KR102573944B1 - Method for correcting motion of pet image using mri image - Google Patents

Abstract

The present technology discloses a motion compensation method of a PET image using an MRI image. A specific implementation example of this technology separates radiation detection data obtained from PET into a plurality of dynamic frames by time to track motion changes over time, and separates each separated frame data by detector ring angle to determine the size of an object in an image. Image data candidates with different positions and postures are generated, and among the generated candidate groups, raw data similar to MRI are collected and reconstructed to correct motion in the PET image, thereby minimizing noise and errors caused by the motion of the object during imaging. Thereby, the image quality can be improved.

Description

Motion correction method of PET image using MRI image {METHOD FOR CORRECTING MOTION OF PET IMAGE USING MRI IMAGE}

The present invention relates to a method for correcting motion of a PET image using an MRI image, and more particularly, by correcting motion estimated from a PET image using an MRI image, noise and errors due to motion of an object during PET imaging can be minimized. It relates to a technology capable of improving video quality.

Medical images used for cell, preclinical, clinical tests, and patient diagnosis are generally classified into structural images and functional images. Structural images refer to structural and anatomical images of the human body, and functional images directly or indirectly image functional information about human body cognition and sensory functions.

Structural and anatomical imaging technologies include computed tomography (CT) and magnetic resonance imaging (MRI), and technology that observes the physiological and biochemical actions of the human body to visualize functional information. As an example, a positron emission tomography (PET) device is widely used.

Most of the recent motion correction methods of a subject in a PET image in a PET MRI convergence device utilize a separate motion tracking device or extract motion information from an MRI obtained through simultaneous MRI imaging to correct the PET image.

However, in an environment where multiple PET-MRI images are required but simultaneous imaging is not possible or a motion estimation device is not provided, subject movement correction in the PET image cannot be corrected, and the image may be damaged due to noise and errors generated by the movement of the object during imaging. The limit of quality deterioration has been reached.

Therefore, the technical problem to be achieved by the present invention is to minimize noise and errors due to the movement of an object during PET imaging by correcting the motion estimated from the PET image using the MRI image, thereby improving the image quality. The purpose of this study is to provide a motion compensation method for PET images using images.

The object of the present invention is not limited to the above-mentioned object, and other objects and advantages of the present invention not mentioned above can be understood by the following description and will be more clearly understood by the examples of the present invention. It will also be readily apparent that the objects and advantages of the present invention may be realized by means of the instrumentalities and combinations thereof set forth in the claims.

According to this feature, a motion correction method of a PET image using an MRI image according to an embodiment is

dividing the radiation detection data obtained from the PET into a plurality of dynamic frame data according to the detected time, and then reconstructing one frame image with each dynamic frame data; and

The method may include estimating the motion and posture of the object based on a comparison between the frame image and a reference image obtained from MRI, and then correcting the motion of the PET image.

Preferably, the motion correction step,

If the projection data of the reference image frame of MRI exists in the projection data of detectors in adjacent rings of PET, the movement and posture of the object are estimated with the angle of the detector ring of PET, and image data candidates with different positions and postures of the tracked object are selected. It may include generating steps.

Preferably, the motion correction step,

The method may include compensating motion of the object by collecting image data of the same MRI as the image data candidate groups and reconstructing a PET image.

According to an embodiment, radiation detection data obtained from PET is separated into a plurality of dynamic frames by time to track movement changes over time, and each separated frame data is separated by detector ring angle to determine the location and location of an object in an image. Image data candidates with different postures are generated, and among the generated candidates, raw data similar to MRI are collected and reconstructed to correct motion in the PET image, thereby minimizing noise and errors caused by the motion of the object during imaging, Accordingly, the image quality can be improved.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the present invention serve to further understand the technical idea of the present invention, the present invention is the details described in such drawings should not be construed as limited to
1 is an overall flow chart showing a PET image motion correction process according to an embodiment.
2 is a conceptual diagram of motion and posture tracking according to an embodiment.

Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only, and may be modified and implemented in various forms. Therefore, the embodiments are not limited to the specific disclosed form, and the scope of the present specification includes changes, equivalents, or substitutes included in the technical spirit.

Although terms such as first or second may be used to describe various components, such terms should only be construed for the purpose of distinguishing one component from another. For example, a first element may be termed a second element, and similarly, a second element may be termed a first element.

It should be understood that when an element is referred to as being “connected” to another element, it may be directly connected or connected to the other element, but other elements may exist in the middle.

Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "have" are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, but one or more other features or numbers, It should be understood that the presence or addition of steps, operations, components, parts, or combinations thereof is not precluded.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and unless explicitly defined in this specification, it should not be interpreted in an ideal or excessively formal meaning. don't

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings.

FIG. 1 is a flowchart illustrating a motion correction process of a PET image using an MRI image according to an embodiment, and FIG. 2 is a conceptual diagram illustrating motion and posture tracking shown in FIG. 1 .

Referring to FIGS. 1 and 2 , a system for compensating motion of a PET image using an MRI image according to an embodiment separates radiation detection data obtained from PET into a plurality of dynamic frames by time, tracks motion changes over time, and , Separated frame data is separated for each detector ring angle to generate an image data candidate group having different positions and postures of the object in the image, and the same MRI images of the generated candidate groups are collected and reconstructed to correct motion in the PET image. Accordingly, the system may include an image reconstruction step 100 and a motion reconstruction step 200.

Here, in the image reconstruction step 100, radiation detection data obtained from PET is separated into a plurality of dynamic frame data according to the detected time, and then one frame image is reconstructed with each dynamic frame data.

In the motion reconstruction step 200, the movement and posture of the object are estimated based on the comparison between the frame image and the reference image obtained from the MRI, and then the motion of the PET image is corrected. It may be provided with a tracking step 210 and a motion correction step 230 .

In the motion and posture tracking step 210, when the projection data of the reference image frame of the MRI exists in the projection data of the detectors in the adjacent PET ring, the movement and posture of the object are estimated with the angle of the detector ring of the PET, and the motion and posture of the tracked object are measured. An image data candidate group having different positions and postures may be generated.

Referring to FIG. 2 , when projection data from detectors in the same ring of PET exist on a direct plane of projection data of a reference image frame of MRI, it is determined that there is no motion of the object.

In addition, if there is projection data from detectors in an adjacent ring of PET on the cross plane of the projection data of the reference image frame of MRI, it is determined that there is movement of the object, and the location and location of the object are separated by detector ring angle. An image data candidate group having different postures is generated.

In the motion correction step 300, the PET image in which the motion of the object is corrected can be output by receiving the image data candidate group, collecting MRI image data identical to the image data candidate group, and reconstructing the PET image.

Therefore, according to an embodiment, the task is to separate the radiation detection data obtained from PET into a plurality of dynamic frames by time to track motion changes over time, and to separate each separated frame data by detector ring angle so as to be included in the image. Image data candidates with different positions and postures of the object are generated, and among the generated candidates, raw data similar to MRI are collected and reconstructed to correct motion in the PET image, thereby minimizing noise and errors caused by the motion of the object during imaging. and thus improve the image quality.

The embodiments described above may be implemented as hardware components, software components, and/or a combination of hardware components and software components. For example, the devices, methods and components described in the embodiments may include, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate (FPGA). array), programmable logic units (PLUs), microprocessors, or any other device capable of executing and responding to instructions. A processing device may run an operating system (OS) and one or more software applications running on the operating system. A processing device may also access, store, manipulate, process, and generate data in response to execution of software. For convenience of understanding, there are cases in which one processing device is used, but those skilled in the art will understand that the processing device includes a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it can include. For example, a processing device may include a plurality of processors or a processor and a controller. Other processing configurations are also possible, such as parallel processors.

Software may include a computer program, code, instructions, or a combination of one or more of the foregoing, which configures a processing device to operate as desired or processes independently or collectively. The device can be commanded. Software and/or data may be any tangible machine, component, physical device, virtual equipment, computer storage medium or device, intended to be interpreted by or provide instructions or data to a processing device. , or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed on networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer readable media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. Computer readable media may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on a computer readable medium may be specially designed and configured for the embodiment or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. Included are hardware devices specially configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, as well as machine language codes such as those produced by a compiler. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, the described techniques may be performed in an order different from the method described, and/or components of the described system, structure, device, circuit, etc. may be combined or combined in a different form than the method described, or other components may be used. Or even if it is replaced or substituted by equivalents, appropriate results can be achieved.

100: frame image reconstruction step
200: motion correction step
210: movement and posture tracking step
230: motion correction step

Claims (3)

dividing the radiation detection data acquired from the PET into a plurality of dynamic frame data according to the detected time, and then reconstructing one frame image with each dynamic frame data; and
If the projection data of the reference image frame of the MRI exists in the projection data of the detectors in the adjacent ring of the PET, the motion and posture of the object are estimated by the angle of the detector ring of the PET, the motion and posture of the object are estimated, and then the movement of the PET image Including the step of correcting,
The step of correcting the motion is,
When projection data from detectors in the same ring of the PET exist on a direct plane of the projection data of the reference image frame of the MRI, it is determined that there is no movement of the object;
PET image using MRI image, characterized in that when there is projection data by detectors in an adjacent ring of PET on a cross plane of the projection data of the reference image frame of the MRI, it is determined that there is movement of the object. motion correction method.
The method of claim 1, wherein the motion correction step
If the projection data of the reference image frame of MRI exists in the projection data of detectors in adjacent rings of PET, the movement and posture of the object are estimated with the angle of the detector ring of PET, and image data candidates with different positions and postures of the tracked object are selected. A motion correction method of a PET image using an MRI image, comprising the step of generating.
The method of claim 2, wherein the motion correction step,
A method of correcting motion of a PET image using an MRI image, further comprising compensating motion of an object by reconstructing a PET image by collecting image data of the same MRI as the image data candidate group.