Device testing

Abstract

A method 402 for lifetime testing radiotherapy equipment comprises outputting a set of instructions to a robot. The instructions define a series of one or more physical manipulations to be applied by

Description

Technical field Embodiments of the disclosure relate to device testing, and particularly to methods and apparatus for mechanical testing of radiotherapy devices. Background Radiotherapy is the treatment of tumours or other abnormal growths in patients, through the application of high-energy ionizing radiation such as x-rays, electrons and protons. Such radiation damages or kills the cancerous cells, and so treats the tumour or abnormal growth. The radiation also damages healthy cells (albeit to a lesser extent), and therefore great care and effort is spent ensuring that the radiation is targeted only at the cancerous cells and not at the healthy cells. In practice, some damage to healthy cells as a result of radiotherapy is inevitable; however, various techniques are employed to reduce or minimize such damage, while increasing or maximizing the therapeutic effect on the cancerous cells. By enhancing the accuracy, effectiveness and safety of cancer treatment, patients’ outcomes and quality of life are also improved. Various equipment is used to ensure that radiotherapy treatment is safe, accurate and repeatable. For example, the radiation can be applied most accurately when the location of the target (e.g., the tumour, abnormal growth, etc) is accurately known. To help achieve this, medical imaging is used extensively before and often during treatment, such that the target is imaged and its location indexed with respect to the radiotherapy apparatus. For this purpose, fiducial markers can be placed on the patient or on equipment or framework placed around the patient, to provide reference points with known locations relative to the radiotherapy apparatus and relative to the target. It is also beneficial to reduce or minimize movement of the patient during treatment, and various devices can be used to help support the patient in a particular position while they undergo treatment. To verify that such equipment aligns with the necessary performance, safety and quality criteria, product verification is of great importance. Verification of products plays an important role in the evaluation and release process for products. It serves as a means to demonstrate compliance with requirements through various methods such as testing, analysis, inspection, or demonstration. By conducting verification tests, requirements associated with risks and other aspects can be addressed, ensuring that products meet certain criteria. The requirements often pertain to the durability of the product, ensuring its optimal functioning throughout its lifespan. Testing for durability is often referred to as “lifetime testing”. Summary Lifetime testing typically involves the repeated application of some movement or force to the equipment undergoing testing, analogous to the normal movements that are expected to be applied to the equipment during its normal use. By repeating these movements a large number of times, the lifetime of the equipment and also its performance over that lifetime can be measured and analysed. This is of critical importance in medical areas such as radiotherapy, where safety and reliability are paramount. One problem with existing lifetime testing used in radiotherapy is that it involves human interactions with the equipment. Humans struggle to replicate the movements for lifetime testing consistently, and this can lead to reduced confidence in the lifetime testing itself. Embodiments of the disclosure address this problem by providing a method for lifetime testing radiotherapy equipment. The method comprises: outputting a set of instructions to a robot. The instructions define a series of one or more physical manipulations to be applied by the robot to the radiotherapy equipment, and include an instruction for the robot to perform the series repeatedly until a stopping criterion is reached. Apparatus for performing the method set out above is also provided. For example, one aspect of the disclosure provides a computing apparatus comprising: a memory storing computer-executable instructions; and a processor configured to execute the instructions to carry out the method set out above. A further aspect provides an apparatus for lifetime testing radiotherapy equipment. The apparatus is configured to: output a set of instructions to a robot, the instructions defining a series of one or more physical manipulations to be applied by the robot to the radiotherapy equipment, and including an instruction for the robot to perform the series repeatedly until a stopping criterion is reached. Yet further aspects provide a computer program, a non-transitory computer-readable storage medium and a computer program product for performing the method. These aspects of the disclosure provide a reliable automated mechanism for lifetime testing radiotherapy equipment The robot repeats the cycle of physical manipulations with consistent force and in a consistent way, increasing confidence in the outcome of the lifetime testing. Another aspect of the disclosure provides a gripping mechanism for a robot. The gripping mechanism comprises: first and second fingers, movable in a direction towards or apart from each other for respectively gripping or releasing an object. The first finger comprises a first finger body and a first protuberance extending laterally from the first finger body. When the gripping mechanism is in the closed state, the first protuberance defines a first gripping space at a distal end of the first and second fingers, and a second gripping space at a proximal end of the first and second fingers. Brief description of the drawings Exemplary embodiments will now be described, by way of example only, with reference to the following drawings, in which: Figure 1 shows examples of radiotherapy equipment; Figure 2 shows a testing system according to embodiments of the disclosure; Figure 3 shows a gripping mechanism according to embodiments of the disclosure; Figure 4 is a flowchart of a method according to embodiments of the disclosure; Figure 5 is a series of diagrams showing physical manipulations applied by a robot to radiotherapy equipment; and Figure 6 is a schematic diagram showing a computing apparatus according to embodiments of the disclosure. Detailed description Figure 1 shows examples of radiotherapy equipment according to embodiments of the disclosure. In the particular example shown, the equipment 100 is used within stereotactic radiosurgery, that is, radiotherapy which involves the application of numerous precision radiation beams from different directions in a three-dimensional stereotactic framework. Such equipment is most commonly used for the treatment of targets within the brain, but can also be used to treat other parts of the body. The equipment comprises a fiducial box 102, a fiducial box frame 104, a stereotactic arc system 106 and a head support 108. The fiducial box 102 is used before treatment to hold fiducial markers (not illustrated) which are small objects that are attached to the patient’s head during medical imaging processes, such as CT scans or MRI. These markers serve as reference points for accurate alignment and positioning during the radiation treatment session. The frame 104 is used to secure the stereotactic arc system 106 and the fiducial box 102 to the patient’s head. Together, the frame 104, fiducial box 102 and arc system 106 provide a rigid, head-immobilizing system that helps ensure precise and stable positioning of the patient during the treatment, as well as the precise and stable positioning of treatment devices (e.g., on the arc system). This is crucial for achieving accurate and consistent targeting of the radiation to specific treatment targets. The head support 108 further supports the head at an appropriate angle during treatment. These pieces of stereotactic radiotherapy equipment are examples of radiotherapy equipment to which embodiments of the present disclosure can be applied. Those skilled in the art will appreciate that there is numerous other radiotherapy equipment to which embodiments of the disclosure can also be applied, such as: patient support equipment, a magnetic resonance imaging (MRI) receiver device for an integrated radiotherapy-MRI system and more. Figure 2 is a schematic diagram showing a testing system according to embodiments of the disclosure. The system comprises a robot 200, which itself comprises an articulated arm 202, a gripper mechanism 206, and a mounting bracket 204 connecting the gripper mechanism 206 to the arm 202. The arm 202 comprises a plurality of linkages connected together by rotatable joints. The joints may be rotatable around more than one axis and, in the illustrated embodiment, the arm 202 is able to manoeuvre in six axes. Rotation of the joints and movement of the arm 202 more generally may be controlled using any suitable mechanism, such as pneumatics, motors, etc. The gripping mechanism 206 comprises first and second fingers, which are arranged so as to oppose each other. The mechanism can be made to grip objects by bringing the fingers together, or to release objects by moving the fingers apart. In the illustrated embodiment, the fingers are rotatably coupled to the bracket 204, such that rotation of each finger in opposite directions relative to the bracket 204 causes the fingers to move towards or apart from each other. Those skilled in the art will appreciate that alternative mechanisms may be used to grip or release objects, and the present disclosure is not limited to that shown in Figure 2. The robot 200 may be mounted to a base (not illustrated). In use, the base may be fixed in place (e.g., by its weight or some suitable mounting mechanism) such that force can be applied by the robot to equipment undergoing test, without causing movement of the base. For example, such that the robot can push or pull the equipment (or part of the equipment) without itself moving. The robot 200 may also be known as a collaborative robot, or cobot. Such devices possess the capacity to operate close to humans in a secure manner. One notable advantage of employing a robot or Cobot for accuracy assessment lies in its ability to consistently conduct tests under controlled conditions with identical or varying force, speed, and movement. Movement of the robot 200 may be controlled by instructions (e.g., software code, control signals, etc) received from a computer device or other suitable control device, such as the apparatus 600 described below. Figure 3 shows a gripping mechanism according to embodiments of the disclosure. The mechanism comprises a first finger 300 and a second finger 350. In the illustrated embodiment, the fingers are shown from different perspectives. Thus the first finger 300 is described primarily with reference to features that facilitate gripping and manipulation of objects, as these are visible in Figure 3; the second finger 350 is described primarily with reference to features that facilitate attachment of the finger 350 to the robot 200. Both fingers may in fact be identical, with each finger comprising both gripping / manipulation features and attachment features. As shown in Figure 3, the first finger 300 comprises a finger body 302 and a protuberance 304 that extends laterally away from the finger body 302. The effect of the protuberance 304 is to divide the gripping space defined by the first and second fingers in two: a first space 306 at the distal (far) end of the finger 300; and a second space 308 at a proximal (near) end of the finger 300. That is, when the first and second figures 300, 350 are brought together into a closed or gripping state, there is a first gripping space 306 at a distal end of the fingers, and a second gripping space 308 at a proximal end of the fingers. The first gripping space 306 is an open volume (i.e., open at the end of the fingers 300, 350), and thus can advantageously be used to grip or pinch objects which are located close to a larger surface. That is, where it isn’t possible for the fingers to reach past the object due to impacting on the larger surface beyond. Examples may include a handle or other manipulable feature of a larger object. The first gripping space 306 may also advantageously be used for pushing a gripped object, as the presence of the protuberance 304 provides a surface against which a gripped object exerts force when the gripping mechanism is pushed. In contrast, the second gripping space 308 is closed at its distal end by virtue of the protuberance 304 which engages with or abuts the second finger 350. Note that, in the illustrated embodiment, the second finger 350 also comprises a respective protuberance 354; however, in other embodiments, the protuberance 304 may engage with or abut the second finger (e.g., the body of the second finger) directly when in the closed state. As the second gripping space 308 is closed at its distal end, it is suitable for gripping and pulling objects. That is, the action of the protuberance 304 is to provide a surface against which a gripped object exerts force when the gripping mechanism is pulled. The object can therefore be pulled with increased force, without requiring significant gripping force. Those skilled in the art will appreciate that the presence of an object in the first or second gripping spaces 306, 308 may prevent the protuberance 304 from engaging directly with the second finger 350 when the fingers are in the closed state. For example, where the object is wider than the space in which it is gripped, the protuberance 304 will typically not engage with the second finger. Nonetheless, the protuberance 304 in either case provides a surface against which a gripped object exerts force when the mechanism is pushed (when the object is in the first gripping space 306) or pulled (when the object is in the second gripping space 308). The second finger 350 comprises a finger body 352. On the opposite side of the finger body to the gripping / manipulation features, the finger 350 comprises a groove 356 and one or more retaining flanges 358. In use, attachment points on the gripping mechanism (e.g., see mechanism 206 and fingers shown in Figure 2) are inserted into the groove 356. The retaining flanges 356 affix the fingers securely to the attachment points, and screws or other suitable tightening devices (not shown) may be used to clamp the fingers to the attachment points and prevent slippage. The fingers 300, 350 may be made from any suitable material, such as hard plastic. In embodiments of the disclosure, the gripping features (e.g.., the first and second gripping spaces 306, 308) may be covered in a softer material (e.g., rubber or soft plastic) to facilitate gripping and reduce wear and tear on the fingers 300, 350 and the equipment under test. Figure 4 is a flowchart of a method according to embodiments of the disclosure. The method comprises, in step 402, outputting a set of instructions to a robot (such as the robot 200 described above with respect to Figure 2). The instructions define a series of one or more physical manipulations to be applied by the robot to radiotherapy equipment (such as the equipment 100 described above with respect to Figure 1). The instructions further include an instruction for the robot to perform the series repeatedly until a stopping criterion is reached. The instructions may comprise software code, control signals or any other suitable instruction which is understandable by the robot to perform the physical manipulations defined therein. According to embodiments of the disclosure, the physical manipulations may comprise one or more of: gripping or releasing a part of the radiotherapy equipment; twisting a part of the radiotherapy equipment; pulling or pushing a part of the radiotherapy equipment; and raising or lowering a part of the radiotherapy equipment. The series of manipulations may be defined such that the equipment under test is returned to the same condition (that is, the same position, orientation and state) as when the series of manipulations started. In this way, the manipulations can be performed repeatedly without additional steps to reset the equipment between consecutive series. The stopping criterion may be any suitable criterion, but may comprise one or more of: a number of repetitions of the series being performed; and failure of the radiotherapy equipment. The testing may also be stopped responsive to some input from a user or safety device. Figure 5 shows a series of diagrams showing physical manipulations applied by a robot to radiotherapy equipment and, in particular, to a fiducial box 102 as shown above. The box 102 comprises two side walls (which may be made of plastic), which are fixed on opposite sides of an upper frame at their respective upper edges. At their respective lower edges, the side walls are releasably coupled to a base by a clip which can be released by action of a handle. In use, the handle is rotated upwards and the sidewalls pulled outwards to release the sidewalls from the base. The joints between the side walls and the upper frame flex to allow the lower edge of the sidewalls to clear the base and permit the sidewalls (and the upper frame) to be removed from the base. Figure 5 shows a series of physical manipulations that may be defined to lifetime test the fiducial box: - The fiducial box begins in the “closed state”, in which the sidewalls are connected to the base. - In diagram 502, the robot 200 grips the handle located on one side wall and rotates it upwards. This action releases the side wall from the base. Where the handle is located close to the side wall, the robot may utilize the first gripping space 306 described above for gripping the handle. - In diagram 504, the robot 200 pulls on the handle to flex the side wall outwards such that the lower edge of the side wall clears the base. The handle is then pushed such that the side wall returns to its original unflexed state. This action mimics the action of a human user decoupling the side wall from the base. As the action comprises pulling, the robot may utilize the second gripping space 308 for gripping the handle in this action. Where the robot used the first gripping space 306 for gripping and rotating the handle, it may temporarily release the handle in order to change the gripping space that is used. - In diagram 506, the robot 200 rotates the handle downward to secure the side wall to the base. This action is the opposite of that described above with respect to diagram 502. Where the handle is located close to the side wall, the robot may utilize the first gripping space 306 described above for gripping the handle in this action. This series of manipulations may be performed repeatedly, many times, in order to replicate the lifetime of the fiducial box 102. Information gathered from such testing may be used to inform and improve future designs, so as to increase the effective lifetime of the equipment. Figure 6 is a schematic diagram of a computing apparatus 600 according to embodiments of the disclosure, which may be used to transmit instructions to a robot such as the robot 200 described above, according to the method described with respect to Figure 4. The apparatus 600 comprises processing circuitry 602, a non-transitory computer readable medium 604 and one or more interfaces 606. The processing circuitry 602 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 600 components, such as the memory 604, network node 600 functionality. For example, the processing circuitry 602 may be configured to cause the network node to perform the method as described with reference to Figure 4. The memory 604 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 602. The memory 604 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 602 and utilized by the network node 600 (e.g., for performing the method of Figure 4). The memory 604 may be used to store any calculations made by the processing circuitry 602 and / or any data received via the communication interface 606. In some embodiments, the processing circuitry 602 and memory 604 are integrated. The interface(s) 606 may comprise a wired or wireless interface for communicating with a robot, e.g., for outputting instructions to the robot as described above with respect to Figure 4. For example, the interface(s) 606 may comprise a radio interface using any suitable communication protocol (e.g., Bluetooth, IEEE 802.11, New Radio, Long Term Evolution, etc). Additionally or alternatively, the interface(s) 606 may comprise a wired interface (e.g., optical fibres, cables, electrical wires, etc) over which instructions can be transmitted. The methods of the present disclosure may be implemented in hardware, or as software modules running on one or more processors. The methods may also be carried out according to the instructions of a computer program, and the present disclosure also provides a computer readable medium having stored thereon a program for carrying out any of the methods described herein. A computer program embodying the disclosure may be stored on a computer readable medium, or it could, for example, be in the form of a signal such as a downloadable data signal provided from an Internet website, or it could be in any other form. It should be noted that the above-mentioned examples illustrate rather than limit the disclosure, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended embodiments. The word “comprising” does not exclude the presence of elements or steps other than those listed in an embodiment or claim, “a” or “an” does not exclude a plurality, and a single processor or other unit may fulfil the functions of several units recited in the embodiments. Any reference signs in the claims shall not be construed so as to limit their scope.

Claims

1. A method for lifetime testing radiotherapy equipment, the method comprising: outputting a set of instructions to a robot, the instructions defining a series of one or more physical manipulations to be applied by the robot to the radiotherapy equipment, and including an instruction for the robot to perform the series repeatedly until a stopping criterion is reached.2.The method according to claim 1, wherein the robot comprises a gripping mechanism for gripping the radiotherapy equipment.3.The method according to claim 2, wherein the gripping mechanism comprises first and second opposing fingers, movable between a closed state and an open state.4.The method according to claim 3, wherein the first finger comprises a first finger body and a first protuberance extending laterally from the first finger body.

5. The method according to claim 4, wherein the first protuberance engages with the second finger when the gripping mechanism is in the closed state.

6. The method according to claim 5, wherein the second finger comprises a second finger body and a second protuberance extending laterally from the second finger body, and wherein the first protuberance engages with the second protuberance when the gripping mechanism is in the closed state.7.The method according to any one of claims 3 to 6, wherein, when the gripping mechanism is in the closed state, the first protuberance defines a first gripping space at a distal end of the first and second fingers, and a second gripping space at a proximal end of the first and second fingers.8.The method according to claim 7, wherein the first gripping space is open ended at the distal end of the first and second fingers.

9. The method according to any one of claims 2 to 8, wherein the robot further comprises an articulated arm, and wherein the gripping mechanism is mounted on a distal end of the articulated arm.

10. The method according to any one of the preceding claims, wherein the radiotherapy equipment comprises one or more of: a fiducial frame for medical imaging during radiotherapy; radio-surgery equipment; a stereotactic frame for radiotherapy; patient support equipment; a stereotactic support; a magnetic resonance imaging, MRI, receiver device for an integrated radiotherapy-MRI system.

11. The method according to any one of the preceding claims, wherein the physical manipulations comprise one or more of: gripping or releasing a part of the radiotherapy equipment; twisting a part of the radiotherapy equipment; pulling or pushing a part of the radiotherapy equipment; raising or lowering a part of the radiotherapy equipment.

12. The method according to any one of the preceding claims, wherein the stopping criterion comprises one or more of: a number of repetitions of the series being performed; and failure of the radiotherapy equipment.

13. A computing apparatus comprising:a memory storing computer-executable instructions; anda processor configured to execute the instructions to carry out the method of any of claims 1 to 12.

14. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of any of claims 1 to 12.

15. A non-transitory computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method of any of claims 1 to 12.

16. A computer program product comprising the computer-readable storage medium of claim 15.

17. Use of a physical robot to lifetime test radiotherapy equipment.

18. A gripping mechanism for a robot, the gripping mechanism comprising:first and second fingers, movable in a direction towards or apart from each other for respectively gripping or releasing an object;wherein the first finger comprises a first finger body and a first protuberance extending laterally from the first finger body, andwhen the gripping mechanism is in the closed state, the first protuberance defines a first gripping space at a distal end of the first and second fingers, and a second gripping space at a proximal end of the first and second fingers.

19. The gripping mechanism according to claim 18, wherein the first gripping space is open ended at the distal end of the first and second fingers.

20. The gripping mechanism according to claim 18 or 19, wherein the second gripping space is for gripping and pulling the object.

21. The gripping mechanism according to any one of claims 18 to 20, wherein the second figure comprises a second finger body and a second protuberance extending laterally from the second finger body.

Images