MOVABLE MODULAR PHANTOM OF THE HUMAN ABDOMINAL ZONE

Abstract

This utility model relates to medicine, specifically to anatomical phantoms of the human abdominal region. The device comprises a liver phantom, made of elastic two-component moldable silicone, with integrated tumor and vascular structures, and cavities equipped with access ports for the administration of radiopaque fluid. The liver phantom is mounted in an elastic support, which is a replaceable module simulating the soft tissues of the human abdominal region, and is subject to controlled deformation in the cranio-caudal direction, generated by a movable piston. The drive and electronic components of the device are located outside the imaging area, reducing artifacts in the resulting medical images.Deformation parameters, including a deformation magnitude of 5 to 50 mm, a deformation rate of 5 to 10 mm / s, and a frequency of 5 to 30 cycles per minute, are programmably set as adjustable values ​​using the control unit's microcontroller, ensuring reproducible displacement of integrated tumor models from 2 to 16 mm. The liver phantom, designed as a replaceable module, can be replaced due to wear or with replacement modules made of various materials, with varying anatomical structures and tumor model locations, including for simulating various clinical and training scenarios. The elastic support is designed as a replaceable module and can be swapped with other replaceable modules, each with a different internal cavity shape.

Description

[0001] Technical field

[0002] The utility model relates to medicine, in particular to anatomical phantoms of the human abdominal area, used for practicing minimally invasive surgical interventions, setting up and calibrating diagnostic medical equipment, as well as research and development in the field of robotic surgery.

[0003] During minimally invasive procedures, it is important to consider the movement of organs caused by the patient's breathing. In particular, the liver, being a large and mobile organ, is subject to significant displacement, complicating the positioning of surgical instruments during surgical procedures. Realistic simulation of respiratory deformations of the liver phantom is necessary to improve the safety of procedures by providing the opportunity to practice organ movements and positioning surgical instruments relative to moving tumor models during minimally invasive procedures.

[0004] State of the art

[0005] The prior art includes medical phantoms used for training specialists, testing medical devices and research using medical imaging methods, including liver models for ultrasound diagnostics (US), computed tomography (CT) and magnetic resonance imaging (MRI).

[0006] KR Patent 102051116 B1, published in January 2020 (copyright holder: Korea Research Institute of Standards and Science, KRISS), proposes a method for fabricating a liver phantom and describes the phantom itself. The patent describes a step-by-step process for producing the model: from fabricating a liver mold based on 3D models obtained using CT and MRI scans to filling the formed outer shell with a phantom fluid simulating the physical characteristics of human liver parenchyma. The patent also describes the ability to integrate tumor models of varying sizes and hardness into the phantom structure, enabling the reproduction of various stages and types of liver tissue lesions. Pigmented silicone is used to fabricate the internal, scaled-down liver model, while the outer shell is formed from transparent silicone.A distinctive feature of this method is the fabrication of a scaled-down liver model, the formation of a molding shell of a specified thickness over it, and then filling the resulting cavity with phantom fluid, which together approximates the physical properties of the phantom to liver tissue. This solution is applicable for calibrating ultrasound and CT / MRI imaging systems, as well as for educational and research purposes requiring the reproduction of pathological processes in liver tissue. A drawback of this approach is the lack of a mechanism for dynamically simulating phantom motion and deformation, making it impossible to simulate the organ's natural mobility during surgical procedures. Furthermore, the method does not allow for controlled variation of the mechanical properties of the liver parenchyma or the entire organ during fabrication; variability in stiffness has only been described for tumors, limiting the realism of tactile simulation.

[0007] US Patent 20080298540 A1, published in December 2008 (copyright holder: McGill University), describes a deformable phantom for simulating the movement of a patient's organs. The device comprises a chamber filled with a first liquid substance and a deformable phantom made of a material equivalent to human organ tissue, with an open end for communication with a second substance, such as air outside the chamber. A pressure-changing mechanism is also provided—either in the chamber or in the phantom itself—causing the second substance to flow through the open end, converting the phantom from a normal state to a deformed one, thereby simulating respiratory deformations. The device also includes markers simulating vascular-bronchial bifurcations, as well as a simulated tumor with the ability to accommodate a radiation dosimeter. A lung phantom made of a porous spongy material with an elastic shell is presented as an example of a simulated organ.Although the proposed system allows for simulating changes in organ volume, the movement control method essentially amounts to regulation. Furthermore, the presented phantom is primarily designed for radiotherapy applications and does not provide sufficient anatomical detail for fully practicing minimally invasive surgical procedures.

[0008] Patent WO 2018091265 A1, published in 2018 (copyright holder - Institut National de la Santé et de la Recherche Médicale, INSERM), discloses a phantom device, a simulation system, and a method for preparing a system for detecting a pathological lesion affected by respiratory motion. The device comprises a housing with an internal space divided by a flexible membrane simulating tissue at the boundary between two adjacent anatomical structures, forming two compartments filled with materials simulating different anatomical structures, such as the liver or lungs. To simulate respiratory motion, a drive system is provided, consisting of an electric motor and a motion transmission mechanism, to which simulated tumors are attached. When the electric motor is activated, the simulated tumor moves along the longitudinal axis of the device housing, contacts the membrane, and deforms it toward the second compartment, simulating the effect of respiration on the organ's shape.The device allows for pre-configured image recording parameters, including for computed tomography examinations. Although the described phantom can simulate tumor displacement caused by breathing, its design is not intended for surgical procedures, as there is no explicit provision for interaction between surgical instruments and the phantom.

[0009] The prototype is US Patent 8535061 B2, published in September 2013 (copyright holder - The Regents of the University of California). The authors disclose an elastic model of the human torso designed to simulate movements caused by breathing and heartbeat under clinical conditions. The phantom includes an elastic, hermetically sealed, fluid-filled container in the shape of a torso, inside which are placed the main anatomical models: an elastic imitation of the lungs, a imitation of the heart made of two elastic membranes with walls of different thicknesses with spiral thickenings to generate realistic twisting motion and a porous filler in the intermembrane cavity, as well as an elastic imitation of the aorta, a phantom of the liver, stomach, and intestines.A key feature is the heart and lung motion control system, which includes pumps, valves, and a controller that allows for the regulation of breathing and heartbeat patterns with controlled speed and amplitude. Additionally, reservoirs and tubes are provided for delivering radiocontrast fluid to various cavities of the phantom. The presented design is oriented toward combined cardiorespiratory torso deformations, with the abdominal organs, when open, realized as sealed elastic containers of constant volume, limiting the accurate reproduction of their deformations when simulating various clinical scenarios. The motion control system used relies on fluid or air injection, which may not provide sufficient flexibility in simulating dynamic processes characteristic of soft tissues and also limits the interaction of surgical instruments with the phantom.The modularity of the design is not explicitly stated, which limits the possibility of adapting the phantom for practicing various surgical procedures.

[0010] Thus, existing solutions do not provide comprehensive modeling of abdominal organs with a modular structure, controlled deformation, and instrumental access for practicing surgical procedures, which significantly limits the potential for using the phantoms in question for practicing minimally invasive surgical interventions, setting up and calibrating diagnostic medical equipment, and research and development in the field of robotic surgery.

[0011] Terms and Definitions

[0012] The following terms and abbreviations are used in this description. Unless otherwise specified, the terms have the meanings generally accepted in the relevant technical field.

[0013] Craniocaudal direction is the anatomical direction from the head to the feet along the longitudinal axis of the human body.

[0014] Instrument access - the ability to guide, insert and manipulate surgical instruments within the phantom through its surface.

[0015] Computed tomography (CT) is a medical imaging method based on recording the attenuation of X-ray radiation with the subsequent formation of tomographic images.

[0016] CT slice is a two-dimensional tomographic image of a given thickness, formed based on CT data within the scanning area.

[0017] The liver phantom is an element of a mobile modular phantom of the human abdominal area, made in the form of a replaceable module simulating the human liver with integrated imitations of tumors and vascular structure.

[0018] Elastic support is an element of a movable modular phantom of the human abdominal area, made in the form of a replaceable module simulating the soft tissues of the human abdominal area and intended for the installation of a replaceable module of the liver phantom.

[0019] Problem of the utility model

[0020] The objective of the utility model is to improve the quality of training medical personnel in minimally invasive surgical interventions and the effectiveness of developing solutions in the field of robotic surgery through the use of a mobile modular phantom of the human abdominal area, capable of simulating the dynamic deformation of the liver under the influence of respiratory movements, including reproducing the mobility of simulated tumors.

[0021] Technical result

[0022] The technical result is an expansion of the functional capabilities of a mobile modular phantom of the human abdominal area due to the controlled imitation of respiratory deformations of the liver phantom with a reproducible displacement of integrated tumor imitations while maintaining instrumental access, as well as due to the implementation of the liver phantom in the form of a replaceable module, allowing its replacement both due to wear and tear and with replaceable modules with different anatomical structures or localizations of tumor imitations, including phantom design options manufactured taking into account the anatomical features of specific patients, as well as specialized replaceable modules intended for training and practicing minimally invasive surgical interventions.

[0023] The essence of the utility model

[0024] The stated problem is solved, and the technical result is achieved by implementing a mobile modular phantom of the human abdominal area as a single device. It comprises a liver phantom, designed as a replaceable module and made of elastic material with integrated imitation of the vascular structure and tumors, as well as an actuator unit in which an electric drive, via a screw transmission, acts on a movable piston, ensuring deformation of the liver phantom in the cranio-caudal direction, thereby simulating the movement of the diaphragm during respiration, while maintaining instrumental access to the phantom. The drive and electronic components are located outside the medical imaging area, minimizing artifacts in the resulting medical images. The liver phantom is designed as a replaceable module and is located in an elastic support simulating the soft tissues of the abdominal area and ensuring relative displacement of internal structures during deformation.The elastic support is made in the form of a replaceable module, and it is possible to replace it with other replaceable modules made with different options for the shape of the internal cavity.

[0025] The deformation parameters, including the deformation magnitude from 5 to 50 mm, the deformation speed from 5 to 10 mm / s and the frequency from 5 to 30 cycles per minute, are set programmatically as adjustable values ​​by the microcontroller of the control unit, which ensures reproducible displacement of the integrated tumor simulators from 2 to 16 mm.

[0026] The liver phantom and integrated tumor models are made from a two-component castable silicone with additives that influence the material's acoustic properties, such as echogenicity and sound velocity for ultrasound examinations, and radiographic density to ensure the distinction between healthy liver tissue and tumors, with sufficient contrast for visualization in computed tomography (CT) studies. Various liver phantom designs, in the form of replaceable modules, are manufactured with different parenchyma and tumor model material compositions, enabling the simulation of various tissue types depending on the clinical or educational scenario. The design features interchangeable modules of the elastic support and liver phantom, allowing for rapid transition between clinical scenarios.

[0027] Brief description of drawings

[0028] Fig. 1 - general view of the assembled movable modular phantom of the human abdominal area: base, elastic support made in the form of a replaceable module and simulating the soft tissues of the human abdominal area, liver phantom made in the form of a replaceable module, movable piston, ball screw transmission, rail linear guides, stepper motor with encoder, control unit, power supply, emergency power off button.

[0029] Fig. 2 - a liver phantom made in the form of a replaceable module, containing liver parenchyma with an integrated vascular structure and five tumor imitations.

[0030] Fig. 3 - a liver phantom made in the form of a replaceable module, with an alternative arrangement of imitations of tumors and cavities of the integrated vascular structure compared to the variant of their arrangement in Fig. 2.

[0031] Fig. 4 - prototype of a mobile modular phantom of the human abdominal area with replaceable modules of a liver phantom and an elastic support simulating the soft tissues of the human abdominal area.

[0032] The items shown in the images correspond to the following:

[0033] 101 - Device base.

[0034] 102 - Stepper motor with encoder.

[0035] 103 - Stepper motor driver with encoder.

[0036] 104 - Control unit.

[0037] 105 - Power supply.

[0038] 106 - Emergency power off button.

[0039] 107 - A liver phantom, made in at least one embodiment as a replaceable module.

[0040] 108 - An elastic support, made in at least one embodiment in the form of a replaceable module.

[0041] 109 - Movable piston.

[0042] 110 - Linear rail guides.

[0043] 111 - Ball screw.

[0044] 201 - Integrated tumor simulators.

[0045] 202, 203, 204 - Cavities of the integrated vascular structure.

[0046] 301 - Integrated tumor simulators (additional design, Fig. 3).

[0047] 302, 303, 304 - Cavities of the integrated vascular structure (additional design option, Fig. 3).

[0048] Description of the utility model

[0049] The diagram shown in Fig. 1 shows one embodiment of a mobile modular phantom of the human abdominal area. The base (101) of the device contains control and actuator units, including a stepper motor with an encoder (102) with a driver (103) for the stepper motor with an encoder, a control unit (104), a power supply (105), and a button (106) for emergency power off of the device in the event of an emergency. The deformation in the cranio-caudal direction of the liver phantom (107), placed in an elastic support (108) simulating the soft tissues of the human abdominal area, is achieved by moving the movable piston (109) along linear rail guides (110), wherein the movement of the movable piston is realized by means of a ball screw transmission (111), driven into rotation by a stepper motor with an encoder (102).

[0050] In the diagram shown in Fig. 2, the liver phantom (107) is designed as a replaceable module and represents a monolithic volume of liver parenchyma with integrated imitations of five tumors (201), pre-placed in a mold before pouring the parenchyma. The internal vascular structure of the liver phantom (107) is designed as three cavities (202, 203, and 204) of complex shape, formed during pouring and equipped with technological access for the introduction of radiocontrast fluid.

[0051] Fig. 3 shows a variant of the liver phantom (107) with a different arrangement of tumor imitations (301) and cavities of the integrated vascular structure (302, 303 and 304) while maintaining the external geometric parameters.

[0052] Figure 4 shows a prototype of a mobile modular phantom of the human abdominal area with replaceable modules of a liver phantom and an elastic support.

[0053] In one embodiment, the liver phantom parenchyma is made from a flexible, two-component, castable silicone with a platinum catalyst. The formulation is selected to provide mechanical properties and acoustic characteristics suitable for ultrasound imaging and radiographic density sufficient to distinguish the parenchyma from tumor simulants in computed tomography. The tumor simulant material is selected based on the same criteria, ensuring increased radiographic density relative to the parenchyma material.

[0054] The liver phantom is manufactured using a 3D model. A split-section casting mold is created using 3D printing. Tumor imitations, as well as vascular structure imitations, made from water-soluble 3D printing material, are first placed and fixed into the mold cavity. The liver phantom parenchyma material is then poured into the mold, vacuum degassed, and cured. After curing, the liver phantom is removed from the mold and soaked in water until the vascular structure imitations completely dissolve, forming internal cavities.

[0055] Examples of application of the utility model

[0056] In one application, a mobile modular phantom of the human abdominal area is used as a training simulator for medical personnel performing minimally invasive liver procedures. Using the phantom, it is possible to practice selecting and optimizing access trajectories to target structures, as well as guiding and holding surgical instruments in simulated tumors, taking into account their displacement during respiratory deformities.

[0057] In another application, a mobile modular phantom of the human abdominal area is used as a test device in the development, configuration, and comparative testing of robotic systems, navigation equipment, and software designed for planning and performing minimally invasive liver interventions. The phantom enables the study of instrument guidance and tracking systems under controlled respiratory deformations, the verification of respiratory displacement compensation algorithms, and the comparison of planned and actual trajectories of surgical instrument insertion relative to simulated tumors and vascular structures. The interchangeable liver phantom modules and elastic support allow for a wide range of test scenarios, including variations in the anatomical complexity, depth, and relative positions of target structures.

Claims

1. A modular phantom of the human abdominal area with deformation by breathing, comprising a base, an elastic cradle, a liver phantom placed therein, made of an elastic material and including imitations of tumors and a vascular structure in the form of cavities, an actuator with a movable piston installed with the possibility of linear movement along rail linear guides and deformation of the liver phantom in the cranio-caudal direction, and a drive with a control unit, wherein the drive is made in the form of a stepper motor with an encoder and is kinematically connected to the movable piston through a ball-screw transmission, the microcontroller of the control unit is configured to set the parameters of deformation of the liver phantom, the elastic cradle for placing the liver phantom is mounted on the base separately from the actuator unit and the drive with a control unit for forming slices of computed tomography,and the radiographic density of the material simulating the parenchyma of the liver phantom is different from the radiographic density of the material simulating the tumors.

2. A modular phantom according to paragraph 1, characterized in that the microcontroller is configured to set the deformation value from 5 to 50 mm, the deformation rate from 5 to 10 mm / sec, and the deformation frequency from 5 to 30 cycles per minute.

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