluid entering said outer chamber from said one or more first fluid port will push said sealing part towards said second end while said inner fluid in said inner chamber will be pushed out from said one or more second fluid port; and said inner fluid entering said inner chamber from said one or more second fluid port will push said sealing part towards said first end while said outer fluid in said outer chamber will be pushed out from said one or more first fluid port.

[0013] This invention further provides a system for controlling said actuator when being used in a medical imaging modality. In one embodiment, said system comprises: (a) a first part for placement within a room for said medical imaging modality, comprising: (i) said actuator; (b) a second part for placement outside said room, comprising: (i) a pair of motor-driven syringes and a first microcontroller; (c) a third part bridging between said first and second part, comprising: (i) transmission tubings connected to one of said pair of motor-driven syringes at one end and said one or more first fluid port or said one or more second fluid port at another end; said pair of motor- driven syringes are controlled by said first microcontroller to follow a program to driveand precisely adjust fluid entering said one or more first fluid port and said one or more second fluid port.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1A is a detailed schematic of the concentric bellows-based linear actuator showing each component of the actuator integrated with the optical fiber-based sensing system. 1-1: Fluid port 1; 1-2: Fluid port 2; 1-3: Guide rails; 1-4: Rigid cylindrical shell; 1-5: Inner bellow; 1-6: Outer bellow (Concentric bellows); 1-7: Rigid skeleton; 1-8: Instrument; I -9: Instrument adapter; 1-10: Optical fibre-based sensor.

[0015] Figure IB shows the linear motion and force-generating process with concentric bellows deformation in cross-section view showing how the actuator manipulates the instrument through the bellow deformation. 1-11: Inner chamber; 1-12: Outer chamber.

[0016] Figure 2 is a detailed schematic of the optical fiber-based sensing system for integration with the bellow actuators used for linear displacement sensing showing each component of the fiber-based linear encoder. 2-1: Coded disks (with slits); 2-2: Compliant support; 2-3: self-aligning base; 2-4: Optical fibers; 2-5: laser emitter; 2-6: photoelectric sensors.

[0017] Figure 3 is a schematic of the detailed integrated system setup showing each component of the closed-loop integrated system including the fluid-pressure-based soft sensing system for force sensing, the optical fiber-based sensing system for linear displacement sensing, and the fluid-driven concentric-bellows-based linear actuator under MRI conditions.DETAILED DESCRIPTION OF THE INVENTION

[0018] Magnetic Resonance Imaging (MRI) is increasingly utilized in robotic needlebased clinical diagnosis and therapy due to its exceptional high-resolution and soft tissue contrast capabilities. Within this context, a needle driver plays a pivotal role in MRI-guided robotic systems, enabling in-bore needle placement under continuous MR imaging. However, existing actuator designs for needle drivers face significant constraints due to the high magnetic field and bore size of the MR scanner, often lacking high-performance attributes, particularly in terms of substantial output force and extended stroke within a compact form factor. This patent introduces three key innovations: l)An MRI-safe fluid-driven concentric bellows-based linear actuator designed for one degree-of-freedom manipulation. 2)An MRI-safe optical fiber-based sensing system, seamlessly integrated with the actuator for precise linear displacementsensing. 3)An MRI-safe fluid pressure-based soft sensing system, also integrated with the actuator, for accurate force sensing.

[0019] These MRI-safe actuators and sensing systems are characterized by their exceptional compactness, extended motion stroke, and substantial output force. They represent a significant leap forward in current technologies for MRI-safe robots operating in restrictive medical imaging environments, particularly within MRI settings.

[0020] A magnetic resonance imaging (MRI)-safe actuator with integrated displacement sensor and fluid pressure-based force sensing has been developed for robotic applications in medical imaging environments, such as MRI, that imposes strict restrictions on the material due to the potential negative influence on the machine operation, imaging quality, and most importantly safety issues. Several inventions are introduced, including l)An MRI-safe fluid-driven concentric bellows-based linear actuator to perform 1 degree-of-freedom manipulation, such as insertion and withdrawal, of tools including but not limited to needles, ablation probes, and brachytherapy devices in a medical imaging environment including but not limited to MRI and computed tomography (CT); 2) An MRI-safe optical fiber-based sensing system for integration with the bellows actuators used for linear displacement sensing, and closed-loop control in a medical imaging environment including but not limited to MRI and CT ; 3)An MRI-safe fluid pressure-based soft sensing system for integration with the bellow actuators used for force sensing, and closed-loop control in a medical imaging environment including but not limited to MRI and CT.

[0021] This invention provides an actuator for use with medical imaging modalities. In one embodiment, said actuator comprises: (a) a shell comprising a first end with one or more first fluid port and a second end with one or more second fluid port; and (b) a concentric bellows comprising an outer bellows and an inner bellows; wherein an inner chamber is formed between said outer bellows and said inner bellows; wherein said inner chamber contains inner fluid and is connected to said one or more second fluid port; (c) an instrument adapter comprising a sealing part and a connection part; said sealing part forms an outer chamber with said shell at said first end; said outer chamber contains outer fluid; said connection part protrudes into said inner bellows for connection with an instrument inserted from said second end; wherein said outer fluid entering said outer chamber from said one or more first fluid port will push said sealing part towards said second end while said inner fluid in said inner chamber will be pushed out from said one or more second fluid port; and said inner fluid entering said innerchamber from said one or more second fluid port will push said sealing part towards said first end while said outer fluid in said outer chamber will be pushed out from said one or more first fluid port.

[0022] In one embodiment, said concentric bellows comprises skeletons adapted to slide along a set of guiding rails within said shell.

[0023] In one embodiment, said instrument is selected from the group consisting of needles, ablation probes, and brachytherapy devices.

[0024] In one embodiment, said medical imaging modalities comprises magnetic resonance imaging or computed tomography.

[0025] In one embodiment, said actuator further comprises a pair of motor-driven syringes and transmission tubings; wherein said transmission tubings are connected to one of said pair of motor-driven syringes at one end and said one or more first fluid port or said one or more second fluid port at another end; said pair of motor-driven syringes are controlled by a microcontroller to follow a program to drive and precisely adjust said outer fluid and said inner fluid from entering or leaving said one or more first fluid port and said one or more second fluid port respectively.

[0026] In one embodiment, said actuator further comprises an optical fiber-based sensing system at said second end for measuring displacement of said instrument, wherein said optical fiber-based sensing system comprises a first coded disk, a second coded disk, three optical fiber through-beam units and a self-aligning base; said first coded disk and said second coded disk are adapted to sandwich said instrument and rotate along with displacement of said instrument; one of said three optical fiber through-beam units is associated with said first coded disk to measure displacement; the other two of said three optical fiber through-beam units are associated with said second coded disk to achieve two phases to measure direction.

[0027] In one embodiment, each of said three optical fiber through-beam units comprises a laser emitter, a pair of optical fibers and a photoelectric sensor.

[0028] In one embodiment, said first and second coded disk comprises an edge with a groove for sandwiching said instrument.

[0029] In one embodiment, said self-aligning base comprises a symmetrical compliant supporting structure for applying lateral force to said first and second coded disks to sandwich said instrument.

[0030] This invention further provides a system for controlling said actuator when being used in a medical imaging modality. In one embodiment, said system comprises:(a) a first part for placement within a room for said medical imaging modality, comprising: (i) said actuator; (b) a second part for placement outside said room, comprising: (i) a pair of motor-driven syringes and a first microcontroller; (c) a third part bridging between said first and second part, comprising: (i) transmission tubings connected to one of said pair of motor-driven syringes at one end and said one or more first fluid port or said one or more second fluid port at another end; said pair of motor- driven syringes are controlled by said first microcontroller to follow a program to drive and precisely adjust fluid entering said one or more first fluid port and said one or more second fluid port.

[0031] In one embodiment, said system further comprises a fluid pressure-based soft sensing system in said second part, comprising one or more pressure sensors for measuring pressure in said inner chamber or said outer chamber via said transmission tubings and a second microcontroller for converting said pressure into force.

[0032] In one embodiment, said system further comprises an optical fiber-based sensing system, wherein, in said first part, said optical fiber-based sensing system comprises a first coded disk, a second coded disk, three optical fiber through-beam units and a self-aligning base at said second end; said first coded disk and said second coded disk are adapted to sandwich said instrument and rotate along with displacement of said instrument; one of said three optical fiber through-beam units is associated with said first coded disk to measure displacement; the other two of said three optical fiber through-beam units are associated with said second coded disk to achieve two phases to measure direction; each of said three optical fiber through-beam units comprises (a) a laser emitter and a photoelectric sensor in said second part; (b) an optical fiber in said third part.

[0033] In one embodiment, said first and second coded disk comprises an edge with a groove for sandwiching said instrument; or said self-aligning base comprises a symmetrical compliant supporting structure for applying lateral force to said first and second coded disks to sandwich said instrument.

[0034] In one embodiment, said concentric bellows comprises skeletons adapted to slide along a set of guiding rails within said shell.

[0035] In one embodiment, said medical imaging modalities comprises magnetic resonance imaging or computed tomography.

[0036] This invention provides a magnetic resonance imaging (MRI)-safe fluid-driven concentric-bellows-based linear actuator to perform 1 degree-of-freedom manipulation,such as insertion and withdrawal, of instruments including but not limited to needles, ablation probes, and brachytherapy devices in a medical imaging environment including but not limited to MRI and computed tomography (CT).

[0037] This invention provides an MRI-safe optical fiber-based sensing system for integration with the bellow actuators used for linear displacement sensing, and closed- loop control in a medical imaging environment including but not limited to MRI and CT.

[0038] This invention provides an MRI-safe fluid pressure-based soft sensing system for integration with the bellows actuators used for tool force sensing, and closed-loop control in a medical imaging environment including but not limited to MRI and CT.

[0039] Detailed description of Figure 1:

[0040] The fluid-driven concentric bellows-based linear actuator consists of four main components: concentric bellows with skeletons, a cylindrical shell, an instrument adaptor, and an instrument.

[0041] The concentric bellows is formed by two layers of bellows with the same length and geometric structure concentrically but with different diameters (i.e. outer bellows and inner bellows). One end is closed (Instrument adaptor), while the other is left open for fluid supply (Fluid port 1). Similar to a traditional single-layer bellows, the concentric bellows would expand or contract in the axial direction due to pressure difference while the radial deformation remains self-constrained. However, the conventional bellow design is single-acting, limiting pressure to act only from inside the bellow relative to the atmospheric pressure. A typical double-acting bellows actuator necessitates two bellows arranged in series, generating force output between them. This configuration requires the integration of a force redirecting mechanism, resulting in double the size of a single-acting bellows and higher design complexity. In contrast, the concentric bellows design offers the advantage of pressure acting on both the inside and outside of the outer bellow while maintaining the footprint similar to that of a single bellows actuator. The inner bellows serves as a deployable seal, allowing the instrument to be separated from the fluid. This novel configuration achieves doubleacting actuation without requiring additional bellows connected in series or additional complex mechanisms. Moreover, this design facilitates the storage of surgical instruments within the actuator, significantly improving its compactness when compared to other existing double-acting fluid-based actuators.

[0042] The internal space of the cylindrical shell is divided into two chambers filledwith fluid. The first chamber is located in the annulus region between the two concentric bellows, indicated as the inner chamber. The second chamber is enclosed by the cylindrical shell and the outer bellows, indicated as the outer chamber. When there is a specific fluid volume change in both chambers, the close end of the concentric bellows attached to the instrument adaptor will undergo axial deformation due to the fluid pressure, resulting in the axial movement of the instrument adaptor. Therefore, if the fluid volume increases in the outer chamber while simultaneously decreasing in the inner chamber, the bellows will contract, pushing the instrument outward. Conversely, when the fluid volume decreases in the outer chamber while simultaneously increasing in the inner chamber, the bellows will extend, causing the instrument to retract into the actuator. An electro-hydrostatic system formed by a pair of motor-driven syringes was used to control the actuator. The motors are controlled by a microcontroller to follow a program to drive and precisely adjust the volume of the fluid inside the actuator via two fluid-transmission tubings.

[0043] The neutral state of the actuator, where the instrument is completely stored, is defined as when the concentric bellow is in the maximum length under the natural state. The instrument extends out of the actuator when the concentric bellow contracts from the natural state. The working space of the actuator equals the deformation length of the concentric bellow.

[0044] Similar to traditional bellows, the concentric bellows can buckle when unrestricted. These bucklings have the potential to consume some of the bellow length, resulting in inaccurate output displacement. The bellows might also collapse due to the radial deformation under large pressure. A rigid structural reinforcement, namely the skeleton, is designed to constrain the radial deformation on the outer edge of every bellow segment. The positioning slots on the bellow skeleton can slide along the guiding rails on the inner wall of the cylindrical chamber. This linear guiding mechanism prevents the units from buckling during deformation.

[0045] Detailed description of Figure 2:

[0046] A specialized optical fiber-based incremental linear encoder has been developed since no marking for encoding can be made on the instrument. The encoder primarily collects data by blocking the optical beam intermittently. It consists of three main components, including a pair of coded disks, three optical fiber through-beam units, and a self-aligning base. The coding disk has slits that alternately block and allow the passage of light as the coding disk rotates.

[0047] An optical fiber through-beam unit is formed by a laser emitter, a pair of optical fibers, and a photoelectric sensor. The laser emitter is located in the MRI control room and emits laser beams toward one end of an optical fiber, which transmits the laser to the other end of the fiber located inside the MR environment and emits it outward. The laser emitted from the fiber passes through the slits on the coding disk and is received by another fiber, allowing the laser to be transmitted back to the control room where it can be detected by a photoelectric sensor. Two optical fiber through-beam units are used in one coded disk to achieve two phases (AB -channel) of encoding for directional recognition.

[0048] The two coding disks sandwich the instrument and are fixed to the self-aligning base integrated into the actuator. When the instrument displaces, it brings the coded disks to rotate and the displacement of the instrument can be collected by counting the optical signal received by the photoelectric sensors. To increase the contact area with the instrument, the edges of the coded disks are designed with grooves that fit the instrument. On the base, a symmetrical compliant supporting structure is strategically positioned to apply lateral force to the coded disks. This design ensures that both sets of coded disks exert sufficient and equal force to centrally clamp the instrument, effectively preventing any slipping that leads to misalignment between the coded disks and the instrument. Moreover, by adding an extra optical fiber through-beam unit to the extra coded disk aligned in phase with the other disk, the optical signal can be differentiated and provides additional sets of optical signal combinations, resulting in an enhanced resolution of the encoder.

[0049] Detailed description of Figure 3:

[0050] A fluid pressure-based soft sensing system integrated into the fluid-driven concentric-bellows-based linear actuator has been designed to sense the external force acting on the instrument axially during the manipulation. The soft sensing system is based on the pressure change inside the two chambers of the actuator under external force. Benefiting from the deformable concentric bellow design, the external force can apply pressure to the fluid in the chambers with minimal deviation caused by friction. The pressure change can be transmitted to the industrial pressure sensor in the control room via the fluid-transmission tubings shared with the electro-hydrostatic system. With sufficiently accurate experimental characterization, the pressure data can be converted into force by the microcontroller and achieve real-time force sensing.

[0051] References[1] R. Monfaredi, K. Cleary, and K. Sharma, “Mri robots for needlebased interventions: systems and technology,” Annals of biomedical engineering, vol. 46, pp. 1479-1497, 2018.[2] H. Su, K.-W. Kwok, K. Cleary, I. lordachita, M. C. Cavusoglu, J. P. Desai, and G. S. Fischer, “State of the art and future opportunities in mri-guided robot-assisted surgery and interventions,” Proceedings of the IEEE, vol. 110, no. 7, pp. 968-992, 2022.[3] S. Shao, B. Sun, Q. Ding, W. Yan, W. Zheng, K. Yan, Y. Hong, and S. S. Cheng, “Design, modeling, and control of a compact smaactuated mr-conditional steerable neurosurgical robot,” IEEE Robotics and Automation Letters, vol. 5, no. 2, pp. 1381— 1388, 2020.[4] K. M. Elbannan and S. P. Salisbury, “Design of a two degreeof-freedom, mri- compatible actuator,” in 2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2012, pp. 940-943.[5] H. Su, W. Shang, G. Cole, G. Li, K. Harrington, A. Camilo, J. Tokuda, C. M. Tempany, N. Hata, and G. S. Fischer, “Piezoelectrically actuated robotic system for mri-guided prostate percutaneous therapy,” IEEE / ASME transactions on mechatronics, vol. 20, no. 4, pp. 1920- 1932, 2014.[6] S. S. Cheng, X. Wang, and J. P. Desai, “Design and analysis of a remotely-actuated cable-driven neurosurgical robot,” in 2017 IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS). IEEE, 2017, pp. 1685-1690.[7] B. Yang, U.-X. Tan, A. McMillan, R. Gullapalli, and J. P. Desai, “Design and implementation of a pneumatically-actuated robot for breast biopsy under continuous mri,” in 2011 IEEE international conference on robotics and automation. IEEE, 2011, pp. 674-679.[8] D. Wu, G. Li, N. Patel, J. Yan, R. Monfaredi, K. Cleary, and I. lordachita, “Remotely actuated needle driving device for mriguided percutaneous interventions,” in 2019 International Symposium on Medical Robotics (ISMR). IEEE, 2019, pp. 1-7.[9] X. Wang, S. S. Cheng, and J. P. Desai, “Design, analysis, and evaluation of a remotely actuated mri-compatible neurosurgical robot,” IEEE robotics and automation letters, vol. 3, no. 3, pp. 2144-2151, 2018.

[0010] S. S. Cheng, X. Wang, S. Jeong, M. Kole, S. Roys, and R. P. Gullapalli, “Mechanical design and evaluation of a selectively- actuated mri-compatible continuum neurosurgical robot,” in 2021 IEEE / RSJ International Conference on Intelligent Robots and Systems (IROS). IEEE, 2021, pp. 2498-2503.

[0011] G. S. Fischer, A. Krieger, I. lordachita, C. Csoma, L. L. Whitcomb, and G. Fichtinger, “Mri compatibility of robot actuation techniques- a comparative study,” in Medical Image Computing and Computer Assisted Intervention-MICCAI 2008: 11th International Conference, New York, NY, USA, September 6-10, 2008, Proceedings, Part II 11. Springer, 2008, pp. 509-517.

[0012] P. Shokrollahi, J. M. Drake, and A. A. Goldenberg, “Signal-to-noise ratio evaluation of magnetic resonance images in the presence of an ultrasonic motor,” Biomedical engineering online, vol. 16, pp. 1-12, 2017.

[0013] N. Hungr, I. Bricault, P. Cinquin, and C. Fouard, “Design and validation of a ct- and mri-guided robot for percutaneous needle procedures,” IEEE transactions on robotics, vol. 32, no. 4, pp. 973-987, 2016.

[0014] D. Navarro-Alarcon, S. Singh, T. Zhang, H. L. Chung, K. W. Ng, M. K. Chow, and Y. Liu, “Developing a compact robotic needle driver for mri-guided breast biopsy in tight environments,” IEEE Robotics and Automation Letters, vol. 2, no. 3, pp. 1648- 1655, 2017.

[0015] B. L. Boland, S. Xu, B. Wood, and Z. T. H. Tse, “High speed pneumatic stepper motor for mri applications,” Annals of biomedical engineering, vol. 47, pp. 826-835, 2019.

[0016] V. Groenhuis and S. Stramigioli, “Rapid prototyping high-performance mr safe pneumatic stepper motors,” IEEE / ASME transactions on mechatronics, vol. 23, no. 4, pp. 1843-1853, 2018.

[0017] D. Stoianovici, D. Song, D. Petrisor, D. Ursu, D. Mazilu, M. Mutener, M. Schar, and A. Patriciu, ““mri stealth” robot for prostate interventions,” Minimally Invasive Therapy & Allied Technologies, vol. 16, no. 4, pp. 241-248, 2007.

[0018] V. Groenhuis, F. J. Siepel, and S. Stramigioli, “Sunram 5: A magnetic resonancesafe robotic system for breast biopsy, driven by pneumatic stepper motors,” in Handbook of Robotic and Image-Guided Surgery. Elsevier, 2020, pp. 375-396.

[0019] Y. Chen, K.-W. Kwok, andZ. T. H. Tse, “An mr-conditional hightorque pneumatic stepper motor for mri-guided and robot-assisted intervention,” Annals of biomedical engineering, vol. 42, pp. 1823- 1833, 2014.

[0020] A. Pfeil, L. Barbe, B. Wach, A. Bruyas, F. Geiskopf, M. Nierenberger, and P. Renaud, “A 3d-printed needle driver based on auxetic structure and inchworm kinematics,” in International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, vol. 51807. American Societyof Mechanical Engineers, 2018, p. V05AT07A057.

[0021] G. Ganesh, R. Gassert, E. Burdet, and H. Bleuler, “Dynamics and control of an mri compatible master-slave system with hydrostatic transmission,” in IEEE International Conference on Robotics and Automation, 2004. Proceedings. ICRA’04. 2004, vol. 2. IEEE, 2004, pp. 1288-1294.

[0022] J. P. Whitney, M. F. Glisson, E. L. Brockmeyer, and J. K. Hodgins, “A low-friction passive fluid transmission and fluid-tendon soft actuator,” in 2014 IEEE / RSJ international conference on intelligent robots and systems. IEEE, 2014, pp. 2801-2808.

[0023] N. Burkhard, S. Frishman, A. Gruebele, J. P. Whitney, R. Goldman, B. Daniel, and M. Cutkosky, “A rolling-diaphragm hydrostatic transmission for remote mr-guided needle insertion,” in 2017 IEEE international conference on robotics and automation (ICRA). IEEE, 2017, pp. 1148-1153.

[0024] J. Simonelli, Y.-H. Lee, C.-W. Chen, X. Li, S. Mikaiel, D. Lu, H. H. Wu, and T.- C. Tsao, “Hydrostatic actuation for remote operations in mr environment,” IEEE / ASME Transactions on Mechatronics, vol. 25, no. 2, pp. 894-905, 2019.

[0025] K.-H. Lee, K. C. D. Fu, Z. Guo, Z. Dong, M. C. Leong, C.-L. Cheung, A. P.-W. Lee, W. Luk, and K.-W. Kwok, “Mr safe robotic manipulator for mri-guided intracardiac catheterization,” IEEE / ASME Transactions on Mechatronics, vol. 23, no. 2, pp. 586-595, 2018.

[0026] Z. Dong, Z. Guo, K.-H. Lee, G. Fang, W. L. Tang, H.-C. Chang, D. T. M. Chan, and K.-W. Kwok, “High-performance continuous hydraulic motor for mr safe robotic teleoperation,” IEEE Robotics and Automation Letters, vol. 4, no. 2, pp. 1964-1971, 2019.

[0027] A. Gruebele, S. Frishman, and M. R. Cutkosky, “Long-stroke rolling diaphragm actuators for haptic display of forces in teleoperation,” IEEE Robotics and Automation Letters, vol. 4, no. 2, pp. 1478-1484, 2019.

[0028] S. Frishman, A. Kight, I. Pirozzi, M. C. Coffey, B. L. Daniel, and M. R. Cutkosky, “Enabling in-bore mri-guided biopsies with force feedback,” IEEE transactions on haptics, vol. 13, no. 1, pp. 159-166, 2020.

[0029] H. Su, M. Zervas, G. A. Cole, C. Furlong, and G. S. Fischer, “Realtime mri-guided needle placement robot with integrated fiber optic force sensing,” in 2011 IEEE international conference on robotics and automation. IEEE, 2011, pp. 1583-1588.

[0030] G. Li, H. Su, G. A. Cole, W. Shang, K. Harrington, A. Camilo, J. G. Pilitsis, and G. S. Fischer, “Robotic system for mri-guided stereotactic neurosurgery,” IEEEtransactions on biomedical engineering, vol. 62, no. 4, pp. 1077-1088, 2014.

[0031] D. Stoianovici, C. Kim, D. Petrisor, C. Jun, S. Lim, M. W. Ball, A. Ross, K. J. Macura, and M. E. Allaf, “Mr safe robot, fda clearance, safety and feasibility of prostate biopsy clinical trial,” IEEE / ASME Transactions on Mechatronics, vol. 22, no. 1, pp. 115-126, 2016.

[0032] M. U. Farooq and S. Y. Ko, “A decade of mri compatible robots: Systematic review,” IEEE Transactions on Robotics, pp. 1-23, 2022.

[0033] S. S. Dhaliwal, T. Chettibi, S. Wilby, W. Polak, A. L. Palmer, N. Reynaert, and R. Merzouki, “Review of clinical and technological consideration for mri-guided robotic prostate brachytherapy,” IEEE Transactions on Medical Robotics and Bionics, vol. 3, no. 3, pp. 583- 605, 2021.

[0034] Y. Chen, I. Godage, H. Su, A. Song, and H. Yu, “Stereotactic systems for mri- guided neurosurgeries: a state-of-the-art review,” Annals of biomedical engineering, vol. 47, pp. 335-353, 2019.

[0035] M. Mahvash and P. E. Dupont, “Mechanics of dynamic needle insertion into a biological material,” IEEE Transactions on Biomedical Engineering, vol. 57, no. 4, pp. 934-943, 2009.

[0036] X. Chen, J. Yi, J. Li, J. Zhou, and Z. Wang, “Soft-actuator-based robotic joint for safe and forceful interaction with controllable impact response,” IEEE Robotics and Automation Letters, vol. 3, no. 4, pp. 3505-3512, 2018.

Claims

What is claimed is:

1. An actuator for use with medical imaging modalities, comprising: a. A shell comprising a first end with one or more first fluid port and a second end with one or more second fluid port; b. A concentric bellows comprising an outer bellows and an inner bellows; wherein an inner chamber is formed between said outer bellows and said inner bellows; wherein said inner chamber contains inner fluid and is connected to said one or more second fluid port; and c. An instrument adapter comprising a sealing part and a connection part; said sealing part forms an outer chamber with said shell at said first end; said outer chamber contains outer fluid; said connection part protrudes into said inner bellows for connection with an instrument inserted from said second end; wherein said outer fluid entering said outer chamber from said one or more first fluid port will push said sealing part towards said second end while said inner fluid in said inner chamber will be pushed out from said one or more second fluid port; and said inner fluid entering said inner chamber from said one or more second fluid port will push said sealing part towards said first end while said outer fluid in said outer chamber will be pushed out from said one or more first fluid port.

2. The actuator of claim 1, wherein said concentric bellows comprises skeletons adapted to slide along a set of guiding rails within said shell.

3. The actuator of claim 1, wherein said instrument is selected from the group consisting of needles, ablation probes, and brachytherapy devices.

4. The actuator of claim 1, wherein said medical imaging modalities comprises magnetic resonance imaging or computed tomography.

5. The actuator of claim 1, further comprises a pair of motor-driven syringes and transmission tubings; wherein said transmission tubings are connected to one of said pair of motor-driven syringes at one end and said one or more first fluid port or said one or more second fluid port at another end; said pair of motor- driven syringes are controlled by a microcontroller to follow a program to drive and precisely adjust said outer fluid and said inner fluid from entering or leavingsaid one or more first fluid port and said one or more second fluid port respectively.

6. The actuator of claim 1, further comprising an optical fiber-based sensing system at said second end for measuring displacement of said instrument, wherein said optical fiber-based sensing system comprises a first coded disk, a second coded disk, three optical fiber through-beam units and a self-aligning base; said first coded disk and said second coded disk are adapted to sandwich said instrument and rotate along with displacement of said instrument; one of said three optical fiber through-beam units is associated with said first coded disk to measure displacement; the other two of said three optical fiber through- beam units are associated with said second coded disk to achieve two phases to measure direction.

7. The actuator of claim 6, wherein each of said three optical fiber through-beam units comprises a laser emitter, a pair of optical fibers and a photoelectric sensor.

8. The actuator of claim 6, wherein said first and second coded disk comprises an edge with a groove for sandwiching said instrument.

9. The actuator of claim 6, wherein said self-aligning base comprises a symmetrical compliant supporting structure for applying lateral force to said first and second coded disks to sandwich said instrument.

10. A system for controlling said actuator of claim 1 when being used in a medical imaging modality, comprising: a. A first part for placement within a room for said medical imaging modality, comprising said actuator of claim 1 ; b. A second part for placement outside said room, comprising a pair of motor-driven syringes and a first microcontroller; c. A third part bridging between said first and second part, comprising transmission tubings connected to one of said pair of motor-driven syringes at one end and said one or more first fluid port or said one or more second fluid port at another end; said pair of motor-driven syringes are controlled by said first microcontroller to follow a program to drive and precisely adjust fluid entering said one or more first fluid port and said one or more second fluid port.

11. The system of claim 10, further comprising a fluid pressure-based soft sensing system in said second part, comprising one or more pressure sensors for measuring pressure in said inner chamber or said outer chamber via said transmission tubings and a second microcontroller for converting said pressure into force.

12. The system of claim 10, further comprising an optical fiber-based sensing system, wherein, in said first part, said optical fiber-based sensing system comprises a first coded disk, a second coded disk, three optical fiber through- beam units and a self-aligning base at said second end; said first coded disk and said second coded disk are adapted to sandwich said instrument and rotate along with displacement of said instrument; one of said three optical fiber through- beam units is associated with said first coded disk to measure displacement; the other two of said three optical fiber through-beam units are associated with said second coded disk to achieve two phases to measure direction; each of said three optical fiber through-beam units comprises: a. a laser emitter and a photoelectric sensor in said second part; and b. an optical fiber in said third part.

13. The system of claim 12, wherein said first and second coded disk comprises an edge with a groove for sandwiching said instrument; or said self-aligning base comprises a symmetrical compliant supporting structure for applying lateral force to said first and second coded disks to sandwich said instrument.

14. The system of claim 10, wherein said concentric bellows comprises skeletons adapted to slide along a set of guiding rails within said shell.

15. The system of claim 10, wherein said medical imaging modalities comprises magnetic resonance imaging or computed tomography.

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