A folded 3D ultrasound transducer for minimally invasive interventions

Abstract

This invention provides a foldable 3D ultrasound transducer for minimally invasive intervention, comprising: an acoustic ink delivery conduit and an external control device. The acoustic ink delivery conduit has a foldable flexible ultrasound transducer unit arranged circumferentially at its front end, and a foldable shape memory alloy frame arranged circumferentially. The external control device is electrically connected to the shape memory alloy frame via a cable and is used to drive the shape memory alloy frame to unfold and retract. When unfolded, the shape memory alloy frame supports the flexible ultrasound transducer unit to unfold and form an ultrasound transducer surface. The external control device is also signal-connected to the flexible ultrasound transducer unit via a cable and is used to drive the flexible ultrasound transducer unit to generate ultrasound waves. This foldable 3D ultrasound transducer can solve the problems of low energy transmission efficiency, interference from bone reflection, and incompatibility with minimally invasive surgery scenarios associated with traditional external HIFU transducers.

Description

Technical Field

[0001] This invention belongs to the field of 3D ultrasonic printing technology and relates to a foldable 3D ultrasonic transducer for minimally invasive intervention. Background Technology

[0002] 3D ultrasonic printing is an emerging additive manufacturing technology, particularly promising in the field of bioprinting. This technology uses high-intensity focused ultrasound to drive the precise deposition and curing of acoustic ink materials, and is widely used in tissue engineering, drug delivery, and in vivo repair. Traditional ultrasonic 3D printing systems typically employ external high-intensity focused ultrasound (HIFU) transducers, which have significant limitations in energy transfer efficiency, printing speed, and printing accuracy. External HIFU transducers need to penetrate multiple layers of human tissue. Due to differences in acoustic impedance and uneven tissue composition, ultrasound waves undergo significant energy attenuation, scattering, and reflection during propagation, leading to reduced energy utilization efficiency and decreased acoustic ink curing efficiency and printing accuracy. In particular, the presence of bone in the ultrasound propagation path significantly reflects ultrasound waves, forcing the external HIFU transducer to carefully design its focusing path to avoid bone, further limiting its applicability. Furthermore, the large size of external HIFU transducers and the complexity of the ultrasound propagation path limit the accuracy of focal point positioning, and they cannot be delivered to the target area in vivo via an interventional sheath, limiting their application in high-precision scenarios such as deep tissue repair. Current technology lacks an ultrasonic transducer that can be delivered within the body via a sheath and unfolded into a fully functional state. Traditional rigid transducers are large and lack flexibility, while existing flexible transducers have not yet achieved an integrated design for folding and unfolding, nor are they customized in size for minimally invasive surgical instruments, making it difficult to meet the size and functional requirements of minimally invasive surgery. Therefore, there is an urgent need for a miniature ultrasonic transducer that can be delivered via an interventional sheath and act directly on the target area, avoiding interference caused by ultrasound penetration of human tissue, and improving the efficiency and accuracy of 3D ultrasonic printing in minimally invasive interventional surgery. Summary of the Invention

[0003] The purpose of this invention is to provide a foldable 3D ultrasound transducer for minimally invasive intervention, which aims to solve the problems of low energy transmission efficiency, interference from bone reflection, and inability to adapt to minimally invasive surgery scenarios of traditional external HIFU transducers.

[0004] This invention is achieved through the following technical solution: A foldable 3D ultrasound transducer for minimally invasive intervention includes: an acoustic ink delivery conduit and an external control device. The front end of the acoustic ink delivery conduit is provided with a foldable flexible ultrasound transducer unit along the circumferential direction and a foldable shape memory alloy frame along the circumferential direction. The external control device is electrically connected to the shape memory alloy frame via a cable and is used to drive the shape memory alloy frame to unfold and retract. When the shape memory alloy frame unfolds, it supports the flexible ultrasound transducer unit to unfold and form an ultrasound transducer surface. The external control device is signal connected to the flexible ultrasound transducer unit via a cable and is used to drive the flexible ultrasound transducer unit to generate ultrasound waves.

[0005] Preferably, the flexible ultrasonic transducer unit is a PVDF film.

[0006] Furthermore, the flexible ultrasonic transducer unit is composed of four fan-shaped PVDF films.

[0007] Preferably, the shape memory alloy frame is made of nickel-titanium alloy.

[0008] Preferably, the diameter of the ultrasonic transducer surface is 8-12 mm.

[0009] Preferably, the diameter of the flexible ultrasonic transducer unit in the folded state is 4-6 mm.

[0010] Preferably, the external control device includes a signal generator and a power amplifier connected to the signal generator. The power amplifier is signal-connected to the flexible ultrasonic transducer unit. The signal generator is used to generate a sinusoidal electrical signal, and the power amplifier is used to amplify the sinusoidal electrical signal and transmit it to the flexible ultrasonic transducer unit. The flexible ultrasonic transducer unit converts the amplified sinusoidal electrical signal into ultrasonic waves for emission.

[0011] Preferably, when the folded 3D ultrasonic transducer is used, the front end of the acoustic ink delivery conduit is guided by a guide wire.

[0012] Preferably, when the folded 3D ultrasound transducer is used, it is delivered to the target area using an interventional sheath.

[0013] Compared with the prior art, the present invention has the following beneficial effects: First, the foldable 3D ultrasonic transducer of this invention employs a flexible ultrasonic transducer unit and a shape memory alloy frame, combining the flexibility of the flexible ultrasonic transducer unit with the controllable deformation capability of the shape memory alloy. This enables miniaturization of the ultrasonic transducer (diameter only 4-6mm during delivery) and in vivo self-deployment (8-12mm after deployment). It is delivered directly to the target area in vivo via an interventional sheath and unfolds into a complete ultrasonic transducer surface at the designated location. The ultrasonic waves act directly on the target area without penetrating multiple layers of human tissue, significantly reducing energy attenuation and scattering interference. This design of direct in vivo ultrasonic emission significantly improves energy transfer efficiency, ensuring rapid curing and high-precision deposition of acoustic ink, making it particularly suitable for tissue engineering or microstructure construction scenarios requiring high printing precision. Simultaneously, it avoids interference from tissue propagation, making ultrasonic wave focusing more stable and reliable, providing technical assurance for precise printing in complex environments. Second, the foldable 3D ultrasonic transducer of this invention is delivered via a guide wire and interventional sheath, allowing for flexible navigation to the target area, bypassing high-impedance tissues such as bone, and directly unfolding and emitting ultrasonic waves in vivo. This design eliminates the need for complex external pathway planning, significantly simplifying the procedure and improving surgical flexibility and applicability. Particularly in deep tissue repair or endovascular procedures, the foldable 3D ultrasound transducer easily avoids bone interference, ensuring efficient ultrasound transmission and precise focusing, thereby enhancing the reliability and success rate of 3D printing. Furthermore, the foldable 3D ultrasound transducer perfectly adapts to the size requirements of minimally invasive surgical sheaths, allowing for easy delivery to the target area within the body via standard sheaths and unfolding into a fully functional state at the designated location, without the need for additional external equipment. Simultaneously, its direct in vivo action eliminates reliance on complex in vitro simulation experiments, simplifying and increasing efficiency. Intraoperative precise positioning and deployment via guidewire significantly reduces operational difficulty and improves surgical efficiency, making it particularly suitable for high-precision minimally invasive scenarios such as endovascular repair and deep tissue repair. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 The ultrasonic transducer surface of a fully unfolded folded 3D ultrasonic transducer in working condition.

[0016] Figure 2 A folded 3D ultrasound transducer for delivery in an interventional sheath.

[0017] Figure 3A foldable 3D ultrasonic transducer that unfolds during operation.

[0018] Figure 4 A foldable 3D ultrasonic transducer for withdrawal. Detailed Implementation

[0019] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0021] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0022] The folded 3D ultrasonic transducer of the present invention mainly consists of the following parts: (1) Acoustic ink delivery conduit 1: used to deliver acoustic ink to the target area. The acoustic ink absorbs sound and generates heat under the action of ultrasound, completes the curing process, and forms a precise 3D printed structure. The flexible ultrasonic transducer unit 2 and the shape memory alloy frame 3 are fixed to the front end of the acoustic ink delivery conduit 1, and the entire folded 3D ultrasonic transducer is pulled synchronously by pulling the acoustic ink delivery conduit 1.

[0023] (2) Foldable flexible ultrasonic transducer 2: It is arranged around the front end of the acoustic ink delivery conduit 1 in the circumferential direction; the flexible ultrasonic transducer 2 is arranged around the acoustic ink delivery conduit 1 in the folded state, which is convenient for delivery through the interventional sheath 6; in the unfolded state, it forms a complete ultrasonic transducer surface to ensure sufficient ultrasonic emission area and focusing accuracy.

[0024] Specifically, the flexible ultrasonic transducer unit 2 can be made of polyvinylidene fluoride (PVDF) film. PVDF film has flexibility and excellent biocompatibility, and as a piezoelectric material, it can generate ultrasonic waves under the action of electrical signals, making it suitable for ultrasonic wave emission within the body. More specifically, the flexible ultrasonic transducer unit 2 is composed of four fan-shaped PVDF films. In the unfolded state, the four PVDF films are arranged in a cross shape, forming a complete ultrasonic transducer surface with a diameter of 10 mm. Figure 1 ).

[0025] (3) Shape memory alloy (SMA) frame: The shape memory alloy’s superelasticity and shape memory effect are used to realize the controllable deformation of the flexible ultrasonic transducer 2. The SMA frame is kept in a folded state at room temperature, which facilitates the delivery of the interventional sheath 6; in the target area in the body, the trigger temperature is reached by electric heating, which drives the shape memory alloy frame 3 to unfold to the preset shape, supporting the flexible ultrasonic transducer 2 to form a complete ultrasonic transducer surface.

[0026] Specifically, the shape memory alloy frame 3 can be made of nickel-titanium alloy with a trigger temperature of 50°C.

[0027] (4) External control device and cable 4: The external control device is electrically connected to the shape memory alloy frame 3 via cable 4 and is used to drive the shape memory alloy frame 3 to expand and contract. When the shape memory alloy frame 3 expands, it supports the flexible ultrasonic transducer unit 2 to expand and form an ultrasonic transducer surface. The external control device is signal connected to the flexible ultrasonic transducer unit 2 via cable 4 and is used to drive the flexible ultrasonic transducer unit 2 to generate ultrasonic waves.

[0028] Specifically, the external control device includes a signal generator and a power amplifier connected thereto. The power amplifier is connected to the flexible ultrasonic transducer unit 2. The signal generator generates a sinusoidal electrical signal, which is amplified by the power amplifier and transmitted to the flexible ultrasonic transducer unit 2. The flexible ultrasonic transducer unit 2 converts the sinusoidal electrical signal into ultrasonic energy to generate ultrasound waves, which are then focused onto the acoustic ink delivered into the body through the acoustic ink delivery conduit 1, thereby achieving in vivo curing of the acoustic ink.

[0029] The foldable 3D ultrasonic transducer of the present invention can switch between folded and unfolded states. In the folded state, the diameter is only 4-6mm. The foldable 3D ultrasonic transducer can be precisely delivered to the target area in the body through the interventional sheath 6 using the traction guide wire 5. When it reaches the target area, the flexible ultrasonic transducer unit 2 is unfolded by the unfolding support of the shape memory alloy frame 3, thereby forming an ultrasonic transducer surface. The flexible ultrasonic transducer unit 2 is controlled by an external control device to generate ultrasonic waves for 3D ultrasonic printing.

[0030] The foldable 3D ultrasonic transducer of the present invention achieves in vivo ultrasonic 3D printing through the following steps: (1) Delivery stage: such as Figure 2 As shown, the folded 3D ultrasound transducer, in its folded state (5 mm in diameter), is guided into the target area (such as blood vessels or deep tissues) through the interventional sheath 6 (8 mm in diameter, 24 Fr) by the guide wire 5. Its compact design in the folded state ensures it fits the size requirements of standard minimally invasive surgical sheaths.

[0031] (2) Development stage: such as Figure 3 As shown, upon reaching the target area, the guide wire 5 guides the flexible ultrasonic transducer unit 2 out of the interventional sheath 6. The external control device supplies power to the shape memory alloy frame 3 via the cable 4, heating the shape memory alloy to the trigger temperature (e.g., 50°C), triggering the shape memory effect of the SMA frame, causing the flexible ultrasonic transducer unit 2 to unfold from its folded state into a complete ultrasonic transducer surface. Simultaneously, the localized heating of the SMA frame does not lead to a significant increase in the regional temperature. Supported by the SMA frame, the flexible ultrasonic transducer unit 2 forms a focusing structure at a specific angle, ensuring uniform emission and focusing of ultrasonic waves.

[0032] (3) Ultrasonic 3D Printing Stage: The flexible ultrasonic transducer 2 generates high-intensity focused ultrasonic waves under the drive of the external control device, which directly act on the acoustic ink delivered through the acoustic ink delivery conduit 1. The acoustic ink absorbs sound and generates heat under the action of ultrasonic waves, and quickly solidifies to form the predetermined 3D printed structure. Since the transducer works directly in the target area inside the body, the ultrasonic waves do not need to penetrate multiple layers of human tissue, which significantly reduces energy attenuation and scattering interference, while avoiding the influence of bone reflection.

[0033] (4) Recycling stage: such as Figure 4 As shown, after printing is completed, the folded 3D ultrasound transducer is pulled back through the interventional sheath 6 to restore the folded state of the folded 3D ultrasound transducer. It is then withdrawn from the body through the guide wire 5 and the interventional sheath 6 to ensure the low invasiveness of the minimally invasive operation.

[0034] Specifically, the operation process of the foldable 3D ultrasonic transducer of the present invention is as follows: (1) Device delivery: Under real-time X-ray angiography in the interventional operating room, the folded 3D ultrasound transducer is loaded into the interventional sheath 6 and guided by the guide wire 5 to advance to the target area along the predetermined path. During delivery, the 3D ultrasound transducer has a diameter of only 4-6 mm, which is compatible with the standard interventional sheath 6, reducing surgical trauma.

[0035] (2) In-body unfolding and printing: After the 3D ultrasonic transducer reaches the target area, the external control device supplies power through cable 4, triggering the SMA frame to unfold at the trigger temperature, and the flexible ultrasonic transducer unit 2 forms the ultrasonic transducer surface. Subsequently, acoustic ink is injected into the target area through acoustic ink delivery conduit 1. The flexible ultrasonic transducer unit 2 is driven to emit ultrasonic waves through a signal generator (1 MHz sine wave, 336 mV) and a power amplifier (47 dB gain), with an electrical power of 100 W and an acoustic power of about 3 W. The focal acoustic intensity is 2.5-3 MPa and the focal point size is about 0.1 mm, driving the acoustic ink to solidify. The acoustic ink (hydrogel-based material) solidifies at an acoustic intensity of 2.5-3 MPa at a rate of about 0.1 mm / s, supporting a resolution of 0.1-0.2 mm, forming a high-precision 3D printed structure.

[0036] (3) Device withdrawal: After printing is completed, the guide wire 5 pulls back the acoustic ink delivery catheter 1, which drives the entire folded 3D ultrasonic transducer to retract backward. When the flexible ultrasonic transducer unit 2 and the shape memory alloy frame 3 retract, they are refolded under the action of the interventional sheath 6 and withdrawn from the body through the guide wire 5 and the interventional sheath 6 to complete the minimally invasive operation.

Claims

1. A foldable 3D ultrasound transducer for minimally invasive intervention, characterized in that, include: An acoustic ink delivery conduit (1) and an external control device are provided. The front end of the acoustic ink delivery conduit (1) is provided with a foldable flexible ultrasonic transducer unit (2) along the circumferential direction, and the acoustic ink delivery conduit (1) is provided with a foldable shape memory alloy frame (3) along the circumferential direction. The external control device is electrically connected to the shape memory alloy frame (3) through a cable (4) and is used to drive the shape memory alloy frame (3) to unfold and retract. When the shape memory alloy frame (3) unfolds, it supports the flexible ultrasonic transducer unit (2) to unfold and form an ultrasonic transducer surface. The external control device is signal connected to the flexible ultrasonic transducer unit (2) through a cable (4) and is used to drive the flexible ultrasonic transducer unit (2) to generate ultrasonic waves. The flexible ultrasonic transducer unit (2) is a PVDF film.

2. The foldable 3D ultrasound transducer for minimally invasive intervention as described in claim 1, characterized in that, The flexible ultrasonic transducer unit (2) is composed of four fan-shaped PVDF films.

3. The foldable 3D ultrasound transducer for minimally invasive intervention according to claim 1, characterized in that, The shape memory alloy frame (3) is made of nickel-titanium alloy.

4. The foldable 3D ultrasound transducer for minimally invasive intervention according to claim 1, characterized in that, The diameter of the ultrasonic transducer surface is 8-12 mm.

5. The foldable 3D ultrasound transducer for minimally invasive intervention according to claim 1, characterized in that, The diameter of the flexible ultrasonic transducer unit (2) in the folded state is 4-6 mm.

6. The foldable 3D ultrasound transducer for minimally invasive intervention according to claim 1, characterized in that, The external control device includes a signal generator and a power amplifier connected to the signal generator. The power amplifier is connected to the flexible ultrasonic transducer (2). The signal generator is used to generate a sinusoidal electrical signal. The power amplifier is used to amplify the sinusoidal electrical signal and transmit it to the flexible ultrasonic transducer (2). The flexible ultrasonic transducer (2) converts the amplified sinusoidal electrical signal into ultrasonic waves for emission.

7. The foldable 3D ultrasound transducer for minimally invasive intervention according to claim 1, characterized in that, In use, the front end of the acoustic ink delivery conduit (1) is guided by a guide wire (5).

8. The foldable 3D ultrasound transducer for minimally invasive intervention according to claim 1, characterized in that, In use, the folded 3D ultrasonic transducer is delivered to the target area using an interventional sheath (6).

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