CN115489122A - Method and system for constructing quality control simulation model of magnetic resonance radiotherapy machine - Google Patents
Method and system for constructing quality control simulation model of magnetic resonance radiotherapy machine Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/30—Auxiliary operations or equipment
- B29C64/386—Data acquisition or data processing for additive manufacturing
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/05—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves
- A61B5/055—Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1048—Monitoring, verifying, controlling systems and methods
- A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/30—Auxiliary operations or equipment
- B29C64/379—Handling of additively manufactured objects, e.g. using robots
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
- B29C64/30—Auxiliary operations or equipment
- B29C64/386—Data acquisition or data processing for additive manufacturing
- B29C64/393—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y40/00—Auxiliary operations or equipment, e.g. for material handling
- B33Y40/20—Post-treatment, e.g. curing, coating or polishing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B33—ADDITIVE MANUFACTURING TECHNOLOGY
- B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
- B33Y50/00—Data acquisition or data processing for additive manufacturing
- B33Y50/02—Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1048—Monitoring, verifying, controlling systems and methods
- A61N5/1049—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam
- A61N2005/1055—Monitoring, verifying, controlling systems and methods for verifying the position of the patient with respect to the radiation beam using magnetic resonance imaging [MRI]
Abstract
The invention provides a method and a system for constructing a quality control simulation die body of a magnetic resonance radiotherapy machine, which are used for generating a first simulation die body by importing a structural file of the obtained die body to be constructed into a 3D printing reconstruction system, then determining a target position to be measured and required measuring equipment, obtaining a second simulation die body by inserting an equipment plug-in of the required measuring equipment into the target position to be measured, performing 3D printing on the second simulation die body to obtain a hollowed die body, then obtaining imaging parameter information of a medical image of the die body to be constructed, fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ, adding an adhesive into the filling materials of the target area and the interested organ according to the corresponding concentration ratio, adding the adhesive, filling the mixture into the hollowed die body, and cooling to obtain the quality control simulation die body.
Description
Technical Field
The invention relates to the technical field of magnetic resonance radiotherapy, in particular to a method and a system for constructing a quality control simulation die body of a magnetic resonance radiotherapy machine.
Background
In recent years, in order to solve the problem that the resolution of soft tissue guided by X-ray images of the traditional treatment machine is insufficient, and the change of a tumor and surrounding organs at risk cannot be clearly captured, a magnetic resonance system and a radiotherapy system are integrated on the same platform, and the MR radiotherapy machine enters the field of radiotherapy. At present, the planning design of radiotherapy is mostly intensity modulated radiotherapy, and the planning field is various and the shapes are different; the MR imaging center and the radiation therapy center may often be offset; the MR image may be distorted by magnetic field or other factors, the secondary electrons are changed by lorentz force in the static magnetic field, and the actual motion path is twisted, resulting in electron flow effect, and thus affecting the dose distribution in the MR radiotherapy machine. Aiming at the problems of the MR radiotherapy machines, the quality control steps and the corresponding die bodies of the MR radiotherapy machines are designed by experts and physicists in the industry to carry out the quality control of MR images and dosage, wherein the steps comprise a water tank, a daily inspection die body, a strength-adjusting verification die body, an image verification die body and the like.
However, due to the strict requirements of magnetic resonance on the working environment and safety, the conventional radiotherapy machine quality control module cannot be directly applied to the MR radiotherapy machine. Most of the existing quality control detection die bodies for the MR radiotherapy machine depend on import or manufacturer configuration, are expensive, have relatively single functions and are difficult to use. The MR accelerated research shows that the geometric distortion, the dose influence and the like of the MR image are closely related to the size and the position of a phantom, for example, the geometric distortion of the MR image is basically controlled within 1mm in a volume 20cm away from the center, the image distortion is rapidly increased beyond the range, and the image distortion of a partial area is greater than 2mm in a range 20-25 cm away from the center. In addition, the tumor location and size are different for each patient, and if the phantom of the prior art is adopted, only the image and the irradiated dose of the current phantom can be displayed, and the current phantom cannot be associated with the target area and organs which are clinically concerned.
Disclosure of Invention
The invention aims to provide a construction method of a quality control simulation model body of a magnetic resonance radiotherapy machine, which solves the application defect of the existing quality control model body by customizing and designing the individual quality control simulation model body according to clinical requirements, can meet the individualized treatment requirements of clinical cases, can be independently used for the quality control of images and dosage of the MR radiotherapy machine, can realize end-to-end test verification from image guidance to dosage verification, and provides reliable quality guarantee for the radiotherapy application of the magnetic resonance radiotherapy machine.
In order to achieve the above objects, it is necessary to provide a method and a system for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine.
In a first aspect, an embodiment of the present invention provides a method for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine, where the method includes the following steps:
acquiring a structure file of a die body to be constructed; the structural files include Structure files of the patient's outer contour, target region, and organ of interest;
importing the structure file into a 3D printing reconstruction system to generate a first simulation model body;
determining the position of a target to be measured of the first simulation model body and required measuring equipment; the target position to be detected comprises a target area position and an interested organ position;
acquiring an equipment plug-in corresponding to equipment to be measured, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, and performing 3D printing on the second simulation die body to obtain a hollowed die body;
acquiring imaging parameter information of a medical image of a die body to be constructed, and fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ according to the imaging parameter information;
and adding filling materials of the target area and the interested organ into the adhesive according to the corresponding concentration ratio, heating, fusing and filling the adhesive to the corresponding position of the hollowed die body, and cooling to obtain the quality control simulation die body.
Further, the 3D print reconstruction system includes a 3D slicer system.
Further, the medical images include CT images and MR images; the imaging parameter information comprises T1 relaxation time, T2 relaxation time and CT values of a target area and an interested organ; the filling material comprises a material for adjusting T1 relaxation time, a material for adjusting T2 relaxation time and a material for adjusting CT value.
Further, the material for adjusting the T1 relaxation time is one of gadolinium trichloride, nickel diethylenetriaminepentaacetate chelate and gallium; the material for adjusting the T2 relaxation time is agarose; the CT value adjusting material is one of barium sulfate, calcium carbonate and glass microspheres; the adhesive is one of carrageenan and gelatin.
Further, the step of obtaining imaging parameter information of the medical image of the phantom to be constructed, and fitting and determining the concentration ratio of the filling materials corresponding to the target area and the interested organ according to the imaging parameter information comprises:
according to the preset concentration gradient, independently adding a material for adjusting T1 relaxation time, a material for adjusting T2 relaxation time and a material for adjusting CT value into an adhesive respectively to obtain T1 relaxation time, T2 relaxation time and CT value under different corresponding concentration values;
according to the T1 relaxation time, the T2 relaxation time and the CT value under different concentration values, a corresponding T1 relaxation time model, a T2 relaxation time model and a corresponding CT value model are obtained through fitting;
and respectively determining the concentration ratios of the filling materials corresponding to the target area and the interested organ according to the imaging parameter information of the target area and the interested organ and by combining the T1 relaxation time model, the T2 relaxation time model and the CT numerical model.
Further, the step of heating and fusing and filling to the corresponding position of the hollowed-out die body comprises:
and heating according to a preset temperature, and filling the hollow mold body to a corresponding position after uniformly stirring.
Further, the step of cooling to obtain the quality control simulation die body further comprises:
and packaging the outer opening of the quality control simulation die body by adopting a thermoplastic material.
In a second aspect, an embodiment of the present invention provides a system for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine, where the system includes:
the structure acquisition module is used for acquiring a structure file of the die body to be constructed; the structural files include Structure files of the patient's outer contour, target region, and organ of interest;
the die body pre-modeling block is used for importing the structure file into a 3D printing reconstruction system, generating a first simulation die body, and determining a target position to be measured and required measuring equipment of the first simulation die body; the target position to be detected comprises a target area position and an interested organ position;
the plug-in configuration module is used for acquiring an equipment plug-in corresponding to equipment to be measured, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, and performing 3D printing on the second simulation die body to obtain a hollowed-out die body;
the concentration selection module is used for acquiring imaging parameter information of a medical image of a die body to be constructed, and fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ according to the imaging parameter information;
and the die body generating module is used for adding the filling materials of the target area and the interested organ into the adhesive according to the corresponding concentration ratio, heating, fusing and filling the filling materials to the corresponding position of the hollowed die body, and cooling to obtain the quality control simulation die body.
In a third aspect, an embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor implements the steps of the method when executing the computer program.
In a fourth aspect, the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps of the above method.
The method comprises the steps of guiding a structural file of a to-be-constructed die body to a 3D printing reconstruction system to generate a first simulation die body, determining a target position to be measured and required measuring equipment, obtaining an equipment plug-in of the required measuring equipment, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, performing 3D printing on the second simulation die body to obtain a hollowed die body, obtaining imaging parameter information of a medical image of the to-be-constructed die body, fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ, adding an adhesive into the filling materials of the target area and the interested organ according to the corresponding concentration ratio, heating, melting, filling the mixture into the hollowed die body, and cooling to obtain the quality control simulation die body. Compared with the prior art, the method for constructing the quality control simulation model body of the magnetic resonance radiotherapy machine can design the individual quality control simulation model body according to the clinical requirement customization, effectively meets the individual treatment requirement of clinical cases, can be independently used for the quality control of the image and the dosage of the MR radiotherapy machine, can realize the end-to-end test verification from the image guide to the dosage verification, and provides reliable quality assurance for the radiotherapy application of the magnetic resonance radiotherapy machine.
Drawings
FIG. 1 is a schematic flow chart of a method for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine according to an embodiment of the present invention;
FIG. 2 is a schematic representation of a two-dimensional medical image and a corresponding three-dimensional reconstructed image in an embodiment of the invention;
FIG. 3 is a schematic structural diagram of a system for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine according to an embodiment of the present invention;
fig. 4 is an internal structural diagram of a computer device in the embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments, and it is obvious that the embodiments described below are part of the embodiments of the present invention, and are only used for illustrating the present invention, but not for limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In consideration of the problem that the quality control die body of the conventional radiotherapy machine cannot be used for the MR radiotherapy machine due to strict requirements of magnetic resonance on working environment and safety, the existing quality control detection die body for the MR radiotherapy machine mostly depends on import or manufacturer configuration, is single in function, high in price and incapable of meeting clinical individual differentiation requirements, and further cannot provide good quality guarantee application defects for magnetic resonance radiotherapy application, the invention provides a 3D printing-based magnetic resonance radiotherapy machine quality control simulation die body construction method for customizing a quality control simulation die body so as to ensure the high-precision effect of treatment; the following embodiment will explain the construction method of a quality control simulation phantom of a magnetic resonance radiotherapy machine in detail.
In one embodiment, as shown in fig. 1, a method for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine is provided, which includes the following steps:
s11, obtaining a structure file of a die body to be constructed; the Structure file may be understood as treatment-related Structure data for a specific case, including the Structure file of the patient's outer contour, target area and organ of interest; wherein the outer contour of the patient is understood to be the skin; an organ of interest may be understood as a tissue that a radiologist believes is more affected by the target irradiation, also called an organ at risk; the Structure file may be understood as a Structure (Structure) dicom file stored in a corresponding region where a doctor delineates on a CT image or an MR image of the radiation therapy planning system as shown in the left side of fig. 2.
S12, importing the structure file into a 3D printing reconstruction system, generating a first simulation die body, and determining a target position to be measured and required measuring equipment of the first simulation die body; the target position to be detected comprises a target area position and an interested organ position; the 3D printing reconstruction system may use a 3D system for interpreting files in dicom format in principle, and in this embodiment, a 3D slicer system is preferably used; the required measuring equipment adopts dosage measuring equipment required by treatment of a nuclear magnetic resonance radioactive machine according to a patient, and comprises an ionization chamber, a semiconductor detector, a film, a thermoluminescent dosimeter and the like;
and after the acquired Structure files of the outer contour, the target area and the interested organ of the patient are loaded to a 3D printing reconstruction system, the 3D printing reconstruction system can complete 3D reconstruction of the required printing Structure files, and a first simulation phantom without the additive amount measurement plug-in is obtained. The position of the target to be measured on the corresponding first simulation model body is understood as a case part needing to be measured, and can be determined according to the condition of an actual case, and the required measuring equipment is selected according to the actual treatment requirement.
S13, obtaining an equipment plug-in corresponding to equipment to be measured, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, and performing 3D printing on the second simulation die body to obtain a hollow die body; the required measuring equipment and the equipment plug-in are required to be matched for use, the size and the shape of the measuring equipment are possibly different, the specific equipment plug-in can be rectangular or cylindrical, the measuring equipment is inserted into the measuring equipment from outside to inside, namely, the plug hole of the equipment plug-in is required to be customized according to the shape and the size of the measuring equipment, the equipment plug-in can be fixed in the 3D printing reconstruction system for the commonly used measuring equipment in advance, and if a new measuring equipment is required to be used, the equipment plug-in can be added into the system through sketching as long as the size of the new measuring equipment is known. After the measuring equipment is inserted into the corresponding equipment plug-in, the equipment plug-in is inserted into the 3D target position to be measured of the reconstructed first simulation die body to replace the corresponding tissue, namely, the position of the tumor (target area) or normal interested organ tissue through which the plug-in passes is directly replaced by the corresponding equipment plug-in, and a second simulation die body containing the required measuring equipment (an ionization chamber measuring hole and a film cross section inserting hole) as shown in the right image of the figure is obtained; the second simulation die body obtained so far comprises basic outlines of the exterior and the interior of the simulation die body, hollow-out die bodies with hollow-out target areas and interested organ positions can be obtained through 3D printing, required filling materials can be filled into the hollow-out positions according to the following steps, and a complete individual customized quality control simulation die body is constructed and obtained.
S14, acquiring imaging parameter information of a medical image of a die body to be constructed, and fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ according to the imaging parameter information; wherein the medical images comprise CT images and MR images; the imaging parameter information comprises T1 relaxation time, T2 relaxation time and CT values of a target area and an interested organ; the filling material can be understood as a material which actually influences T1 relaxation time, T2 relaxation time and CT value, and comprises a material for adjusting T1 relaxation time, a material for adjusting T2 relaxation time and a material for adjusting CT value, concretely, the selection of various materials can be determined by combining the prior art according to actual requirements, and preferably, the material for adjusting T1 relaxation time can be gadolinium trichloride, nickel chelate with diethylenetriamine pentaacetic acid, gallium and the like; adjusting T2 relaxation time material to be agarose, etc.; materials for adjusting CT value are barium sulfate, calcium carbonate, glass microspheres and the like; the adhesive can theoretically use hydrogel with high biological, chemical and physical similarity with tissues, and carrageenan or gelatin is preferably used in the embodiment. It should be noted that the selection of the above materials is not limited to the listed contents, and if other materials that affect the T1 relaxation time, the T2 relaxation time and the CT value are adopted, the implementation of the method of the present invention will not be affected, that is, the present invention is also within the protection scope of the present invention;
in the actual process of filling the hollowed-out mold body, it is necessary to determine a chemical component a to be used for adjusting the T1 relaxation time, a chemical component B for adjusting the T2 relaxation time, and a chemical component C for adjusting the CT value according to actual application requirements, and read T1, T2, and CT values respectively corresponding to specific organs and target areas in CT and MR scan images through a treatment planning system, for example, an average value obtained in 1.5T MR scanning of a prostate is: t1=1245, T2=92, HU =34; the average values corresponding to the liver were: t1=609, T2=47, HU =50; namely, the T1, T2 and CT values corresponding to different parts are different, the concentration ratios of the required filling materials are different, and after the T1 relaxation time adjusting material, the T2 relaxation time adjusting material and the CT value adjusting material are determined, the concentration ratios of the filling materials of the target area and the interested organs are further determined for actual filling;
specifically, the step of obtaining imaging parameter information of a medical image of a phantom to be constructed, and fitting and determining the concentration ratio of the target area and the filling material corresponding to the organ of interest according to the imaging parameter information includes:
according to the preset concentration gradient, independently adding a material for adjusting T1 relaxation time, a material for adjusting T2 relaxation time and a material for adjusting CT value into an adhesive respectively to obtain T1 relaxation time, T2 relaxation time and CT value under different corresponding concentration values; it should be noted that the concentration value of the a material affecting the T1 relaxation time, the concentration value of the B material affecting the T2 relaxation time, and the concentration value of the C material affecting the CT number are linearly related to the inverse of the T1 relaxation time, the inverse of the T2 relaxation time, and the CT number;
fitting to obtain a corresponding T1 relaxation time model, a T2 relaxation time model and a corresponding CT numerical model according to the T1 relaxation time, the T2 relaxation time and the CT numerical values under different concentration values; the model is obtained by fitting respectively taking the reciprocal of T1 relaxation time, the reciprocal of T2 relaxation time and a CT value as dependent variables, and taking the concentration value of an A material influencing T1 relaxation time, the concentration value of a B material influencing T2 relaxation time and the concentration value of a C material influencing the CT value as independent variables; in the specific fitting process, the T1 relaxation time and the T2 relaxation time under different concentration values need to be firstly converted into corresponding inverse values, then the inverse values are combined with corresponding CT values for use, and a T1 relaxation time model, a T2 relaxation time model and a CT value model which are needed are obtained by combining the concentration values of the corresponding A material, the B material and the C material for fitting; correspondingly, the T1 relaxation time model, the T2 relaxation time model and the CT numerical model can be expressed as:
Y＝aX 1 +bX 2 +cX 3 +e (1)
wherein Y represents the inverse of T1 relaxation time, the inverse of T2 relaxation time and CT number of the organ/target volume; x 1 、X 2 And X 3 Respectively representing the concentration ratios of A, B and C materials influencing the T1 relaxation time, the T2 relaxation time and the CT value (namely concentration values linearly related to the reciprocal of the T1 relaxation time, the reciprocal of the T2 relaxation time and the CT value); a. b and C represent the fitting parameters for materials A, B and C, respectively, which can be directly determined by linear fitting, and e is a constant term;
respectively determining the concentration ratios of filling materials corresponding to the target area and the interested organ according to the imaging parameter information of the target area and the interested organ and by combining a T1 relaxation time model, a T2 relaxation time model and a CT numerical model; wherein, the solution process of the concentration ratio of the target region or the interested organ can be understood as that a ternary linear equation set can be obtained by substituting the actually measured T1, T2 and CT corresponding to the target region or the interested organ into the formula (1), and the solution can obtain the corresponding X 1 、X 2 And X 3 Thus obtaining the corresponding concentration ratio.
S15, adding filling materials of the target area and the interested organ into an adhesive according to the corresponding concentration ratio, heating, fusing and filling the adhesive to the corresponding position of the hollowed die body, and cooling to obtain a quality control simulation die body; wherein, the step of heating and fusing and filling to the corresponding position of the hollowed-out die body comprises:
heating according to a preset temperature, uniformly stirring, and filling to a corresponding position of the hollowed-out mold body; the corresponding preset temperature is preferably more than 60 ℃, namely, materials A, B and C which influence T1 relaxation time, T2 relaxation time and CT value and correspond to the target area and the interested organ are added to the adhesive according to the obtained concentration ratio, heated and stirred to be uniformly fused, filled into the corresponding area of the hollow mold body, and the 3D quality control simulation mold body shown on the right side of the graph 2 can be obtained after the solution is cooled and converted into a solid state; in addition, in order to prevent the filler in the mold body from shaking and separating, the embodiment preferably encapsulates the outer opening of the quality control simulation mold body with a thermoplastic material, wherein the thermoplastic material includes PLA, which is not limited herein.
Through the steps, the fact that the target region, the sensor interesting organ and the measuring plug-in are simultaneously obtained by adopting a 3D printing method can be achieved, the requirement of clinical cases for diversification is met, images and dosage results are convenient to analyze, and a high-precision quality control simulation model body for treatment is ensured, the quality control simulation model body can replace a patient, and finally the total dosage error caused in the whole process from MR scanning positioning to plan execution is measured, and if the model body is used for monitoring the dosage of a target position according to the following method steps:
1) Performing CT scanning on the quality control simulation model; 2) After scanning, rigidly registering the medical image of the quality control simulation die body and the medical image of the patient, ensuring that the positions of the two are kept consistent, and setting positioning mark points; 3) Transmitting the image file to a treatment planning system; 4) Transplanting the completed patient plan to the phantom CT image, and carrying out dose calculation again to obtain the point dose D calculation or two-dimensional dose distribution of the plug-in dosimeter; 5) Placing the mold body on an MR treatment machine according to the positioning mark point, and placing measuring equipment to execute a treatment plan after MR scanning; 6) Reading point dose D measurements of ionization chamber/thermoluminescent one-dimensional devices, directly comparing point dose deviation δ = (D measurement-D calculation)/D calculation, or scanning film dose distributions, using two-dimensional dose throughput rate gamma to assess dose variation.
Meanwhile, the quality control simulation model can be used for realizing the quantitative comparison of the MR image and the CT image, and finding whether image distortion or artifacts caused by software and hardware of a machine exist or not, wherein the specific detection process is as follows:
1) Under the condition that the MR or CT image quality control result is good, scanning CT, T1 and T2 images of a quality control simulation model body, and setting the images as the reference of respective types of images;
2) When a quality control simulation phantom is scanned daily, quantitative analysis is carried out by using the following formulas of mean absolute error MAE, peak signal-to-noise ratio PSNR and gamma:
wherein y is the actual value of the pixel of the scanned image, yi is the value of the pixel of the reference image, and n is the number of all pixels in the phantom; r is a radical of hydrogen 2 (y, yi) represents the distance squared of the two pixel locations, Δ d represents the distance tolerance, which may be on the 1 or 2mm scale; delta 2 (y, yi) represents the square of the difference in value between two pixels, and Δ D represents the difference in value tolerance, which can be measured in terms of 1% or 2%. The lower the PSNR and gamma values are, the greater the difference from the original reference image is, and the higher the probability of occurrence of artifacts or distortion.
In conclusion, the quality control simulation phantom obtained by the method can effectively monitor the reasonable use of the dosage of the target position of the patient and the reliability of the medical image, and ensure the high precision of treatment and the treatment safety of the patient.
According to the method, after the structural file corresponding to the acquired case is imported into a 3D printing reconstruction system for 3D reconstruction, measuring equipment required in the actual treatment process is inserted into the target position to be measured, a 3D printing technology is adopted to obtain the hollowed-out die body, the concentration ratio of filling materials corresponding to a target area and an interested organ is determined according to the T1 relaxation time, the T2 relaxation time and the CT value of the medical image of the actual case, an adhesive is added into the filling materials of the target area and the interested organ according to the corresponding concentration ratio to be heated and melted and filled into the hollowed-out die body, and the hollowed-out die body is cooled and sealed to obtain the quality control simulation die body.
It should be noted that, although the steps in the above-described flowcharts are shown in sequence as indicated by arrows, the steps are not necessarily executed in sequence as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise.
In one embodiment, as shown in fig. 3, there is provided a quality control simulation phantom construction system for a magnetic resonance radiotherapy machine, the system comprising:
the structure acquisition module 1 is used for acquiring a structure file of a die body to be constructed; the Structure files include Structure files of the patient's outer contour, target area and organ of interest;
the die body pre-modeling block 2 is used for importing the structure file into a 3D printing reconstruction system, generating a first simulation die body, and determining a target position to be measured and required measuring equipment of the first simulation die body; the target position to be detected comprises a target area position and an interested organ position;
the plug-in configuration module 3 is used for acquiring an equipment plug-in corresponding to equipment to be measured, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, and performing 3D printing on the second simulation die body to obtain a hollowed-out die body;
the concentration selection module 4 is used for acquiring imaging parameter information of a medical image of a die body to be constructed, and fitting and determining the concentration ratio of the target area and the filling material corresponding to the interested organ according to the imaging parameter information;
and the die body generating module 5 is used for adding the filling materials of the target area and the interested organ into the adhesive according to the corresponding concentration ratio, heating, fusing and filling the filling materials to the corresponding position of the hollowed die body, and cooling to obtain the quality control simulation die body.
For the specific limitation of the model construction system for quality control simulation of a magnetic resonance radiotherapy machine, reference may be made to the above limitation of the method for constructing the model for quality control simulation of a magnetic resonance radiotherapy machine, and details are not described herein again. All modules in the magnetic resonance radiotherapy machine quality control simulation phantom construction system can be completely or partially realized through software, hardware and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
Fig. 4 shows an internal structure diagram of a computer device in one embodiment, and the computer device may be a terminal or a server. As shown in fig. 4, the computer apparatus includes a processor, a memory, a network interface, a display, and an input device, which are connected through a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device comprises a nonvolatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operating system and the computer program to run on the non-volatile storage medium. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program is executed by a processor to realize a method for constructing a quality control simulation phantom of the magnetic resonance radiotherapy machine. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, a key, a track ball or a touch pad arranged on the shell of the computer equipment, an external keyboard, a touch pad or a mouse and the like.
It will be appreciated by those of ordinary skill in the art that the architecture shown in FIG. 4 is a block diagram of only a portion of the architecture associated with the disclosed aspects and is not intended to limit the computing devices to which the disclosed aspects may be applied, as a particular computing device may include more or less components than those shown, or may combine certain components, or have a similar arrangement of components.
In one embodiment, a computer device is provided, comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the steps of the above method being performed when the computer program is executed by the processor.
In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored, which computer program, when being executed by a processor, carries out the steps of the above-mentioned method.
To sum up, the method and system for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine provided by the embodiments of the present invention realize that after a first simulation phantom is generated by importing a structural file of the obtained to-be-constructed phantom into a 3D printing reconstruction system, a target position to be measured and a required measurement device are determined, a device plug-in of the required measurement device is inserted into the target position to be measured to obtain a second simulation phantom, the second simulation phantom is 3D printed to obtain a hollow phantom, imaging parameter information of a medical image of the phantom to be constructed is obtained, concentration ratios of filling materials corresponding to a target region and an interested organ are determined by fitting, the filling materials of the target region and the interested organ are added with an adhesive according to the corresponding concentration ratios, heated and melted and filled into the hollow phantom, and cooled to obtain a technical scheme of the quality control simulation phantom, the method and system for constructing the quality control simulation phantom of the magnetic resonance radiotherapy machine can customize and design individual quality control simulation according to clinical requirements, effectively meet requirements of individualized radiotherapy, can be used for quality control of MR radiotherapy machine images and dosage alone, and can realize reliable quality control and provide verification of radiotherapy for end-to-end radiotherapy, and quality verification of radiotherapy machines.
The embodiments in the present specification are described in a progressive manner, and all the embodiments are directly referred to the same or similar parts, and each embodiment is mainly described as different from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment. It should be noted that, the technical features of the embodiments may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several preferred embodiments of the present application, and the description thereof is specific and detailed, but not to be understood as limiting the scope of the invention. It should be noted that, for those skilled in the art, without departing from the technical principle of the present invention, several improvements and substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the present patent application shall be subject to the protection scope of the claims.
Claims (10)
1. A construction method of a quality control simulation phantom of a magnetic resonance radiotherapy machine is characterized by comprising the following steps:
acquiring a structure file of a die body to be constructed; the structural files include Structure files of the patient's outer contour, target region, and organ of interest;
importing the structure file into a 3D printing reconstruction system, generating a first simulation die body, and determining a target position to be measured and required measuring equipment of the first simulation die body; the target position to be detected comprises a target area position and an interested organ position;
acquiring an equipment plug-in corresponding to equipment to be measured, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, and performing 3D printing on the second simulation die body to obtain a hollowed die body;
acquiring imaging parameter information of a medical image of a die body to be constructed, and fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ according to the imaging parameter information;
and adding filling materials of the target area and the interested organ into the adhesive according to the corresponding concentration ratio, heating, fusing and filling the adhesive to the corresponding position of the hollowed die body, and cooling to obtain the quality control simulation die body.
2. The method of constructing quality control simulated phantom for a magnetic resonance radiotherapy machine of claim 1, wherein said 3D printing reconstruction system comprises a 3D slicer system.
3. The method of claim 1, wherein the medical images include CT images and MR images; the imaging parameter information comprises T1 relaxation time, T2 relaxation time and CT values of a target area and an interested organ; the filling material comprises a material for adjusting T1 relaxation time, a material for adjusting T2 relaxation time and a material for adjusting CT value.
4. The method for constructing the quality control simulation phantom of the magnetic resonance radiotherapy machine according to claim 3, wherein the material for adjusting the relaxation time of T1 is one of gadolinium trichloride, nickel diethylenetriaminepentaacetate chelate and gallium; the material for adjusting the T2 relaxation time is agarose; the CT value adjusting material is one of barium sulfate, calcium carbonate and glass microspheres; the adhesive is one of carrageenan and gelatin.
5. The method of claim 4, wherein the step of obtaining imaging parameter information of a medical image of the phantom to be constructed and fitting and determining the concentration ratio of the filling materials corresponding to the target region and the organ of interest according to the imaging parameter information comprises:
according to the preset concentration gradient, independently adding a material for adjusting T1 relaxation time, a material for adjusting T2 relaxation time and a material for adjusting CT value into a binding agent to obtain T1 relaxation time, T2 relaxation time and CT value under different corresponding concentration values;
fitting to obtain a corresponding T1 relaxation time model, a T2 relaxation time model and a corresponding CT numerical model according to the T1 relaxation time, the T2 relaxation time and the CT numerical values under different concentration values;
and respectively determining the concentration ratios of the filling materials corresponding to the target area and the interested organ according to the imaging parameter information of the target area and the interested organ and by combining the T1 relaxation time model, the T2 relaxation time model and the CT numerical model.
6. The method for constructing a quality control simulation phantom of a magnetic resonance radiotherapy machine according to claim 1, wherein the step of heating and melting and filling the mold body to the corresponding position of the hollowed-out phantom comprises the steps of:
and heating according to a preset temperature, and filling the hollow mold body to a corresponding position after uniformly stirring.
7. The method for constructing a quality control simulation phantom for a magnetic resonance radiotherapy machine according to claim 1, wherein the step of cooling to obtain the quality control simulation phantom further comprises:
and (3) adopting a thermoplastic material to carry out external opening packaging on the quality control simulation die body.
8. A system for constructing quality control simulation phantom of a magnetic resonance radiotherapy machine is characterized by comprising:
the structure acquisition module is used for acquiring a structure file of the die body to be constructed; the structural files include Structure files of the patient's outer contour, target region, and organ of interest;
the die body pre-modeling block is used for importing the structure file into a 3D printing reconstruction system, generating a first simulation die body, and determining a target position to be measured and required measuring equipment of the first simulation die body; the target position to be detected comprises a target area position and an interested organ position;
the plug-in configuration module is used for acquiring an equipment plug-in corresponding to equipment to be measured, inserting the equipment plug-in to the target position to be measured to obtain a second simulation die body, and performing 3D printing on the second simulation die body to obtain a hollowed-out die body;
the concentration selection module is used for acquiring imaging parameter information of a medical image of a die body to be constructed, and fitting and determining the concentration ratio of filling materials corresponding to a target area and an interested organ according to the imaging parameter information;
and the die body generating module is used for adding the filling materials of the target area and the interested organ into the adhesive according to the corresponding concentration ratio, heating, fusing and filling the filling materials to the corresponding position of the hollowed die body, and cooling to obtain the quality control simulation die body.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method of any of claims 1 to 7 are implemented when the computer program is executed by the processor.
10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 7.
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