Patent Application
20240087119
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2022-143797, filed Sep. 9, 2022, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a medical image diagnosis system and a tissue characteristic estimation method.
In peripheral blood vessels or new feeding vessels of cancer cells that have progressed to some extent, an EPR (enhanced permeability and retention) effect occurs. The EPR effect is such a phenomenon that there occur an enhancement in vascular permeability due to dilation of gaps between vascular endothelial cells, and an enhancement in accumulation of a vascular permeant substance due to lymphatic system underdevelopment. It is known that the vascular endothelial cell gap is about 5 to 50 nm in normal cells, and is about 100 to 200 nm or more at a time when the EPR effect occurs.
A DDS (drug delivery system) utilizing the EPR effect has been devised. In the DDS utilizing the EPR effect, nano-particles are processed or a drug is sealed by using a liposome or the like, thereby controlling the particle size to a several-hundred nm size, and drug particles are delivered to a cancer tissue. It is assumed that the particle size of drug particles to be delivered to a cancer tissue, the kind of drug, and so forth vary in accordance with a tumor characteristic such as a progress degree, type, or the like of cancer, but there is no method of appropriately determine these.
According to one embodiment, a medical image diagnosis system includes an imaging unit, a reconstruction unit, an estimation unit and a display control unit. The imaging unit applies one-time or multiple-time medical imaging to a subject to which a plurality of drugs having a tissue accumulation property, which corresponds to a tissue characteristic, are administered successively or simultaneously. The reconstruction unit reconstructs one or a plurality of medical images, based on one or a plurality of set of raw data acquired by the one-time or multiple-time medical imaging. The estimation unit estimates a tissue characteristic of a target region included in the subject, based on a spatial distribution of the drugs rendered on the one or the plurality of medical images. The display control unit displays the estimated tissue characteristic on a display device.
Hereinafter, referring to the accompanying drawings, embodiments of a medical image diagnosis system and a tissue characteristic estimation method are described in detail.
As illustrated in
The imaging apparatus 110 includes a gantry 120 and a bed 130. The gantry 120 is a substantially cylindrical machinery structure including an opening that forms an imaging space. The gantry 120 includes, in a housing, a rotating frame having a substantially cylindrical shape and a stationary frame that supports the rotating frame such that the rotating frame is rotatable around a rotational axis. Specifically, the stationary frame rotatably supports the rotating frame via a slip ring. In the rotating frame, an X-ray generating device and an X-ray detection device are attached to the rotating frame such that the X-ray generating device and X-ray detection device are opposed to each other, with the rotational axis being interposed.
The X-ray generating device includes an X-ray tube and a high-voltage generator. The X-ray tube generates X-rays in accordance with the control of tube voltage and tube current by the high-voltage generator. The X-ray detection device includes an X-ray detector and data collection circuitry. The X-ray detector detects X-rays that are generated from the X-ray tube and pass through the subject. In one example, the X-ray detector includes a plurality of semiconductor detection elements formed by compound semiconductors or the like, which are densely arranged in a two-dimensional fashion with respect to a channel direction and a column direction. The semiconductor detection elements capture incident X-ray photons, and convert the X-ray photons into an electric signal having an electric charge corresponding to the energy of the X-ray photons. The data collection circuitry counts X-ray photons, based on the electric signal. In one example, the data collection circuitry counts, by a pulse-height discriminator, the number of X-ray photons in regard to each of a plurality of bins, and collects spectral data representing a distribution of the number (count number) of X-ray photons over the bins. To be more specific, the spectral data is collected in regard to each of views, which mean data sampling points with respect to the X-ray tube rotational direction. Note that the bin means an energy band. The spectral data is transmitted to the console.
The bed 130 includes a table top on which the subject is placed, and a base that movably supports the table top. The subject and the table top are positioned such that a to-be-imaged region of the subject is positioned in the imaging space. Note that the to-be-imaged region according to the present embodiment may be any region if the region includes a tumor, such as a chest part, a waist part, a leg part, an arm part, or a head part. The present embodiment is applicable to both of a benign tumor and a malignant tumor. The malignant tumors can be classified into a carcinoma (malignant epithelial tumor) and a sarcoma (malignant nonepithelial tumor), and the present embodiment is applicable to both malignant tumors. In the description below, it is assumed that the tumor is cancer that is a malignant tumor.
With the progress of cancer, the EPR effect occurs in a peripheral blood vessel or new feeding vessel of the cancer tissue 22, the vascular endothelial cells 25 contract, and gaps G2 between the vascular endothelial cells 25 dilate. As illustrated in
The imaging apparatus 110 executes PCCT imaging on the subject in accordance with the control by the console 140. A plurality of drugs having a tumor accumulation property, which corresponds to a tumor characteristic, are administered successively or simultaneously to the subject. The tumor characteristic means the progress degree or type of a tumor. The tumor accumulation property means a capability of accumulation of a drug in a tumor. The imaging apparatus 110 applies one-time or multiple-time PCCT imaging to the subject to which drugs having a tumor accumulation property, which corresponds to a tumor characteristic, are administered successively or simultaneously, and collects one or a plurality of spectral data that are collected by the one-time or multiple-time medical imaging. If a plurality of drugs can be distinguished and visualized by one-time PCCT imaging, it suffices that the PCCT imaging is executed only once. If a plurality of drugs cannot be distinguished and visualized by one-time PCCT imaging, the PCCT imaging needs to be executed multiple times.
It is assumed that the tumor characteristic according to the first embodiment is a progress degree for evaluating the degree of progress of cancer. In one example, the progress degree can be expressed by a TNM classification, a stage of disease, or the like. The TNM classification is defined by a combination of factors of a size (T) of a tumor, a degree (N) of metastasis of a lymph node, and a degree (M) of remote metastasis to other regions. The combination of the factors corresponds to the stage of disease. The progress degree may be defined by the size (T) of a tumor, the degree (N) of metastasis of a lymph node, or the degree (M) of remote metastasis to other regions, or some other freely selected index may be used. In the present embodiment, it is assumed that the gap dilates in accordance with the progress degree. In the first embodiment, a plurality of drugs having different particle sizes are injected into the subject. The progress degree of a target cancer tissue is estimated based on a spatial distribution of the drugs in a target region. In the description below, it is assumed that the progress degree is the stage of disease.
In other words, in a case where neither the drug particle 31 nor the drug particle 32 is distributed in the cancer tissue, this means that the progress degree is “1”; in a case where the drug particle 31 is not distributed in the cancer tissue but the drug particle 32 is distributed in the cancer tissue, this means that the progress degree is “2”; and in a case where both the drug particle 31 and the drug particle 32 are distributed in the cancer tissue, this means that the progress degree is “3”. In this manner, in the case where the tumor characteristic is the progress degree, the tumor accumulation property means the ease of accumulation in a tumor, which corresponds to the particle size of the drug.
The drug according to the present embodiment may be of any kind, if the drug can be visualized by PCCT imaging. Specifically, a contrast agent that can be visualized by PCCT imaging may be used, or a drug, in which a curative medicine for a cancer tissue, such as an anticancer drug, is labeled with a high atomic number substance, may be used. As the high atomic number substance, a freely selected heavy metal, such as gold, silver or platinum, may be used.
The console 140 is a computer that controls the imaging apparatus 110. The console 140 includes processing circuitry 150, a communication device 160, a display device 170, an input device 180 and a storage device 190. The processing circuitry 150, communication device 160, display device 170, input device 180 and storage device 190 are connected to be capable of mutually communicating information.
The processing circuitry 150 includes a processor such as a CPU (Central Processing Unit). The processor starts a tumor characteristic estimation program that is installed in the storage device 190 or the like, thereby implementing an imaging control function 151, a reconstruction function 152, an estimation function 153 and a display control function 154. The functions 151 to 154 may not necessarily be implemented by single processing circuitry. A plurality of independent processors may be combined to constitute processing circuitry, and the respective processors may implement the functions 151 to 154 by executing the tumor characteristic estimation program. In addition, the functions 151 to 154 may be implemented as modules constituting the tumor characteristic estimation program, or may be implemented as individual hardware.
By implementing the imaging control function 151, the processing circuitry 150 controls the various devices of the imaging apparatus 110 in accordance with an imaging sequence for PCCT imaging. The processing circuitry 150 controls the various devices of the imaging apparatus 110 in order to apply one-time or multiple-time PCCT imaging to a subject to which a plurality of drugs having a tumor accumulation property, which corresponds to a tumor characteristic, are administered successively or simultaneously. In accordance with the control by the processing circuitry 150, the imaging apparatus 110 executes one-time or multiple-time PCCT imaging on a to-be-imaged region of the subject, and collects one or a plurality of spectral data relating to the to-be-imaged region. Specifically, the drugs are labeled with mutually different high atomic number substances, and the processing circuitry 150 executes, as the one-time or multiple-time PCCT imaging, K-edge imaging and/or material decomposition using spectral analysis on targets that are high atomic number substances included in the respective drugs.
By implementing the reconstruction function 152, the processing circuitry 150 reconstructs one or a plurality of PCCT images, based on one or a plurality of spectral data collected by one-time or multiple-time PCCT imaging. A reconstruction algorithm is not particularly limited, and use can be made of, as appropriate, analytical reconstruction using FBP (filtered back projection), iterative approximation reconstruction that iteratively updates images in such a manner as to optimize an objective function in which various models are formulated, and machine learning reconstruction in which denoise processing by a neural network is assembled in the iterative approximation reconstruction.
By implementing the estimation function 153, the processing circuitry 150 estimates a tumor characteristic of a target region included in the subject, based on a spatial distribution of a plurality of drugs rendered on one or a plurality of PCCT images. The target region is a tumor, or a tissue that is suspected to be a tumor, which is a target of estimation of a tumor characteristic. As described above, in the first embodiment, the tumor characteristic is the progress degree. Specifically, the processing circuitry 150 estimates that the progress degree is a first progress degree in a case where only a drug of a first particle size, among a plurality of drugs, is distributed in the target region on one or a plurality of medical images, and estimates that the progress degree is a second progress degree that is more advanced than the first progress degree, in a case where a drug of a second particle size greater than the particle size of the first particle size, among the drugs, is distributed in the target region on one or a plurality of medical images. In addition, in a case where each of the drug of the first particle size and the drug of the second particle size is distributed in the target region, the processing circuitry 150 estimates that the progress degree is a third progress degree that is less advanced than the first progress degree.
By implementing the display control function 154, the processing circuitry 150 displays various information on the display device 170. In one example, the processing circuitry 150 displays the PCCT image, progress degree, and the like. In another example, the processing circuitry 150 visually distinguishably displays the drugs rendered on one or a plurality of PCCT images.
The communication device 160 is an interface for connection to the drug injection apparatus 200, a work station, a PACS (Picture Archiving and Communication System), a HIS (Hospital Information System), a RIS (Radiology Information System), or the like, via a LAN (Local Area Network) or the like. The communication device 160 transmits and receives various data to and from a connection destination.
The display device 170 displays various information in accordance with the display control function 154 of the processing circuitry 150. As the display device 170, use can be made of, as appropriate, a liquid crystal display (LCD), a cathode ray tube (CRT) display, an organic electro-luminescence (EL) display (OELD), a plasma display, or some other freely chosen display. Besides, the display device 170 may be a projector.
The input device 180 accepts various input operations from a user, converts an accepted input operation to an electric signal, and outputs the electric signal to the processing circuitry 150. Specifically, the input device 180 is connected to input devices such as a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad, and a touch panel display. The input device 180 outputs to the processing circuitry 150 an electric signal corresponding to an input operation to the input device 180. In addition, the input device 180 may be an input device provided in some other computer that is connected via a network or the like. The input device 180 may be a speech recognition device that converts a voice signal collected by a microphone into an instruction signal.
The storage device 190 is a storage device that stores various data, such as a ROM (Read Only Memory), a RAM (Random Access Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), an integrated circuit storage device, or the like. The storage device 190 stores, for example, a treatment support program or the like. The storage device 190 may be, aside from the above-mentioned storage devices, a portable storage medium such as a CD (Compact Disc), a DVD (Digital Versatile Disc) or a flash memory, or a drive device that reads and writes various information from and to a semiconductor memory element or the like. The storage device 190 may be provided in some other computer that is connected to the X-ray CT apparatus 100 via a network.
The drug injection apparatus 200 is a machinery apparatus that injects a drug into a subject. Specifically, the drug injection apparatus 200 includes a cylinder that is a mechanism that discharges a drug, and control circuitry that controls the operation of the cylinder by motor driving. Note that the cylinder may be operated based on machine control by the control circuitry, or may be operated manually by a worker.
Next, a progress degree estimation process by the medical image diagnosis system 1.
As illustrated in
As illustrated in
Another order of execution may be an order of “injection of drug of particle size ‘small’”→“injection of drug of particle size ‘large’”→“PCCT imaging”. If it is confirmed that the drug of particle size “small” does not accumulate in the target tumor, the drug of particle size “large” may not be injected, for example, in order to reduce the load on the subject, and to shorten the processing time. If the degree of interference between the drug of particle size “small” and the drug of particle size “large” can be ignored, the drug of particle size “small” and the drug of particle size “large” may be injected at the same time.
The drug of particle size “large” and the drug of particle size “small” are labeled with high atomic number substances with different K-edges, such that the drug of particle size “large” and the drug of particle size “small” can be distinguished on the PCCT image by K-edge imaging. To be more specific, it is assumed that the high atomic number substances of the drugs have different K-edges to such a degree that the high atomic number substances can be distinguished by the energy resolution of the X-ray detection device.
If step S401 is executed, the processing circuitry 150 reconstruct the PCCT image by implementing the reconstruction function 152 (step S402). The processing circuitry 150 executes the reconstruction of the PCCT image, each time the drug injection is performed. In step S402, the processing circuitry 150 generates the PCCT image relating to the target tumor, by applying the reconstruction process to the spectral data collected in each PCCT imaging. To be more specific, the processing circuitry 150 generates, based on spectral data of a bin to which the K-edge of the drug of particle size “large” belongs, a first PCCT image representing a spatial distribution of the count number of the bin, and generates, based on spectral data of a bin to which the K-edge of the drug of particle size “small” belongs, a second PCCT image representing a spatial distribution of the count number of the bin. The first PCCT image represents the spatial distribution of the drug of particle size “large”, and the second PCCT image represents the spatial distribution of the drug of particle size “small”. Then, the processing circuitry 150 composites the first PCCT image and the second PCCT image, and generates a composite image representing the spatial distribution of the drug of particle size “large” and the drug of particle size “small”. It is preferable to allocate, to each of pixels of the composite image, a label representing the kind of the bin, to which the count number allocated to the pixel belongs, or presenting the kind of the drug corresponding to the bin. Here, the label corresponding to the drug of particle size “large” is referred to as “large drug label”, and the label corresponding to the drug of particle size “small” is referred to as “small drug label”.
If step S402 is executed, the processing circuitry 150 estimates the progress degree of the target tumor by implementing the estimation function 153 (step S403). In step S403, the processing circuitry 150 estimates the progress degree of the target tumor, based on the spatial distribution of the drugs included in the composite image reconstructed in step S402.
As illustrated in a middle column of
In step S403, the processing circuitry 150 extracts the drug of particle size “large” and the drug of particle size “small” from the composite image. Specifically, the processing circuitry 150 can extract the drug of particle size “large” and the drug of particle size “small”, based on the kind of the label allocated to each pixel. Then, if the drug of particle size “large” and the drug of particle size “small” are extracted, the progress degree “3” is estimated. If only the drug of particle size “small” is extracted, the progress degree “2” is estimated. If neither the drug of particle size “large” nor the drug of particle size “small” is extracted, the progress degree “1” is estimated. Whether the pixel of the processing target is the drug of particle size “large” or the drug of particle size “small” can be distinguished by the count number allocated to the pixel, or by the pin to which the count number belongs.
If step S403 is executed, the processing circuitry 150 displays the progress degree estimated in step S403, by implementing the display control function 154 (step S404). In step S404, the processing circuitry 150 displays the progress degree on the display device 170 with a freely selected layout.
As illustrated in
Note that the display screen I7 illustrated in
By the above, the progress degree estimation process according to the first embodiment is terminated.
According to the above-described progress degree estimation process, the progress degree of the target tumor can be estimated by using PCCT images relating to the subject to which a plurality of drugs with different particle sizes are administered. Since the progress degree of the target tumor is understood, the progress degree can helpfully be used in formulating a future treatment policy such as a medication treatment or radiation treatment. In addition, according to the present embodiment, since the gap between vascular endothelial cells, which corresponds to the progress degree of the target tumor, can be specified, it becomes possible to appropriately design the particle size of drug particles that are to be delivered to the target tumor. Furthermore, in the present embodiment, since the medical images, in which the spatial distribution of drugs is visualized by PCCT imaging, are collected, the exposure dose can be reduced, compared to ordinary X-ray CT imaging.
The above-described progress degree estimation process is not limited to the above-described processing procedure, and omission, addition and/or modification can freely be made without departing from the spirit of the invention. In one example, although the drugs to be injected into the subject are described as being the drug of particle size “large” and the drug of particle size “small”, the sizes of the drugs are not limited to these, and drugs of any particle size may be injected. In addition, the number of kinds of particle sizes is not limited to two, and drugs of three or more kinds of particle sizes may be injected.
In the above-described progress degree estimation process, the processing circuitry 150 is described as estimating the stage of disease as the progress degree, but a TNM classification may be estimated by a similar method. As the TNM classification, a level may be estimated in regard to each of all factors of T, N and M, or a level may be estimated in regard to one or two specific factors.
In another example, although the X-ray CT apparatus 100 is described as executing PCCT imaging, the X-ray CT apparatus 100 may execute single energy CT (SECT) imaging or dual energy CT (DECT) imaging if drugs of different particle sizes can be distinguished. In addition, the processing circuitry 150 may convert a SECT image acquired by SECT imaging, or a DECT image acquired by DECT imaging, into a PCCT image. In one example, this conversion can be executed by using a neural network that is trained to convert a SECT image or a DECT image into a PCCT image. In another example, if a distribution of drugs can be visualized, a magnetic resonance imaging apparatus, an ultrasonic diagnosis apparatus, a PET (Positron Emission Tomography) apparatus, or a SPECT (Single Photon Emission CT) apparatus may be used instead of the X-ray CT apparatus 100.
In another example, although the processing circuitry 150 is described as being provided in the X-ray CT apparatus 100, the processing circuitry 150 may be provided in a PET apparatus 300, or may be provided in a computer (for example, an image processing apparatus) that is different from the X-ray CT apparatus 100.
A medical image diagnosis system 1 according to an applied example uses a vasodilator drug in addition to a drug for contrast-enhancing a cancer tissue. By using the vasodilator drug, the progress degree can be estimated in greater detail. Processing circuitry 150 according to the applied example estimates the progress degree of the target tumor, based on a comparison between a spatial distribution of a drug of a specific particle size among a plurality of drugs on a medical image at a time when the vasodilator drug is not administered to the subject, and a spatial distribution of the drug of the specific particle size on a medical image at a time when the vasodilator drug is administered to the subject. Hereinafter, the medical image diagnosis system 1 according to the applied example is described. In the description below, structural elements having substantially the same functions as in the first embodiment are denoted by like reference signs, and an overlapping description is given only where necessary.
The vasodilator drug according to the applied example has an effect of dilating a gap between vascular endothelial cells by dilating a blood vessel. By dilating the gap between vascular endothelial cells, extravascular leakage of drug particles in the blood vessel is promoted. In one example, as the vasodilator drug, use can be made of a spontaneous carbon monoxide releasing drug (NOC-18) sealed in a liposome. By the administration of the spontaneous carbon monoxide releasing drug, the liposome is absorbed in the cancer tissue by the EPR effect, and then carbon monoxide (NO) is gradually released and induces vasodilation. In another example, as the vasodilator drug, use can be made of serum albumin in which S-Nitrosothiol for achieving local vasodilation is incorporated.
Before the administration of the vasodilator drug, since the blood vessel does not dilate, the gap between vascular endothelial cells is the gap G81, and the drug 8 cannot pass through the gap G81. Here, by administering the vasodilator drug, vasodilation is induced, and the gap dilates from G81 to G82. Accordingly, after the administration of the vasodilator drug, the drug 8 passes through the gap G82, and accumulates in the target tumor.
The processing circuitry 150 according to the applied example estimates the progress degree of the target tumor, based on the comparison between the spatial distributions of the drug of the specific particle size before and after the administration of the vasodilator drug. In the case of the example of
The processing circuitry 150 determines whether the drug accumulates in the target tumor on the PCCT image before the administration of the vasodilator drug. If the drug accumulates in the target tumor, the processing circuitry 150 determines that the progress degree is “1”. If the drug does not accumulate in the target tumor, the processing circuitry 150 compares the PCCT image before the administration of the vasodilator drug and the PCCT image after the administration of the vasodilator drug, and determines whether the drug accumulates in the target tumor, with respect to only the PCCT image after the administration of the vasodilator drug. Specifically, the processing circuitry 150 generates a difference image between the PCCT image before the administration of the vasodilator drug and the PCCT image after the administration of the vasodilator drug, and if the drug accumulates in the target tumor on the difference image, the processing circuitry 150 determines that the drug accumulates in the target tumor, with respect to only the PCCT image after the administration of the vasodilator drug. In this case, although the target tumor is suspected to be cancer, this means that the progress degree is less than “1”. Accordingly, the processing circuitry 150 estimates that the progress degree is “0+”. “0+” means an intermediate between “0” and “1”. On the other hand, if the drug does not accumulate in the target tumor on the difference image, the processing circuitry 150 estimates that the progress degree is “0”. The estimation result of the progress degree is displayed on the display device 170.
According to the applied example, by comparing the spatial distributions of a drug of a specific particle size before and after the administration of a vasodilator drug, a detailed progress degree can be estimated, compared to the case where the vasodilator drug is not used. In particular, even in such a case where cancer is present but the gap between vascular endothelial cells is still narrow, the presence of cancer can be detected at an early stage.
In the above first embodiment, the tumor characteristic is described as being the progress degree. It is assumed that a tumor characteristic according to a second embodiment is a tumor type. The tumor type means a pathological classification of a tumor, such as whether a primary focus or not, whether a metastasis focus or not, whether benign or not, or the like. In this case, a plurality of drugs have a tumor type sensitivity as a tumor accumulation property. The tumor type sensitivity of the drug means the ease with which the drug is taken in the target tumor in accordance with the tumor type. Hereinafter, a medical image diagnosis system 2 according to the second embodiment is described. In the description below, structural elements having substantially the same functions as in the first embodiment are denoted by like reference signs, and an overlapping description is given only where necessary.
The PET apparatus 300 detects, by a gamma ray detector, a pair of gamma rays emitted from the body of the subject to which a PET drug is administered. The PET drug includes glucose, and a radioactive isotope that is attached to the glucose and emits a positron. A cancer cell takes in a greater amount of glucose than a normal cell. If the PET drug is administered to the subject, a large amount of the PET drug is taken in the cancer cell. A positron is emitted from the radioactive isotope included in the taken-in PET drug, and pair annihilation occurs with a nearby electron. In accordance with the pair annihilation, a pair of gamma rays of 511 keV occur at about 180 degrees. The gamma ray detector detects the generated gamma rays. Based on the energy and detection position information of the detected gamma rays, the PET apparatus 300 generates a PET image representing the spatial distribution of the PET drug or radioactive isotope. As described above, since a large amount of the PET drug is taken in the cancer cell, the PET image can be expressed as an image in which the distribution of cancer cells in the body of the subject is visualized. The data of the PET image is supplied to the X-ray CT apparatus 100.
By implementing an estimation function 155, the processing circuitry 150 according to the second embodiment estimates the tumor type of the target tumor included in the subject, based on the spatial distribution of a plurality of drugs, which is rendered on one or a plurality of PCCT images. In the second embodiment, a first drug among a plurality of drugs accumulates in tumors of a plurality of tumor types, and a second drug accumulates in a tumor of a specific tumor type among the tumor types. The processing circuitry 150 estimates the tumor type, based on a difference between the spatial distribution of the first drug, which is rendered on a first medical image at a time when the first drug is administered to the subject, and the spatial distribution of the second drug, which is rendered on a second medical image at a time when the second drug is administered to the subject. In one example, the first drug is a PET drug used for PET imaging, and the second drug is a drug used for PCCT imaging. Specifically, the first medical image is a PET image, and the second medical image is a PCCT image.
By implementing a display control function 156, the processing circuitry 150 displays various information on the display device 170. In one example, the processing circuitry 150 displays a PET image, a PCCT image, a tumor type, and the like.
As illustrated in
If step S1001 is executed, the PET apparatus 300 reconstructs the PET image, based on the gamma ray detection data collected by the PET imaging executed in step S1001 (step S1002). On the PET image, all types of cancer existing in the subject are rendered.
If step S1002 is executed, the X-ray CT apparatus 100 executes PCCT imaging on the subject to which the second drug having a second tumor type sensitivity is administered (step S1003). As illustrated in
As illustrated in
On the other hand, in a case where the stomach cancer is a metastasis focus of the liver cancer, if the PCCT drug including an anticancer drug for treating the liver cancer is injected, the PCCT drug is taken into not only the liver cancer but also the stomach cancer. In other words, in a case where all of a plurality of cancers contrast-enhanced by the PET drug are contrast-enhanced by the PCCT drug, it can be said that these cancers have a relationship of a primary focus and a metastasis focus. To be more specific, it can be estimated that the cancer of a region that is the target of the anticancer drug included in the injected PCCT drug is a primary focus, and the cancer of another region is a metastasis focus.
If step S1003 is executed, the X-ray CT apparatus 100 reconstructs the PCCT image (step S1004). In step S1004, by implementing the reconstruction function 152, the processing circuitry 150 reconstructs a PCCT image representing the spatial distribution of count numbers of the PCCT drug, based on the spectral data collected by the PCCT imaging (K-edge imaging) in step S1003.
If step S1004 is executed, the X-ray CT apparatus 100 estimates the tumor type (primary focus or metastasis focus) of the target tumor (step S1005). In step S1005, by implementing the estimation function 155, the processing circuitry 150 estimates the tumor type (primary focus or metastasis focus) of each target tumor, based on a difference between the spatial distribution of the PET drug, which is rendered by the PET image reconstructed in step S1002, and the spatial distribution of the PCCT drug, which is rendered by the PCCT image reconstructed in step S1004. Specifically, the processing circuitry 150 specifies a cancer area from the PET image, based on the spatial distribution of the PET drug. As described above, in the PET image, all cancers included in the subject are visualized. Similarly, the processing circuitry 150 specifies a cancer area from the PCCT image, based on the spatial distribution of the PCCT drug. In the PCCT image, only the cancer, which is the target of the anticancer drug included in the injected PCCT drug, or the metastasis focus of the cancer, is visualized.
Next, the processing circuitry 150 compares the PET image and the PCCT image, and, if a cancer area is present at the same part of both images, the processing circuitry 150 estimates that the cancer type corresponding to the cancer area is a primary focus. On the other hand, if there is a cancer area that is not included in the PCCT image but is included in the PET image, the processing circuitry 150 estimates that the cancer type corresponding to the cancer area is a metastasis focus.
If step S1005 is executed, the X-ray CT apparatus 100 displays the tumor type (primary focus or metastasis focus) estimated in step S1005 (step S1006). In step S1006, by implementing the display control function 156, the processing circuitry 150 displays the tumor type on the display device 170 with a freely selected layout.
As illustrated in
Note that the display screen I12 illustrated in
By the above, the tumor type estimation process according to the second embodiment is completed.
According to the above-described tumor type estimation process, the tumor type (primary focus/metastasis focus) can be estimated by using the PET image and PCCT image relating to the subject to which drugs with mutually different tumor type sensitivities are administered. Here, by executing not only PCCT imaging but also PET imaging, the exposure dose of the subject can be reduced, compared to entirely executing PCCT imaging. In addition, by including the anticancer drug in the PCCT drug, the tumor type can be estimated while a medication treatment is being performed. By estimating the tumor type, a future anticancer drug treatment can effectively be performed. For example, according to the above-described process, even in a case where only a liver cancer and a metastasis focus thereof were considered to be present in a subject, it can be understood that a primary focus in another primary focus region is present. It is thus possible to be aware that an anticancer drug that is effective to the cancer of the another primary focus region should be used. In other words, an optimal anticancer drug for the subject can individually be selected, and, by extension, the medication treatment can effectively be performed. Furthermore, since the amount of the anticancer drug to be used can be reduced, it is expected that side effects can also be reduced.
The above-described tumor type estimation process is not limited to the above-described processing procedure, and omission, addition and/or modification can freely be made without departing from the spirit of the invention. If cancers of all tumor types can be contrast-enhanced by the PCCT drug, PCCT imaging may be executed instead of PET imaging. In this case, it is preferable that the first drug includes an iodine preparation that contrast-enhances tumors of a plurality of types, and the second drug includes an anticancer drug for a tumor of a specific type. Note that in a case where the image quality of an anticancer drug on the PCCT image is poor, the anticancer drug may be labeled with a high atomic number substance. In addition, since it suffices that a drug accumulating in cancer is visualized, if such a drug is present, a magnetic resonance imaging apparatus, an ultrasonic diagnosis apparatus, a PET apparatus, or a SPECT apparatus may be used instead of the X-ray CT apparatus 100.
In another example, although the X-ray CT apparatus 100 is described as executing PCCT imaging, the X-ray CT apparatus 100 may execute SECT imaging or DECT imaging if drugs of different particle sizes can be distinguished. In addition, the processing circuitry 150 may convert a SECT image acquired by SECT imaging, or a DECT image acquired by DECT imaging, into a PCCT image. In one example, this conversion can be executed by using a neural network that is trained to convert a SECT image or a DECT image into a PCCT image.
In another example, although the processing circuitry 150 is described as being provided in the X-ray CT apparatus 100, the processing circuitry 150 may be provided in the PET apparatus 300, or may be provided in a computer (for example, an image processing apparatus) that is different from the X-ray CT apparatus 100 and the PET apparatus 300.
According to the above-described various embodiments, the medical image diagnosis system 1, 2 includes an imaging unit, a reconstruction unit, an estimation unit, and a display control unit. The imaging unit applies one-time or multiple-time medical imaging to a subject to which a plurality of drugs having a tissue accumulation property, which corresponds to a tissue characteristic, are administered successively or simultaneously. The reconstruction unit reconstructs one or a plurality of medical images, based on one or a plurality of set of raw data acquired by the one-time or multiple-time medical imaging. The estimation unit estimates a tissue characteristic of a target region included in the subject, based on a spatial distribution of the drugs rendered on the one or the plurality of medical images. The display control unit displays the estimated tissue characteristic on a display device.
In the case of the first embodiment, the imaging unit corresponds to the imaging apparatus 110 of the X-ray CT apparatus 100, and the reconstruction unit, estimation unit and display control unit correspond to the processing circuitry 150. In the case of the second embodiment, the imaging unit corresponds to the imaging apparatus 110 of the X-ray CT apparatus 100 and the PET apparatus 300, and the reconstruction unit, estimation unit and display control unit correspond to the processing circuitry 150 of the X-ray CT apparatus 100.
According to the above-described configuration, the tissue characteristic can be estimated from the spatial distribution of the drugs, by utilizing the relationship between the tissue characteristic and the tissue accumulation property. Since it suffices that drug injection and medical imaging are executed for the subject, the tissue characteristic can be estimated by means with a small load on the subject. In addition, by estimating the tissue characteristic, a future treatment policy can appropriately be formulated. For example, at a time point when the tissue characteristic of the target region is estimated, the tissue accumulation property for the target region is already known, and it is thus possible to helpfully use this in designing drugs that are administered to the target region.
In the above-described first embodiment and second embodiment, it is assumed that the target region is a tumor, or a tissue that is suspected to be a tumor. In addition, it is assumed that the tissue characteristic is the progress degree or type of a tumor, and the tissue accumulation property is a capability of accumulation of a drug in a tumor. However, the present embodiment is not limited to this. Specifically, the target region is not limited to a tumor or the like, and may be any tissue if the target region is a biological tissue having such a property as accumulating a drug. Accordingly, the tissue characteristic may be the progress degree of mutation or the type of a target tissue, and the tissue accumulation property may be such a capability that a drug accumulates in the target tissue. In addition, the tumor type sensitivity according to the second embodiment means the ease with which the drug is taken in the target tissue in accordance with the tissue type. It is assumed that the tissue type includes any pathological classification, as well as a classification of a malignancy degree, such as whether benign or malignant.
According to at least one of the above-described embodiments, the characteristic of a tissue, in which a drug accumulates, can appropriately be determined.
The term “processor” used in the above description means, for example, circuitry such as a CPU, a GPU, an application specific integrated circuit (ASIC), or a programmable logic device (for example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD) or a field programmable gate array (FPGA)). The processor implements functions by reading and executing a program stored in the storage circuitry. Note that, instead of storing the program in the storage circuitry, such a configuration may be adopted that the program is directly assembled in the circuitry of the processor. In this case, the processor implements functions by reading and executing the program assembled in the circuitry of the processor. On the other hand, in a case where the processor is, for example, an ASIC, the functions are directly assembled as logic circuitry in the circuitry of the processor, instead of the program being stored in the storage circuitry. Note that the processors in the embodiments are not limited to cases where each processor is constituted as single circuitry, and a plurality of independent circuities may be combined to constitute one processor and to implement functions thereof. Furthermore, a plurality of constituent elements in
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-143797 | Sep 2022 | JP | national |
