Head positioning device and oral cavity cone beam CT system

Abstract

The invention relates to a head positioning device and an oral cavity cone beam CT system, and relates to the technical field of medical instruments. The device comprises a forehead structure used for supporting the forehead of a patient and serving as a reference for connecting the device with an external frame; the supporting structure is connected to the forehead structure and used for providing vertical supporting and adjusting functions; the locking structure is mounted at the top of the supporting structure and used for applying constraining force to the head of the patient from the upper portion or the side portion; wherein the forehead gear structure, the supporting structure and the locking structure work together to achieve adjustable fixing of the head of a patient. Through cooperative work of the three parts of structures, multi-dimensional adjustment and precise fixation of the head of a patient can be achieved, pressure is effectively dispersed, local indentation and discomfort are avoided, meanwhile, the stability of a positioning reference is ensured, and the image quality is improved.

Description

TECHNICAL FIELD

[0001] The application relates to a positioning structure, in particular to a head positioning device and an oral cone beam CT system. BACKGROUND

[0002] In clinical scenarios such as oral CBCT examination, orthodontic treatment planning and maxillofacial surgery navigation, a head clamp (head positioning device) is a key device to ensure imaging accuracy and treatment safety. Oral CBCT needs to obtain high-precision three-dimensional images of teeth, jaw bones, temporomandibular joints and other parts, and the stability and fit of head fixation are extremely high. Even if the patient's head moves slightly, it may cause blurred images, overlapping of anatomical structures, and thus affect medical decisions such as lesion diagnosis and implant placement planning. However, the existing head clamp for oral CBCT has the following core technical defects, which seriously restrict the clinical application effect: Poor adaptability and obvious pressure concentration: the locking structure of the existing head clamp is mostly a whole rigid clamp plate or a single arc band, which cannot adapt to the complex three-dimensional curved surface of the maxillofacial and head of different patients (adults / children, normal head type / special head type), especially the forehead, parietal bone and temporal region that need to be fixed during oral CBCT examination. Rigid contact easily forms point / line contact pressure concentration, not only causing the patient to unconsciously move the head during the examination process due to discomfort, but also possibly affecting local blood circulation due to long-term compression, causing dizziness, skin marks and other problems. For complex CBCT scanning scenarios that require long-term fixed posture, this defect is more prominent.

[0003] Unstable reference fixation and easy deviation of positioning accuracy: the connection between the forehead of the head clamp and the diagnosis and treatment bed guide rail of the oral CBCT equipment is mostly simple insertion or single screw fixation, lacking a precise locking mechanism; at the same time, the support structure and the forehead structure of the head clamp are rigidly connected as a whole, without angle adjustment and secondary locking function. Under the conditions of slight movement of the patient's head during installation, examination process or equipment operation vibration, the head clamp is easy to slide and deflect slightly, causing the head positioning reference to deviate, making the spatial position of the anatomical structure in the CBCT image distorted, affecting the accurate formulation of subsequent medical plans. SUMMARY

[0004] The purpose of the present application is to provide a head positioning device to solve the problems raised in the background art.

[0005] To achieve the above purpose, the present application provides the following technical solutions: According to an aspect of the present application, a head positioning device comprises: a forehead rest structure for supporting a forehead of a patient and serving as a reference for connecting the device to an external frame; a support structure connected to the forehead rest structure for providing vertical support and adjustment functions; and a locking structure installed on a top of the support structure for applying a restraining force to the patient's head from above or from the side; wherein the forehead rest structure, the support structure and the locking structure work together to achieve adjustable fixation of the patient's head.

[0006] According to the head positioning device of at least one embodiment of the present application, the forehead rest structure comprises: a forehead rest main body support constituting a main frame of the forehead rest structure; a forehead rubber pad arranged at an upper end of the forehead rest main body support for direct contact with the forehead of the patient; and a carbon fiber rod mounting hole arranged on the forehead rest main body support for inserting an external carbon fiber rod; wherein the inside of the carbon fiber rod mounting hole is integrated with a locking structure for locking and fixing the carbon fiber rod after insertion.

[0007] According to the head positioning device of at least one embodiment of the present application, the forehead rubber pad is made of soft biocompatible material and is detachably or fixedly connected to the forehead rest main body support by buckle connection or adhesion.

[0008] According to the head positioning device of at least one embodiment of the present application, the support structure is provided with two groups symmetrically connected to the two sides of the forehead rest structure; each group of the support structure comprises a support base and a support rod; the lower end of the support rod is movably connected to the support base to achieve angle adjustment and / or height adjustment.

[0009] According to the head positioning device of at least one embodiment of the present application, the support structure is integrated with a self-locking linear lifting mechanism, which comprises: a first guide rod with a rack arranged on the support base; a gear arranged inside the support rod and always engaged with the rack; and a ratchet mechanism cooperating with the gear to achieve one-way locking; through the engagement transmission of the gear and the rack and the self-locking action of the ratchet, the support rod can be lifted and locked at any height.

[0010] According to the head positioning device of at least one embodiment of the present application, the support structure is integrated with a quick adjustment and locking mechanism, which comprises: a gear slot plate with a series of slot arranged on the support base; and a special-shaped cam rotatably arranged inside the support rod; by rotating the special-shaped cam to disengage the slot of the gear slot plate, the support rod can be freely lifted; after releasing the operation, the special-shaped cam resets and re-engages with the slot to achieve quick locking.

[0011] According to at least one embodiment of the head positioning device of the present invention, a fastening hole is provided on the side of the support base, and a positioning pin is inserted to form a mechanical limit after the angle of the support rod is adjusted.

[0012] According to at least one embodiment of the head positioning device of the present invention, the support base is detachably connected to the forehead structure via a male-female plug-in structure.

[0013] According to another aspect of the present invention, a locking structure employing the above-described head positioning device is provided, comprising: a connecting beam, the two ends of which are respectively connected to the top of the support structure on both sides; at least one set of pressing units, each set of pressing units comprising a pressing rod and a buffer connector; the upper end of the pressing rod is connected to the connecting beam, and the lower end is connected to the buffer connector through a direction adjustment structure, such that the buffer connector can adaptively conform to the curvature of the patient's head.

[0014] According to at least one embodiment of the head positioning device of the present invention, the direction adjustment structure is a ball hinge structure, the end of the clamping rod is provided with a ball head, and the upper part of the buffer connector is provided with a ball socket for accommodating the ball head and a locking component.

[0015] According to at least one embodiment of the head positioning device of the present invention, the locking structure further includes a head buffer pad disposed between the two buffer connectors, the head buffer pad being flexibly connected via a connecting beam assembly.

[0016] According to at least one embodiment of the head positioning device of the present invention, the connecting crossbeam adopts a crossbeam frame with a reinforced structure.

[0017] According to another aspect of the present invention, an oral cone-beam CT system employing the above-described head positioning device is provided, comprising the head positioning device as described in any one of the claims, for positioning and fixing the head of the subject being imaged.

[0018] Compared with the prior art, the beneficial effects of the present invention are: Excellent adaptability and comfort: This invention can accurately adapt to the jaw and head contours of different patients through a dual-sided independently adjustable support structure and a ball-joint connected buffer connector. Combined with a medical-grade soft forehead pad and buffer mechanism, it forms a uniform surface contact constraint, effectively disperses pressure, avoids discomfort and indentations, reduces unconscious micro-movements of patients, and improves examination tolerance.

[0019] Precise and stable positioning: The carbon fiber rod mounting holes of the forehead clip structure have a built-in precision locking mechanism. Combined with the limiting design of the support structure and modular assembly, it ensures that the head clip is firmly connected to the CBCT equipment without slippage or deflection, ensuring a constant positioning benchmark. This greatly improves the spatial position accuracy of anatomical structures in the images and provides a reliable basis for the formulation of diagnosis and treatment plans. Attached Figure Description

[0020] Figure 1 This is an overall assembly structure diagram of the basic head positioning device according to an embodiment of the present invention; Figure 2 This is an enlarged view of the forehead structure of the basic head positioning device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the cooperation between the support structure and the locking structure of the basic head positioning device according to an embodiment of the present invention; Figure 4 This is an overall assembly structure diagram of a head positioning device with dual-sided independent adjustment and end-adaptive fitting according to an embodiment of the present invention. Figure 5 This is a detailed diagram of the support structure angle adjustment and limiting structure of the head positioning device with dual-sided independent adjustment and end adaptive fitting according to an embodiment of the present invention. Figure 6 This is a schematic diagram of the distributed pressing unit of the locking structure of the head positioning device with dual-sided independent adjustment and end adaptive fitting according to an embodiment of the present invention; Figure 7 This is an overall assembly structure diagram of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 8 This is a detailed structural diagram of the third support base of the self-locking precision linear lifting head positioning device according to an embodiment of the present invention; Figure 9 This is a detailed view of the external structure of the third support rod of the self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 10 This is an anatomical diagram of the internal gear and ratchet self-locking transmission system of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 11 This is a schematic diagram of the overall locking structure of the self-locking precision linear lifting head positioning device according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the head buffer pad and the second connecting beam assembly of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 13This is a detailed diagram showing the connection between the second buffer connector and the second clamping rod of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 14 This is an overall structural diagram of the head positioning device for adjusting and locking the irregular cam and slot plate according to an embodiment of the present invention. Figure 15 This is a detailed structural diagram of the fourth support base of the head positioning device with an adjustable locking mechanism for irregularly shaped cams and slot plates according to an embodiment of the present invention. Figure 16 This is an anatomical diagram of the internal irregular cam structure of the fourth support rod of the head positioning device for adjusting and locking irregular cam and slot plate according to an embodiment of the present invention. Figure 17 This is a schematic diagram of the locking structure of the cam and slot of the head positioning device for adjusting and locking the irregular cam and slot plate according to an embodiment of the present invention. Figure 18 This is a detailed drawing of the locking structure of the head positioning device for adjusting and locking the irregular cam and slot plate according to an embodiment of the present invention.

[0021] 1. Forehead structure 101. First carbon fiber rod mounting hole 102. First forehead pad 103. First Amount Main Support 111. Second carbon fiber rod mounting hole 112. Second forehead pad 113. Second Amount Main Support 121. Third carbon fiber rod mounting hole 122. Third forehead pad 123. Third-tier main support frame 131. Fourth carbon fiber rod mounting hole 132. Fourth forehead pad 133. Fourth Grade Main Support 2. Supporting structure 201. First Support Base 202. First support rod 211. Second support base 212. Second support rod 2111. Fastening the socket 221. Third Support Base 2211. First guide rod mounting base 2212. Limiting Structure 2213, First Guide Rod 222. Third support rod 2221. First support slide bar 2222 Locking part mounting joint 2223, First fixed position mounting slot 2224. Parallel Structure 2225. Ratchet mounting structure 2226. Ratchet 2227. Gear 231. Fourth Support Base 2311. Second guide rod mounting base 2312, Second Guide Rod 2313, Gear Slot Plate 232. Fourth support rod 2321. Second support slide bar 2322. Buffer Protection Structure 2323, Irregularly Shaped Cam 2324. Second fixed position mounting slot 3. Locking structure 311. First clamping rod 312. First buffer connector 313. First connecting beam 321. Second clamping rod 322. Second Buffer Connector 323. Second connecting beam 324. Head cushioning pad 325. Second connecting beam assembly 331. Third clamping rod 332. Third Buffer Connector 333. Third connecting beam 334. Connecting crossbeam frame Detailed Implementation The head positioning device of the present invention will be described in detail below with reference to the accompanying drawings. Those skilled in the art will understand that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0022] Example 1 Existing head positioning devices suffer from poor adaptability, significant pressure concentration, and unstable reference fixation, which can easily lead to slight head movements in patients, thus affecting the accuracy of clinical applications such as oral CBCT examinations and orthodontic treatment planning. Please refer to [link to relevant documentation]. Figures 1 to 3 This embodiment provides a head positioning device, which constructs a forehead support structure 1, a support structure 2, and a locking structure 3, solving the problems of reference offset, poor adaptability, and pressure concentration in existing devices, and achieving adjustable and stable fixation of the patient's head.

[0023] A head positioning device, comprising: Forehead support structure 1 is used to support the patient's forehead and serves as a reference for connecting the device to the external frame; Support structure 2, connected to the lintel structure 1, provides vertical support and adjustment functions; and Locking structure 3, installed on top of support structure 2, is used to apply restraint to the patient's head from above or the side; Among them, the forehead support structure 1, the support structure 2 and the locking structure 3 work together to achieve adjustable fixation of the patient's head.

[0024] The forehead support structure 1 is the spatial positioning reference unit of the entire device. Its lower end or side wall is provided with standardized interfaces such as T-slots, dovetail slots, positioning pin holes or male and female plug structures for detachable and highly repeatable mechanical connection with the CBCT equipment bed rails, headrest brackets or third-party positioning platforms. The upper surface of the forehead support structure 1 is an arc-shaped support surface adapted to the curvature of the human forehead. The radius of curvature of this arc is 80mm to 150mm, including 100mm, 120mm or 140mm.

[0025] The support structure 2 is a dual-degree-of-freedom adjustment actuator, consisting of two sets symmetrically arranged on the left and right sides of the bracket structure 1. Each set of support structures 2 is connected to the bracket structure 1 via a detachable connection structure such as a quick-release buckle, threaded fastener, or magnetic positioning component. The main body of the support structure 2 is a vertically extending rod-shaped or frame-shaped support. The support structure 2 has at least one degree of adjustment freedom, and the adjustment function is realized through a mechanical adjustment mechanism, such as a hinge with a limit pin, a rack and pinion self-locking mechanism, a shaped cam and slot plate quick-locking mechanism, or a lead screw and nut fine-tuning mechanism. The top of the support structure 2 is provided with a standardized installation interface such as an M6 threaded hole, a guide groove, or a positioning pin hole for rigid or flexible connection with the locking structure 3.

[0026] The locking structure 3 is a flexible constraint execution unit, installed on the top of the support structure 2, and spans the two sides of the support structure 2 through the first connecting beam 313, the second connecting beam 323, and the third connecting beam 333. The constraint direction of the locking structure 3 includes vertical downward and upward constraint and / or horizontal inward and lateral constraint, depending on the clinical positioning requirements. When using upward constraint, the locking structure 3 applies controllable pressure to the top or occipital region of the patient's head through one or more sets of clamping units. When using lateral constraint, the locking structure 3 applies symmetrical pressure to the temporal region or preauricular region of the patient through laterally extending clamping arms or flexible bands. The clamping unit includes a first clamping rod 311, a second clamping rod 321, and a third clamping rod 331, and a first buffer connector 312, a second buffer connector 322, and a third buffer connector 332, wherein the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331 are rigid transmissions. The force-bearing components are made of stainless steel, titanium alloy, or carbon fiber rods; the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332 are elastic / flexible contact components with a thickness of 5mm to 20mm, including 8mm, 12mm, or 18mm; the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332 are provided with a directional adjustment structure such as a ball joint, universal joint, or dual-axis rotary joint between them and the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331, so that the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332 can adaptively deflect within the range of -25° to -10° or 10° to 25° to conform to the curvature of different patients' heads; the directional adjustment structure is equipped with locking components such as locking nuts, eccentric clamping blocks, or knob-type friction brakes, which can lock the posture after adjustment.

[0027] Under the reference constraint of the forehead structure 1, the spatial pose of the locking structure 3 is precisely adjusted and rigidly supported; the locking structure 3 performs the final flexible and adaptive head constraint on the stable platform provided by the support structure 2; the three are physically connected and functionally coupled to achieve multi-dimensional, adjustable and stable head fixation.

[0028] Through the above technical solution, this application achieves the following: Because the forehead structure 1 provides a highly repeatable connection reference and forehead support surface, combined with the dual-degree-of-freedom adjustment capability of the support structure 2 and the adaptive directional adjustment and buffer contact of the locking structure 3, the device can flexibly adjust the constraint position, direction and force according to individual patient differences; thereby, without generating local high pressure points, the patient's head is stably constrained in a predetermined spatial posture, effectively suppressing micron-level shaking caused by breathing, swallowing or tension during the examination, avoiding motion artifacts and spatial misalignment of anatomical structures in CBCT images, and improving the imaging clarity and measurement accuracy of key anatomical features such as tooth root apex, alveolar bone density, and temporomandibular joint space.

[0029] Example 2 The forehead support structure in Example 1 suffers from unstable connection with the external frame and concentrated pressure at the forehead contact interface, affecting the stability of the positioning reference and patient tolerance. Please refer to... Figures 4 to 6 This embodiment provides a split-type forehead support structure 1, including multiple forehead support main brackets, a forehead rubber pad, and carbon fiber rod mounting holes with locking structures. The forehead support main brackets form a rigid load-bearing frame that conforms to the contours of the human forehead; the forehead rubber pads are made of soft, biocompatible materials to disperse forehead contact pressure; the carbon fiber rod mounting holes have built-in locking structures to achieve high-precision, high-rigidity connection with external carbon fiber rods. This structure solves the dual problems of forehead support reference offset and contact pressure concentration, improving the initial reference stability of head positioning.

[0030] The apex structure 1 includes: The first tier main support 103, the second tier main support 113, the third tier main support 123 and the fourth tier main support 133 constitute the main frame of the tier structure 1; The first forehead adhesive pad 102, the second forehead adhesive pad 112, the third forehead adhesive pad 122, and the fourth forehead adhesive pad 132 are disposed at the upper ports of the first forehead support main bracket 103, the second forehead support main bracket 113, the third forehead support main bracket 123, and the fourth forehead support main bracket 133, for direct contact with the patient's forehead; and The first carbon fiber rod mounting hole 101, the second carbon fiber rod mounting hole 111, the third carbon fiber rod mounting hole 121 and the fourth carbon fiber rod mounting hole 131 are provided on the first bracket main body support 103, the second bracket main body support 113, the third bracket main body support 123 and the fourth bracket main body support 133, for inserting external carbon fiber rods. The first carbon fiber rod mounting hole 101, the second carbon fiber rod mounting hole 111, the third carbon fiber rod mounting hole 121 and the fourth carbon fiber rod mounting hole 131 are internally integrated with locking structures for locking and fixing the carbon fiber rod after it is inserted.

[0031] The first ridge support main bracket 103, the second ridge support main bracket 113, the third ridge support main bracket 123, and the fourth ridge support main bracket 133 are rigid load-bearing structures used to support the first ridge pad 102, the second ridge pad 112, the third ridge pad 122, and the fourth ridge pad 132 and provide mounting bases for the first carbon fiber rod mounting holes 101, the second carbon fiber rod mounting holes 111, the third carbon fiber rod mounting holes 121, and the fourth carbon fiber rod mounting holes 131. Their structural form can be an integral molded part or it can be composed of multiple sub-components combined by threaded connection, snap connection, or welding.

[0032] The first forehead pad 102, the second forehead pad 112, the third forehead pad 122, and the fourth forehead pad 132 are made of soft biocompatible material, and their surfaces are provided with microtextures or flexible bump arrays to enhance static friction with the skin and improve breathability. The first forehead pad 102, the second forehead pad 112, the third forehead pad 122, and the fourth forehead pad 132 are connected to the first forehead support main bracket 103, the second forehead support main bracket 113, and the fourth forehead pad 132 by snap-fit ​​connection or adhesive bonding. The three forehead support main brackets 123 and the fourth forehead support main bracket 133 are detachable or fixedly connected. The snap-fit ​​connection includes, but is not limited to, the dovetail groove and the rib, the elastic claw and the limiting groove, or the rotation locking buckle. The bonding method includes medical pressure-sensitive adhesive bonding, UV curing adhesive bonding, or hot melt adhesive bonding. The thickness of the first forehead pad 102, the second forehead pad 112, the third forehead pad 122, and the fourth forehead pad 132 is 3mm to 8mm to balance cushioning performance and structural compactness.

[0033] The first carbon fiber rod mounting hole 101, the second carbon fiber rod mounting hole 111, the third carbon fiber rod mounting hole 121, and the fourth carbon fiber rod mounting hole 131 are through or blind holes with a diameter slightly larger than the outer diameter of the fitted carbon fiber rod, forming a clearance fit with a clearance of 0.1mm to 0.5mm. These mounting holes are positioned along the thickness direction of the first forehead support main bracket 103, the second forehead support main bracket 113, the third forehead support main bracket 123, and the fourth forehead support main bracket 133, with their axes perpendicular to the contact surfaces of the first forehead pad 102, the second forehead pad 112, the third forehead pad 122, and the fourth forehead pad 132, ensuring that the carbon fiber rod remains orthogonal to the patient's forehead reference plane after insertion. The locking structure is integrated into the inner wall of the first carbon fiber rod mounting hole 101, the second carbon fiber rod mounting hole 111, the third carbon fiber rod mounting hole 121, and the fourth carbon fiber rod mounting hole 131. It can be an elastic deformation ring, an eccentric set screw, a rotary cam clamping component, or a double-bevel wedge self-locking sleeve. When the carbon fiber rod is inserted, the locking structure is triggered by manual screwing, pressing, or rotating to perform radial contraction or clamping action, thereby achieving radial locking of the carbon fiber rod. For example, the first carbon fiber rod mounting hole 101 uses an elastic friction sleeve, the second carbon fiber rod mounting hole 111 uses an eccentric set screw, the third carbon fiber rod mounting hole 121 uses a rotary cam clamping component, and the fourth carbon fiber rod mounting hole 131 uses a double-bevel wedge sleeve.

[0034] The first forehead support main bracket 103, the second forehead support main bracket 113, the third forehead support main bracket 123, and the fourth forehead support main bracket 133, along with the first forehead rubber pad 102, the second forehead rubber pad 112, the third forehead rubber pad 122, and the fourth forehead rubber pad 132, work synergistically with the first carbon fiber rod mounting hole 101, the second carbon fiber rod mounting hole 111, the third carbon fiber rod mounting hole 121, and the fourth carbon fiber rod mounting hole 131. The first forehead support main bracket 103, the second forehead support main bracket 113, the third forehead support main bracket 123, and the fourth forehead support main bracket 133 work synergistically. 23 and the fourth front bracket 133 provide structural rigidity and assembly reference; the first front rubber pad 102, the second front rubber pad 112, the third front rubber pad 122 and the fourth front rubber pad 132 achieve uniform pressure distribution and reduce local pressure through soft materials and ergonomic curved surfaces; the first carbon fiber rod mounting hole 101, the second carbon fiber rod mounting hole 111, the third carbon fiber rod mounting hole 121 and the fourth carbon fiber rod mounting hole 131 and their built-in locking structure ensure repeatability and anti-disturbance stability when connected to the external carbon fiber rod.

[0035] Example 3 The support structures in Examples 1 and 2 are rigid, one-piece designs, which cannot achieve independent adjustment of angle and height. This makes them unsuitable for patients with different head shapes and sitting postures, easily leading to head tilt and pressure imbalance. Please refer to... Figures 14 to 18 This embodiment provides a bilaterally symmetrical adjustable support structure 2. Each support structure consists of a support base and a support rod. The lower end of the support rod is movably connected to the support base through a rotary joint, a sliding joint, or a combined kinematic joint, to achieve angle adjustment, height adjustment, or a combination of both. This structure constructs an adjustable gantry that can be adjusted bidirectionally in the sagittal plane, solving the problems of rigid fixed support structures and poor adaptability, and improving the universality of the device for patients of different body types.

[0036] In one optional embodiment, this application also provides a support structure 2 provided in two sets, symmetrically connected to both sides of the forehead structure 1; each set of support structure 2 includes a first support base 201, a second support base 211, a third support base 221 and a fourth support base 231, and a first support rod 202, a second support rod 212, a third support rod 222 and a fourth support rod 232. The lower ends of the first support rod 202, the second support rod 212, the third support rod 222, and the fourth support rod 232 are movably connected to the first support base 201, the second support base 211, the third support base 221, and the fourth support base 231 to achieve angle adjustment and / or height adjustment.

[0037] The support structure 2 consists of two sets, symmetrically connected to both sides of the forehead support structure 1. This means that the two sets of support structures are located on both sides of the forehead support structure 1, symmetrically arranged along the sagittal plane of the patient, and their spatial positional relationship satisfies mirror symmetry. After installation, the two sets of support structures together form an adjustable gantry structure. The opening of the gantry structure faces the front of the patient's head and is used to support and constrain the locking structure 3. The symmetrical arrangement ensures that the supporting reaction forces acting on both sides of the patient's head are equal in magnitude and symmetrical in direction, thereby avoiding head deflection or tilting caused by unilateral force. The connection method between the support structure 2 and the forehead support structure 1 can be any one of the following: male-female insertion, threaded fastening, snap-fit, or pin positioning. The specific connection structure can be selected according to the actual assembly requirements, and this embodiment does not impose any special limitations on this.

[0038] Each set of support structures 2 includes a first support base 201, a second support base 211, a third support base 221, and a fourth support base 231, as well as a first support rod 202, a second support rod 212, a third support rod 222, and a fourth support rod 232. Each set of support structures consists of one support base and one support rod. The first support base 201, the second support base 211, the third support base 221, and the fourth support base 231 are rigid load-bearing components, and their bottoms are equipped with mounting structures adapted to external mounting platforms such as CBCT treatment bed guide rails, support interfaces, or fixed base plates, such as countersunk screw holes, T-slots, positioning bosses, or magnetic surfaces. The first support rod 202, the second support rod 212, the third support rod 222, and the fourth support rod 232 are all load-bearing components. The struts 222 and 232 are vertically extending load-bearing members. Their cross-sectional shapes can be circular, square, rectangular, or polygonal, and their materials can be aluminum alloy, stainless steel, or carbon fiber composite materials. The specific dimensions and wall thickness can be set according to the maximum load-bearing requirements and lightweight requirements. This application embodiment does not impose any special limitations on this. The upper ends of the first support rod 202, the second support rod 212, the third support rod 222, and the fourth support rod 232 are used to connect the first connecting beam 313, the second connecting beam 323, and the third connecting beam 333 of the locking structure 3. The lower ends are connected to the first support base 201, the second support base 211, the third support base 221, and the fourth support base 231 through a movable connection.

[0039] The movable connection between the lower ends of the first support rod 202, the second support rod 212, the third support rod 222, and the fourth support rod 232 and the first support base 201, the second support base 211, the third support base 221, and the fourth support base 231 means that the lower ends of the support rods are not rigidly fixed to the support bases, but are connected through a mechanical structure that allows relative movement. This movable connection structure can be a revolute joint such as a pin with a bearing, a hinge, or a ball joint; a prismatic joint such as a linear guide rail with a slider, a guide sleeve with a shaft; or a compound kinematic joint such as a universal joint or a ball joint with a limit stop. In embodiment 2, the lower end of the second support rod 212 is rotatably connected to the second support base 211 via a pin, thereby achieving pitch angle adjustment around the horizontal axis. In this embodiment, the lower end of the fourth support rod 232 is slidably embedded in the second guide rod 2312 provided inside the fourth support base 231, and is further assisted by a shaped cam 2323 cooperating with a gear slot plate 2313 to achieve multi-level height adjustment and locking. The specific form of the above-mentioned movable connection structure can be selected according to the requirements of adjustment accuracy, ease of operation and locking reliability, and this application embodiment does not impose any special limitations on this.

[0040] The purpose of angle and / or height adjustment is as follows: the support rod can be displaced or rotated in at least one degree of freedom through the movable connection between the support rod and the support base; angle adjustment refers to the rotation of the support rod around a horizontal axis, thereby changing its tilt angle relative to the frontal structure 1 to adapt to the lateral contour curvature of different patients' temporal to parietal regions; height adjustment refers to the translation of the support rod in the vertical direction, thereby adjusting the overall installation height of the locking structure 3 to match different patients' head height and sitting posture height; "and / or" indicates that the two can be achieved individually or simultaneously; for example, in the same set of support structures, angle and height adjustment can be simultaneously supported by a combined structure such as a lifting slide with tilt adjustment; after adjustment, reliable locking can be achieved by fasteners such as locking screws, eccentric wheels, pawls, elastic limiting structures such as snap rings, springs, or mechanical pins such as positioning pins inserted into fastening holes 2111; the locking method should ensure no loosening, no rebound, and no creep during CBCT scanning. The specific values ​​of adjustment range, adjustment accuracy, and locking holding force are not limited in the embodiments of this application.

[0041] Example 4 The height adjustment of the support structure in Example 3 relies on traditional threaded or friction pairs for locking, which suffers from problems such as adjustment lag, easy slippage, and accuracy degradation, failing to guarantee long-term positioning stability. Please refer to... Figures 7 to 10This embodiment integrates a self-locking linear lifting mechanism into the support structure 2, including a first guide rod 2213 with a rack, a gear 2227 meshing with the rack, and a one-way anti-reverse ratchet 2226 mechanism. The lifting of the support rod is achieved through the meshing transmission of the gear and rack, while the one-way anti-reverse characteristic of the ratchet mechanism enables instant self-locking at any height. This mechanism overcomes the shortcomings of traditional lifting and locking methods, ensuring the accuracy and stability of the support rod height adjustment, and is suitable for the positioning needs of children and elderly patients.

[0042] In an optional embodiment, this application also provides a head positioning device, wherein the support structure 2 integrates a self-locking linear lifting mechanism, the mechanism comprising: A first guide rod 2213 with a rack is mounted on the support base 221; and The gear 2227, which is constantly meshed with the rack, is located inside the support rod 222, and the ratchet 2226 mechanism, which cooperates with the gear 2227 to achieve one-way anti-reverse mechanism; The support rod 222 can be raised, lowered, and locked at any height through the meshing transmission of gear 2227 and rack, and the self-locking action of ratchet 2226.

[0043] The support rod 222 is a hollow tubular structure. The bottom of its inner cavity is provided with a gear mounting seat and a ratchet mounting structure 2225 for coaxially mounting the gear 2227 and the ratchet 2226. The gear 2227 is rotatably supported in the mounting seat through a rotating shaft and always maintains constant meshing with the rack on the first guide rod 2213.

[0044] Example 5 The height adjustment of the support structure in Example 3 is cumbersome, requiring tools to tighten bolts, which cannot meet the needs of rapid clinical positioning and makes it difficult to temporarily lock the position midway. Please refer to... Figures 14 to 17 In this embodiment, a quick adjustment and locking mechanism is integrated into the support structure 2, including a gear slot plate 2313 with a series of slots, a rotatable irregular cam 2323, and a return spring. The irregular cam 2323 can release the axial constraint of the support rod, realizing free lifting and lowering; after the release operation, the return spring drives the cam to reset and engage in the slot, completing the quick locking.

[0045] In an optional embodiment, this application also provides a head positioning device, wherein the support structure 2 integrates a quick adjustment and locking mechanism, the mechanism comprising: A gear slot plate 2313 with a series of slots is disposed on the support base 231; and A shaped cam 2323 is rotatably disposed inside the support rod 232; By rotating the irregular cam 2323 to disengage from the slot of the gear slot plate 2313, the support rod 232 can be raised and lowered freely; after the release operation, the irregular cam 2323 resets and re-engages with the slot, achieving quick locking.

[0046] Example 6 The support structure in Example 3 lacks a reliable mechanical limiting structure after angle adjustment, making it susceptible to angle drift due to external disturbances and affecting the stability of the head positioning posture. Please refer to... Figures 4 to 5 In this embodiment, multiple sets of fastening holes 2111 are provided on the side of the support base 211. After the support rod 212 has completed angle adjustment, the insertion of the positioning pin forms rigid interference with the corresponding hole, thereby mechanically limiting the rotational freedom of the support rod. This structure solves the problem of support rod angle drift and ensures the stability of the support structure's posture throughout the CT scan process.

[0047] In an optional embodiment, the present application also provides that the support base 211 has a fastening hole 2111 on its side, which is used to form a mechanical limit after the angle of the support rod 212 is adjusted by inserting a positioning pin.

[0048] The fastening insertion hole 2111 is a through hole opened on the side wall of the support base 211. Its axis is perpendicular to the rotation axis of the support rod 212. The hole diameter is matched with the outer diameter of the matching positioning pin to ensure reliable rigid interference after insertion. There are multiple fastening insertion holes 2111, which are distributed in a circular direction or in a linear array to meet the limiting requirements of the support rod 212 at different adjustment angles.

[0049] Example 7 The locking structure in Example 1 is an integral rigid splint or a single-curved strap, which cannot adapt to the three-dimensional curvature of the patient's head, easily leading to concentrated point / line contact pressure and inducing uncomfortable micro-movements in the patient. Please refer to... Figure 3 , Figure 6 , Figure 11 This embodiment provides a distributed locking structure 3, including a connecting beam, multiple sets of clamping units, and a direction adjustment structure. The connecting beam forms a rigid load-bearing frame; each clamping unit consists of a rigid clamping rod and a flexible buffer connector; the direction adjustment structure allows the buffer connector to adaptively deflect and conform to the curved surface of the head. This structure achieves a three-level coordinated constraint of "rigid frame, flexible end, and adaptive adjustment," solving the problems of poor adaptability and pressure concentration in traditional locking structures.

[0050] In an optional embodiment, this application also provides a locking structure 3 comprising: The first connecting beam 313 and the second connecting beam 323 are respectively connected at both ends to the top of the supporting structures 2 on both sides. At least one set of clamping units, each set of clamping units including a first clamping rod 311, a second clamping rod 321 and a third clamping rod 331, a first buffer connector 312, a second buffer connector 322 and a third buffer connector 332; The upper ends of the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331 are connected to the first connecting beam 313 and the second connecting beam 323, and the lower ends are connected to the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332 through a direction adjustment structure, so that the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332 can adaptively conform to the curvature of the patient's head.

[0051] The first connecting beam 313 and the second connecting beam 323 are rigid load-bearing components used to form a stable lateral connection between the tops of the two supporting structures 2, constituting the overall load-bearing frame of the locking structure 3; their materials can be aluminum alloy, stainless steel, or carbon fiber composite materials, and their cross-sectional shape can be rectangular, circular, or I-shaped. The dimensions can be set according to the spacing of the supporting structures 2 and the load-bearing requirements, for example, the width is 20mm to 50mm and the thickness is 5mm to 15mm. This application embodiment does not make any special limitations on this; the two ends of the first connecting beam 313 and the second connecting beam 323 are provided with The support structure 2 has mounting holes or slots for the top interface, allowing for detachable connection via bolts, plug-in fitting, or quick-release fasteners. In some embodiments, the first connecting beam 313 and the second connecting beam 323 are designed in sections, with the middle section being telescopic or foldable to accommodate patients with different head widths. In other embodiments, the first connecting beam 313 and the second connecting beam 323 integrate a height fine-tuning mechanism, such as knob-type lifting adjustment components located at both ends of the beam, for fine calibration of the overall beam height within ±2mm after connection.

[0052] The clamping unit is a distributed constraint execution unit used to independently apply controllable constraint forces under the rigid reference provided by the first connecting beam 313 and the second connecting beam 323. Each set of clamping units is arranged axially along the first connecting beam 313 and the second connecting beam 323, and the number can be set to one, two, or three sets according to clinical needs. For example, one set can be arranged above the forehead, in the parietal region, and in the occipital region to cover key anatomical sites of the head. The first clamping rod 311, the second clamping rod 321, and the third clamping rod 331 are force transmission rods, and their upper ends are provided with connection structures that match the first connecting beam 313 and the second connecting beam 323, for example... The mounting base with internal threads, ball joint, or sliding guide sleeve can be quickly installed and removed by manual tightening, wrench locking, or spring clip. The lengths of the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331 can be set to 80mm to 160mm according to the patient's head size. The rod material can be lightweight alloy or reinforced plastic, and the surface can be provided with anti-slip texture or scale markings for visual adjustment. The lower end of the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331 is provided with a direction adjustment structure mounting position. This mounting position forms a mechanical cooperation relationship with the direction adjustment structure and does not participate in the direction adjustment function itself.

[0053] The first buffer connector 312, the second buffer connector 322 and the third buffer connector 332 are flexible contact terminal components that come into direct contact with the patient's scalp or hair. Their main structure includes a shell, an internal buffer element and a contact surface layer.

[0054] The orientation adjustment structure is a key mechanism for realizing the adaptive spatial attitude of the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332. Its core function is to allow the first buffer connector 312, the second buffer connector 322, and the third buffer connector 332 to deflect about at least one rotational degree of freedom during the application of vertical pressure by the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331, thereby automatically aligning the local normal of the contact area. The orientation adjustment structure can be a ball joint structure, a universal joint structure, a dual-axis hinge structure, or a flexible hinge structure. When a ball joint structure is used, the ends of the first clamping rod 311, the second clamping rod 321, and the third clamping rod 331 are provided with ball heads.

[0055] Through the above technical solution, this application achieves the following: the first connecting beam 313 and the second connecting beam 323 provide a rigid reference for cross-support; the clamping unit realizes distributed force output; and the direction adjustment structure endows the first buffer connector 312, the second buffer connector 322 and the third buffer connector 332 with spatial posture self-adaptation capability. This effectively solves the problems of pressure concentration, patient discomfort and constraint instability caused by the inability of traditional locking structures to adapt to three-dimensional head shapes, and significantly improves the fit, comfort and image stability of head positioning in oral CBCT examination.

[0056] Example 8 Current cone-beam computed tomography (CBCT) systems for the oral cavity use generic headrests or simple straps, lacking the ability to adapt to the anatomical features of the maxillofacial region. This can easily lead to slight head movements in patients, causing motion artifacts and spatial misalignment of anatomical structures. Please refer to [link / reference]. Figure 1 , Figure 4 , Figure 7 , Figure 14 This embodiment provides an oral cone-beam CT system integrating the aforementioned head positioning device, including a CBCT main unit, a patient bed, and a head positioning device. The head positioning device is rigidly connected to the CBCT main unit through a standardized interface of the forehead support structure. The support structure enables independent bilateral adjustment and multiple locking, while the locking structure provides flexible adaptive constraint. This system solves the problem of poor adaptability of existing CBCT headrests, maintaining sub-millimeter-level stability of the patient's head during scanning and improving the imaging clarity and measurement accuracy of key anatomical features.

[0057] In one optional embodiment, an oral cone-beam CT system is provided, including the head positioning device described above, for positioning and fixing the head of the subject being photographed.

[0058] The oral cone-beam CT system includes a CBCT main unit with an X-ray source, a flat panel detector, a rotating gantry, a patient bed, an image reconstruction workstation, and a control terminal. The head positioning device, as an independent and detachable module, connects to the CBCT main unit's dedicated guide rail or positioning interface via the first carbon fiber rod mounting holes 101, 111, 121, and 131 on the forehead support structure 1, and is rigidly locked by a built-in locking structure. Two sets of support structures 2 are symmetrically installed on both sides of the forehead support structure 1, including a first support base 201 and a second support base 211. The third support base 221 and the fourth support base 231 form a mechanical limit with the lateral guide rail or base of the CBCT patient bed through a male-female plug-in structure or fastening plug 2111; the locking structure 3 is located above the patient's head, and its first connecting beam 313, second connecting beam 323 and third connecting beam 333 are rigidly connected to the top of the two side support structures 2 at both ends respectively. The first buffer connector 312, second buffer connector 322 and third buffer connector 332 in the pressing unit adaptively fit the patient's forehead and temporal curved surface under the constraint of the ball hinge structure, and form a flexible surface contact constraint with the head buffer pad 324.

[0059] Through the above technical solution, the head positioning device is embedded as a dedicated subsystem into the overall architecture of the oral cone-beam CT scanner: a high-rigidity, zero-offset connection benchmark with the CBCT equipment is established using the forehead structure 1; relying on the bilateral independent adjustment and multiple locking mechanisms of the support structure 2, including angle limiting, height self-locking, and rapid slot locking, the device is precisely positioned and vibration-resistant on the patient bed; then, through the distributed compression unit and curved adaptive buffer mechanism of the locking structure 3, uniform, controllable, and repositionable constraint forces are applied to the forehead, parietal bone, and bilateral temporal regions without causing patient discomfort; ultimately, the subject's head maintains sub-millimeter-level spatial stability during the entire CBCT scan cycle, eliminating motion artifacts and supporting advanced clinical applications such as precise implant planning, invisible appliance design verification, and preoperative navigation in maxillofacial surgery.

[0060] The above description is merely a preferred embodiment that embodies the innovative concept of this invention. Any reasonable changes and interpretations made by those skilled in the art to the details after understanding the spirit and essence of this invention should be considered as not departing from the protection scope of this invention.

[0061] The preferred embodiments of this patent have been described in detail above. However, this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.

Claims

1. A head positioning device, characterized by The application relates to a head fixing device for fixing a patient's head, which comprises the following components: a forehead structure (1) for supporting the forehead of a patient and serving as a reference for connecting the device to an external frame; a support structure (2) connected to the forehead structure (1) for providing vertical support and adjustment functions; and a locking structure (3) installed on the top of the support structure (2) for applying a restraining force to the head of a patient from above or from the side; wherein the forehead structure (1), the support structure (2) and the locking structure (3) work together to achieve adjustable fixing of the head of a patient. The forehead structure (1) comprises:

2. The head positioning device of claim 1, wherein, a forehead structure main support (103, 113, 123, 133) constituting the main frame of the forehead structure (1); a forehead rubber pad (102, 112, 122, 132) arranged at the upper end of the forehead structure main support (103, 113, 123, 133) for directly contacting the forehead of a patient; and a carbon fiber rod mounting hole (101, 111, 121, 131) arranged on the forehead structure main support (103, 113, 123, 133) for inserting an external carbon fiber rod; wherein the inside of the carbon fiber rod mounting hole (101, 111, 121, 131) is integrated with a locking structure for locking and fixing the carbon fiber rod after insertion. The forehead rubber pad (102, 112, 122, 132) is made of soft biocompatible material and is detachably or fixedly connected to the forehead structure main support (103, 113, 123, 133) through buckle connection or adhesion.

3. The head positioning device of claim 2, wherein, The support structure (2) is provided with two groups and is symmetrically connected to the two sides of the forehead structure (1); each group of the support structure (2) comprises a support base (201, 211, 221, 231) and a support rod (202, 212, 222, 232); 4. The head positioning device of claim 1, wherein, the lower end of the support rod (202, 212, 222, 232) is movably connected to the support base (201, 211, 221, 231) to realize angle adjustment and / or height adjustment. The support structure (2) is integrated with a self-locking linear lifting mechanism, which comprises:

5. The head positioning device of claim 4, wherein, a first guide rod (2213) with a rack arranged on the support base (221); and a gear (2227) arranged in the support rod (222) and always meshing with the rack, and a ratchet wheel (2226) mechanism cooperating with the gear (2227) to realize one-way locking; the lifting and locking of the support rod (222) at any height are realized through the meshing transmission of the gear (2227) and the rack and the self-locking action of the ratchet wheel (2226). The support structure (2) is integrated with a quick adjustment and locking mechanism, which comprises:

6. The head positioning device of claim 4, wherein, a gear slot plate (2313) with a series of slot arranged on the support base (231); and a special-shaped cam (2323) rotatably arranged in the support rod (232). ​ The support rod (232) can be freely lifted by rotating the special-shaped cam (2323) to disengage the clamping groove of the gear clamping groove plate (2313); after the release operation, the special-shaped cam (2323) is reset and re-engaged with the clamping groove to achieve quick locking.

7. The head positioning device of claim 4, wherein, The support base (211) is provided with a fastening insertion hole (2111) on the side, which is used to insert a positioning pin to form mechanical limiting after the angle adjustment of the support rod (212).

8. The head positioning device of claim 4, wherein, The support base (211) is detachably connected with the forehead structure (1) through a male-female plug-in structure.

9. The head positioning device according to any one of claims 1 to 8, characterized in that, The locking structure (3) comprises: a connecting cross beam (313, 323) connected with the top of the support structure (2) on both sides; at least one set of pressing units, each set of the pressing units comprising a pressing rod (311, 321, 331) and a buffer connector (312, 322, 332); the upper end of the pressing rod (311, 321, 331) is connected with the connecting cross beam (313, 323), and the lower end is connected with the buffer connector (312, 322, 332) through a direction adjusting structure, so that the buffer connector (312, 322, 332) can be adaptively fitted to the curved surface of the patient's head.

10. The head positioning device of claim 9, wherein, The direction adjusting structure is a ball hinge structure, the end of the pressing rod (311, 321, 331) is provided with a ball head, and the upper part of the buffer connector (312, 322, 332) is provided with a ball socket accommodating the ball head and a locking part.

11. The head positioning device of claim 9, wherein, The locking structure (3) further comprises a head buffer pad (324) arranged between the buffer connectors (322) on both sides, and the head buffer pad (324) is flexibly connected through a connecting cross beam assembly (325).

12. The head positioning device of claim 9, wherein, The connecting cross beam adopts a cross beam framework (334) with a reinforcing structure.

13. An oral cone-beam CT system, characterized by comprising: The head positioning device according to any one of claims 1 to 12 is used to position and fix the head of a photographed object.

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