A robotic surgical system and needle insertion device

Abstract

Broadly speaking, the present techniques generally relate to a robotic surgical system. In particular, the present application provides a needle insertion device that is compatible with MRI and CT machines.

Description

[0001] A Robotic Surgical System and Needle Insertion Device

[0002] Field

[0003] The present application generally relates to a robotic surgical system. In particular, the present application provides a needle insertion device that is compatible with MRI and CT machines.

[0004] Background

[0005] MRI-guided intervention for the liver and kidney has achieved considerable progress in tumour diagnosis and treatment over the past two decades. However, due to the space constraints associated with the narrow and deep bore of the M Rl machines, it is still extremely challenging for clinicians to position and drive the needle-shaped probes used to deliver treatment where the targeted tumoral mass is located. MRI-compatible robotic systems have been investigated by several research teams worldwide, both in academia and industry, to overcome the challenges associated with the limited workspace inside the bore of MRI machines to enable the transition from CT-guided to MRI-guided intervention.

[0006] The applicant has therefore identified the need for an improved needle insertion device that can be used as part of a robotic surgical system in an MRI or CT machine.

[0007] Summary

[0008] In a first approach of the present techniques, there is provided a robotic surgical system comprising: a needle insertion device, comprising: a sliding rail; a first arch-shaped component provided on, and moveable along, the sliding rail; a first carriage coupled to, and moveable along, the first arch-shaped component; a second arch-shaped component provided on, and moveable along, the sliding rail, the second arch-shaped component being parallel to the first arch-shaped component; a second carriage coupled to, and moveable along, the second arch-shaped component; a needle holder coupled to the first and second carriages; and at least one control mechanism connected to the needle insertion device for controlling the movement of any one or more of the first arch-shaped component, second archshaped component, first carriage and second carriage to thereby drive movement of the needle holder with multiple degrees of freedom.

[0009] One end of each of the first and second arch-shaped components may be slidably- coupled to the sliding rail. The arch-shaped components may be mounted to a slider of the / each sliding rail.

[0010] The sliding rail may comprise a first sliding rail and a second sliding rail, arranged in parallel, and wherein a first end of each of the first and second arch-shaped components may be slidably-coupled to the first sliding rail, and a second end of each of the first and second arch-shaped components may be slidably-coupled to the second sliding rail.

[0011] The first arch-shaped component and second arch-shaped component may be independently moveable along the sliding rail.

[0012] Each of the first arch-shaped component and second arch-shaped component may comprise two parallel sub-arches that are coupled together.

[0013] The control mechanism may control the first and second arch-shaped components to move in unison along the sliding rail, thereby moving the needle holder along a longitudinal axis of the needle insertion device.

[0014] The needle holder may be indirectly coupled to the first and second carriages. The needle holder may be coupled to a connector, which may be an I-shaped (i.e. capital letter T or the Roman numeral for "1”) connector, an H-shaped connector, or similar. The connector may be connected to the first and second carriages. It will be understood that the connector may have any suitable shape and that the I-shape and H-shape are non-limiting. For example, the needle insertion device may further comprise: a first arm connected at one end to a first connection point on the connector and at another end to the first carriage, and a second arm connected at one end to a second connection point on the connector and at another end to the second carriage, wherein the first arm and second arm are offset from each other. As explained in more detail with respect to the Figures, the connector may be connected to the first arm via a first hinge or hinged connection, and to the second arm via a second hinge or hinged connection.

[0015] The first carriage may comprise a first pair of scissor mechanisms, and the first arm of the connecting component may be connected to the first pair of scissor mechanisms. The second carriage may comprise a second pair of scissor mechanisms, and the second arm of the connecting component may be connected to the second pair of scissor mechanisms. As noted below with reference to the Figures, each pair of scissor mechanisms may comprise sub-scissor mechanisms. That is, the first pair of scissor mechanisms may comprise a first and second sub-scissor mechanism, and the same for the second pair of scissor mechanisms.

[0016] Operating the first pair of scissor mechanisms may cause the first connection point on the connector to move in a transverse plane of the needle insertion device. Similarly, operating the second pair of scissor mechanisms may cause the second connection point on the connector to move in the transverse plane of the needle insertion device. Thus, movement of the pairs of scissor mechanisms causes movement of the needle holder via movement of the connector.

[0017] Moving the first pair of scissor mechanisms causes the first connection point on the connector to move along a longitudinal axis of the needle insertion device. The movement of the first pair of scissor mechanisms is caused by moving the first arch-shaped component. This thereby causes rotation of the connector about the first hinge. Similarly, moving the second pair of scissor mechanisms causes the second connection point on the connector to move along the longitudinal axis of the needle insertion device. This thereby causes rotation of the connector about the second hinge.

[0018] Moving the first carriage along the first arch-shaped component causes the first connection point on the connector to move in a transverse plane of the needle insertion device, and moving the second carriage along the second arch-shaped component causes the second connection point on the connector to move in the transverse plane of the needle insertion device.

[0019] The needle holder may be configured to hold a needle probe, a biopsy needle, or a needle-shaped instrument.

[0020] The needle insertion device may comprise a plurality of needle holders.

[0021] The or each needle holder may be any shape and type, such as J-shape, Y-shape, release-and-loadable, or un-release-and-load loadable needle holder. The needle holder may be connected to any position or location on the connector.

[0022] The at least one control mechanism drives movement of a needle in the needle holder into a phantom, or a human or animal body located within the needle insertion device.

[0023] The robotic surgical system may further comprise an imaging system for capturing an image or video of the needle holder, wherein the control mechanism processes the image or video captured by the imaging system to determine a position of a needle in the needle holder relative to the human or animal body.

[0024] The carriages may be driven by any one or more of: timing belt drive, gear drive, chain drive or mechanical transmission components. It will be understood that these are non- exhaustive example techniques for driving the carriages.

[0025] The at least one control mechanism may drive movement of the needle according to at least one movement constraint.

[0026] The at least one movement constraint may comprise one or both of: a patient-specific constraint that depends on the human or animal body located within the needle insertion device, and a pathology-dependent constraint.

[0027] The imaging system may be a computerised tomography imaging system or a magnetic resolution imaging system.

[0028] The at least one control mechanism may control the movement of a control mechanism connected to the needle insertion device for controlling the movement of any two or more of the first arch-shaped component, second arch-shaped component, first carriage and second carriage in an asynchronous manner or in a synchronous manner. The needle holder may be located between the first and second arch-shaped components.

[0029] Alternatively, the needle holder may be located on one side of the first and second archshaped components.

[0030] In a second approach of the present techniques, there is provided a needle insertion device comprising: a sliding rail; a first arch-shaped component provided on, and moveable along, the sliding rail; a first carriage coupled to, and moveable along, the first arch-shaped component; a second arch-shaped component provided on, and moveable along, the sliding rail, the second arch-shaped component being parallel to the first arch-shaped component; a second carriage coupled to, and moveable along, the second arch-shaped component; and a needle holder coupled to the first and second carriages; wherein movement of any one or more of the first arch-shaped component, second arch-shaped component, first carriage and second carriage drives movement of the needle holder with multiple degrees of freedom.

[0031] The features described above with respect to the first approach apply equally to the second approach and therefore, for the sake of conciseness, are not repeated.

[0032] Brief description of the drawings

[0033] Implementations of the present techniques will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0034] Figure 1A is a schematic diagram illustrating the top-down view of a needle insertion into the trunk of a patient in an MRI scanner;

[0035] Figure 1 B shows a perspective view of an MRI scanner;

[0036] Figure 2A is a perspective view of a needle insertion device for use in, for example, an MRI scanner bore;

[0037] Figure 2B is a zoomed-in view of the first arch-shaped component of Figure 2A;

[0038] Figure 2C is a zoomed-in view of the first carriage of Figure 2A;

[0039] Figure 2D is a zoomed-in view of a portion of the first carriage of Figure 2A;

[0040] Figure 2E is a zoomed-in view of a connected unit of the first carriage of Figure 2A;

[0041] Figure 2F shows a zoomed-in view of the needle holder of Figure 2A;

[0042] Figure 3 is a plan view of the first arch-shaped component and first carriage;

[0043] Figure 4A is a zoomed-in plan view of a portion of a carriage, and in particular, a portion which is connected to a timing belt;

[0044] Figure 4B is a perspective view of a portion of the portion of the carriage of Figure 4A;

[0045] Figure 5 is a close-up perspective view of the scissor mechanisms of the first carriage;

[0046] Figure 6A is a zoomed-in perspective view of the double-hinged connecting component and needle holder; Figure 6B is a zoomed-in side view of the double-hinged connecting component and needle holder using the arrangement of Figure 6A;

[0047] Figures 6C and 6D show the axes about which the needle 112 is able to rotate using the arrangement of Figure 6A;

[0048] Figure 6E is a schematic diagram showing how the double-hinged connecting component and needle holder of Figure 6A achieves needle rotation around the short axis;

[0049] Figure 6F is a schematic diagram showing how the double-hinged connecting component and needle holder of Figure 6A achieves needle rotation around the long axis;

[0050] Figure 6G is a zoomed-in perspective view of an alternative arrangement of the doublehinged connecting component and needle holder;

[0051] Figure 6H is a zoomed-in side view of the alternative arrangement;

[0052] Figure 6I is a schematic diagram showing how the alternative arrangement achieves needle rotation around the short axis;

[0053] Figure 6J is a schematic diagram showing how the alternative arrangement achieves needle rotation around the long axis;

[0054] Figures 7A to 7C are schematic diagrams showing how contraction and expansion of the scissor mechanisms cause movement of the needle holder;

[0055] Figure 8 is a schematic diagram showing how when the first and second carriages are offset from one another, the needle holder is caused to tilt or pivot in a plane;

[0056] Figure 9 is a schematic diagram showing how when the first and second carriages move in unison, in parallel and in the same direction, along the first and second arch-shaped components, the needle holder is caused to move in a plane perpendicular to the longitudinal axis of the needle insertion device;

[0057] Figures 10A to 10C show side views of the first and second arch-shaped components of the needle insertion device and illustrate how the movement of the first and second archshaped components causes movement of the needle holder;

[0058] Figures 11 A and 11 B show side views of the first and second arch-shaped components of the needle insertion device, and illustrate how the movement of the first and second archshaped components causes movement of the needle holder;

[0059] Figures 12A to 12C show side views of the first and second arch-shaped components of an alternative arrangement of the needle insertion device and illustrate how the movement of the first and second arch-shaped components causes movement of the needle holder;

[0060] Figures 13A and 13B show side views of the first and second arch-shaped components of the alternative arrangement of the needle insertion device, and illustrate how movement of the first and second arch-shaped components causes movement of the needle holder; Figure 14 is a side view of an arch-shaped component showing an arrangement of the timing belt; and

[0061] Figure 15 is a diagram which illustrates the movement of the carriages.

[0062] Detailed description of the drawings

[0063] Broadly speaking, the present techniques generally relate to a robotic surgical system. In particular, the present application provides a needle insertion device that is compatible with MRI and CT machines.

[0064] Figure 1A is a schematic diagram illustrating the top-down view of a needle insertion into the trunk of a patient in an MRI scanner. Diagnostic imaging techniques, such as computed tomography (CT), ultrasound and magnetic resonance imaging (MRI) scanning are highly effective imaging methods for imaging tissue and for diagnosing diseases, especially MRI in soft tissue, such as cancer in the liver and kidneys. The insertion of needles guided by imaging techniques is a promising way of providing greater precision and accuracy for clinicians in diagnosing and treating soft tissue cancers. For example, ultrasound machines are often used for performing guided biopsies which involve the insertion of a needle for the diagnosis of cancers in soft tissue organs residing close to the surface of the skin.

[0065] However, in the case of needle insertion guided by an MRI scanner for soft tissue situated deeper within the human body, the situation is more complex. Whilst a powerful and safe imaging technique, the environment within and surrounding an MRI scanner presents unique challenges. The magnetic field of the MRI scanner makes needle insertion techniques using conventional electronics unviable. Furthermore, the in-situ insertion of needles within the bore of the MRI scanner itself is difficult because of the geometric constraints of the bore. A typical MRI scanner has an inner cylindrical bore with a diameter of 60 cm - 70 cm which the patient occupies for the duration of the scan. This means that, during the scan, there is a confined space between the skin of the patient and the inner wall of the MRI bore. Typically, the Skin-to-Wall distance is 20 cm - 25 cm. Moreover, the patient is positioned beyond the reach of clinicians within the MRI bore. Consequently, it is extremely difficult for clinicians to perform needle insertion manually.

[0066] Notwithstanding the challenges posed by the geometric constraints of the MRI bore, the positioning and extent of soft tissue organs such as the liver and kidneys present challenges for effective needle insertion. For example, the positioning and size of the human liver means that a tumour within the liver can, in principle, be positioned in a depth range of 50 mm - 150 mm below the surface of the skin. Furthermore, the variation in the Skin-to-Wall distance means that needle insertion perpendicular to the skin surface is not always possible for needles with the required depth range. Therefore, it is critical that any needle inserted has a range of insertion angles to provide maximum depth coverage across the entire volume of a given soft tissue organ.

[0067] Therefore, there are several criteria that a needle insertion device for use in an MRI scanner must satisfy to be clinically effective for soft tissue organs positioned deep below the skin surface. Firstly, the device must be suitable for use in the environment of the strong magnetic field of the MRI scanner. Secondly, the device must be suitable for needle insertions in a large depth range. Thirdly, the device must provide a range of insertion angles with respect to the skin surface.

[0068] Figure 2A is a perspective view of a needle insertion device 100 for use in, for example, an MRI scanner bore. The needle insertion device 100 comprises a sliding rail. In some cases, there may be a single sliding rail. In other cases, there may be two sliding rails, which may be arranged to be substantially parallel to each other. The or each sliding rail may comprise a guided rail (wall), a slider, and a lead screw. Figure 2 shows an example needle insertion device having two sliding rails 124A, 124B. In use, the sliding rail(s) may be arranged to be parallel to a longitudinal axis of the bore of the MRI scanner. The needle insertion device 100 comprises a first arch-shaped component 102 provided on, and moveable along, the sliding rails 124A, 124B. The needle insertion device 100 comprises a first carriage 106 coupled to, and moveable along, the first arch-shaped component 102. The needle insertion device 100 comprises a second arch-shaped component 104 provided on, and moveable along, the sliding rails 124A, 124B, the second arch-shaped component 104 being parallel to the first arch-shaped component 102. The needle insertion device 100 comprises a second carriage 108 coupled to, and moveable along, the second arch-shaped component 104. The arch shape of the arch-shaped components 102, 104 makes the needle insertion device 100 suitable for positioning and use inside the bore of an MRI scanner. The arch-shaped components may be mounted on the slider of the sliding rails 124A, 124B.

[0069] The needle insertion device 100 comprises a needle holder 110 coupled to the first and second carriages 106, 108. In Figure 2A, a needle 112 is shown as being held in the needle holder 110. The needle holder 110 may be configured to hold a needle probe or a biopsy needle. In some cases, the needle insertion device 100 may comprise a plurality of needle holders (not shown here).

[0070] The needle insertion device 100 is part of a robotic surgical system (not shown in Figure 2A). The robotic surgical system comprises at least one control mechanism that is connected to the needle insertion device 100 for controlling the movement of any one or more of the first arch-shaped component 102, second arch-shaped component 104, first carriage 106 and second carriage 108 to thereby drive movement of the needle holder 110 with multiple degrees of freedom. In some cases, one control mechanism may be used to drive movement of the arch-shaped components along the sliding rail(s), and another control mechanism may be used to drive movement of the carriages (and the scissor mechanisms thereof, described below).

[0071] As noted above, the first arch-shaped component 102 and second arch-shaped component 104 are movable along the sliding rail or sliding rails. There are two ways to move the arch-shaped components and thereby control the movement and position of the needle holder 110.

[0072] Firstly, the control mechanism may control the first and second arch-shaped components 102, 104 to move in unison along the sliding rail(s), thereby moving the needle holder 110 along a longitudinal axis of the needle insertion device 100. This enables the needle holder 110 to be moved along a length of a patient so that the needle holder is positioned in the vicinity of an area of interest of the patient. That is, movement of the first and second arch-shaped components in unison along the sliding rail(s) drives movement of the needle holder 110 along an axis parallel to the sliding rail and, in use, along a longitudinal axis of the bore of the MRI scanner.

[0073] Secondly, the control mechanism may control the first arch-shaped component 102 and second arch-shaped component 104 to move independently along the sliding rail(s). As explained in more detail below, the movement of one of the arch-shaped components towards or further away from the other of the arch-shaped components (which may be static or moving), causes the needle 112 to pivot such that needle 112 points towards one or other of the arch-shaped components. The way in which the carriages 106, 108 are coupled to the needle holder enable the needle 112 to pivot when the arch-shaped components are moved independently. This is explained in more detail below with respect to Figures 1 B, 2F and 11A and 11 B. Generally speaking, one end of each of the first and second arch-shaped components 102, 104 may be slidably-coupled to the sliding rail. In an alternative arrangement, as shown in Figure 2, the sliding rail 124 may comprise a first sliding rail 124A and a second sliding rail 124B, arranged in parallel. In this arrangement, a first end of each of the first and second arch-shaped components 102, 104 may be slidably-coupled to the first sliding rail 124A, and a second end of each of the first and second arch-shaped components may be slidably-coupled to the second sliding rail 124B.

[0074] Figure 2B is a zoomed-in view of the first arch-shaped component 102 of Figure 2A. It can be seen from Figures 2A and 2B that each of the first arch-shaped component 102 and second arch-shaped component 104 may comprise two parallel sub-arches that are coupled together. Specifically, the first arch-shaped component 102 may be formed of a first sub-arch 102A and a second sub-arch 102B, and the second arch-shaped component 104 may be formed of a first sub-arch 104A and a second sub-arch 104B. In some cases, the number of sub-arches may be more than two. The sub-arches provide more stability to each archshaped component. The sub-arches also provide more stability to the carriages 106, 108 which are provided on each arch-shaped component. The sub-arches of each arch-shaped component may be fixedly coupled together, in order to provide stability to the arch-shaped component. Any suitable mechanism may be used to fixedly couple together the sub-arches. Since the sub-arches of each arch-shaped component are fixedly coupled together, when the control mechanism is used to move an arch-shaped component, individual movement of a single sub-arch is not possible.

[0075] The first and second arch-shaped components 102, 104 form a track or rail for the carriages 106, 108 to move along. Figure 2B shows that each sub-arch of the arch-shaped component is actually formed of two arches, which together form a rail for one of the carriages. Specifically, as shown in Figure 2B, the arch-shaped component 102 comprises the first subarch 102A and the second sub-arch 102B, where the first sub-arch 102A is formed of two arches 102A-1 , 102A-2 which together form a rail or track for carriage 106, and where the second sub-arch 102B is formed of two arches 102B-1 , 102B-2 which together form a rail or track for carriage 106. The second arch-shaped component 104 has a similar construction, as shown in Figure 2A. Each arch of the sub-arches may be fixedly coupled together so that they form a sturdy track / rai I for the carriages. Any suitable mechanism may be used to fixedly couple together the arches of the sub-arches. For example, a grooved bracket 118 may be slidably coupled to each sliding rail 124A, 124B to receive each of the arches 102A-1 , 102A- 2, 102B-1 , 102B-2 of the sub-arches 102A and 102B. At least one connecting rod, screw or bolt through a hole on each arch may be used to connect the arches 102A-1 and 102A-2, and arches 102B-1 and 102B-2, to the grooved bracket 118 . As mentioned above, the sub-arches themselves may be fixedly coupled together so that the control mechanism moves the subarches together when an arch-shaped component is moved. The control mechanism may be coupled to a plurality of rail motors 116, which drive any one or more of the first arch-shaped component 102, second arch-shaped component 104. The control mechanism may further be coupled to a plurality of motors 122, which drive any one or more of the first carriage 106 and second carriage 108 via a pair of drive shafts 202. The action of the rail motors 116 in combination with the motors 122 may drive movement of the needle holder 110 with multiple degrees of freedom. Figure 2B shows one rail motor 116 and one pair of motors 122 coupled to the first arch-shaped component 102. Other motors can be seen in Figure 2A.

[0076] As mentioned above, the needle insertion device 100 comprises a needle holder 110 coupled to the first and second carriages 106, 108. The function and movement of the carriages 106, 108 are now described. As noted above, the first carriage 106 is coupled to the first arch-shaped component 102, and the second carriage is coupled to the second arch-shaped component 104. Generally speaking, the first carriage 106 may be coupled to each sub-arch (if any) of the first arch-shaped component 102, and the second carriage may be coupled to each sub-arch (if any) of the second arch-shaped component 104. In other words, it will be understood that whether each arch-shaped component is formed of a single arch, or multiple sub-arches, that the carriages are coupled to the whole of their respective arch-shaped component.

[0077] Figure 2C is a zoomed-in view of the first carriage 106 of Figure 2A. In the version shown in Figures 2A and 2C, the first carriage 106 is coupled to the two sub-arches 102A,B of the first arch-shaped component 102, and the second carriage 108 is coupled to the two subarches 104A,B of the second arch-shaped component 104. Each carriage 106, 108 is formed of two sub-carriages, where each sub-carriage is coupled together and is coupled to one of the sub-arches. Specifically, in the arrangement shown in Figures 2A and 2C, the first carriage 106 is formed of a first sub-carriage 106A and a second sub-carriage 106B. The first subcarriage 106A is movably coupled to the first sub-arch 102A, the second sub-carriage 106B is movably coupled to the second sub-arch 102B, and the first sub-carriage 106A is fixedly coupled to the second sub-carriage 106B by, for example, a connecting bar 114 (explained below). Similarly, the second sub-carriage is movably coupled to the first sub-arch 104A, the second sub-carriage is movably coupled to the second sub-arch 104B, and the first subcarriage is fixedly coupled to the second sub-carriage by, for example, the connecting bar 114.

[0078] As noted above, the control mechanism controls the movement of one or both of the first carriage 106 and second carriage 108 to thereby drive movement of the needle holder 110 with multiple degrees of freedom. Referring to the first carriage 106, the first sub-carriage 106A and second sub-carriage 106B are fixedly coupled together via a connecting means. For example, at least one connecting bar 114 may be used to fixedly couple together the first sub-carriage 106A and the second sub-carriage 106B. In the example shown in Figure 2C, two connecting bars 114 are used to couple together the sub-carriage 106A, B. (In some cases, each connecting bar 114 may itself be formed of two or more shorter bars that are fixedly connected together to create the connecting bar 114 of the desired length). Similarly, the first sub-carriage and second sub-carriage of carriage 108 are fixedly coupled together via a connecting means. In the example shown in Figure 2A, two connecting bars 114 are used to couple together the sub-carriages of carriage 108. Since the sub-carriages of each carriage are fixedly coupled together, when the control mechanism is used to drive movement of a carriage, individual movement of a single sub-carriage is not possible.

[0079] As shown in Figure 2C, the first sub-carriage 106A comprises two portions that are coupled to the sub-arch 102A but are not directly coupled to each other, and the second sub- carriage 106B comprises two portions that are coupled to the sub-arch 102B but are not directly coupled to each other. This means that the two portions of each sub-carriage are moveable relative to each other on their respective sub-arch. In other words, the two portions of a sub-carriage may be moved towards each other or further apart along the sub-arch to which they are coupled. The two portions of a sub-carriage may be moved at the same or different speeds. An advantage of this ability to move the portions of a sub-carriage relative to each other is explained below.

[0080] One connecting bar 114 connects together one portion of the first sub-carriage 106A and one portion of the second sub-carriage 106B, such that these portions form a connected unit 106C of carriage 106. Another connecting bar 114 connects together another portion of the first sub-carriage 106A and another portion of the second sub-carriage 106B, such that these portions form a connected unit 106D of carriage 106. Connected units 106C and 106D are shown via the dashed boxes in Figure 2C. It will be understood that the portions within each connected unit 106C, 106D are rigidly connected together and therefore cannot move relative to each other. It will also be understood that the connected units 106C and 106D are able to move relative to each other. An advantage of doing so is explained below.

[0081] Figure 2D is a zoomed-in view of a portion of the first carriage 106 of Figure 2A. Specifically, Figure 2D shows a zoomed-in view of the first sub-carriage 106A. It can be seen that the first sub-carriage 106A is moveably coupled to the arches 102A-1 , 102A-2 which form sub-arch 102A of the first arch-shaped component 102. As mentioned above, each sub-arch forms a track or rails for the carriages to move along. It can be seen in Figure 2D that the carriages comprise a plurality of wheels 120, which engage with the track / rails provided by the sub-arches. Here, the wheels 120 of sub-carriage 102A are engaged with (i.e. provided on) the arches 102A-1 , 102A-2 of sub-arch 102A. In this way, the carriage 106, when driven by the control mechanism, is able to slide or travel along the sub-arches.

[0082] Figure 2E is a zoomed-in view of a portion of the first carriage 106 of Figure 2A. Specifically, Figure 2E shows a zoomed-in view of a portion of the first sub-carriage 106A and a portion of the second sub-carriage 106B. It can be seen that the first sub-carriage 106A is moveably coupled to the arches 102A-1 , 102A-2 which form the first sub-arch 102 A of the first arch-shaped component 102. It can also be seen that the second sub-carriage 106B is movably coupled to the arches 102B-1 , 102B-2 which form the second sub-arch 102B of the first arch-shaped component 102.

[0083] As mentioned above, each sub-arch forms a track or rails for the carriages to move along. It can be seen in Figure 2E that the wheels 120 of sub-carriage 102A are engaged with (i.e. provided on) the arches 102A-1 , 102A-2 of sub-arch 102A, and the wheels 120 of subcarriage 102B are engaged with (i.e. provided on) the arches 102B-1 , 102B-2 of sub-arch 102B. In this way, the carriage 106, when driven by the control mechanism, is able to slide or travel along the sub-arches.

[0084] Figure 2A shows the needle holder 110 coupled to the first carriage 106 and second carriage 108. This is now described in more detail with reference to Figure 2F. Figure 2F shows a zoomed-in view of the needle holder 110 of Figure 2A. The needle insertion device 100 comprises a connector 148, to which the needle holder 110 is connected. The needle holder may be coupled to a connector, which may be an I-shaped (i.e. capital letter T or the Roman numeral for "1”) connector, an H-shaped connector, or similar. The connector may be connected to the first and second carriages. It will be understood that the connector may have any suitable shape and that the I-shape and H-shape are non-limiting. The needle insertion device 100 comprises a first arm 140 connected at one end to a first connection point on the connector 148 and at another end to the first carriage 106. The needle insertion device 100 comprises a second arm 142 connected at one end to a second connection point on the connector 148 and at another end to the second carriage 108.

[0085] The connector 148 is connected to the first arm 140 via hinge 144, and to the second arm 142 via hinge 146. The connector 148 may be I-shaped, as shown in Figure 2F, where the I-shaped connector 148 forms / comprises hinges 144 and 146. Specifically, one end of the I-shaped connector 148 forms hinge 144, and another end of the I-shaped connector 148 forms hinge 146. As shown in Figures 2A and 2F, the first arm 140 and second arm 142 are offset from each other. In this way, the first arm 140 and second arm 142 are connected at different points along a length of the needle holder 110. Movement of the first and second arms 140, 142 causes the needle holder to tilt towards one of the arch-shaped components, as indicated by dashed arrow A. That is, movement of the first and second arms 140, 142 causes movement of the connector 148 about hinges 144 and 146, respectively, which thereby causes movement of the needle holder.

[0086] Movement by the first arm 140 causes the connector 148 to rotate about hinge 144, and movement by the second arm 142 causes the connector 148 to rotate about hinge 146. For example, referring to Figure 2F, if the first arch-shaped component 102 were moved further away from the second arch-shaped component 104, the connected units 106C and 106D would move closer together. The first carriage 106 would cause a force to be applied to the needle holder, via the first arm 140, which would pull the top of the needle holder and change the location of the needle holder in the vertical direction (where the first arm 140 is connected to the needle holder) towards the first carriage, which would thereby cause the needle 112 to tilt towards the second carriage 108. Similarly, if the first arch-shaped component 102 were moved towards the second carriage, the connected units 106C and 106D would move further apart. The first carriage 106 would cause a force to be applied to the needle holder, via the first arm 140, which would push the top of the needle holder down (where the first arm 140 is connected to the needle holder) towards the second carriage, which would thereby cause the needle 112 to tilt towards the first carriage 106.

[0087] In this way, movement of one or both of the first and second arch-shaped components 102, 104 along the sliding rail(s), and first and second carriages (and in particular, the connected units 106C and 106D) causes the tilting of the needle holder 110 (and needle 112 therein). In other words, the needle holder may pivot in a plane which contains the endpoints of the first arm 140 and second arm 142, and the rotation axis would be the centre line of the first arm 140 or second arm 142, or the axis which is parallel to them.

[0088] The position of each carriage 106, 108 (and therefore the connected units 106C, 106D) along the respective arch-shaped components 102, 104 will be referred to herein as an azimuthal position. That is, the angular position of a carriage with respect to the corresponding arch-shaped component is the azimuthal position of the carriage. As such, there may be an azimuthal offset between the first and second carriages 106, 108. The azimuthal offset quantifies a difference between the azimuthal position of the first carriage 106 along the first arch-shaped component 102 and the azimuthal position of the second carriage 108 along the second arch-shaped component 104. The first and second carriages may be azimuthally aligned when their azimuthal positions are the same.

[0089] If the first carriage 106 is moved so that it is offset from the second carriage 108 (i.e. so there is an azimuthal offset), such that the carriages 106, 108 are not aligned on their respective arch-shaped components (which may be achieved by the corresponding scissor mechanisms being contracted or expanded, and the corresponding arch-component moving along the sliding rail(s)), the needle holder 110 is caused to tilt or pivot around the longitudinal axis direction of the needle insertion device, as indicated by dotted arrow B. For example, referring to Figure 2F, if the first carriage 106 were moved along the first arch-shaped component 102 in one direction such that the first carriage 106 is offset from the second carriage 108, (which may be achieved by the corresponding scissor mechanisms being contracted or expanded, and the corresponding arch-component moving along the sliding rail(s)), the first carriage 106 would cause a force to be applied to the needle holder, via the first arm 140, which would pull the top of the needle holder (where the first arm 140 is connected to the needle holder) in the same direction. In turn, the needle holder would rotate, tilt or pivot in around the longitudinal axis of the needle insertion device. Similarly, if the first carriage 106 were moved along the first arch-shaped component 102 in the opposite direction such that the first carriage 106 is offset from the second carriage 108, in the meanwhile, the corresponding scissor mechanisms need to be contracted or expanded, and the corresponding arch-component may move along the sling rail(s), the first carriage 106 would cause a force to be applied to the needle holder, via the first arm 140, which would pull the top of the needle holder (where the first arm 140 is connected to the needle holder) in the same direction. In turn, the needle holder would rotate, tilt or pivot in around the longitudinal axis direction of the needle insertion device. In this way, movement of one or both of the carriages 106, 108 (also scissor mechanism) along their respective arch-shaped components 102, 104, and corresponding arch-shaped components cause the tilting of the needle holder 110 (and needle 112 therein).

[0090] In other words, in order to tilt the needle in the manner shown in Figures 11 A and 11 B, the first carriage, second carriage, or both the first and second carriages need to be moved together with the first arch-shaped component, second arch-shaped component, or both first and second arch-shaped components. This tilting along a longitudinal axis of the needle insertion device is also shown in Figure 2F. This means that the carriages and arch-shaped component may need to be moved together to achieve tilting.

[0091] If the needle holder begins in a vertical position in a reference or starting position, the tilting movement requires connected units 106C and 106D (shown in Figure 2C) to be close together, and arch-shaped components to move along the sliding rail(s).

[0092] If the needle holder needs to rotate from the position in Figure 11A to the position in Figure 11 B, the first arch-shaped component needs to move to the right. Simultaneously, the two sub-carriages of the first arch-shaped component slide apart along the arch-shaped component, causing the end of the scissor mechanism to move upward. If the two subcarriages slide closer together, the end position of the scissor structure is caused to descend. The rotation axis of this tilt as shown in Figure 11 would be the centre line of the hinge 144 or hinge 146 or the axis which is parallel to them.

[0093] The first and second carriages 106, 108 are preferably driven independently along their respective arch-shaped components. The carriages may be driven by a system of timing belts in each arch-shaped component, wherein the timing belts are driven by motors 122 positioned at a base of each arch-shaped component (see Figure 2B). The timing belts may comprise a plurality of indentations or teeth enabling their coupling to the drive shafts 202. The rail motors 116 and motors 122 may be any combination of ultrasonic, piezoelectric, pneumatic, hydraulic or cable-driven motors, or any other combination of MRI-compatible motors. It can be seen from Figures 2A and 2F that the first and second arms 140, 142 of the double-hinged connecting component are coupled to the first and second carriages, respectively, via other components. These other components, and their function, are now described.

[0094] Figure 14 is a side view of an arch-shaped component showing an arrangement of the timing belt 200. As depicted in the diagram at the top of Figure 14, there are some holes 1400 on each sub-arch. The line connecting the centres of the upper and lower holes is aligned with the radius direction of each sub-arch . Those holes are used for mounting a plurality of timing belt support components 1402. The timing belt support components 1402 need to be distributed on each sub-arch. Excessive placement increases friction during the operation of the timing belt, thereby increasing the required drive torque to the motor 122. Conversely, insufficient placement can cause the timing belt 200 to fall below the lower edge of the arcshaped component, leading to interference with other components and affecting the robot's motion during its operation. Example installation positions are shown in Figure 14, but this arrangement is not limiting. While an even distribution is preferable, a non-uniform distribution is also acceptable. However, it is crucial to ensure that the timing belt does not fall below the lower edge of the arch-shaped component.

[0095] In the middle diagram in Figure 14, a portion of a single timing belt is shown on each sub-arch, as well as the timing belt support components 1402. The timing belt support components 1402 is shown in more detail in the lower diagram in Figure 14, and each timing belt support components 1402 comprises a bearing 1404, a roller 1406 and two bearing supports. The timing belt support components 1402 are mounted between arches.

[0096] The top and middle diagrams in Figure 14 illustrate the winding method. One end of the timing belt connects to the wheels connecting bar 114 on the carriage, while the other end connects to the tension adjustment part 204 on the drive carriage. The timing belt needs to be sequentially placed on the bearings 1404 of the timing belt support components and then wound around the shaft 202 of first motor 122. After that, the timing belt needs to pass through the gaps between the bearings 1404 and the rollers 1406, reaching the shaft of the second motor, and then once again sequentially placed on the bearings 1404 of the timing belt support components 1406. Overall, the tooth surface of the timing belt will always touch the bearing 1404, while the smooth surface of the timing belt will always touch the roller 1406.

[0097] This arrangement method saves space and avoids interference with the space below the arch-shaped component. Patients can lie beneath the arch-shaped component. Additionally, the timing belt support components ensure the distance between the two arches 102B-1 and 102B-2. This dual-purpose feature not only supports the timing belt but also ensures the distance between the two arches 102B-1 and 102B-2, thereby improving the stability of arch-shaped components.

[0098] The first carriage 106 comprises a first scissor mechanism 130 and a second scissor mechanism 132. The first scissor mechanism 130 is coupled to the second scissor mechanism 130 via connecting bars 114. Specifically, since the connecting bars are provided in each connected unit 106C and 106D, the first scissor mechanism 130 is coupled to the second scissor mechanism via connected units 106C, 106D. The first scissor mechanism 130 is also coupled to the second scissor mechanism 132 via a first scissor connecting bar 150. However, the first scissor connecting bar 150 is not rotatably connected to the first and second scissor mechanisms. The second scissor mechanism 132 is also connected to the first arm 140 of the double-hinged connecting component. The first arm 140 is rotatably connected to the second scissor mechanisms 132, such that the first arm is able to rotate. The first arm 140 may also be aligned with the first scissor connecting bar 150. As will be explained in more detail below, the connected units 106C, 106D may be moved closer together or further apart along the first arch-shaped component 102 to enable the scissor mechanisms 130 and 132 to be expanded or contracted. Since the second scissor mechanism 132 is also connected to the first arm 140 of the double-hinged connecting component, moving the connected units 106C, 106D closer together forces the first arm 140 to be displaced away from the first carriage 106.

[0099] The second carriage 108 comprises a first scissor mechanism 134 and a second scissor mechanism 136. The first scissor mechanism 134 is coupled to the second scissor mechanism 136 via connecting bars 114. The first scissor mechanism 134 may also be coupled to the second scissor mechanism 136 via a second scissor connecting bar 152. The first scissor mechanism 134 is connected to the second arm 142 of the double-hinged connecting component. The second arm 142 is rotatably connected to the first 134, such that the second arm is able to rotate. The connected units of the second carriage 108 may be moved closer together or further apart along the second arch-shaped component 104 to enable the scissor mechanisms 134 and 136 to be contracted or expanded. Since the scissor mechanisms are also connected to the second arm 142 of the double-hinged connecting component, moving the connected units of the second carriage 108 closer together forces the second arm 142 to be displaced away from the second carriage 108.

[0100] When all four scissor mechanisms 130 to 136 are operated together in the same way (contracted or expanded), the needle holder moves in a transverse plane of the needle insertion device. For example, if the four scissor mechanisms are operated such that the connected units of each carriage 106, 108 are brought closer together, the needle holder moves in one direction in a transverse plane of the needle insertion device. Similarly, if the four scissor mechanisms are operated such that the connected units of each carriage 106, 108 are moved further apart, the needle holder moves in an opposite direction in a transverse plane of the needle insertion device. This enables the needle holder to be moved in and out of a patient body, during use of the needle insertion device.

[0101] The mechanisms for moving the needle holder 110 are now summarised. The control mechanism may control: 1. the first and second arch-shaped components 102, 104 to move in unison, in the same direction, along the sliding rail(s) 124, thereby moving the needle holder 110 along a longitudinal axis of the needle insertion device 100; and / or

[0102] 2. the first and / or second arch-shaped components 102, 104 to move away from each other (or closer together), (while the scissor mechanism 130, 132 and 134,136 that us coupled to the corresponding arch-shaped components contract or expand), thereby causing one end of the needle holder to tilt towards one of the arch-shaped components (or both, in the alternative arrangement described below); and / or

[0103] 3. the first and second carriages 106, 108 to move in unison, in parallel and in the same direction, along the first and second arch-shaped components 102, 104, respectively, thereby causing the needle holder to move in a plane perpendicular to the longitudinal axis of the needle insertion device 100; and / or

[0104] 4. the first and / or second carriages 106, 108 to be offset from one another, thereby causing the needle holder to tilt or pivot around a longitudinal axis of the needle insertion device 100; and / or

[0105] 5. four scissor mechanisms 130 to 136 for fine control of the needle holder, to move the needle into and out of a patient.

[0106] It will be appreciated that any of the movement mechanisms 1 - 5 above may be combined in any way to achieve more complex movement trajectories in order to meet the requirements of surgical procedures.

[0107] Turning briefly to Figure 1 B, this shows a perspective view of an MRI scanner 10. The MRI scanner 10 comprises a bore 12, in which a patient lies during the scanning process, and a scanning bed 14, on which the patient lies. One way to understand the movement of various elements of the needle insertion device 100 is now explained. As shown in Figure 1 B, two directions are useful for understanding the movement of various elements: a long-axis direction and a short-axis direction. It will be understood there are countless long axes in the long-axis direction and countless short axes in the short-axis direction.

[0108] The needle holder can be moved / rotated about a rotation axis so that the needle 112 pivots towards one or other of the arch-shaped components. The rotation axis is in the shortaxis direction but is not a specific fixed axis, because the relevant rotation axis depends on the location of the carriages 106, 108 on the arch-shaped components.

[0109] In the example shown in Figure 8, when the first and second carriages do not move with an offset , the rotation axis is in the long-axis direction but not a specific axis, because the relevant rotation axis depends on the current location of the carriages 106, 108.

[0110] In the example shown in Figure 9, when the first and second carriages move without an offset , the rotation axis is the centre line of the MRI scanning bore (indicated in Figure 1 B). If there is no rotation in the short-axis direction, the needle holder moves in a transverse plane. However, if there is a rotation along the short-axis direction, the needle holder moves in a 2D plane having a conical surface shape.

[0111] For translational motion, the needle holder may be manipulated to move along the long axis, short axis, and vertical direction (indicated in Figure 1 B). For movement along the long- axis direction, the first and second arch-shaped components move together along the sliding rail. For movement along the short-axis direction, the first and second carriages may move together along the arch in the same direction. Meanwhile, the connected units, such as 106C, 106D / 108C, 108D, move close or far away (106C and 106D are a pair), and the speed may differ. For movement along the vertical-axis direction, the connected units, such as 106C, 106D / 108C, 108D (106C and 106D are a pair), move close or far away, and the speed may differ. Meanwhile, the first and second carriages may slide along the arch, but the direction may be the same or differ.

[0112] There is a special case where movement occurs along the radial direction of the arc radius of the arch-shaped components. In this case, connected units, 106C and 106D move close or far away to each other, meanwhile, 108C and 108D move close or far away to each other. The movement of 106C, 106D, and 108C, 108D is synchronized, implying a simultaneous approach or separation, possibly at the same or different speeds.

[0113] Generally speaking, a synchronous movement of a first and second component of the needle insertion device is defined herein as one which maintains the relative displacement in the direction of movement between the first and second components. For example, a synchronous movement of the two carriages along the arch-shaped components is one which maintains an azimuthal offset between the first and second carriages (where the offset may be 0). Conversely, an asynchronous movement of the two carriages is one which changes their azimuthal offset. The same definitions apply to synchronous and asynchronous movements of other components of the needle insertion device, such as the scissor mechanisms described below.

[0114] The two carriages 106, 108 enable movement of the needle holder in two ways, as described above. The direction of movement of the needle holder depends on how the two carriages move along the arch-shaped components with respect to one another. Firstly, synchronous movement of the two carriages along the arch-shaped components, which maintains their azimuthal offset, enables movement of the needle holder in a plane perpendicular to the longitudinal axis of the needle insertion device. It will be appreciated that the orientation of the needle holder may be parallel to the plane perpendicular to the longitudinal axis of the device or oriented at an angle with respect to the perpendicular plane. Secondly, asynchronous movement of the two carriages along the arch-shaped components, which changes their azimuthal offset, enables rotation of the needle holder about the longitudinal axis of the device. In the meanwhile, the corresponding scissor mechanisms would also expand or contract. Rotation about the longitudinal axis will be referred to as azimuthal rotation herein. Therefore, synchronous and / or asynchronous movement of the two carriages enables translational movement of the needle holder in the plane perpendicular to the longitudinal axis or conical surface and / or azimuthal rotation of the needle holder.

[0115] Figure 3 is a plan view of the first arch-shaped component 102 and first carriage 106. As mentioned above, each arch-shaped component may comprise two sub-arches (here 102A, 102B). Each sub-arch 102A, 102B may comprise a timing belt 200 and a pair of drive shafts 202 positioned at each end of the arch-shaped component 102. As noted above, the drive shafts 202 may be driven by the plurality of motors 122 (not shown in Figure 3). That is, the first sub-arch 102A may comprise a first timing belt and a first pair of drive shafts, and the second sub-arch 102B may comprise a second timing belt and a second pair of drive shafts.

[0116] As explained above, the connected units 106C and 106D may be driven together. In connected unit 106D, there may be a first drive carriage 106D-1 connected to the first timing belt of the first sub-arch 102A and a driven carriage connected to the second sub-arch 102B. The first drive carriage may be connected to the timing belt via a first tension adjustment mechanism. In connected unit 106C, there may be a second drive carriage 106C-1 connected to the second timing belt of the second sub-arch 102B and a driven carriage connected to the first sub-arch. The second drive carriage may be connected to the timing belt via a tension adjustment mechanism which comprises the same features as the first tension adjustment mechanism. Consequently, the movement of the carriages is enabled by the connection of the first and second drive carriages with the timing belt 200 via the tension adjustment mechanisms. The driven carriage may not be connected to the timing belt. In other words, in each connected unit, the portion of the first sub-carriage which is in that connected unit may be connected to the first timing belt (and is therefore, the drive carriage), and the portion of the second sub-carriage which is in that connected unit may not be connected to the timing belt (and is therefore, the driven carriage). A single connection between each connected unit and a timing belt is sufficient to drive movement of the connected unit.

[0117] Movement of the first and second connected units 106C, 106D, which changes the relative displacement between the carriages, enables contraction and / or expansion of the corresponding scissor mechanisms. When the relative displacement decreases, the first 106D-1 and second 106C-1 drive carriages are driven towards each other along the subarches by the first timing belt in the first sub-arch and the second timing belt in the second sub-arch rotating towards each other. This may be achieved by operating the plurality of motors 122 in a forward direction, and the scissor mechanism expands. When the relative displacement increases, the first 106D-1 and second 106C-1 drive carriages are driven away from each other along the sub-arches by the first timing belt in the first sub-arch and the second timing belt in the second sub-arch rotating away from each other and the scissor mechanism contracts. That is, expansion and / or contraction of the scissor mechanism is enabled by changing the relative displacement of the first and second connected units via the connection between the drive carriages and the corresponding timing belts in each sub-arch.

[0118] Figure 15 is a diagram which illustrates the movement of the carriages. As shown in Figure 3, in order to open / expand the scissor mechanisms, two things need to happen: (1) the active / drive carriage of 106D needs to slide to the right and (2) the active / drive carriage of 106C needs to slide to the left. From the perspective of the shaft of the motor (Figure 15), motors 1.1 and 1.2 pull the timing belt and need to rotate clockwise (move forward) simultaneously. Similarly, motors 2.1 and 2.2 pull the timing belt and need to rotate clockwise (move forward) simultaneously. Thus, all our motors rotate in the same direction (clockwise). The situation is similar when closing / contracting the scissor mechanisms, except then the motors rotate in the opposite direction (anti-clockwise). It will be understood that motors 1.1 , 1.2, 2.1 and 2.2 are the same as motors 122 described earlier.

[0119] Figure 4A is a zoomed-in plan view of a portion of a carriage 106, 108, and in particular, a portion which is connected to a timing belt and functions as a driver of each connected unit (e.g. connected unit 106C or 106D). Figure 4B is a perspective view of a portion of the portion of the carriage of Figure 4A. The drive carriage enables movement of the corresponding connected unit along the arch-shaped component. As mentioned above, the carriages may comprise a plurality of wheels which make contact with the arch-shaped components. As shown in Figure 4B, each portion of a carriage may comprise an upper set of wheels, which make contact with an upper portion of an arch-shaped component, and a lower set of wheels, which make contact with a lower portion of the arch-shaped component. As mentioned above, the drive carriage may comprise a first tension adjustment mechanism 204, wherein the drive carriage is connected to the corresponding timing belt via the first tension adjustment mechanism 204. The tension between the drive carriage and the corresponding driving belt may be adjusted by, for example, rotating a screw or bolt 206 in the tension adjustment mechanism. The drive carriage may comprise a second tension adjustment mechanism 208 The second tension adjustment mechanism enables the adjustment of the contact force between the upper and lower sets of wheels and the upper and lower portions of the archshaped components.

[0120] Figure 5 is a close-up perspective view of the scissor mechanisms of the first carriage 106. As explained above, the first carriage 106 comprises a first scissor mechanism 130 and a second scissor mechanism 132. The first scissor mechanism 130 is coupled to the second scissor mechanism 132 via connecting bars 114. The first scissor mechanism 130 is also coupled to the second scissor mechanism 132 via a first scissor connecting bar 150. However, the first scissor connecting bar 150 is not rotatably connected to the first and second scissor mechanisms. The second scissor mechanism 132 is also connected to the first arm 140 of the double-hinged connecting component. The first arm 140 is rotatably connected to the second scissor mechanisms 132, such that the first arm is able to rotate, as indicated by the black arrow. The scissor mechanisms 130 and 132 enable the connected units 106C, 106D to be moved closer together or further apart along the first arch-shaped component 102. Since the second scissor mechanism is also connected to the first arm 140 of the double-hinged connecting component, and by virtue of the connection between the first 130 and second 132 scissor mechanisms via the scissor connecting bar 150, moving the connected units 106C, 106D closer together forces the first arm 140 to be displaced away from the first carriage 106, as indicated by the double-headed arrow.

[0121] Figure 6A is a zoomed-in perspective view of the needle holder 110 and double-hinged connecting component. As explained above, the needle insertion device 100 comprises a double-hinged connecting component to couple together the first and second carriages to the needle holder. The double-hinged connecting component comprises a first arm 140 connected at one end to a first point on the needle holder 110 and at another end to the first carriage 106. The double-hinged connecting component comprises a second arm 142 connected at one end to a second point on the needle holder 110 and at another end to the second carriage 108. The needle holder 110 is connected to the first arm 140 via hinge 144, and to the second arm 142 via hinge 146. As mentioned above, movement of the arch-shaped components and / or scissor mechanisms causes movement of the needle holder 110.

[0122] The hinge 144 may be a rotation joint, or a rotation joint combined with a prismatic joint. Figure 6B shows the hinge 144 as a rotation joint. Figures 6C and 6D show the axes about which the needle 112 is able to rotate using the arrangement of Figure 6A, where the hinge 144 is a rotation joint. Specifically, with the arrangement shown in Figure 6A, the needle 112 is able to rotate around the short axis (Figure 6C), and around the long axis (Figure 6D). Rotation about the short axis occurs by changing the relative position of the first and second arch-shaped components 102 and 104. Since the distance changes along the radial direction shown in Figure 6E, connected units 106C and 106D in the first carriage 106 have to move closer or further apart to ensure that the corresponding scissor mechanisms are contracted or expanded to accommodate changes in the radial direction. Rotation around the long axis occurs by changing the relative position of the first and second carriage 106, 108. Since the distance changes along the radial direction shown in Figure 6F, the connected units 106C and 106D need to move at different speeds which means moving closer or further apart to ensure that the corresponding scissor mechanisms are contracted or expanded to accommodate changes in the radial direction.

[0123] Figures 6G and 6H show, respectively, a zoomed-in perspective view and a zoomed-in side view of an alternative arrangement of the needle holder 110 and double-hinged connecting component with the hinge 144 configuration of a rotation joint combined with a prismatic joint. In the arrangement shown in Figure 6A, two hinges 144 and 146 are connected by connector 148. In the alternative arrangement, the hinge 144 is a rotation joint combined with a prismatic joint. A prismatic joint is a one-degree-of-freedom kinematic pair which constrains the motion of two bodies to moving along a single axis. With the aid of the prismatic joint, the connector 148 may be able to automatically adapt to changes in the distance between the two hinges, 144 and 146, particularly in scenarios depicted in Figures 8 and 11. In other words, this alternative arrangement can realise the needle tilt while without changing the distance along the radial direction. This alternative arrangement may therefore enable easier control and operation.

[0124] With the arrangement shown in Figures 6G and 6H, the needle 112 is also able to rotate around the short axis and long axis. The distance change between two hinges can be adapted automatically with a prismatic joint. Rotation around the short axis occurs by simply changing the relative position of the first and second arch-shaped components 102 and 104. The connected units 106C, and 106D in the first carriage 106 do not have to move close or far away to accommodate changes in the radial direction. Rotation around the long axis occurs by changing the relative position of carriages 106 and 108. It is not necessary to move the connected units 106C and 106D at different speeds. Thus, this alternative arrangement simplifies the control and operation of the robot.

[0125] Figure 6I and 6J show, respectively, how the alternative arrangement achieves needle rotation around the short and long axis. In summary, with the alternative arrangement, for needle rotation around the short axis, it is just necessary to change the relative position of the first and second arch-shaped components 102 and 104. In other words, two arch-shaped components do the differential movement. This may be achieved by: (1) the first arch-shaped components do not move, but the second arch-shaped components move away or close to it; (2) the second arch-shaped components do not move, but the first arch-shaped components move away or close to it; or (3) the first and second arch-shaped components move at the same time, but the speeds between them are different. Similarly, for needle rotation around the long axis, the first carriage 106 and second carriage 108 do the differential movement. This may be achieved by: (1) the first carriage does not move, but the second carriages slides along the second arch-shaped components; (2) the second carriage does not move, but the first carriages slides along the first arch-shaped components; or (3) the first and second carriages slide along the corresponding arch-shaped components at the same time, but the speeds between them are different.

[0126] Figures 7A to 7C are schematic diagrams showing how contraction and expansion of the scissor mechanisms causes movement of the needle holder. Figure 7A shows a side view of the first arch-shaped component and first carriage 106, for example. As shown, the archshaped component may define a plane (the x-y plane here, also referred to as the transverse plane), which is perpendicular to a longitudinal axis of the needle insertion device (defined by the z axis here, which extends into / out of the drawing page). The needle holder is able to move anywhere in this plane by moving the position of the carriages and / or by driving the scissor mechanisms. In Figure 7B, the connected units 106C and 106D of carriage 106 are moved apart from each other relative to the starting position in Figure 7A. It can be seen that expanding the scissor mechanisms and thereby increasing the distance between connected units 106C, 106D causes the needle holder to move in one direction in the transverse plane of the needle insertion device (in this case, upwards). In Figure 7C, the connected units 106C and 106D of carriage 106 are moved closer together relative to the position in Figure 7B. It can be seen that contracting the scissor mechanisms and thereby decreasing the distance between connected units 106C, 106D causes the needle holder to move in an opposite direction in the transverse plane of the needle insertion device (in this case, downwards). Operation of the scissor mechanisms enables the needle holder to be moved in and out of a patient body, during use of the needle insertion device.

[0127] Figure 8 shows how when the first and second carriages 106, 108 are offset from one another, the needle holder is caused to tilt or pivot in a plane (x-y plane here) perpendicular to the longitudinal axis of the needle insertion device 100.

[0128] Figure 9 shows how when the first and second carriages 106, 108 move in unison, in parallel and in the same direction, along the first and second arch-shaped components 102, 104, respectively, the needle holder is caused to move in a plane perpendicular to the longitudinal axis of the needle insertion device 100.

[0129] Figures 10A to 10C show side views of the first and second arch-shaped components of the needle insertion device. Movement of the arch-shaped components causes movement of the needle holder. In Figure 10A, the first and second arch-shaped components are positioned substantially at the centre of their respective sliding rails 124. In Figure 10B, the first and second arch-shaped components 102, 104 have moved in the same direction to one side of the sliding rail(s) 124, thereby moving the needle holder 110 along a longitudinal axis of the needle insertion device 100 (the z axis here). In Figure 10C, the first and second archshaped components 102, 104 have moved in the opposite direction to the other side of the sliding rail(s) 124, thereby moving the needle holder 110 along the longitudinal axis of the needle insertion device 100 (the z axis here).

[0130] Figures 11 A and 11 B show side views of the first and second arch-shaped components of the needle insertion device. Movement of the arch-shaped components and corresponding scissor mechanisms causes movement of the needle holder. It can be seen in Figure 11A that the needle holder and needle are tilted towards the second arch-shaped component. This may be because of the relative positions of the first and second arch-shaped components. For example, if the first arch-shaped component 102 moved along the longitudinal axis away from the second arch-shaped component 102 and corresponding scissor mechanisms also move, the movement causes the top of the needle holder to be pulled in the same direction, and the bottom of the needle holder to tilt towards the second arch-shaped component. In Figure 11 B, the first arch-shaped component 102 has moved towards the second arch-shaped component, and corresponding scissor mechanisms also move. This has caused the needle holder to tilt towards the first arch-shaped component 102. Thus, movement of the first and / or second arch-shaped components 102, 104 towards each other or apart from each other and in the meantime, the corresponding scissor mechanisms also move, cause one end of the needle holder to tilt towards one of the arch-shaped components (or both, in the alternative arrangement described above).

[0131] In Figure 2A, the needle holder 110 is located between the first and second arch-shaped components 102, 104. That is, the needle holder 110 is sandwiched between the first archshaped component 102 and second arch shaped-component 104. However, this is just one possible arrangement. Figures 12A to 13B shown an alternative arrangement, in which the first and second arch-shaped components 102, 104 are next to each other and the needle holder 110 is located on one side. That is, the first arch-shaped component 102 is sandwiched between the needle holder 110 and the second arch-shaped component 104. The mechanisms for moving the needle holder 110 described above apply equally to this arrangement.

[0132] Figures 12A to 13C show side views of the first and second arch-shaped components of the needle insertion device in this alternative arrangement. Movement of the arch-shaped components causes movement of the needle holder. In Figure 12A, the first and second archshaped components are positioned substantially at the centre of their respective sliding rails 124. In Figure 12B, the first and second arch-shaped components 102, 104 have moved in the same direction to one side of the sliding rail(s) 124, thereby moving the needle holder 110 along a longitudinal axis of the needle insertion device 100 (the z axis here). In Figure 12C, the first and second arch-shaped components 102, 104 have moved in the opposite direction to the other side of the sliding rail(s) 124, thereby moving the needle holder 110 along the longitudinal axis of the needle insertion device 100 (the z axis here).

[0133] Figures 13A and 13B show side views of the first and second arch-shaped components of the needle insertion device in this alternative arrangement. Movement of the arch-shaped components and the corresponding scissor mechanisms causes movement of the needle holder. It can be seen in Figure 13A that a bottom of the needle holder and needle are tilted away from the first and second arch-shaped components. This may be because of the relative positions of the first and second arch-shaped components. In Figure 13B, the first archshaped component 102 has moved away from the second arch-shaped component, and in the meanwhile, the corresponding scissor mechanisms also move. This has caused the bottom of the needle holder to tilt towards the arch-shaped components. Thus, movement of the first and / or second arch-shaped components 102, 104 towards each other or apart from each other and also the movement of the corresponding scissor mechanisms cause one end of the needle holder to tilt towards or away from the two arch-shaped components.

[0134] Those skilled in the art will appreciate that while the foregoing has described what is considered to be the best mode and where appropriate other modes of performing present techniques, the present techniques should not be limited to the specific configurations and methods disclosed in this description of the preferred embodiment. Those skilled in the art will recognise that present techniques have a broad range of applications, and that the embodiments may take a wide range of modifications without departing from any inventive concept as defined in the appended claims.

Claims

CLAIMS1 . A robotic surgical system comprising: a needle insertion device, comprising: a sliding rail; a first arch-shaped component provided on, and moveable along, the sliding rail; a first carriage coupled to, and moveable along, the first arch-shaped component; a second arch-shaped component provided on, and moveable along, the sliding rail, the second arch-shaped component being parallel to the first arch-shaped component; a second carriage coupled to, and moveable along, the second arch-shaped component; a needle holder coupled to the first and second carriages; and at least one control mechanism connected to the needle insertion device for controlling the movement of any one or more of the first arch-shaped component, second arch-shaped component, first carriage and second carriage to thereby drive movement of the needle holder with multiple degrees of freedom.

2. The robotic surgical system as claimed in claim 1, wherein one end of each of the first and second arch-shaped components is slidably-coupled to the sliding rail.

3. The robotic surgical system as claimed in claim 1 wherein the sliding rail comprises a first sliding rail and a second sliding rail, arranged in parallel, and wherein a first end of each of the first and second arch-shaped components is slidably-coupled to the first sliding rail, and a second end of each of the first and second arch-shaped components is slidably-coupled to the second sliding rail.

4. The robotic surgical system as claimed in claim 1 , 2 or 3 wherein the first arch-shaped component and second arch-shaped component are independently moveable along the sliding rail.

5. The robotic surgical system as claimed in any preceding claim wherein each of the first arch-shaped component and second arch-shaped component comprise two parallel subarches that are coupled together.

6. The robotic surgical system as claimed in any preceding claim wherein the control mechanism controls the first and second arch-shaped components to move in unison along the sliding rail, thereby moving the needle holder along a longitudinal axis of the needle insertion device.

7. The robotic surgical system as claimed in any preceding claim wherein the needle holder is coupled to a connector, and wherein the needle insertion device further comprises: a first arm connected at one end to a first connection point on the connector and at another end to the first carriage, and a second arm connected at one end to a second connection point on the connector and at another end to the second carriage, wherein the first arm and second arm are offset from each other.

8. The robotic surgical system as claimed in claim 7 wherein: the first carriage comprises a first scissor mechanism, and the first arm of the connecting bar is connected to the first scissor mechanism, and the second carriage comprises a second scissor mechanism, and the second arm of the connecting bar is connected to the second scissor mechanism.

9. The robotic surgical system as claimed in claim 8 wherein: operating the first scissor mechanism causes the first connection point on the connector to move in a transverse plane of the needle insertion device, and operating the second scissor mechanism causes the second connection point on the connector to move in the transverse plane of the needle insertion device.

10. The robotic surgical system as claimed in any of claims 7, 8 or 9 wherein: moving the first arch-shaped component causes the first point on the needle holder to move along a longitudinal axis of the needle insertion device, and moving the second arch-shaped component causes the second point on the needle holder to move along the longitudinal axis of the needle insertion device.11 . The robotic surgical system as claimed in any of claims 7 to 10 wherein: moving the first carriage along the first arch-shaped component causes the first point on the needle holder to move in a transverse plane of the needle insertion device, andmoving the second carriage along the second arch-shaped component causes the second point on the needle holder to move in the transverse plane of the needle insertion device.

12. The robotic surgical system as claimed in any preceding claim wherein the carriages are driven by a timing belt drive, gear drive, chain drive or mechanical transmission components.

13. The robotic surgical system as claimed in any preceding claim wherein the needle holder is configured to hold a needle probe, a biopsy needle, or a needle-shaped instrument.

14. The robotic surgical system as claimed in any preceding claim wherein the needle insertion device comprises a plurality of needle holders.

15. The robotic surgical system as claimed in any preceding claim wherein the at least one control mechanism drives movement of a needle in the needle holder into a phantom, or a human or animal body located within the needle insertion device.

16. The robotic surgical system as claimed in claim 15 further comprising an imaging system for capturing an image or video of the needle holder, wherein the control mechanism processes the image or video captured by the imaging system to determine a position of a needle in the needle holder relative to the human or animal body.

17. The robotic surgical system as claimed in claim 15 or 16 wherein the at least one control mechanism drives movement of the needle according to at least one movement constraint.

18. The robotic surgical system as claimed in claim 17 wherein the at least one movement constraint comprises one or both of: a patient-specific constraint that depends on the human or animal body located within the needle insertion device, and a pathology-dependent constraint.

19. The robotic surgical system as claimed in claim 16, 17 or 18 wherein the imaging system is a computerised tomography imaging system or a magnetic resolution imaging system.

20. The robotic surgical system as claimed in any of claims 1 to 19 wherein the at least one control mechanism controls the movement of a control mechanism connected to the needle insertion device for controlling the movement of any two or more of the first arch-shapedcomponent, second arch-shaped component, first carriage and second carriage in an asynchronous manner.

21. The robotic surgical system as claimed in any of claims 1 to 19 wherein the control mechanism controls the movement of a control mechanism connected to the needle insertion device for controlling the movement of any two or more of the first arch-shaped component, second arch-shaped component, first carriage and second carriage in a synchronous manner.

22. The robotic surgical system as claimed in any one of claims 1 to 21 wherein the needle holder is located between the first and second arch-shaped components.

23. The robotic surgical system as claimed in any one of claims 1 to 21 wherein the needle holder is located on one side of the first and second arch-shaped components.

24. A needle insertion device comprising: a sliding rail; a first arch-shaped component provided on, and moveable along, the sliding rail; a first carriage coupled to, and moveable along, the first arch-shaped component; a second arch-shaped component provided on, and moveable along, the sliding rail, the second arch-shaped component being parallel to the first arch-shaped component; a second carriage coupled to, and moveable along, the second arch-shaped component; and a needle holder coupled to the first and second carriages; wherein movement of any one or more of the first arch-shaped component, second archshaped component, first carriage and second carriage drives movement of the needle holder with multiple degrees of freedom.

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