Medical robots for ultrasound-guided needle placement

Abstract

A medical robot (10) includes a robotic arm (13) equipped with a medical device (15) for guiding a medical instrument (15) along a trajectory defined by an entry point on the patient's skin and a target point on the lesion to be treated within the patient's target anatomy. The medical robot collaborates with an ultrasound probe (40) and a navigation system (30) for determining the position of the robot, the position of the ultrasound probe, and the position of a patient marker (22). The robot is configured to generate a model of the position of the target point and the position of the entry point based on ultrasound images acquired by the ultrasound probe during at least one respiratory cycle of the patient, according to the position of the patient marker. The generated model allows for real-time control of the robotic arm based on the position of the patient marker, thereby precisely guiding the medical instrument.

Description

Technical Field

[0001] The methods and apparatus disclosed in this application belong to the field of robotic devices for assisting practitioners during minimally invasive medical interventions, including the insertion of one or more medical devices into a patient's target anatomical structure. Specifically, the present invention relates to a medical robot configured to track the movement of a target point within a lesion in a patient's target anatomical structure and to adjust the position of the robot's articulated arms in real time to optimally guide the medical device to the target point. Specifically, the movement of the target point may be generated by the patient's breathing or by the insertion of the medical device. Background Technology

[0002] To prepare for minimally invasive interventions to use medical devices to reach target anatomical regions within a patient's target anatomy, practitioners typically plan the intervention based on preoperative medical images (acquired days or weeks before the intervention) or pre-intervention medical images (acquired before the intervention, while the patient is lying on the intervention table). Specifically, minimally invasive medical interventions can target tumors in organs for biopsies or ablation, perform vertebroplasty or osteotomy, or even stimulate specific anatomical regions. Target anatomical structures can include the lungs, kidneys, liver, brain, tibia, knee, vertebrae, etc. Medical devices can include needles, probes, catheters, etc.

[0003] In this planning step, the practitioner defines a target point within the region of the target anatomical structure to be treated. The practitioner also defines the entry point for the medical device on the patient's skin. These two points then define the trajectory the medical device must follow for the medical intervention. In the specific case of soft organs located in the chest, abdomen, or pelvic region, movements related to the patient's breathing and / or local organ deformation due to the insertion of the medical device can cause displacement of the target point during the intervention. Preoperative or pre-intervention medical planning images cannot predict such displacement of the target point during the intervention. Therefore, the location of the target point (i.e., its location within the region to be treated in the target anatomical structure) is often different during the acquisition of medical planning images and during the intervention. Therefore, when planning the insertion of a medical device based on medical planning images, there is a risk that the medical device may not accurately reach the target point.

[0004] Furthermore, if the planned trajectory of the medical device is not adjusted accordingly, there is a risk that the medical device may bend during insertion and fail to reach the target point.

[0005] To limit the displacement of the target point caused by the patient's breathing, it is conceivable that, upon insertion of the medical device, the patient's breathing is blocked at the respiratory cycle phase corresponding to the acquisition of the medical planning image. If the medical intervention is performed under local anesthesia, the patient can voluntarily block their breathing; if the medical intervention is performed under general anesthesia (interruption of mechanical ventilation), breathing is blocked in a controlled manner by the practitioner. However, this solution is not always very accurate, as it is difficult to achieve a precise correspondence between the respiratory cycle phase at the time of acquiring the medical planning image and the respiratory cycle phase at the time of respiratory block during the intervention. Furthermore, this solution presupposes relatively rapid insertion of the medical device, as this must be done while the patient's breathing is blocked.

[0006] It is also conceivable to capture several medical planning images during the patient's respiratory cycle and determine the trajectory least affected by the deformation and displacement of the target anatomical structures caused by respiration. However, there is still a risk that the medical device may not be able to accurately reach the target point.

[0007] The location of the target point can also be tracked throughout the intervention by periodically acquiring intra-interventional medical images (images acquired when the medical device is inserted into the patient). These medical images are typically acquired via computed tomography (CT), X-ray, or magnetic resonance imaging (MRI). However, in the case of CT or X-ray, a disadvantage of this solution is significant radiation exposure to both the patient and the practitioner during the intervention. In the case of MRI, it is necessary to use specific non-magnetic materials, particularly anesthetic materials, which is especially restrictive. This solution also requires the use of bulky imaging equipment throughout the intervention.

[0008] It is also known to track the location of lesions in target anatomical structures with the aid of ultrasound images. However, lesions are not always visible on ultrasound images, and existing solutions often lack accuracy.

[0009] Therefore, it remains necessary to find a solution, especially during intervention, to accurately insert the medical device into the target point within the patient's target anatomical structure in the area to be treated when the target point is displaced due to movement related to the patient's breathing and / or local deformation of the target anatomical structure caused by the insertion of the medical device. Summary of the Invention

[0010] The purpose of the methods and apparatus disclosed in this application is to overcome all or part of the deficiencies of the prior art, especially the aforementioned deficiencies.

[0011] To this end, and specifically according to the first aspect, a medical robot is proposed for assisting a practitioner in treating lesions in a patient's target anatomical structure during a medical intervention. The medical robot includes a robotic arm with a distal end comprising a tool guide designed to guide medical instruments. The medical robot also includes a control unit configured to control the robotic arm. The medical robot is configured to cooperate with a navigation system and an ultrasound probe to be positioned by the practitioner at the patient's target anatomical structure. The control unit is configured to determine, at any time, the positions of robotic markers intended to be attached to the medical robot, patient markers intended to be positioned near the patient's target anatomical structure, and probe markers to be attached to the ultrasound probe, based on information conveyed by the navigation system. During the modeling phase, the control unit is configured to receive multiple ultrasound images acquired by the ultrasound probe during at least one respiratory cycle of the patient, and to generate, from the ultrasound images, a model for assessing the position of the target point at the lesion and the position of the entry point on the patient's skin, regardless of the time considered during the patient's respiratory cycle. During the guidance phase, the control unit is configured to control the robotic arm in real time based on the position of the patient markers to guide the medical device along a trajectory defined by the positions of the target point and the entry point, which are associated with the positions of the patient markers in the model.

[0012] In this application, the term "position" must be understood broadly to describe the location and orientation of an object in a three-dimensional frame of reference (sometimes the term "pose" is used in English literature). The position of markers (patient markers, robot markers, and probe markers), as well as the position of the target point and the position of the entry point, can be defined in either the robot's frame of reference or the navigation system's frame of reference. It should be noted that the robot's frame of reference can be defined relative to the navigation system's frame of reference because the position of the robot markers is known in both the navigation system's frame of reference and the robot's frame of reference (e.g., each joint of the robotic arm includes, for example, an encoder, thus enabling the determination of the position of each articulated element of the robotic arm in the robot's frame of reference, and the control unit a priori knows the position of the robot markers on the robot).

[0013] The modeling phase occurs at the start of the intervention, before the robotic arm is brought close to the target anatomical structure and before the medical device is inserted into the patient. This phase models the motion of the target point and the entry point relative to patient markers during the respiratory cycle. During this phase, the positions of the target point and the entry point are correlated with the position of the patient markers, thus defining their positions based on the patient markers. Therefore, the resulting model can define the positions of the target point and the entry point at any point in the respiratory cycle, corresponding to the trajectory the medical device must follow to accurately reach the target point.

[0014] Once the positions of the target point and the entry point are modeled based on the location of the patient marker, the position of the patient marker can be tracked in real time using a navigation system. This allows the robotic arm to be positioned in real time to guide the medical device along a trajectory defined by the positions of the target point and the entry point, which are associated with the patient marker's location. Specifically, this real-time tracking can be performed before the medical device is inserted.

[0015] This arrangement allows the patient's breathing to be blocked at any point in the respiratory cycle in order to continue inserting the medical device. In fact, regardless of the moment the patient's breathing is obstructed, the robotic arm will be correctly positioned to allow the medical device to be inserted along the intended trajectory.

[0016] Furthermore, it is no longer necessary to block the patient's breathing during the intervention. In fact, the robotic arm moves in real time, so its position is constantly adjusted to guide the medical device along the intended trajectory.

[0017] This invention can also minimize lateral adjustments to the trajectory after insertion of a medical device (such lateral adjustments to the trajectory are usually invasive to the organs traversed by the medical device).

[0018] Therefore, medical devices can be inserted with great precision into the area to be treated, regardless of the timing of insertion during the respiratory cycle. Insertion of medical devices is typically performed by a practitioner, and the goal of medical robots is to guide the practitioner in inserting the device. However, nothing prevents the insertion of medical devices from being automated and controlled by a control unit.

[0019] Furthermore, since the location of the target point and the entry point during the respiratory cycle is modeled based on ultrasound images, patients and practitioners are not exposed to ionizing radiation during the intervention.

[0020] In specific embodiments, the present invention may also include one or more of the following features, which may be employed individually or in all technically possible combinations.

[0021] In a specific implementation plan, during the modeling phase, for each received ultrasound image, the control unit is configured as follows:

[0022] - Determine the location of patient markers and probe markers when acquiring ultrasound images with an ultrasound probe;

[0023] - Obtain analytical images from ultrasound images in which lesions can be seen;

[0024] - Identify the target point at the lesion site and the entry point on the patient's skin on the analyzed image, thereby defining the trajectory that the medical device should follow;

[0025] - Determine the location of the target point and the entry point based on the position of the probe markers;

[0026] - Establish a correlation between the location of the patient marker determined from the ultrasound image, the location of the target point, and the location of the entry point.

[0027] Furthermore, the control unit is configured to model the position of the target point and the position of the entry point as a function of the patient marker position, based on information thus acquired from multiple ultrasound images, regardless of the time considered during the patient's respiratory cycle.

[0028] In a specific implementation, during the guidance phase, upon insertion of the medical device, the control unit is configured to periodically receive new ultrasound images acquired by the ultrasound probe. The control unit is further configured to update the model based on the new ultrasound images.

[0029] Once the operator begins inserting the medical device into the patient, the position of the entry point on the patient's skin is fixed and becomes the pivot point for the robotic arm's movement. However, the positions of the target point, the entry point, and the patient markers can still be tracked in real time using newly acquired ultrasound images during the device insertion phase. This arrangement allows for the consideration of any movement of the target point caused by the insertion of the medical device. The target point can indeed move in the direction of the trajectory it follows during device insertion (especially when the target point is located within a lesion, such as a tumor in soft tissue). Determining the target point's position in real time using ultrasound images allows for real-time updates to the trajectory the medical device will follow, as well as to the position of the robotic arm, to guide the medical device along that trajectory.

[0030] In a specific implementation, during the guidance phase, when the medical device is inserted, the control unit is further configured to determine the position of the medical device for each new ultrasound image received, and adjust the real-time control of the robotic arm according to the position of the medical device.

[0031] This arrangement allows for consideration of the risk of the medical device bending during insertion, and the real-time control of the robotic arm can be adjusted accordingly (so the trajectory that the medical device must follow is no longer a straight line between the entry point and the target point).

[0032] In specific implementations, the analyzed images directly correspond to the ultrasound images. This is especially true when the lesion is visible on the ultrasound image.

[0033] In a specific implementation, the control unit is configured to acquire an analytical image by merging an ultrasound image with a preoperative or pre-interventional reference image on which the lesion can be seen.

[0034] In fact, when a lesion is not visible on an ultrasound image (isoechoic lesion), the location of the target point cannot be directly determined on the ultrasound image. The ultrasound image should then be registered with a reference image of a different modality on which the lesion can be seen. Specifically, this could be preoperative or pre-interventional images acquired via computed tomography, positron emission tomography, or magnetic resonance imaging. The ultrasound image and the reference image are then merged to provide an analytical image on which the lesion can be seen. Registration can be global (registered over the entire target anatomy) or local (optimized registration over a specific region of the target anatomy). Registration can be rigid (through translation and / or rotation) or non-rigid (with deformation). Specifically, this registration can be achieved using an automated learning algorithm based on the identification of specific anatomical structures on the images to be merged.

[0035] In a specific implementation, the radiopaque elements of the patient marker are visible on the reference image, and the control unit is configured to merge the ultrasound image with the reference image by registration based on the position of the patient marker relative to the probe marker when the ultrasound probe acquires an ultrasound image.

[0036] In specific implementation schemes, the reference image is a computed tomography (CT) image, a positron emission tomography (PET) image, or a magnetic resonance imaging (MRI) image.

[0037] In a specific implementation, the ultrasound image received from the ultrasound probe is a B-mode ultrasound image.

[0038] In a specific implementation, the control unit is configured to receive and process ultrasound images acquired by the probe at a rate of at least 15 images per second.

[0039] This arrangement ensures real-time tracking of the target point's position, allowing for real-time adjustments to the robotic arm's position, thus guiding the medical device along the intended trajectory throughout the intervention process.

[0040] In a specific implementation, the medical robot also includes a user interface, which includes a display screen that allows practitioners to view the analyzed images.

[0041] In a specific implementation, the user interface includes an input device that enables practitioners to identify target points and / or entry points, and / or anatomical areas not traversed by medical devices, on analytical images displayed on a screen.

[0042] Therefore, practitioners can use the user interface to plan interventions on pre-intervention images corresponding to the analysis images associated with the first ultrasound image acquired by the ultrasound probe (if the lesion is visible on the ultrasound image, this can be the ultrasound image directly, or a fused image generated by registering the ultrasound image with different modalities on which the lesion is visible). The target point and entry point, defined by the practitioner on the first image, are then automatically determined by the control unit on the subsequent analysis images. Specifically, target point tracking can be achieved through "speckle" deformation analysis or artificial intelligence algorithms by tracking motion in several consecutive ultrasound images ("speckle" refers to a set of rapidly fluctuating small specks that appear in the instantaneous texture of an image and give it a granular appearance). When the lesion is not visible on the ultrasound image, it is advantageous to track the motion of anatomical structures (e.g., blood vessels) near the lesion visible on the ultrasound image to assist in tracking the target point on the analysis image.

[0043] In a specific implementation, the user interface includes an augmented reality device that overlays the analyzed images onto actual images of the patient's body on a display screen.

[0044] Augmented reality devices enable the overlay of moving three-dimensional lesions onto a patient's body, as well as the progress of medical devices during insertion. For example, this could be a screen placed on an intervention table above the patient, or a mask, helmet, or augmented reality glasses. This type of display helps practitioners spatially represent the patient's target anatomy.

[0045] In a specific implementation, the control unit is configured to compare the ultrasound image with a reference image on which the lesion can be seen, and to instruct the practitioner on the direction in which the ultrasound probe should be moved so that the ultrasound image acquired by the ultrasound probe includes the anatomical region where the lesion is located.

[0046] For example, reference images are preoperative or pre-interventional images acquired through computed tomography, positron emission tomography, or magnetic resonance imaging. For example, the direction in which the ultrasound probe should be moved is indicated to the practitioner on the user interface display. According to other examples, the direction in which the ultrasound probe should be moved can be indicated to the practitioner via light signals or through tactile feedback (vibration) from the ultrasound probe or an augmented reality display.

[0047] According to the second aspect, specifically, a medical device is proposed, comprising a medical robot according to any of the above embodiments, and a navigation system and an ultrasound probe designed to cooperate with said medical robot. Attached Figure Description

[0048] The invention will be better understood by reading the following description, which is given by way of non-limiting examples and references. Figures 1 to 15 Given, where:

[0049] [ Figure 1 According to a schematic diagram of a medical device based on the present invention, the medical device includes a medical robot, a navigation system, and a probe;

[0050] [ Figure 2 A schematic diagram of the robotic arm of a medical robot.

[0051] [ Figure 3 [A schematic diagram of a tool guide intended to be attached to the end effector of a robotic arm]

[0052] [ Figure 4 A schematic diagram of a tool guide, showing a device for holding a medical device at its end.

[0053] [ Figure 5 A schematic diagram of a tool guide, showing the positioning of a medical device on the tool guide, and elements detectable by a navigation system that forms "robotic markers";

[0054] [ Figure 6 A diagram illustrating "patient markers," designed to be located near target anatomical structures on a patient.

[0055] [ Figure 7 A schematic diagram of the "probe marker," intended for attachment to the ultrasound probe.

[0056] [ Figure 8 [A schematic diagram of the main steps of the method implemented by the control unit during the modeling phase (when the lesion is visible on the ultrasound image), followed by the phase of real-time control of the robotic arm before insertion of the medical device.]

[0057] [ Figure 9 A schematic diagram of the user interface, which enables practitioners to identify target points and / or entry points and / or hazardous areas on an image, as well as treatment parameters.

[0058] [ Figure 10 A schematic diagram of the preoperative or pre-interventional image (part a in the figure), the ultrasound image (part b in the figure), and the fused image after registration of the preoperative or pre-interventional image and the ultrasound image (part c in the figure).

[0059] [ Figure 11 A schematic diagram of the main steps of the method implemented by the control unit during the planning phase based on preoperative or pre-interventional images, followed by the modeling phase (when the lesion is not visible on ultrasound images).

[0060] [ Figure 12 A schematic diagram illustrating the assessment of patient marker movement during the patient's respiratory cycle.

[0061] [ Figure 13 A schematic diagram illustrating the changes in the location tracking of patient markers over time.

[0062] [ Figure 14 This is a diagram illustrating the process of modeling the target point position based on the patient's marker location and adjusting the robotic arm position in real time.

[0063] [ Figure 15 A schematic diagram of the main steps of the method implemented by the control unit during the medical device insertion phase.

[0064] In these figures, the same reference numerals from one figure to another denote the same or similar elements. For clarity, unless otherwise stated, the elements represented do not necessarily have the same scale.

[0065] Detailed description of at least one embodiment of the present invention

[0066] Figure 1 A medical robot 10 according to the present invention is shown. The medical robot 10 is used to assist practitioners during medical interventions on target anatomical structures of a patient 20 located on an intervention table 21.

[0067] For example, consider minimally invasive or percutaneous medical interventions to treat lesions within a patient's target anatomical structure. This type of intervention typically requires the practitioner to insert one or more medical devices (such as needles, probes, catheters, etc.) into the patient's body at a certain depth to reach the target anatomical region (lesion, such as a tumor) within the target anatomical structure (such as the liver, lungs, kidneys, etc.).

[0068] The medical robot 10 includes a base 11. In the considered example, the base 11 of the medical robot 10 is equipped with movable wheels, which allow the medical robot 10 to move in different directions by translational and / or rotational movements.

[0069] The medical robot 10 also includes an articulated robotic arm 13, one end of which is connected to a base 11. A tool guide 14 is fixed to the other end of the robotic arm 13, designed to guide medical devices 15, such as needles, probes, catheters, electrodes, etc. During medical intervention, the medical robot 10 can be used to assist the practitioner in locating, holding, or guiding the medical device 15. The medical robot 10 then acts as a third hand for the practitioner.

[0070] The medical robot 10 includes a control unit 12 configured to control the movement of a robotic arm 13. The control unit 12 includes, for example, one or more processors 122 and a memory 121 (magnetic hard disk, electronic memory, optical disk, etc.), wherein a computer program product is stored in the memory 121 in the form of a set of program code instructions to implement various steps of a method for positioning the robotic arm 13. The memory 121 may also record images and other information (particularly navigation information) used to implement the method.

[0071] The medical robot 10 may also include a user interface 19, which includes a display screen enabling the practitioner to view ultrasound images or other medical images acquired by the ultrasound probe 40 (e.g., preoperative or pre-interventional reference images of the target anatomy, or fused images acquired by registering the ultrasound images with the reference images). The user interface may also include input devices (keyboard, mouse, touchscreen, etc.) enabling the practitioner to identify target points and / or entry points and / or anatomical areas not traversed by the medical device 15 on the images displayed on the display screen.

[0072] In specific implementations, the user interface may include an augmented reality device for overlaying ultrasound images (or fused images) onto an actual image of the patient's body on a display screen. Such a device helps practitioners spatially represent the patient's target anatomical structures.

[0073] Medical robot 10 is configured to cooperate with navigation system 30 and ultrasound probe 40, which will be positioned by a practitioner at a target anatomical structure on the patient. Medical robot 10 includes a communication module connected to control unit 12 for exchanging data with navigation system 30 and ultrasound probe 40. Navigation system 30 and ultrasound probe 40 also each include a communication module for exchanging data with control unit 12 of medical robot 10. Communication established between control unit 12, navigation system 30, and ultrasound probe can be wired or wireless. For simplicity, the communication modules are not shown. Figure 1 As shown in the image.

[0074] In the considered example, navigation system 30 is an optical navigation system. Navigation system 30 includes two optical sensors 31, corresponding to the two sensors of a stereo camera operating in the infrared radiation range. In the considered example, navigation system 30 also includes a camera 32 operating in the visible light range.

[0075] The control unit 12 is configured to determine, at any time, the position of the robot marker 18 intended to be fixed on the medical robot 10, the position of the patient marker 22 intended to be fixed near the target anatomical structure of the patient, and the position of the probe marker 41 intended to be fixed on the ultrasound probe 40, based on information conveyed by the navigation system 30.

[0076] In this application, the term "position" corresponds to the combination of the position and orientation of an object in a given frame of reference, typically a three-dimensional coordinate system. In English literature, the term "pose" is used to describe the combination of the position and orientation of an object in space.

[0077] The control unit 12 is configured to receive ultrasound images acquired by the ultrasound probe 40.

[0078] The control unit 12 synchronizes the ultrasound images received from the ultrasound probe 40 and the information received from the navigation system 30 in a timely manner so as to associate the location of the lesion with the location of the patient marker 22 at a given time.

[0079] Traditionally, an ultrasound probe 40 includes one or more acoustic wave transmitter-receiver elements (piezoelectric material, capacitive electronic transducer). The ultrasound probe generates ultrasound waves through the indirect piezoelectric effect. Whenever a wave encounters an anatomical structure, a portion of the wave returns as an echo through reflection or scattering (“speck”). This echo is converted into an electric current through the direct piezoelectric effect and then reconstructed into an image. The reconstruction of the ultrasound image depends primarily on the number, size, and location of the transmitter-receiver elements of the probe (lateral and longitudinal resolution), the duration of the emitted pulse, and the echo time (axial and / or depth resolution). The energy of the received echo is then encoded into gray levels. The higher the energy, the whiter the corresponding image portion (pixel). This gray-level encoding is called “luminance,” and the associated ultrasound pattern is called “B-mode.” The images produced by the ultrasound probe 40 can be two-dimensional or three-dimensional. Preferably, the ultrasound probe 40 is capable of generating images at a frequency of at least 15 images per second.

[0080] Type B is particularly suitable when the target anatomical structure is the liver. However, it should be noted that the present invention can also be used with other ultrasound modalities, such as elastography.

[0081] In the examples considered, such as Figure 2As shown, the robotic arm 13 includes six rotary joints 131-136, each possessing six degrees of freedom, enabling the positioning and / or movement of the medical device 15 at any location in three-dimensional space. Advantageously, the joints 131-135 of the robotic arm 13 are misaligned and offset relative to each other, allowing for a greater number of possible configurations of the robotic arm 13. Each joint includes at least one encoder, enabling real-time knowledge of its angular position. The configuration of the robotic arm 13 then corresponds to a set of parameter values ​​taken by the joints 131-136 (e.g., the value of the rotation angle for each joint). The rotary joints 136 correspond to rotation about the main axis of the tool guide 14. However, it should be noted that rotation about the axis of symmetry of the medical device is not necessary (in fact, five degrees of freedom are sufficient for guiding and releasing the medical device). This additional degree of freedom makes it possible to be redundant, and for a given position of the tool guide 14, there is an infinite number of possible configurations of the robotic arm 13. This redundancy is particularly useful for accommodating constraints associated with patient positioning or operating room configuration. This redundancy allows it to be particularly adaptable to the location of the patient's external capsule and markers; for example, if one configuration of the robotic arm hides one of the markers, another configuration of the robotic arm 13 can be used while maintaining the same trajectory for the medical device 15.

[0082] In the examples considered, such as Figure 3 As shown, the tool guide 14 is secured to the robotic arm 13 via a flange 17. The tool guide includes... Figure 3 The spindle 145 is indicated by a dashed line. The tool guide 14 is connected to a force sensor 16, enabling the control unit 12 to determine the force applied to the tool guide 14. This force can be specifically applied when the operator manually moves the robotic arm 13. The force can also correspond to the force applied to the tool guide 14 by the patient's body through the medical device 15.

[0083] In the examples considered, such as Figure 4 and Figure 5As shown, the tool guide 14 includes a body 141 having a base 142 intended to be secured to a flange 17 by screws 143, and a retaining system 146 comprising two parts movable relative to each other. The retaining system 146 is designed to hold a medical device 15 at the end of the body 141 of the tool guide 14 opposite the base 142. The two movable parts of the retaining system 146 may be driven by a drive system such as gears, cams, screws with reverse threads, and / or linear actuators to lock or release the medical device 15. The linear actuator may be reversible (which can then manually or automatically open the retaining system 146 of the tool guide 14 upon command of the control unit 12) or irreversible (which can only automatically open the retaining system 146 of the tool guide 14 upon command of the control unit). For example, the tool guide 14 can be used to guide medical devices of different diameters. For example, such a guide can guide medical devices with diameters between 11 and 21 Ga (ga). Ga. is a commonly used unit of measurement for determining the outer diameter of medical devices such as needles, probes, or catheters (11 Ga. corresponds to an outer diameter of 2.946 mm; 21 Ga. corresponds to an outer diameter of 0.812 mm).

[0084] like Figure 4 and Figure 5 As shown, the tool guide 14 includes a stud 144 designed to receive optical markers 181. Advantageously, the tool guide 14 includes at least three optical markers 181, such that the position of the tool guide 14 can be determined in three spatial dimensions of the reference frame of the navigation system 30. The respective positions of the optical markers 181 of the tool guide 14 relative to each other are known a priori by the navigation device 30 and / or the control unit 12. Advantageously, the geometry of each optical marker 181 is also known a priori. Figure 5 In the example shown, optical marker 181 is spherical.

[0085] A set of optical markers 181 on the tool guide 14 corresponds to robot markers 18.

[0086] The use of at least three optical markers 181 allows for the definition of a plane, and thus a directly orthogonal three-dimensional reference frame with a z-axis perpendicular to that plane and x and y axes within the plane, making the reference frame direct. Therefore, it allows for the determination of the position and orientation of the reference frame formed by the optical markers 181 representing the tool guide 14. The three axes x, y, and z define six degrees of freedom: translation along the x, y, and z axes and rotation about each of these axes.

[0087] The optical marker 181 can be passive or active. A passive optical marker reflects optical radiation emitted by another element (e.g., navigation system 30). For example, a passive optical marker could correspond to a reflective sphere detectable by an infrared stereo camera (e.g., manufactured by Northern Digital Inc.). (used in navigation systems), or corresponding to a black-and-white pattern visible to a stereo camera (e.g., in ClaroNav). (Used in navigation systems). Active optical markers themselves emit optical radiation, such as infrared radiation, that can be detected by navigation system 30.

[0088] However, it should be noted that a single optical marker with a three-dimensional geometric shape can be used instead of the set of spherical optical markers 181.

[0089] Figure 6 The illustration shows a patient marker 22 designed for positioning on a patient 20 near a target anatomical structure. In the considered example, the patient marker 22 comprises four optical markers 23, thereby allowing the position of the patient marker 22 in three spatial dimensions of the reference frame of the navigation system 30 to be determined. The respective relative positions of the optical markers 23 of the patient marker 22 are known a priori by the navigation system 30 and / or the control unit 12. Advantageously, the geometry of each optical marker 23 is also known a priori. Figure 6 In the example shown, optical marker 23 is spherical. The spherical shape allows for optimized reflection of light radiation. The above description of the active or passive type of optical marker 181 for tool guide 14 also applies to optical marker 23 for patient reference 22. Here, it is also conceivable to use a single optical marker with a three-dimensional geometric shape instead of four spherical optical markers 23.

[0090] Optional, such as Figure 6 As shown, patient marker 22 may also include radiopaque markers 24, which are visible on medical images acquired by medical imaging equipment (e.g., computed tomography, magnetic resonance imaging, ultrasound, computed tomography, positron emission tomography, etc.). The respective positions of the radiopaque markers 24 relative to each other are known a priori by navigation device 30 and / or control unit 12. Advantageously, the geometry of the radiopaque markers 24 can also be known a priori. In the considered example, patient marker 22 includes four radiopaque markers 24. For example, the radiopaque markers 24 may be ceramic beads. However, it should be noted that a single radiopaque marker with a three-dimensional geometric feature can be used instead of four spherical radiopaque markers 24.

[0091] Figure 7The illustration shows a probe marker 41 intended to be fixed to an ultrasound probe 40 so that the navigation system 30 can determine the position of the ultrasound probe 40. In the considered example, the probe marker 40 includes three optical markers 42, thereby allowing the position of the probe marker 40 to be determined in three spatial dimensions of the reference frame of the navigation system 30. The respective positions of the optical markers 42 of the probe marker 40 relative to each other are known a priori by the navigation system 30 and / or the control unit 12. Advantageously, the geometry of each optical marker 42 is also known a priori. Figure 7 In the example shown, optical marker 42 is spherical. The spherical shape allows for optimized reflection of light radiation. The description above regarding the active or passive type of optical marker 181 for tool guide 14 also applies to optical marker 42 for probe reference 40. Here, it is conceivable to use a single optical marker with a three-dimensional geometric shape instead of three spherical optical markers 42.

[0092] In the remainder of the specification, by way of non-limiting example, the optical sensor 31 and various optical markers 181, 23, 42 of the navigation system 30 are designed to operate using infrared light radiation. It is also assumed that the optical markers 181, 23, 42 are passive markers. The optical sensor 31 is configured to emit infrared radiation. This infrared radiation is reflected back to the optical sensor 31 by the various optical markers 181, 23, 42. The optical sensor 31 is configured to receive the reflected infrared radiation. The navigation system 30 can then determine the distance between the optical markers 181, 23, 42 and the optical sensor 31 by measuring the time it takes for the infrared light to travel round trip between the optical sensor 31 and the optical markers 181, 23, 42. Knowing the distances between each optical marker 181, 23, 42 and each optical sensor 31, and knowing a priori the arrangement of the optical markers 181, 23, 42 relative to each other on the robot marker 18, patient marker 22, and probe marker 41, the positions of the robot marker 18, patient marker 22, and probe marker 41 in the reference frame of the navigation system 30 can be determined. It should be noted that infrared optical navigation is a well-known method in the field of robot-assisted surgical interventions.

[0093] It should be noted that the present invention is described using an optical navigation system. However, in one variant, nothing prevents the use of an electromagnetic navigation system instead of an optical navigation system. In this case, the various “markers” (patient marker 22, robot marker 18, and probe marker 41) detectable by the navigation system correspond to electromagnetic sensors, the positions of which can be determined by the navigation system in the generated electromagnetic field.

[0094] In the considered example, the control unit 12 of the medical robot 10 is configured to receive information from the navigation system 30 regarding the current position of the robot marker 18 in the reference frame of the navigation system 30. The control unit 12 of the medical robot 10 now knows the current position of the robot marker 18 in the reference frame of the medical robot 10 (via the encoders of joints 131-136). Therefore, the control unit 12 can determine the transition to be performed to define the position of the medical robot 10 in its reference frame from the position in the reference frame of the navigation system 30.

[0095] The control unit 12 is also configured to receive information from the navigation system 30 regarding the positions of the patient marker 22 and the probe marker 41 in the reference frame of the navigation system 30. The control unit 12 can then define the positions of the patient marker 22 and the probe marker 41 in the reference frame of the medical robot 10.

[0096] When the position of probe marker 41 is known at a given time, the position of a visible element on the ultrasound image acquired by ultrasound probe 40 at that time can be determined. Specifically, this visible element can be a target point to be reached at the lesion to be treated, or an entry point of the medical device on the patient's skin. The target point and the entry point define the trajectory to be followed by the medical device 15. When the positions of the target point and the entry point are known, i.e., when the trajectory to be followed by the medical device 15 is defined, the control unit can automatically move the robotic arm 13 into a configuration that allows the tool guide 14 to guide the medical device 15 along the defined trajectory.

[0097] However, as mentioned above, movements associated with a patient's breathing can cause displacement of the target point. Therefore, the trajectory that a medical device must follow at a given moment in a patient's respiratory cycle is different at another moment in the respiratory cycle.

[0098] To address this issue, the control unit 12 is configured to model the movement of the patient marker 22 during at least one respiratory cycle of the patient 20 in a modeling phase prior to surgery. During the modeling phase, the positions of the target point and the entry point are correlated with the position of the patient marker 22. Therefore, the positions of the target point and the entry point can be defined based on the position of the patient marker. Thus, the acquired modeling allows the positions of the target point and the entry point to be defined from the position of the patient marker 22 at any point in the respiratory cycle, corresponding to the trajectory to be followed by the medical device 15 to accurately reach the target point.

[0099] Once the positions of the target point and the entry point are modeled as functions of the position of the patient marker 22, the position of the robotic arm 13 can be continuously determined by tracking the position of the patient marker 22 in real time using the navigation system 30, so as to guide the medical device 15 along a trajectory defined by the positions of the target point and the entry point, which are related to the position of the patient marker 22. Specifically, this real-time tracking can be performed during the guidance phase before the insertion of the medical device 15. The robotic arm 13 is moved in real time to continuously adjust its position to guide the medical device along the desired trajectory.

[0100] Figure 8 The illustration shows the main steps of the method implemented by the control unit 12 during the modeling phase and then the real-time control phase of the robotic arm before the insertion of the medical device 15.

[0101] During the modeling phase, the control unit 12 is configured to receive multiple ultrasound images acquired by the ultrasound probe 40 during at least one respiratory cycle of the patient 20. Therefore, the following steps are repeated throughout the modeling phase:

[0102] - Acquire ultrasound image 201 (the ultrasound image corresponds to an analytical image on which lesions can be seen);

[0103] - At the moment when the ultrasound probe 40 acquires an ultrasound image, determine the position of the patient marker 22 and the position 202 of the probe marker 41;

[0104] - Identify the target point at the lesion site and the entry point 204 on the patient's skin 20 on the analyzed image (the target point and entry point define the trajectory to be followed by the medical device 15);

[0105] - Determine the position of the target point and the position of the entry point 205 from the position of the probe marker 41;

[0106] - This leads to the determination of the correlation 206 between the location of the patient marker 22, the location of the target point, and the location of the entry point based on the ultrasound image.

[0107] At the end of the modeling phase, the control unit 12 is configured to model the position of the target point and the position of the entry point as a function of the position of the patient marker 22, regardless of the time considered in the patient's respiratory cycle, based on information from the various ultrasound images thus acquired.

[0108] Then, during the guidance phase, control unit 12 is configured to control robotic arm 13 in real time. For this purpose, at each moment, control unit 12 performs the following steps:

[0109] - Determine the location of patient markers 301;

[0110] - Use the model to determine the location of the target point and the location of the entry point 302 associated with the location of the patient marker 22;

[0111] - The robotic arm 13 is displaced 303 to adjust the position of the tool guide 14 so that the tool guide 14 guides the medical device 15 according to a trajectory defined by the position of the target point and the position of the entry point determined therefrom.

[0112] The initial determination of the target point at the lesion site and the entry point on the patient's skin is performed, for example, initially on the first analytical image. Then, algorithms can be implemented to track motion in several consecutive analytical images, such as using deformation analysis of speckle (a set of fluctuating points on an image due to wave scattering) or artificial intelligence algorithms, to determine the target point and entry point on each new analytical image.

[0113] The initial determination of the target point and entry point can be done by the practitioner using the graphical interface 19. Figure 9 An example user interface is provided that enables practitioners to identify target points 51 of the treatment area 50, and / or entry points 52 on the patient's skin, and / or danger zones to be avoided (e.g., bones or blood vessels), as well as treatment parameters, on an analyzed image. This step can be facilitated by segmenting certain anatomical regions (target anatomical structures, lesions to be treated, danger zones, etc.) using machine learning algorithms.

[0114] Alternatively, the initial determination of the target point and entry point can be achieved automatically through artificial intelligence algorithms.

[0115] However, the lesion to be treated may not be visible on ultrasound images, for example, because the nature of the lesion means it is not visible (or only barely visible) on ultrasound images. In this case, a pre-intervention reference image (i.e., an image acquired before or at the start of the intervention) or a preoperative image (i.e., an image acquired a few days or weeks before the intervention) on which the lesion can be seen should be used. Specifically, this could be a computed tomography (CT) image, a positron emission tomography (PET) image, or a magnetic resonance imaging (MRI) image. The reference image can be a two-dimensional or three-dimensional image. The initial determination of the target point and entry point can then be performed on the reference image, rather than on the first ultrasound image. Here, the initial determination of the target point and entry point can again be performed by the practitioner (e.g., through...). Figure 9 The graphical interface 19 shown can be used, or it can be done automatically by an artificial intelligence algorithm. Then, the ultrasound image acquired by the ultrasound probe 40 can be registered with a reference image to form an analysis image corresponding to the merged reference image and the ultrasound image. The target point and entry point can then be seen on the analysis image.

[0116] Alternatively, the initial determination of the target point and entry point can be performed on the first analysis image instead of on the reference image.

[0117] Figure 10 This illustration shows the use of preoperative or pre-intervention reference images. Figure 10 Part a) to register ultrasound images ( Figure 10 Part b) is used to form an analytical image generated by registering and merging the reference image with the ultrasound image. Figure 10 (Part c). The lesion 50 to be treated and the target point 51 are visible on the reference image. In the considered example, the reference image was acquired by computed tomography. On the other hand, the lesion to be treated is barely visible on the ultrasound image. The lesion 50 to be treated and the target point 51 are visible on the analytical image generated by registration of the reference image and the ultrasound image.

[0118] For example, this registration is achieved by the control unit 12 using an automatic learning algorithm trained to perform global (registration over the entire anatomical structure) or local (optimization over the target region) registration of computed tomography images and ultrasound images of the target anatomical structure in a rigid manner (translation and rotation) or a non-rigid manner (deformation). The image obtained through this registration is called an analytical image or a fused image.

[0119] If the radiopaque element of patient marker 22 is visible on the reference image, rigid registration can also be performed based on the position of patient marker 22 relative to the position of probe marker 41 at the moment when the ultrasound image is acquired by ultrasound probe 40.

[0120] Figure 11 The illustrations depict the main steps implemented during the planning phase based on preoperative or pre-intervention reference images, and during the modeling phase when the lesion is not visible on ultrasound images.

[0121] Specifically, the planning phase includes step 101 of acquiring a preoperative or pre-interventional reference image, followed by step 102 of identifying a target point 51 and an entry point 52 on the reference image.

[0122] The modeling phase includes and Figure 8 The steps described are essentially the same. For each ultrasound image received during the modeling phase, the control unit 12 is further configured to generate an analysis image in step 203 by registering the ultrasound image with a reference image. Then, the target point and entry point 204 are determined on the analysis image resulting from the registration of the ultrasound image with the reference image (while...). Figure 8 In the case of an ultrasound image, the analyzed image directly corresponds to the ultrasound image.

[0123] When a lesion is not visible on an ultrasound image, it is advantageous to track the movement of anatomical structures (such as blood vessels) that are close to the lesion and visible on the ultrasound image in order to assist in tracking and analyzing target points on the image.

[0124] It should be noted that step 102 is optional if the initial determination of the target point and entry point is performed on the first analysis image rather than on the reference image.

[0125] Once the target point 51 and entry point 52 are determined on the analyzed image, their respective positions can be determined by rigid registration using the known probe marker 41 position relative to the transmitter-receiver element position of the ultrasound probe 40, in the reference frame of the navigation system 30 or the reference frame of the medical robot 10.

[0126] Figure 12-14 Step 207 shows the modeling of the positions of target point 51 and entry point 52 as a function of the position of patient marker 22.

[0127] As an example, Figure 12 The diagram shows a record of the motion followed by the patient marker 22 during a predetermined duration corresponding to several respiratory cycles of the patient. Each point corresponds to the position of the patient marker 22 in the time history on the XY plane of the coordinate system of the navigation system 30 (the motion of the patient marker 22 can also be represented in the reference frame of the medical robot 10). In this example, it can be seen that the movement of the patient marker 22 is mainly along axis 54.

[0128] The motion of patient marker 22 represents the motion of the patient's chest cavity caused by respiration. To better interpret the motion of the marker and by analogy with the patient's respiratory cycle, it is preferable to obtain a one-dimensional curve to illustrate the oscillating motion of the marker over time. There are different methods to obtain such a one-dimensional curve. For example, it can be assumed that the movement of the marker is primarily vertical, thus considering only the Y-axis. However, in this case, part of the amplitude of the marker's motion is lost. According to another example, it is conceivable to perform critical component analysis on the position of the marker. Specifically, the position of the marker can be displayed along critical components corresponding to the main axis 54 of the marker's movement.

[0129] Figure 13 Curve 55 is shown, which describes the movement of patient marker 22 along principal axis 54 over time during recording. The position of patient marker 22 along coordinate axis 54 (M...) P The values ​​are displayed on the vertical axis; time (t) is represented on the horizontal axis. The recording period includes several respiratory cycles of the patient over 20 days.

[0130] like Figure 13As shown, the high position of patient 20's thoracic cavity corresponds to the end of inspiration in the respiratory cycle. This also corresponds to the maximum value of curve 55, which describes the position of patient marker 22 over time. The low position of patient 20's thoracic cavity corresponds to the end of expiration in the respiratory cycle. This also corresponds to the minimum value of curve 55, which describes the position of patient marker 22 over time.

[0131] During the modeling phase, the control unit 12 determines the location of the target point, the location of the entry point, and the location of the patient marker for each analyzed image. These locations can then be correlated to model the changes in the locations of the target point and the entry point over time as a function of the patient marker location.

[0132] Figure 14 For example, during the inspiratory phase of the respiratory cycle, the location of the target point (C) is used as a patient marker (M). P Model of the function of position 56.

[0133] By modeling the changes in the target point and entry point positions over time based on the position of the patient marker, the configuration that the robotic arm 13 must adopt can be determined in real time. This allows the tool guide 14 to be continuously positioned so that it guides the medical device 15 along a trajectory defined by the target point and entry point positions. This real-time adjustment 303 of the robotic arm 13 position can be easily achieved by tracking the position of the patient marker 22 in real time and by evaluating the target point and entry point positions as a function of the patient marker position using the model. This eliminates the need to acquire ultrasound images for real-time adjustment of the robotic arm 13 position during the guidance phase.

[0134] Therefore, a patient's breathing can be blocked at any point in the respiratory cycle to allow for the insertion of medical devices. In fact, the robotic arm will be correctly positioned at any moment, regardless of when the patient's breathing is blocked, to allow the medical device to be inserted along the desired trajectory.

[0135] During the intervention, it is no longer necessary to block the patient's breathing. In fact, the stage of guiding the robotic arm with the aid of a model can continue during the insertion of the medical device. The robotic arm is then controlled in real time, and its position is continuously adjusted to guide the medical device along the desired trajectory. However, it should be noted that the entry point on the patient's skin is fixed during the insertion of the medical device and becomes the fulcrum of rotation for the robotic arm's movement.

[0136] The guidance phase can be entirely based on the model generated in the modeling phase. Therefore, it is not necessary to acquire ultrasound images during the guidance phase.

[0137] However, it is advantageous to consider any displacement of the target point due to the insertion of the medical device. During insertion, the target point can indeed move along the trajectory followed by the medical device (especially when the target point is located in a lesion such as a tumor within soft tissue). The model can then be envisioned to be updated in real time, allowing for the assessment of the target point's position to adjust the trajectory the medical device should follow, and also the assessment of the robotic arm's position to guide the medical device along that trajectory.

[0138] Figure 15 The illustration shows the main steps of a method implemented by control unit 12 during the guidance phase of medical device 15 insertion. Control unit 12 is configured to receive new ultrasound images acquired by ultrasound probe 40. Therefore, the following steps are repeated for each new image:

[0139] -Acquire ultrasound images 401;

[0140] - At the moment when the ultrasound image is acquired by the ultrasound probe 40, the position of the patient marker 22 and the position 402 of the probe marker 41 are determined;

[0141] - Generate analysis image 403 from ultrasound image and reference image (Note: This step is optional if the lesion is directly visible on the ultrasound image);

[0142] -Based on the analysis of the images and the position of the probe marker 41, determine the position of the target point, the position of the entry point, and the position 404 of the medical device 15;

[0143] - Update model 405, which was initially generated during the modeling phase.

[0144] - Adjust the position 406 of robotic arm 13 according to the updated model.

[0145] The position of the medical device is determined for each new ultrasound image received, which also allows any curvature of the medical device to be detected during insertion and the real-time control of the robotic arm to be adjusted accordingly if necessary.

[0146] If the ultrasound probe is not positioned correctly, the lesion may not be within the probe's field of view. It is advantageous to provide practitioners with information on the direction the ultrasound probe must move to ensure the lesion is within the probe's field of view.

[0147] To this end, the control unit 12 can be configured to compare the ultrasound image with a reference image on which the lesion can be seen, and to instruct the practitioner on the direction in which the ultrasound probe 40 should move so that the ultrasound image acquired by the ultrasound probe 40 includes the anatomical region where the lesion is located. For example, this instruction can be provided by a light indicator or a tactile feedback module of the ultrasound probe. Alternatively, the instruction can be provided to the practitioner via a graphical interface 19.

[0148] The above description clearly demonstrates that the proposed device and method, with their various features and advantages, achieve the set objectives.

[0149] Specifically, the medical robot 10 uses respiratory information to position the tool guide 14 in order to accurately and in real time track the location of lesions without requiring specific operations by the practitioner.

[0150] During insertion of the medical device 15, lesions (particularly those in soft tissue) can move along the trajectory. By determining the location of the lesion in the ultrasound image in real time and correlating it with the location of the patient marker 22, the trajectory of the medical device 15 inserted by the robotic arm can be updated in real time. Lateral trajectory readjustment (which typically causes invasive effects on the target anatomy) is minimized. Any curvature of the medical device can be compensated for by tracking its position during insertion.

[0151] The position of the robotic arm 13 is controlled in real time using ultrasound imaging. Therefore, patients and medical staff are not exposed to ionizing radiation during the intervention.

[0152] Lesions that are barely visible or invisible on ultrasound images can be detected by registration using an imaging modality that provides optimal visibility.

Claims

1. A medical robot (10) for assisting a practitioner in treating lesions in a target anatomical structure of a patient (20) during a medical intervention, the medical robot (10) comprising a robotic arm (13) and a control unit (12), the distal end of the robotic arm (13) comprising a tool guide (14) intended for guiding a medical device (15), and the control unit (12) configured to control the robotic arm (13), the medical robot (10) configured to cooperate with a navigation system (30) and an ultrasound probe (40) to be positioned by the practitioner at the target anatomical structure of the patient, the control unit (12) configured to determine at any time, based on information conveyed by the navigation system (30), the position of a robot marker (18) to be attached to the medical robot (10), the position of a patient marker (22) to be positioned near the target anatomical structure of the patient (20), and the position of a probe marker (41) to be attached to the ultrasound probe (40), the medical robot (10) being characterized in that: - During the modeling phase, the control unit (12) is configured to receive multiple ultrasound images acquired by the ultrasound probe (40) during at least one respiratory cycle of the patient, and generate a model from the ultrasound images based on the position of the patient marker (22) for assessing the position of the target point at the lesion and the position of the entry point on the patient's (20) skin, regardless of the time considered in the patient's subsequent respiratory cycles, based on the position of the patient marker at the time of consideration, at which no ultrasound image needs to be acquired; - During the guidance phase, the control unit (12) is configured to control the robotic arm (13) in real time based on the position of the patient marker (22), so that the tool guide (14) can guide the medical device (15) along a trajectory defined by the position of the target point and the position of the entry point associated with the position of the patient marker (22) in the model.

2. The medical robot (10) according to claim 1, wherein during the modeling phase, the control unit (12) is configured to: - For each received ultrasound image, O Determine the position of the patient marker (22) and the position of the probe marker (41) when acquiring the ultrasound image by the ultrasound probe (40); O. Obtain analytical images from the ultrasound images in which lesions can be seen; O Determine the target point at the lesion and the entry point at the patient's (20) skin on the analyzed image, thereby defining the trajectory to be followed by the medical device (15); O Determine the position of the target point and the position of the entry point based on the position of the probe marker (41); O Establish a correlation between the location of the patient marker (22) determined from the ultrasound image, the location of the target point, and the location of the entry point; - Based on the information thus acquired from multiple ultrasound images, the location of the target point and the location of the entry point are modeled as a function of the location of the patient marker (22), regardless of the time considered in the patient's respiratory cycle.

3. The medical robot (10) according to claim 1 or 2, wherein during the guidance phase, when the medical device (15) is inserted, the control unit (12) is configured to periodically receive new ultrasound images acquired by the ultrasound probe (40) and update the model based on the new ultrasound images.

4. The medical robot (10) according to claim 3, wherein during the guidance phase, when the medical device (15) is inserted, the control unit (12) is further configured to determine the position of the medical device (15) for each new ultrasound image received, and to adjust the real-time control of the robotic arm (13) according to the position of the medical device (15).

5. The medical robot (10) according to claim 2, wherein the analyzed image is an ultrasound image and the lesion is visible on the ultrasound image.

6. The medical robot (10) of claim 2, wherein the control unit is configured to acquire the analytical image by merging the ultrasound image with a preoperative or pre-intervention reference image on which lesions can be seen.

7. The medical robot (10) according to claim 6, wherein the radiopaque element (24) of the patient marker (22) is visible on the reference image, and the control unit (12) is configured to merge the ultrasound image with the reference image by registration based on the position of the patient marker (22) relative to the probe marker (41) when the ultrasound image is acquired by the ultrasound probe (40).

8. The medical robot (10) according to claim 6 or 7, wherein the reference image is a computed tomography image, a positron emission tomography image, or a magnetic resonance imaging image.

9. The medical robot (10) according to claim 1 or 2, wherein the ultrasound image received from the ultrasound probe (40) is a B-mode ultrasound image.

10. The medical robot (10) according to claim 1 or 2, wherein the control unit (12) is configured to receive and process ultrasound images acquired by the ultrasound probe (40) at a rate of at least 15 images per second.

11. The medical robot (10) of claim 2 further includes a user interface (19) comprising a display screen that enables a practitioner to view the analyzed images.

12. The medical robot (10) of claim 11, wherein the user interface (19) includes an input device that enables a practitioner to identify target points and / or entry points and / or anatomical areas not traversed by the medical device (15) on an analytical image displayed on the display screen.

13. The medical robot (10) according to claim 11 or 12, wherein the user interface includes an augmented reality device for overlaying the analyzed image with an actual image of the patient's body on the display screen.

14. The medical robot (10) according to claim 1 or 2, wherein the control unit (12) is configured to compare an ultrasound image with a reference image on which a lesion can be seen, and to instruct a practitioner on the direction in which the ultrasound probe (40) should move, such that the ultrasound image acquired by the ultrasound probe (40) includes the anatomical region where the lesion is located.

15. A medical device comprising a medical robot (10) according to any one of claims 1-14, and a navigation system (30) and an ultrasound probe (40) for cooperating with said medical robot (10).

Images