Medical imaging system and method of using the same

Abstract

A medical imaging system comprises: a collimator configured to filter radiation emitted from an object; and a detector configured to detect radiation that has passed through the collimator, wherein the detector comprises a plurality of detector tiles and at least one detector tile is movable relative to the other detector tiles, wherein top surfaces of the plurality of detector tiles can be configured to be coplanar.

Description

[0001] Priority declaration

[0002] This application claims priority to U.S. Patent Application No. 16 / 844,950, filed on April 9, 2020, which claims the benefit of U.S. Provisional Application No. 62 / 832,082, filed on April 10, 2019. Background Art

[0003] In medical imaging such as molecular medical imaging (sometimes called nuclear medical imaging), images representing the distribution of radiopharmaceuticals can be generated for medical diagnosis. Prior to imaging, radiopharmaceuticals are injected into an imaging subject (such as a patient). The radiopharmaceutical emits radioactive photons that can penetrate the body to be detected by a photon detector. Based on information from the received photons, the photon detector can then determine the distribution of the radiopharmaceutical inside the patient. Their distribution represents the physiological function of the patient, and therefore their distribution images provide valuable clinical information for the diagnosis of various diseases and conditions (such as those in cardiology, oncology, neurology, etc.).

[0004] In order to generate an image, the collimator and the detector work together. However, there are various problems with existing collimator and detector designs. For example, the detector is usually organized in a planar shape to obtain data in a two-dimensional (2D) matrix format. The detector usually uses a large scintillator crystal coupled to a photomultiplier tube (PMT) to detect radiation and record its position. Scintillator-based detectors include modules with larger sizes, and the position of the detected radiation is calculated by comparing the outputs of adjacent modules. In some examples, the detector uses a single scintillator coupled to multiple PMTs. Therefore, once deployed (manufactured or installed), the detector is usually designed as a single piece with a fixed shape and size. The deployment of rigid planar detectors provides a limited degree of spatial resolution and results in an inflexible imaging system, thereby limiting the ability of the system to be optimized for different imaging tasks or objects. Therefore, there is a need to improve the detector for nuclear medicine imaging systems. Summary of the invention

[0005] According to various embodiments, the present disclosure provides a medical imaging system. The medical imaging system includes: a collimator configured to filter radiation emitted from an object; and a detector configured to detect radiation that has passed through the collimator, wherein the detector includes a plurality of detector tiles and at least one detector tile is movable relative to other detector tiles, wherein the top surfaces of the plurality of detector tiles can be configured to be coplanar. In some embodiments, the collimator includes a plurality of collimator portions configured as segmented planes. In some embodiments, each of the plurality of detector tiles is movable. In some embodiments, each of the plurality of detector tiles includes a detector base. In some embodiments, the detector base includes a battery pack. In some embodiments, the battery pack can be wirelessly charged. In some embodiments, the detector base includes a wireless communication module. In some embodiments, the detector includes a plurality of detector bases, one of which is shared by at least two detector tiles. In some embodiments, at least one detector tile is configured to be tilted at a certain angle relative to other detector tiles. In some embodiments, at least one detector tile is configured to be tilted by an actuator. In some embodiments, the detector is configured to change shape by moving one or more detector tiles. In some embodiments, the detector is configured to change the rotation and maintain the shape by moving one or more detector tiles.

[0006] According to various embodiments, the present disclosure also provides a medical imaging system. The medical imaging system includes a plurality of collimators configured to filter radiation emitted from a target object; and a detector configured to acquire an image of the target object by detecting radiation that has passed through the collimators, wherein a portion of the collimator is tilted relative to a top surface of the detector. In some embodiments, another portion of the collimator is parallel to the top surface of the detector. In some embodiments, the detector includes a plurality of detector tiles, wherein each detector tile is assigned a collimator. In some embodiments, the top surface of the detector is flat. In some embodiments, a portion of the collimator is tilted at an angle greater than 3 degrees relative to the top surface of the detector. In some embodiments, the medical imaging system also includes a plurality of shields between adjacent collimators.

[0007] According to various embodiments, the present disclosure also provides a method for acquiring a medical image. The method includes: providing a medical imaging system having a deformable detector, the deformable detector including a plurality of detector tiles; determining a configuration of the deformable detector; moving a portion of the plurality of detector tiles so that the deformable detector is configured to the determined configuration; and acquiring an image of a target object through the deformable detector. In some embodiments, the method further includes configuring a plurality of collimators associated with the deformable detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, in accordance with industry standard practice, various features are not drawn to scale and are used for illustration purposes only. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0009] Figure 1 is a schematic diagram of an exemplary nuclear medicine imaging system according to various aspects of the present disclosure.

[0010] Figure 2 is a cross-sectional view of a portion of an imaging system according to various aspects of the present disclosure.

[0011] Figure 3 is a perspective view of an exemplary detector tile according to various aspects of the present disclosure.

[0012] Figure 4 is a perspective view of an exemplary deformable detector according to various aspects of the present disclosure.

[0013] Figures 5A to 5D An embodiment of a detector according to various aspects of the present disclosure is shown from a top view before and after deformation.

[0014] Figures 6A to 6D An alternative embodiment of a detector according to various aspects of the present disclosure is shown from a top view before and after deformation.

[0015] Figure 7 is a cross-sectional view of an imaging system with a flexible detector tile according to various aspects of the present disclosure.

[0016] Figure 8 is a cross-sectional view of an imaging system having a flat detector and a tilted collimator portion according to various aspects of the present disclosure.

[0017] Fig. 9 is a cross-sectional view of an imaging system having a planar detector and a planar collimator with a tilted aperture according to various aspects of the present disclosure.

[0018] Fig.10 is a flow chart of a method of inspecting an object according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0019] The following disclosure provides a lot of different embodiments or examples for realizing different features of the present disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these are merely examples and are not intended to be restrictive. Any changes and other modifications to any other application of the described equipment, system, method, and principle of the present disclosure are fully considered, as would be normally expected by a person of ordinary skill in the art to which the present disclosure relates. For example, the features, components, and / or steps described with respect to one embodiment may be combined with the features, components, and / or steps described with respect to other embodiments of the present disclosure to form another embodiment of the equipment, system, or method according to the present disclosure, although such a combination is not explicitly shown. In addition, the present disclosure may repeat reference numbers and / or letters in various examples. This repetition is for simplicity and clarity, and does not itself specify the relationship between the various embodiments and / or configurations discussed.

[0020] Moreover, in the subsequent disclosure, features on another feature, connected and / or coupled to the other feature may include embodiments in which these features are in direct contact, and may also include embodiments in which additional features may be inserted into these features so that these features may not be in direct contact. In addition, spatially relative terms, such as "lower", "upper", "horizontally", "vertically", "above", "above", "below", "under", "upwardly", "downwardly", "top", "bottom", etc. and their derivatives (e.g., "horizontally", "downwardly", "upwardly", etc.), are used to simplify the relationship between one feature of the present disclosure and another feature. Spatially relative terms are intended to cover different orientations of devices including these features. Further, when "about", "approximately", etc. are used to describe a number or a range of numbers, the term is intended to cover numbers within a reasonable range including the described number, such as within + / -10% of the described number or other values ​​understood by those skilled in the art. For example, the term "about 5 cm" covers a size range from 4.5 cm to 5.5 cm.

[0021] The present disclosure relates generally to the field of medical imaging, and more particularly to the design of deformable detectors for use in nuclear medicine (molecular) imaging systems.The term "deformable" means capable of changing shape, geometry, area, alignment and / or orientation.

[0022] In nuclear medicine (molecular) imaging systems, collimators and detectors work together to generate images representing the distribution of radioactive drugs within an object. However, there are various problems with existing collimator and detector designs. For example, detectors are typically organized in a planar shape to obtain planar projections of an object from multiple angles to reconstruct a three-dimensional (3D) image of the object. Conventional detectors use large scintillation crystals coupled to photomultiplier tubes (PMTs) to detect radiation and record their positions. Scintillator-based detectors include modules of larger size, and the position of the detected radiation is calculated by comparing the outputs of adjacent modules. In some examples, the detector uses a continuous (single-piece) scintillator coupled to multiple PMTs. For example, a type of multi-anode PMT may have a fixed area of ​​52 cm×52 cm. Therefore, conventional detectors are designed to have a module of fixed shape and size once deployed (manufactured or installed). The deployment of rigid planar detectors provides a limited degree of spatial resolution and results in an inflexible imaging system.

[0023] The present disclosure provides a new detector design, wherein the detector includes a plurality of detector modules (or detector tiles). Each module also includes a plurality of cells, and each cell acts individually to generate an image. A cell is also referred to as a pixel circuit. By rearranging the detector tiles, the detector can be deformed to change shape and / or size. This deformable detector design provides flexibility to the imaging system, thereby helping to optimize the imaging performance for different targets and applications. Therefore, the system performance can be improved.

[0024] Many medical imaging systems, such as single photon emission computed tomography (SPECT), computed tomography (CT), and positron emission tomography (PET) imaging systems, use one or more detectors to acquire imaging data, such as gamma ray or photon imaging data. Before acquiring an image, a radioactive drug is usually taken orally or injected into the patient. The radioactive drug undergoes nuclear decay, thereby emitting gamma photons at certain rates and characteristic energies directly or indirectly through annihilation. One or more detector units are placed around the patient or object to record or monitor the emission. In many cases, for the convenience of manufacturing and data processing, the detectors are organized into a planar shape, so that data is acquired in a 2D matrix format, which is generally referred to as a projection. Based on the recorded information including the position, energy, and count of such detection events, an image of the distribution of the radioactive drug can be reconstructed to study the function of certain body parts.

[0025] Figure 1An exemplary nuclear medicine imaging system 100 that can be used for medical examination or treatment of an object such as a patient is shown. The imaging system 100 includes an integrated gantry 102, which also includes a rotor 104 oriented around a gantry central hole 106. The rotor 104 is configured to support one or more detectors 108 (two detectors 108 in relative positions are shown). The rotor 104 is also configured to rotate axially around an axial axis (e.g., the X direction as shown in the figure). Each detector 108 works in conjunction with a collimator 110. The collimator 110 is a device that guides the path of photons. In molecular imaging, photons may come from unknown locations inside the object, which is different from X-rays or CT, where photons are emitted from known source (or multiple sources) locations. Without the collimator 110, photons from all directions can be recorded by the detector 108, and image reconstruction may become difficult. Therefore, the collimator 110 is used to guide possible photon paths so that images can be reconstructed, which is similar to the role of a lens in a photographic camera. The imaging system 100 also includes a patient table 112 coupled to a table support system 114, which can be directly coupled to the floor or can be coupled to the gantry 102 through a base. The patient table 112 is configured to be slidable relative to the table support system 114, which facilitates the patient 150 to enter and leave the examination position substantially aligned with the axial axis. The console 120 provides operation and control of the imaging system 100, such as in any manner known in the art. For example, an operator or technician can use the console 120 to control mechanical movements, such as rotating the rotor 104, moving, rotating or tilting the detector 108 and the collimator 110, and sliding the patient table 112. The imaging system 100 also includes computer components (not shown) for acquiring data and reconstructing nuclear medicine images, such as a data storage unit, an image processor, an image storage unit, a display. In some embodiments, one or more computer components may be partially or completely located at a remote location (e.g., on the cloud). In some embodiments, one or more of these components may exist locally or remotely.

[0026] In some embodiments, the detector 108 is a semiconductor detector, such as a semiconductor detector based on cadmium telluride (CdTe), cadmium zinc telluride (CZT), or high purity germanium (HPGe). In some embodiments, the detector 108 is a scintillator (such as a detector based on sodium iodide (NaI) or cesium iodide (CsI)). In some other embodiments, the detector 108 can also be a scintillator coupled to a compact photomultiplier tube (PMT), a silicon photomultiplier tube (SiPMT), or an avalanche photodiode. One or more radiopharmaceuticals orally or injected into the patient 150 undergo nuclear decay and can emit radiation (e.g., gamma photons) at certain rates and characteristic energies directly or indirectly through annihilation. The detector 108 is placed near the patient 150 to record or monitor the emission. Based on recorded information such as the location, energy, and count of such detection events, an image of the distribution of the radiopharmaceutical can be reconstructed to study the state or function of certain body parts on the patient 150.

[0027] The collimator 110 includes one or more openings, such as through holes. Depending on the number and geometric arrangement of the through holes, the collimator 110 can be a single pinhole, a multi-pinhole, a coded aperture, or an extended coded aperture (also known as extended field imaging, SFI) collimator, or other suitable types of collimators. Depending on the profile of the through holes, the collimator 110 can be a parallel hole collimator, a fan beam collimator, or a cone beam collimator, or other suitable types of collimators. The collimator 110 is placed between the detector 108 and the imaging object (e.g., the patient 150), and the openings on the collimator determine the direction and angular span that radiation can pass through to reach a certain position on the detector.

[0028] In various embodiments, the collimator is essentially a perforated plate, which is usually made of heavy metals such as lead and tungsten. In some embodiments, the collimator is made of a flat plate, which is usually placed parallel to the flat detector surface. Depending on the photon energy it is designed to image, the thickness of the plate is large enough to block most radiation, so that the photons mainly pass through small pinholes on the plate. For example, for the commonly used isotope technetium 99m (99mTc) that emits gamma rays with an energy of about 140keV, for a plate made of lead, a thickness of 3mm is usually sufficient, and for a plate made of tungsten, a thickness of about 2mm is sufficient. The thickness needs to be larger to image higher energy gamma rays. These collimators need to be placed at a certain distance from the detector to allow photons from the designed field of view (FOV) to pass through (one or more) pinholes to spread across the detector surface. In this case, the gap between the collimator and the detector is usually greater than 3cm.

[0029] The imaging system 100 may include other necessary components for an imaging gantry, such as connectors to couple components together (e.g., to connect the detector 108 and the collimator 110 together), motors to cause the components to move, photon shielding assemblies, housing assemblies to house other components, etc. For example, the coupling and shielding assembly 116 may connect the detector 108 and the collimator 110 so that the two move together (e.g., rotate), and the coupling and shielding assembly 116 may prevent radiation (photons) from reaching the detector 108 through other paths other than the collimator 110. In other embodiments, the detector 108 and the collimator 110 may move independently relative to each other.

[0030] Figure 2 1 is a schematic cross-sectional view of a collimator 110 and a detector 108 working together to generate an image representing the distribution of a radiopharmaceutical within an object. In the illustrated embodiment, a coupling and shielding assembly 116 connects the collimator 100 and the detector 108. The collimator 110 is positioned between the patient 150 and the detector 108 and is configured to filter radiation by blocking certain photons and allowing other photons to pass through. The collimator 110 is made of (one or more) heavy metals (such as lead and / or tungsten) or alloys that absorb radiation (e.g., photons). The collimator 110 has an opening 118 built therein to allow some photons to pass through and reach the detector 108. It should be understood that the radiation or photon blocking or absorption performed by the collimator does not need to block 100% of the photons, because a small percentage of photons (e.g., 5% or less) can still penetrate the entire thickness of the radiation absorbing material. The number of escaping photons can decrease exponentially with the thickness of the collimator. In other words, blocking (or other similar terms) means that substantially all photons (eg, 95% or more, or 99% or more) are absorbed by the radiation absorbing material.

[0031] The openings 118 may also be referred to as through holes, tunnels, apertures, or through features—and may have any suitable shape, size, number, and / or distribution within their respective collimators. In some embodiments, the openings 118 may include parallel holes, fan beams, cone beams, slit slats, pinholes, multiple pinholes, coded apertures, openings of any other suitable shape, or combinations thereof. In some embodiments, the collimator 118 is placed close to (e.g., 2 cm or less) the patient 150. Thus, the collimator 118 may use parallel holes or fan beams (converging or diverging) because such features do not require significant separation from the patient 150. In some embodiments, the openings 118 may be angled, converging, or diverging, and may form a fan beam or a cone beam, etc. In one example, the openings 118 include a plurality of pinholes, wherein the number of pinholes may be greater than 11, greater than 23, or greater than 59, or greater than 83. The opening 118 may form a coded aperture pattern, for example, MURA (modified uniform redundant array) of sizes 5, 7, 11, and 13 include 12, 24, 60, and 84 holes, respectively. A greater number of pinholes helps improve imaging sensitivity. Further, the opening 118 may be a single pinhole, multiple pinholes, or a multiple pinhole module (including scattered field imaging (SFI) or coded aperture).

[0032] Still reference Figure 2 , photons can enter at an acceptable angle of incidence (at Figure 2 The acceptable incident angle α is represented by the angle between the line A1 and the vertical direction Z, where the line A1 is the traveling direction of the photon and the direction Z is the normal to the top surface of the collimator 110) and hits the top surface of the collimator 110. If the incident angle is greater than a predetermined threshold, the photon will be absorbed by the collimator 110 (note that in some cases, the photon penetrates a portion of the collimator 110 adjacent to the opening (e.g., a thin area on the sidewall of the opening)). Therefore, the acceptable incident angle α represents a possible range of incident angles for the photon to pass through the opening 118 without passing through a portion of the collimator 110.

[0033] In some embodiments, the threshold ranges from 0° to about 2° or from 0° to about 10°. In one example, a LEHR (low energy high resolution) collimator has an opening diameter of about 1.11 mm and a length of about 24.04 mm, where an acceptable angle of incidence ranges from 0° to about 2.64°. In another example, a GAP (general purpose) collimator has an opening diameter of about 1.40 mm and a length of about 25.4 mm, where an acceptable angle of incidence ranges from 0° to about 3.15°). In yet another example, a LEHS (low energy high sensitivity) collimator has an opening diameter of about 2.54 mm, a length of about 24.04 mm, where an acceptable angle of incidence ranges from 0° to about 6.03°. The acceptable angle of incidence of the collimator 110 is typically less than 10°. Photons that can pass through the collimator 110 are considered to be within the field of view (FOV) of the collimator 110 (within Figure 2 denoted as the space within lines A1 and A2).

[0034] In various embodiments of the present disclosure, the detector 108 is formed of a plurality of detector modules, also referred to as detector tiles or pixel circuitized detectors. For example, the detector 108 may include twenty detector tiles arranged to form a rectangular array having five rows, each row having four detector tiles. Each detector tile is individually used as a micro-detector to capture or record emissions. At least one detector tile or each detector tile is movable relative to the other detector tiles, which reconfigures the detector 108 to form different shapes and / or sizes.

[0035] Figure 3 An exemplary detector patch 200 is shown. The detector patch 200 can be formed of any semiconductor material known in the art, such as cadmium zinc telluride (CdZnTe), commonly referred to as CZT, gallium arsenide (GaAs), and silicon multiplier (SiPM), among others. Specifically, the detector patch 200 includes a crystal 202 formed of a semiconductor material and mounted on a detector base 214. The bottom surface of the crystal 202 includes an array of pixel circuits 212, such as a rectangular array, a square array, or other suitable array. The pixel circuits 212 can have substantially the same size and can also be rectangular or square in shape. In various embodiments, the size of the pixel circuits 212 can range from approximately 1×1 mm to approximately 1×1 mm. 2 To about 4×4mm 2In various embodiments, the pixel circuit pitch P of the array can range from less than 1 mm to about 6 mm. In addition, in the same array, different pixel circuits 212 can have different sizes or geometries. For example, a portion of the pixel circuits 212 located in the center of the array may be larger than the pixel circuits 212 at the periphery, and vice versa. In addition, the number of pixel circuits 212 can be greater or less than 16 (4×4), such as Figure 3 As shown, for example, 256 (16×16) pixel circuits 212 may be provided. It should also be noted that the thickness of the crystal 202 may vary between a few millimeters and a few centimeters. In various embodiments, the size of the detector patch 200 may range from about 4 cm×4 cm to about 10 cm×10 cm, such as 5 cm×5 cm. Also, the shape of the detector patch need not be square, and may be rectangular, hexagonal, etc. In a specific example, a detector patch 200 based on CZT or silicon multiplier (SiPM) is manufactured to a size of 4 cm×4 cm to further include a 16×16 pixel circuit array with a unit pixel circuit size of 2.5 mm×2.5 mm. In operation, each pixel circuit 212 individually records or monitors the amount of emission arriving and generates a signal (e.g., voltage or current) associated with the amount of emission. In some embodiments, the detector base 214 includes appropriate electronic circuits (e.g., ASICs) to collect and process signals from the pixel circuits 212.

[0036] The detector base 214 may include a wired connection unit, such as a bus (not shown), to transmit signals from the ASIC to the control module 120 ( Figure 1 ). Alternatively, the detector base 214 may include a wireless connection unit using technologies such as WiFi and / or Bluetooth to avoid additional wiring that may cause complications during detector deformation. In addition, the detector base 214 may include one or more battery packs to further reduce wiring. The battery pack can be charged during system downtime. The detector base 214 may also include a wireless charging unit that allows the battery pack to be wirelessly charged. In one example, the detector patch 200 completely eliminates wired connections to rely on wireless data transmission and wireless charging to achieve the corresponding functions. As will be discussed below, multiple detector patches 200 will be combined with at least one or each detector patch 200 that is movable relative to other detector patches to form a deformable detector. Each patch in the detector patch can carry its own battery pack. Alternatively, the battery pack can be mounted on a movable detector patch in the detector patch, while other fixed detector patches can have a wire connection to a power source to replace the battery pack for power supply.

[0037] Figure 4A detector 108 is shown that includes a plurality (e.g., 24) of detector tiles 200 arranged to form a rectangular array having four rows of six detector tiles each. It should be noted that the detector 108 may have a larger or smaller array of detector tiles 200 than that shown. Adjacent detector tiles 200 may leave a gap that is less than a predetermined width, such as less than the width of a single detector tile 200. The gap may be as small as is physically achievable, for example. In a particular example, the gap is from about 5% to about 20% of the width of a single detector tile 200. In another example, the gap is less than one pixel circuit pitch P( Figure 3 ) or one detector resolution of the detector tile 200, but greater than zero. Alternatively, adjacent detector tiles 200 may be in physical contact (adjacent) with each other.

[0038] Among the detector tiles 200, at least one detector tile 200 can be mounted on a track (e.g., a slide rail or a guide rail). The track is configured to allow the detector tile 200 to move relative to other detector tiles, thereby changing the contour geometry of the detector 108. The imaging system can adopt a mechanical arm, wherein the finger is attached to the movable detector tile 200. Alternatively, each detector tile 200 can be moved individually along the track relative to each other. In some embodiments, the detector 108 may include at least three individually movable groups, such as three, four, five or six movable detector tiles. In some embodiments, the detector tiles 200 have different sizes and / or geometries. For example, one detector tile can be larger than another, or one detector tile has a square shape and another has a rectangular shape. In addition, a plurality of detector tiles 200 can form a group that moves as a unit. Within the group, the position of the detector tile 200 is fixed. In addition, the detector tiles 200 assigned to the same group can share a single battery pack, rather than each detector tile carrying its own battery pack. And, instead of free transformation, the detector 108 can be transformed into some shapes predetermined for certain imaging tasks. Therefore, the detector 108 can be divided into a plurality of movable groups with different sizes and / or geometric shapes. In some embodiments, the detector 108 may include at least three individually movable groups, such as three, four, five or six movable detector tiles. Each individually movable group may include one or more detector tiles 200, and the position of the detector tiles 200 is relatively fixed within the group. In some embodiments, further, the smallest movable group includes only one detector tile 200. In the illustrated embodiment, the top surfaces of all detector tiles (individually movable or within a movable group) in the detector 108 can be configured to be coplanar, and in this form, the detector tiles operate as a whole, and the images acquired by the detector tiles are stored or represented as an entity, such as in the form of an array or a matrix.

[0039] FIG. 5A to FIG. 5D yes Figure 1 1 is a top view of the detector 108 in the imaging system 100 in FIG. FIG. 5A to FIG. 5D Two embodiments are shown that rotate a rectangular detector without changing its shape or aspect ratio (length / width). Figure 5A and Figure 5BThe detector 108 is shown mechanically rotating as a whole. The X direction marks the axial axis along which the patient 150 lies flat from head to toe. In addition to the rotor 104 that provides for the detector 108 to rotate about an axis, the imaging system 100 can also have a rotation mechanism mounted on the rotor 104 that allows the detector 108 to rotate about its own normal direction. For example, for a detector having a size of 40 cm×50 cm, in a top view in a conventional orientation, the short side (40 cm) is typically aligned with the axial axis so that the long side (50 cm) provides maximum coverage in the lateral direction (Y direction) because a conventional SPECT system equipped with a parallel hole collimator provides a FOV of 50 cm diameter. In Figure 2 In B, the detector 108 is rotated 90 degrees around its center in the XY plane so that the long side is aligned with the axial direction instead to provide different FOVs along the axial axis and in cross-section. In this orientation, the system provides more coverage along the axial direction. One benefit of this orientation is that whole-body images can be acquired in a smaller number of beds.

[0040] As a comparison, Figure 5C and Figure 5D An example of a deformable detector 102 is shown. The deformable detector 102, which has a size of 40 cm×50 cm, includes three detector tiles 102-I, 102-II, and 102-III (alternatively, each of 102-I / II / III may include multiple grouped smaller detector tiles). The detector tiles 102-I and 102-III each have a size of 5 cm×40 cm, and the detector tile 102-II has a size of 40 cm×40 cm. The central detector tile 102-II is fixed, while the other two smaller detector tiles 102-I and 102-II are movable relative to the central detector tile 102-II. In the illustrated embodiment, the detector tile 102-I slides counterclockwise from the top of the central detector tile 102-II to its left side (e.g., pushed by a robotic arm). Similarly, the detector tile 102-II slides counterclockwise from the bottom of the central detector tile 102-II to its right side. The reassembled detector 108 maintains the same shape and size of 40 cm x 50 cm, but changes its alignment equivalently after a 90 degree rotation in the XY plane, similar to Figure 5B The counterpart shown.

[0041] Fig. 6A and Figure 6BAnother example is shown in which the detector 108 can be deformed into different shapes with different aspect ratios. The example shown demonstrates a method of transforming a detector with dimensions of 40 cm×60 cm to 30 cm×80 cm. The detector 108 includes three detector tiles 108-I, 108-II, and 108-III (alternatively, each of 102-I / II / III may include multiple grouped smaller detector tiles). The detector tiles 108-I and 108-III each have dimensions of 10 cm×30 cm, and the detector tile 108-II has dimensions of 30 cm×60 cm. The center detector tile 102-II is fixed, while the other two smaller detector tiles 108-I and 108-II are movable relative to the center detector tile 108-II. During the transformation, the movement paths and directions of the detector tiles 108-I and 108-III are indicated by dashed arrows. After the change, the long side (30 cm) of the movable detector tile 108-I or 108-III is aligned with the short side (30 cm) of the detector tile 108-II. The reassembled detector 108 maintains a 2400 cm 2 The same detector area of ​​​​the detector, but with an elongated shape and a different aspect ratio (from 60 / 40 to 80 / 30).

[0042] There are different ways to transform. For example, Figure 6C and Fig.6D As shown, detector tiles 108-I and 108-III can be rotated and attached to the same side of the detector to achieve the same transformation. During the transformation, the movement paths and directions of detector tiles 108-I and 108-III are indicated by dashed arrows. Under similar principles as disclosed herein, detector 108 can be transformed into various other shapes and aspect ratios depending on the size of the detector tiles or groups of detector tiles. For example, a 40 cm × 60 cm detector can be transformed into a 30 cm × 80 cm detector, such as Figure 6B and 6C As shown, it can be transformed into a detector of 50cm×48cm or 25cm×96cm. Moreover, this deformation can be easily realized with detector tiles.

[0043] In the above illustrated embodiments, the detector tiles are configured to remain coplanar so that the surface of the detector 108 remains flat. At the same time, the detector tiles (or groups of detector tiles) may also be configured to form angles, such as by tilting. Figure 7A cross-sectional view of an imaging system 100 with a deformable detector 108 in yet another embodiment is shown. In the previous embodiment, the top surfaces of the detector tiles of the detector 108 remain coplanar before and after the transformation. In addition to transforming the detector 108 planarly, the detector tiles can also be tilted at a certain angle, such as angles β1 and β2 for detector tiles 108-I and 108-II, respectively. In some applications, such as imaging the heart 152, the imaging object is relatively small compared to the size of the detector. Cardiac imaging is an important clinical application of SPECT, accounting for about 60% of SPECT scans in the United States. In this application, the detector can be bent by dividing into several tilted detector tiles. The human heart is typically 12 cm long and 10 cm wide, which is much smaller than the conventional detector size of about 40 cm×50 cm. Since the size of the heart is much smaller than the detector, the collimators 110-I and 110-II can be designed in two parts, which form a small angle β, such as 6 degrees, 8 degrees, 10 degrees or 12 degrees, to obtain two projections at slightly different angles. In some embodiments, the maximum angle β is limited to less than about 40 degrees or about 60 degrees. Such placement of collimators 110-I and 110-II is referred to as angled collimators. The FOVs of such angled collimators overlap. In some embodiments, the normals of these collimators (a line perpendicular to the center of the collimator, at Figure 7 The common point P0 (or the relatively small volume of space where the organ is located) intersects at a common point P0 (or the relatively small volume of space where the organ is located), which defines the center of the FOV of the system in this configuration.

[0044] The image of the heart 152 can be projected onto two separate tiles of the detector 108 through two collimators 110-I and 110-II. There is a shielding plate 116 between the two tiles of the detector 108 to prevent crosstalk between the two parts, i.e., radiation passing through one collimator and hitting the other tile of the detector. For better signal reception, the detector can be divided into two slightly curved detector tiles so that each tile is parallel to the collimator surface.

[0045] The actuator 216 can be used to raise (tilt) one edge of the detector tile 108-I or 108-II or both. In some embodiments, the actuator 216 extends from the detector base 214. In the illustrated embodiment, the tilted detector tiles 108-I and 108-II form small angles β1 and β2 relative to the top surface of the detector base 214. The angles β1 and β2 can be the same or different, and the relationship is β1+β2=β. In a specific example, β is 6 degrees, β1 is 2 degrees, and β2 is 4 degrees. By tilting the detector tiles 108-I and 108-II at different angles, the exact position of the common point P0 can be finely adjusted. The other edges of the detector tiles 108-I and 108-II can remain adjacent, or have a small gap between them (for example, the gap width is less than the width of the detector tile, or less than 10 cm). In the illustrated embodiment, the two edges can be linked by a hinge 220 and are considered to still be in physical contact. If the two edges remain in physical contact, the two detector tiles 108-I and 108-II can share a common detector base 214 instead of two separate detector bases, such as Figure 7 In an embodiment, further, if the detector 108 includes three or more tilted detector tiles, the tilted detector tiles may still share a common detector base 214 .

[0046] In this case, collimators 110-I and 110-II can be pinholes, multiple pinholes, coded apertures, or other suitable forms. One benefit of this design is that multiple projections of an object can be acquired at one detector position. If the original imaging required 60 projections by rotating the detector to 60 positions, this can now be accomplished using 30 detector positions. In dual opposed detector systems common in clinical systems (e.g., Figure 1 In the imaging system 100 in FIG. 1 , 60 projections required rotating the two opposing detectors to 30 positions respectively. Now, only 15 positions of the two opposing detectors are required to complete the task, thereby reducing the imaging time by half.

[0047] In some embodiments, collimators 110-I and 110-II are separate components. For example, collimator 110-I is mounted to detector tile 108-I so that the two move together (e.g., rotate or tilt), and similarly, collimator 110-II is mounted to detector tile 108-II. Therefore, when actuator 216 extends to tilt the detector tile, each collimator tilts accordingly with the corresponding detector tile. In an alternative embodiment, collimators 110-I and 110-II are manufactured as a single piece with a fixed angle β. Detector tiles 108-I and 108-II are first tilted without collimators attached. After detector tiles 108-I and 108-II have been tilted to a predetermined angle (β1+β2=β), collimators 110-I and 110-II are then manually or automatically mounted on top using a robotic arm.

[0048] In some other embodiments, the detector 108 may remain flat without bending or tilting, while the collimator 110 includes multiple sections positioned at smaller angles, and certain portions of the detector are designated to receive radiation from each of these sections of the collimator (these designated portions of the detector may overlap slightly), such as Figure 8 As shown. Similar to the above combination Figure 7 In some embodiments, the normals of the collimators (the lines passing perpendicularly through the centers of the collimators, at Figure 8In the embodiment shown, imaging can be completed within one-third of the original detector rotation. Since the design is applicable to the case where the detector is not bent, the design is applicable to conventional systems using non-bendable detectors to make it applicable to existing systems using non-bendable detectors. Note that in this embodiment, the collimator portion 110-I / II / III may not be parallel to the detector surface. Here, "non-parallel" means that the angle formed relative to the collimator and the detector surface is greater than the tolerance of mechanical assembly errors, such as an angle greater than 1 degree, or an angle greater than 3 degrees. The collimator 110 (including the collimator portions 110-I / II / III) is considered to be piecewise planar, so that each collimator portion is planar, while some adjacent collimator portions (portions with holes) are not coplanar. The collimator 110 can be manufactured as a single piece, or manufactured as two or three separate pieces and installed separately. Since the detector 108 is not curved, it may be easier to make the collimator 110 as a single piece, and there may still be a shielding plate 116 in between to separate the collimator portions 110-I / II / III to prevent radiation from passing through one collimator and hitting the portion of the detector designated to receive radiation passing through the other collimator.

[0049] In yet another embodiment, similar to the previous embodiment, the collimator may be in a planar shape and include multiple sections, each section having a set of holes inclined at a small angle and directed toward the designed FOV, such as Fig. 9 As shown. In this case, the collimator surface can be parallel to the detector surface, which can also be planar. Also, the holes in each collimator portion (110-I, II, or III) can be parallel to each other. In the illustrated embodiment, the holes in the collimator portions 110-I and 110-III are tilted so that the imaginary lines C1 and C3 passing through the center of the respective collimator portions and parallel to the elongation direction of the holes intersect at a common point P0. The holes in the middle collimator portion 110-II extend along their normal direction, such as Figure 2 The holes shown, and a corresponding dotted line C2 passing through the center of the intermediate collimator portion also extends along the normal direction and passes through the common point P0.

[0050] Reference now Fig.10 , a flow chart of a method 500 for acquiring an image of an object using a deformable detector according to various aspects of the present disclosure is shown. The method 500 is only an example and is not intended to limit the present disclosure to the contents explicitly described in the method 500. Additional operations may be provided before, during, and after the method 500, and some of the operations described may be replaced, eliminated, or moved around for additional embodiments of the method. Figures 1 to 8 Method 500 is described.

[0051] At operation 502, a medical imaging system is provided that is equipped with at least one deformable detector. The deformable detector also includes a plurality of detector tiles. The medical imaging system, the deformable detector, and the detector tiles are similar to Figure 1 The imaging system 100 shown, Figure 4 The deformable detector 108 and Figure 3 Detector tiles are shown. For the sake of brevity, similar aspects are not repeated below.

[0052] At operation 504, a preferred shape, orientation, and / or area of ​​the deformable detector is determined. This consideration may include the size and / or shape of a target object such as a patient or a particular organ or body part of the patient. Another consideration may include the distance of the target object to the detector. In some embodiments, operation 504 selects from a set of predetermined detector configurations.

[0053] In operation 506, the detector is rotated along its normal axis (perpendicular to the detector), or a portion of the detector tile is moved, such as by moving a selected detector tile along a track. For example, operation 506 may require moving only one detector tile, while the other detector tiles remain fixed. Alternatively, two or more detector tiles may be moved. Alternatively, all detector tiles may be moved. Operation 506 may also batch process several detector tiles in a group, so that detector tiles belonging to the same group move together while remaining fixed relative to each other within the group. In one embodiment, the top surfaces of the detector tiles are configured to be coplanar during deformation, in other words, the top surface of the deformable detector remains flat (also referred to as the deformable detector is planar) while the shape (e.g., geometry or aspect ratio) changes, such as Figures 6A-6D ) and / or orientation (e.g., with Figure 5C and 5D In another embodiment, one or more detector tiles are moved to the edge of the deformable detector, or moved a distance away from another portion of the deformable detector, or moved to be stacked behind other detector tiles and closed, which effectively reduces the effective area of ​​the deformable detector. In yet another embodiment, a portion of the detector tiles are tilted to form a non-planar detector, such as Figure 7 shown.

[0054] At operation 508, collimators associated with the deformable detectors are configured. In one embodiment, each collimator is secured to a respective detector tile such that the collimator moves or tilts with the detector tile mounted thereon. Alternatively, the collimator may be assembled or mounted over the detector tile after the detector deformation is complete.

[0055] In operation 510, the medical imaging system acquires an image of a target object by detecting or monitoring an amount of radiation collected by a deformable detector. An image processing unit in the medical imaging system may perform image reconstruction based on an original image acquired from the deformable detector.

[0056] Although not intended to be limiting, one or more embodiments of the present disclosure provide many benefits to molecular imaging of objects such as patients. For example, a deformable detector allows the imaging system to obtain flexibility in spatial resolution when acquiring 3D images and improves step-scan efficiency. Therefore, system performance is improved.

[0057] The foregoing summarizes the features of several embodiments so that those of ordinary skill in the art can better understand aspects of the present disclosure. Those of ordinary skill in the art will appreciate that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or the same advantages as the embodiments introduced herein. Those of ordinary skill in the art will also recognize that such equivalent constructions do not depart from the spirit and scope of the present invention, and that they can make various changes, substitutions and modifications to this article without departing from the spirit and scope of the present disclosure. Accordingly, it is appropriate for the appended claims to be interpreted broadly and in a manner consistent with the present disclosure.

Claims

1. A medical imaging system, comprising: a stand, including a rotor; a plurality of collimators configured to filter radiation emitted from the subject; as well as A plurality of detectors are supported by the rotor, each of the plurality of detectors being configured to detect radiation having passed through a corresponding one of the plurality of collimators, and each detector comprising a plurality of detector tiles and at least one detector tile being movable relative to the other detector tiles, wherein top surfaces of the plurality of detector tiles can be configured to be coplanar, wherein movement of the at least one detector tile comprises sliding the at least one detector tile along one or more tracks. 2 . The medical imaging system of claim 1 , wherein the collimator comprises a plurality of collimator portions configured as piecewise planes. 3 . The medical imaging system of claim 1 , wherein each detector tile of the plurality of detector tiles is movable. 4 . The medical imaging system of claim 1 , wherein each detector tile of the plurality of detector tiles comprises a detector base.

5. The medical imaging system of claim 4, wherein the detector base comprises a battery pack. The medical imaging system of claim 5 , wherein the battery pack is capable of wireless charging.

7. The medical imaging system of claim 4, wherein the detector base comprises a wireless communication module.

8. The medical imaging system of claim 1, wherein the detector comprises a plurality of detector pedestals, wherein one detector pedestal is shared by at least two detector tiles.

9. The medical imaging system of claim 1, wherein the at least one detector tile is configured to be tilted at an angle relative to the other detector tiles.

10. The medical imaging system of claim 9, wherein the at least one detector tile is configured to be tilted by an actuator.

11. The medical imaging system of claim 1 , wherein the detector is configured to change shape by moving one or more detector tiles.

12. The medical imaging system of claim 1, wherein the detector is configured to change rotation and maintain shape by moving one or more detector tiles.

13. A method for acquiring a medical image, comprising: Providing a medical imaging system having a plurality of deformable detectors, each deformable detector of the plurality of deformable detectors comprising a plurality of detector tiles, wherein the plurality of deformable detectors are supported by a rotor of a gantry; determining a configuration of the deformable detector; moving a portion of the plurality of detector tiles such that the deformable detector is configured into the determined configuration, wherein the movement of at least one detector tile comprises sliding the at least one detector tile along one or more tracks; as well as An image of the target object is acquired by the deformable detector by detecting radiation emitted by the target object.

14. The method according to claim 13, further comprising: A plurality of collimators are configured in association with the deformable detector.

15. The method of claim 13, wherein the moving of a portion of the plurality of detector tiles comprises tilting a portion of the plurality of detector tiles.

16. A medical imaging system comprising: a stand, including a rotor; a plurality of collimators configured to filter radiation emitted from the subject; as well as A plurality of detectors are supported by the rotor, each of the plurality of detectors being configured to detect radiation having passed through a corresponding one of the plurality of collimators, and each of the detectors comprising a plurality of detector tiles, wherein top surfaces of the plurality of detector tiles are configurable to be coplanar, some of the plurality of detector tiles are movable, and the detector is configured to change size, shape, orientation, or a combination thereof by moving one or more of the plurality of movable detector tiles.

17. The medical imaging system of claim 16, wherein at least one of the movable detector tiles can be tilted relative to the other detector tiles to produce a non-planar detector surface.

18. A medical imaging system according to claim 17, wherein the collimator includes a plurality of collimator parts, and one of the plurality of collimator parts is associated with at least one of the movable detector tiles and one of the plurality of collimator parts is configured to tilt together with the at least one of the movable detector tiles.

19. The medical imaging system of claim 17, further comprising a shielding plate between the at least one of the movable detector tiles and one of the adjacent detector tiles.

20. The medical imaging system of claim 16, wherein the detector tiles are configured into a plurality of movable groups, and the detector tiles in a single group are moved together as a unit.

21. The medical imaging system of claim 20, wherein the detector tiles in a single group share a battery pack.

Images