Variable stiffness ct scan bed and variable stiffness method

Abstract

The application provides a variable rigidity CT scanning bed and a rigidity variable method, and relates to the field of medical imaging devices.The variable rigidity CT scanning bed comprises a liftable scanning bed, the scanning bed comprises a bed frame and a bed plate, the bed plate can move along the length direction of the bed frame, and a coil is arranged on the bed plate; a honeycomb core material is arranged in the bed plate, the core material comprises a plurality of holes, an electromagnetic rheological fluid is arranged in the holes, and the electromagnetic rheological fluid is located in the magnetic field range generated by the coil.By dynamically improving the rigidity, the application inhibits the slight sag of the conventional bed plate in the scanning process, and fundamentally solves the geometric distortion artifact and motion artifact problems caused by the deformation of the bed plate.

Description

Technical Field

[0001] This invention relates to the field of medical imaging devices, and in particular to a variable stiffness CT scanning bed and a method for making the stiffness variable. Background Technology

[0002] The CT scanning bed is a key subsystem of the CT system, responsible for patient support, positioning, and transport. CT scanning beds are typically designed as long cantilever beam structures. When the bed supports a patient and extends deep into the gantry, the end of the bed will deflect under gravity due to the increasing cantilever length, resulting in "sagging." This sagging not only leads to positional deviations in the scan plane but can also cause geometrical distortions in the image, severely affecting the doctor's judgment of lesion size and location. Therefore, minimizing sagging while ensuring lightweight bed and high X-ray transmittance through materials science and structural mechanics has become a core issue in the field of medical device engineering.

[0003] The materials used for CT scanning beds have evolved from early wood-based panels, phenolic resin boards, or insulating bakelite boards to composite materials, which have become the mainstream choice for high-end CT scanning bed panels. However, the following shortcomings are commonly observed in practical clinical applications:

[0004] 1. Bed Deformation and Artifacts: Traditional CT scanning beds are mainly made of single-layer metal or plastic materials. Although they meet the requirements in terms of load-bearing capacity, if the bed sags or deforms slightly during scanning, it can easily lead to nonlinear penetration paths of the X-ray beam, resulting in motion artifacts or geometric distortion artifacts, which seriously affect the spatial resolution of the image and the accuracy of diagnosis.

[0005] 2. The contradiction between stiffness and transmittance: To suppress bed board sagging, traditional methods usually involve increasing the thickness of the bed board or adding rib structures. However, increasing the thickness directly leads to a longer distance between the patient and the X-ray source. At the same time, the X-ray attenuation coefficient of the bed board material itself is high, resulting in an increased radiation dose to the patient, and at certain angles, refraction artifacts may occur.

[0006] 3. Limitations of fixed stiffness: The stiffness of the bed board in existing technology is usually a fixed value and cannot be dynamically adjusted according to different scanning modes (such as conventional CT scan, spiral CT scan, and CT fluoroscopy). This "one-size-fits-all" design cannot balance scanning accuracy and patient comfort.

[0007] In summary, there is an urgent need for a CT scanning bed with variable stiffness to solve the many problems mentioned above. Summary of the Invention

[0008] To address the aforementioned problems, the first aspect of this invention provides a variable stiffness CT scanning bed that can suppress the slight sagging of a traditional bed during the scanning process, thus solving the problems of geometric distortion artifacts and motion artifacts caused by bed deformation.

[0009] The first aspect of the present invention provides a variable stiffness CT scanning bed, comprising a height-adjustable scanning bed, the scanning bed comprising a bed frame and a bed board, the bed board being movable along the length direction of the bed frame, and a coil being provided on the bed board; the bed board having a honeycomb core material inside, the core material comprising a plurality of holes, the holes having an electromagnetic rheodynamic fluid inside, the electromagnetic rheodynamic fluid being located within the magnetic field range generated by the coil.

[0010] In one feasible embodiment, the bed board is provided with reinforcing ribs extending along the length of the bed board.

[0011] In one feasible embodiment, the coil is located on the left and right sides of the bed board, or above or below the bed board, or on the inner surface of the bed board.

[0012] In one feasible embodiment, the honeycomb core material is made of any one of polypropylene, PVC foam, or aramid.

[0013] In one feasible embodiment, the bed board is made of carbon fiber material and the thickness of the bed board is 1.0~2.0 mm.

[0014] In one feasible embodiment, the scanning bed further includes a base and a first drive member disposed on the base, the first drive member being capable of driving the scanning bed to move up and down.

[0015] In one possible embodiment, the bed frame further includes a second drive member, which can drive the bed board to move along the length of the bed frame.

[0016] A second aspect of the present invention provides a scanning system based on a variable stiffness CT scanning bed, comprising a variable stiffness CT scanning bed as provided in the first aspect of the present invention, and further comprising: a host computer, a scanning frame, a grating ruler, and a mechanical sensor; the grating ruler is disposed on the bed frame, and the mechanical sensor is disposed on the base; the host computer is connected to the scanning bed, the coil, the scanning frame, the grating ruler, and the mechanical sensor respectively.

[0017] The present invention also provides a method for variable stiffness of a CT scanning bed, employing a scanning system based on a variable stiffness scanning bed as provided in the second aspect of the present invention, comprising:

[0018] The host computer sends a signal to control the bed board to gradually extend out of the bed frame and into the interior of the scanning frame;

[0019] The grating ruler reads the extension distance of the bed board in real time and feeds it back to the host computer, while the mechanical sensor reads the center of gravity load in real time and feeds it back to the host computer.

[0020] The host computer calculates the deflection of the bed board based on the extension distance and load, and then determines whether to apply DC current to the coil based on the deflection and extension distance. If DC current is applied to the coil, the coil will generate a magnetic field. Under the action of the magnetic field, the yield stress of the electromagnetic rheodynamic fluid increases to resist the deformation of the bed board.

[0021] In one feasible implementation, the host computer calculates the deflection of the bed board based on the extension distance and load, and then determines whether to apply direct current to the coil based on the deflection and extension distance. The deflection of the bed board is then calculated according to Formula 1.

[0022]

[0023] in, Expressed as the deflection of the bed board, Represented as center of gravity load, This is expressed as the distance the bed board extends out. Expressed as the elastic modulus, It is expressed as the equivalent cross-sectional moment of inertia that varies with the state of the electromagnetic rheodynamic fluid.

[0024] The variable stiffness CT scanning bed and variable stiffness method provided by this invention have the following beneficial effects:

[0025] 1) Elimination of scanning artifacts: By dynamically increasing stiffness, the slight sagging of the traditional bed board during the scanning process is suppressed, fundamentally solving the problems of geometric distortion artifacts and motion artifacts caused by bed board deformation.

[0026] 2) Reducing patient radiation dose: During the scanning phase, the increased rigidity of the bed board mainly comes from magnetic field control. Therefore, the bed board can be made of an extremely thin single-layer structure or a new low-density material (such as carbon fiber), which greatly reduces the blocking coefficient of the bed board to X-rays and reduces the radiation dose received by the patient.

[0027] 3) Improve patient comfort and safety: During patient transfer, the bed board is restored to a soft state, reducing the discomfort caused by an overly hard bed board, while also facilitating the movement of patients by nursing staff and getting them on and off the bed.

[0028] 4) Adaptable to multiple scanning modes: The variable stiffness characteristics of this invention make it not only suitable for traditional CT scans, but also adaptable to the high requirements of high-precision spiral CT or minimally invasive surgical navigation systems. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the variable stiffness CT scanning bed in this invention.

[0030] Figure 2 This is a schematic diagram of the bed board structure in this invention.

[0031] Figure 3 This is a cross-sectional view of the bed board in this invention.

[0032] Figure 4 This is a framework diagram of the scanning system in this invention.

[0033] Figure Labels

[0034] Scanning bed 1

[0035] Bed Frame 1-1

[0036] Bed board 1-2

[0037] Base 1-3

[0038] Coil 2

[0039] Core material 3

[0040] Hole 3-1

[0041] Reinforcing rib 4

[0042] Host computer 5

[0043] Scanning rack 6 Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "internal", "left and right sides", "above", "below", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0046] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0047] This invention provides a variable stiffness CT scanning bed, such as... Figure 1 and Figure 2 As shown, the device includes a height-adjustable scanning bed 1, which comprises a bed frame 1-1 and a bed board 1-2. The bed board 1-2 is movable along the length of the bed frame 1-1. The scanning bed 1 can be a conventional medical scanning bed. Notably, the bed board 1-2 is also equipped with a coil 2. The interior of the bed board 1-2 is provided with a honeycomb core material 3, which includes multiple holes 3-1. Electromagnetic rheological fluid is disposed inside the holes 3-1, and the electromagnetic rheological fluid is located within the magnetic field generated by the coil 2. For illustration, the coil 2 is used to generate a magnetic field to change the structure of the electromagnetic rheological fluid. The electromagnetic rheological fluid is characterized by exhibiting Newtonian fluid behavior under zero magnetic field conditions. Under the influence of an external magnetic field, the magnetic particles instantaneously (<10ms) align along the magnetic field lines into a chain or cluster structure, transforming into a solid-like structure with extremely high yield stress, thereby greatly improving the equivalent shear modulus of the bed board 1-2.

[0048] A key problem this invention addresses is the tendency for the bed board to sag or deform slightly during scanning, which can easily lead to nonlinear X-ray beam penetration, resulting in motion artifacts or geometric distortion artifacts that severely affect image spatial resolution and diagnostic accuracy. This invention improves the deformation resistance of the bed board 1-2 without altering its thickness by filling the interior of the bed board 1-2 with a core material 3 and an electromagnetic rheodynamic fluid. Simply put, when the bed board 1-2 extends and sags or deforms slightly, a magnetic field alters the structure of the electromagnetic rheodynamic fluid, increasing the equivalent shear modulus of the bed board 1-2 and thus resisting sagging or deformation. When the bed board 1-2 does not sag or deform slightly, the magnetic field can be removed, ensuring patient comfort while lying on the bed board 1-2. In summary, this invention eliminates scanning artifacts: by dynamically increasing stiffness, it suppresses the slight sagging of traditional bed boards during scanning, fundamentally solving the problems of geometric distortion artifacts and motion artifacts caused by bed board deformation.

[0049] Specifically, the electromagnetic rheodynamic fluid can be a hydrocarbon-based magnetorheological fluid with high magnetic permeability and low viscosity (such as Lord's MRF-132DG type), with a zero-field viscosity of 0.112 Pa⋅s and a maximum yield stress of 45 kPa under a magnetic field of 250 kA / m.

[0050] Furthermore, such as Figure 3 As shown, the bed board 1-2 has reinforcing ribs 4 extending along its length. In one specific implementation, there are four reinforcing ribs 4, two of which contact the inner top surface of the bed board 1-2 and two of which contact the inner bottom surface of the bed board 1-2, thereby enhancing the shear modulus of the bed board 1-2.

[0051] Furthermore, such as Figure 3 As shown, the coil 2 is located on the left and right sides of the bed plate 1-2, or above or below the bed plate 1-2, or on the inner surface of the bed plate 1-2. In a specific implementation, the coil 2 is located on the inner top or bottom surface of the bed plate 1-2, between the core material 3 and the inner top or bottom surface. The coil 2 can be a conventional flexible printed circuit thin film coil 2, which is made by etching micron-level aluminum foil. Aluminum not only has minimal attenuation of X-rays, but also easily forms a uniform vertical magnetic field.

[0052] Furthermore, the honeycomb core material 3 is made of any one of polypropylene, PVC foam, or aramid. Additionally, other materials with low X-ray attenuation can also be used as the honeycomb core material 3.

[0053] Furthermore, the bed board 1-2 is made of carbon fiber, and its thickness is 1.0~2.0 mm. Even further, the bed board 1-2 is hot-pressed using T700 grade high-strength carbon fiber woven prepreg, reducing its thickness to 1.5 mm.

[0054] Furthermore, such as Figure 4 As shown, the scanning bed 1 further includes a base 1-3 and a first driving member disposed on the base 1-3, the first driving member being capable of driving the scanning bed 1 to rise and fall. In one specific implementation, the first driving member is a scissor lift.

[0055] Furthermore, the bed frame 1-1 also includes a second driving component, which can drive the bed board 1-2 to move along the length direction of the bed frame 1-1. In one specific implementation, the second driving component is a drive motor, which is equipped with a ball screw to allow the bed board 1-2 to extend outward or retract inward along the length direction of the bed frame 1-1. Specifically, the drive motor can be any one of a stepper motor, a DC geared motor, or a servo motor, preferably a servo motor equipped with an encoder.

[0056] A second aspect of the present invention provides a scanning system based on a variable stiffness scanning bed, such as... Figure 4 As shown, the variable stiffness CT scanning bed provided in the first aspect of the present invention further includes: a host computer 5, a scanning gantry 6, a grating ruler, and a mechanical sensor; the grating ruler is mounted on the bed frame 1-1, and the mechanical sensor is mounted on the base 1-3; the host computer 5 is connected to the scanning bed 1, coil 2, scanning gantry 6, grating ruler, and mechanical sensor respectively. For illustration, the host computer 5 can be a conventional computer, or a corresponding control program can be directly installed in a medical computer to realize the necessary operating actions of the present invention. The scanning gantry 6 is a common CT scanning gantry and will not be described in detail. The grating ruler is used to measure the extension distance of the bed plate 1-2, and typically includes a scanning head that moves with the bed plate 1-2 and a scale fixed on the bed frame 1-1. The scanning head is essentially a light source; the light emitted by the scanning head hits the scale and is detected by the optical sensor built into the scale to obtain the extension distance of the bed plate 1-2. Specifically, the optical sensor inside the scale is pre-coded in real time to determine its position, so the position of the received light can be directly converted into the extension distance. The mechanical sensor is used to detect the center of gravity load. Generally, multiple mechanical sensors are distributed. The center of gravity load refers to the load at the common center point of multiple mechanical sensors. The mechanical sensor can be a resistance strain gauge sensor (the elastic body deforms under force, causing the resistance value of the strain gauge attached to it to change, which is converted into an electrical signal through a Wheatstone bridge), a piezoelectric sensor (using the piezoelectric effect of certain crystals, the surface generates charge when subjected to force, which is measured by a charge amplifier), or a capacitive sensor (the force is measured by changing the distance or relative area of ​​two electrode plates by external force, causing the capacitance value to change).

[0057] This invention also provides a method for variable stiffness scanning bed, characterized in that it employs a scanning system based on a variable stiffness scanning bed as provided in the second aspect of this invention, comprising:

[0058] Step 1) The host computer 5 sends a signal to control the bed board 1-2 to gradually extend out of the bed frame 1-1 and into the scanning gantry 6. In CT scanning, this is a routine procedure. After the patient lies on the bed board 1-2, the bed board 1-2 gradually extends into the scanning gantry 6. When the scanning area is inside the scanning gantry 6, the bed board 1-2 stops moving, and the scanning gantry 6 scans the patient.

[0059] Step 2) The grating ruler reads the extension distance of the bed board 1-2 in real time and feeds it back to the host computer 5, while the force sensor reads the center of gravity load in real time and feeds it back to the host computer 5. Specifically, the working principle of the grating ruler has been described above and will not be repeated here. For the force sensor, a specific embodiment will be used for illustration. In one specific embodiment, a force sensor is provided at each of the four corners of the base 1-3. The four force sensors are used to detect the load, and according to the principle of torque balance, the center load is the sum of the loads of the four force sensors. The unit of load is generally selected as Newton.

[0060] Step 3) The host computer 5 calculates the deflection of the bed board 1-2 based on the extension distance and load, and then determines whether to apply direct current to the coil 2 based on the deflection and extension distance. If direct current is applied to the coil 2, the coil 2 will generate a magnetic field. Under the action of the magnetic field, the yield stress of the electromagnetic rheodynamic fluid increases to resist the deformation of the bed board 1-2. Further, the deflection of the bed board 1-2 is calculated according to Formula 1:

[0061]

[0062] in, This is expressed as the deflection of bed board 1-2. Represented as center of gravity load, This is represented by the extension distance of bed board 1-2. Expressed as the elastic modulus, It is expressed as the equivalent cross-sectional moment of inertia that varies with the state of the electromagnetic rheodynamic fluid.

[0063] In one specific embodiment, when detected The host computer 5 drives the power supply to output a gradually changing DC current of 0 to 3.0 A to the coil 2. Furthermore, the host computer 5 has a deflection-current mapping table set inside to accurately convert the deflection into current. For example, when the deflection is 0.6, the current is 0.62 A; when the deflection is 0.8, the current is 0.81 A.

[0064] Example

[0065] Taking a high-permeability, low-viscosity hydrocarbon-based magnetorheological fluid (such as Lord's MRF-132DG type) as an example, when the DC current of coil 2 is 0-3.0 A, coil 2 generates a vertical magnetic field of approximately 0-200 kA / m. The hydrocarbon-based magnetorheological fluid solidifies instantaneously, and the bending stiffness of the entire bed plate 1-2 is instantly "locked" and increased by approximately 3.5 times.

[0066] Using a 100 kg patient as the experimental subject, when the bed board 1-2 was extended 1.5 meters, the bending at the farthest end of the bed board 1-2 was less than 1 mm. After the scan, the bed board 1-2 retracted, the coil 2 was de-energized, and the electromagnetic rheodynamic fluid returned to a liquid state within 0.1 seconds, eliminating internal residual stress. The bed board 1-2 returned to its pliability to facilitate movement and make the scanned patient feel comfortable.

[0067] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A scanning system based on a variable stiffness CT scanning bed, characterized in that: The system includes a height-adjustable scanning bed, a host computer, a scanning frame, a grating ruler, and a force sensor. The scanning bed comprises a bed frame, a bed board, a base, and a first driving component mounted on the base. The first driving component can drive the scanning bed to move up and down. The bed board can move along the length of the bed frame and is also equipped with a coil. The bed board has a honeycomb core material inside, which includes multiple holes. Electromagnetic rheodynamic fluid is placed inside the holes and is located within the magnetic field generated by the coil. The grating ruler is mounted on the bed frame, and the force sensor is mounted on the base. The host computer is connected to the scanning bed, the coil, the scanning frame, the grating ruler, and the force sensor. The host computer is configured to: control the bed board to gradually extend out of the bed frame and into the interior of the scanning frame, receive the bed board extension distance read in real time by the grating ruler and the center of gravity load read in real time by the mechanical sensor, and calculate the deflection of the bed board according to Formula 1. ； in, Expressed as the deflection of the bed board, Represented as center of gravity load, This is expressed as the distance the bed board extends out. Expressed as the elastic modulus, It is expressed as the equivalent cross-sectional moment of inertia that varies with the state of the electromagnetic rheodynamic fluid; When L > 400 mm and δ > 0.5 mm, the driving power supply outputs a gradually changing DC current of 0 to 3.0 A to the coil to generate a vertical magnetic field, and to increase the yield stress of the electromagnetic rheodynamic fluid under the action of the magnetic field to resist the deformation caused by the sagging of the bed plate.

2. The scanning system based on a variable stiffness CT scanning bed according to claim 1, characterized in that: The bed board has reinforcing ribs extending along its length inside.

3. The scanning system based on a variable stiffness CT scanning bed according to claim 1, characterized in that: The coil is located on the left and right sides of the bed board, or above or below the bed board, or on the inner surface of the bed board.

4. The scanning system based on a variable stiffness CT scanning bed according to claim 1, characterized in that: The honeycomb core material is made of any one of polypropylene, PVC foam, or aramid.

5. The scanning system based on a variable stiffness CT scanning bed according to claim 1, characterized in that: The bed board is made of carbon fiber and has a thickness of 1.0~2.0 mm.

6. The scanning system based on a variable stiffness CT scanning bed according to claim 1, characterized in that: The bed frame also includes a second driving component, which can drive the bed board to move along the length of the bed frame.

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