A portable and compact positron emission tomography (PET) system that can adapt in real time.

Abstract

The present invention relates to a portable and compact positron emission tomography (PET) system adaptable in real time, a detector unit included in the system, and an image reconstruction method. The system comprises a computer connected to a perception unit, a robot unit, a user interface and imaging unit, and a perception unit, which processes received data and generates appropriate responses for each unit, and a user interface and imaging module for displaying reconstructed and correlated images of the patient being detected in real time.

Description

Technical Field

[0001] The present invention relates to a portable and small positron emission tomography (PET) system or a single photon emission computed tomography (SPECT) imaging system that can be adapted in real time. Specifically, the present invention is a portable and small tool for on-site use, not limited to diagnosing neurodegenerative diseases such as dementia.

Background Art

[0002] Current PET systems are large and expensive, and there are limitations in widespread use and access. Observing the target area of a patient or adjusting the diagnosis in real time can be achieved by a system that can be freely operated with only minimal restrictions imposed on the patient.

Summary of the Invention

Means for Solving the Problems

[0003] To overcome the above-mentioned challenges, the present invention proposes a compact imaging system that addresses the above-mentioned problems. Such a compact system needs to effectively handle data, power, and heat so that it operates independently of a stationary framework for operation. The present invention provides a portable and compact positron emission tomography (PET) system or single-photon emission tomography (SPECT) imaging system for close-range detection and organ-specific imaging, primarily comprising: a robotic unit for supporting, setting up, and orienting a detection unit in a planned configuration; a perception unit including an imaging module for tracking patient movement and guiding the robotic unit to orient the imaging system, and achieving motion correction by maintaining a constant relative orientation between the imaging system and the patient being detected, thereby acquiring a predetermined subset; a computer for coordinating the main units to perform image acquisition in a planned series of orientations and image a desired target region; and a user interface and imaging unit for viewing the patient in real time and for imaging reconstructed PET activity images superimposed on patient changes that can be calculated from computed tomography (CT) images or magnetic resonance imaging (MRI) images. This invention enables highly automated and smooth operation, can be easily transported from one location to another, can be easily assembled and operated in remote locations, is inexpensive, and can be widely adopted.

[0004] The present invention provides a portable and compact positron emission tomography (PET) system that can be adapted in real time, and comprises the following configuration. A front-end readout comprising at least one small, handheld gamma-ray detector module for processing signals to convert gamma rays into visible light, convert visible light into analog electrical signals, and output serialized data; at least one connecting cable for connecting to at least one detector module that processes signals to output serialized data; and at least one detector unit including a data acquisition unit (DAQ) for data acquisition to serialize the data and to advance the configuration of the settings. A computer or central processing unit (CPU) connected to at least one detector unit, robot unit, user interface and imaging unit, and perception unit, which transmits control signals, receives data from each unit, processes the received data, and generates appropriate responses for each unit. A robot unit connected to a CPU for mechanically holding, positioning, and orienting each of the at least one detector units, including a C-shaped arm holder for holding at least one detector unit, a multi-axis robotic arm connected to the C-shaped arm holder for receiving input from a computer for final position, speed, and positioning, a height adjustment arm for adjusting the vertical height based on input from the computer, and a distance adjustment arm for adjusting the distance horizontally from at least one detector unit, and a computer-connected controller for controlling the positioning of the multi-axis robotic arm, height adjustment arm, and distance adjustment arm to a suitable location for acquiring images. A perception unit equipped with sensors, including a video unit, for calibration using 1D, 2D, or 3D standard reference signals, to align coordinates with the robot unit and capture the position and orientation of the patient to be detected. It includes a user interface and imaging module for the user to input variables for the current imaging plan and for displaying reconstructed and re-registered images of the patient.

[0005] The present invention further provides a detector unit for use in a portable and compact positron emission tomography (PET) system, comprising the following configuration. A crystal for converting gamma rays emitted from a target area of ​​a patient that is to be detected and has been marked with a radioactive marker into visible light in proportion to the energy of the gamma photons, A silicon photomultiplier (SiPM) for detecting visible light from at least one crystal, converting the visible light into an analog electrical signal proportional to the input visible light and correlated with the arrival time and intensity of the event, thereby detecting gamma-ray incidence on the crystal at the crystal level, wherein each SiPM is provided with multiple channels, up to 64 channels, connected one-to-one with reading means for receiving electrical signals from the corresponding SiPMs at the channel level, and within the reading means, the SiPM signal is converted into a threshold signal time, start and end timestamps representing arrival time information are registered in the digital converter each time, the digitized event is stored in a 48-bit event along with all 64 channels of the reading means in an internal FIFO, the approximate energy of the original gamma-ray event and data from each reading means are sent in series, and a field-programmable gate array (FPGA) for reading data from the reading means arranges the data from the multiple reading means and passes it to a serializer, transmitting the data losslessly via a connecting cable. The system includes a data acquisition unit (DAQ) that receives event data from a corresponding serializer and deserializes it using the GMSL protocol, an FPGA-DAQ that receives the deserialized event data from each separate deserializer and arranges it in an internal FIFO, achieving unbiased acquisition from multiple data streams, the packaged information is then sent to a computer via a bridge chip, and the data is received and stored by the computer. A USB 3.0 compatible cable, which has two serial link channels, two sets of configuration and control I / O pins, two RST channels, two clock channels, and two power channels, is a connection cable for connecting to a DAQ unit. A computer that connects to other key units of a signal and data processing system by transmitting control signals, receives data from each unit, processes the received data to generate appropriate responses to the key units, and enables the signal and data processing system to function as a state machine that interacts and generates responses based on the patient's position, and that, for any short time interval, inputs information from nearby units, compares it with the imaging plan, calculates the target position of the robotic arm, issues commands to the robotic unit, reconstructs the image, and co-registers it with the patient's existing DICOM (CT or MRI) image or another highly matching DICOM image, and transmits the currently registered image to the imaging unit for real-time monitoring.

[0006] The present invention further provides a polygonal reconstruction method for use in a PET system, which involves multiple steps for forward and back projection of each separate data corresponding to different angles, where the basis space is related to a detection area defined by coordinate axes, and each rotated direction is reconstructed by reorienting the image from the previous angle to the current angle, finally returning to the basis space, and iterative reconstruction is performed according to the following algorithm.

[0007]

number

[0008] [Figure 1a] Figure 1a is a schematic diagram of a complete imaging system according to the present invention. [Figure 1b] Figure 1b is a diagram of a physical model of the overall structure of the PET system according to the present invention. [Figure 1c] Figure 1c is a block diagram of a robot unit included in the PET system of the present invention. [Figure 2] Figure 2 is a block diagram showing the operation of a detector unit 110, which includes at least one small, handheld gamma-ray detector module according to the present invention. [Figure 3] Figure 3 is a block diagram showing the operation of multiple detector units according to the present invention. [Figure 4] Figure 4 is a simplified diagram of the signal flow of the detector unit according to the present invention. [Figure 5] Figure 5 is a block diagram of a perception unit, showing its sub-components: a depth-sensing camera, a safety proximity camera, and a temperature sensor for monitoring ambient temperature. [Figure 6] Figure 6 is a block diagram of the user interface and imaging unit, which shows the lower-level components of the system. [Figure 7]FIG. 7 is a diagram of channels whose gamma ray absolute energy threshold has been corrected and calibrated, showing on the left a sample of the 16-channel energy spectrum for the standard radioactive 22Na source and the intrinsic activity from the crystal, and on the right the energy spectrum for the standard 22Na source for all 1024 channels after calibration for precise energy prediction, where an energy resolution of 8% full width at half maximum (FWHM) has been achieved. [Figure 8] It is a diagram of the time resolution measured as the FWHM of the time delay histogram between the reference channel, which shows a coincidence counting time resolution of 282 ps FWHM, and all 512 channels of the module. [Figure 9] It is an exploded view of the main units of the detector unit included in the PET system of the present invention.

Best Mode for Carrying Out the Invention

[0009] As described in the drawings, the portable and small positron emission tomography (PET) system according to the present invention that can be adapted in real time includes a robot unit, at least one detector unit for processing PET signals and data, and a reconstruction method.

[0010] At least one detector unit for processing PET signals and data according to the present invention has the following configuration. At least one small and portable gamma ray detector module including a front-end readout section, a power supply, a high-voltage circuit that is a circuit for supplying the required voltage to the SiPM enabled by an input receiving FPGA regarding the input voltage and HV setting value, and a HV DAC that is a circuit for receiving an input from the FPGA and setting the HV value specific to the designated HV circuit. A temperature sensor that reads temperature values and transmits digital outputs to an FPGA, a regulator that receives an input voltage in the range of 5 to 15V and outputs a voltage of 1.8V to supply power to on-board electronic devices, a regulator 15→1.8V, a regulator that receives an input voltage in the range of 5 to 15V and outputs a voltage of 1.8V to supply power to on-board electronic devices, a regulator 15→3.3V, and A programmable clock generator that receives an input from a crystal oscillator, performs serial data streaming through a clock buffer to a reading means or an ASIC, and generates outputs of a plurality of clocks input to the ASIC to provide a reference for a PLL in the ASIC. An SiPM with up to 64 channels each connected one-to-one to a readout ASIC, which is for detecting gamma photons entering a PET module, detecting visible light from an inorganic scintillator crystal and converting it into an electrical signal correlated with the arrival time and light intensity of an event. Any inorganic scintillator capable of converting gamma rays into visible light, a crystal optically coupled to the sensitive side of the SiPM to ensure maximum light transmission, the coupling between the SiPM and the crystal can be one-to-one, or many-to-one, or one-to-many, or many-to-many, and light sharing and isolation, if used, can be achieved by various techniques such as using a fully reflective material between each crystal, using a partially reflective material between each crystal, using a material for another light sharing on any crystal surface to ensure transmission of visible light from one crystal to another, and the reflective substance can be a specular reflector, a scattering reflector, or a partial reflector. An ASIC that reads signals from a SiPM at the channel level, shapes the signals, segments the signals according to pre-set thresholds, codes the arrival time and the time when the threshold is exceeded by employing a tuned voltage-controlled oscillator and time-to-digital converter, stores the events in an internal buffer and transmits them in series, can be configured to adjust the thresholds, shield individual read channels, adjust the PLL, and adjust analog circuit settings, the ASIC used in this circuit is the STiC3 developed in Heidelberg, but any circuit capable of reading SiPMs, extracting arrival times in the range of 1 picosecond to 10 nanoseconds, extracting energy information, and packing it into individual events of several bytes in length can be used to design this system, and an ASIC in which up to 64 channels of the SiPM are read one by one, A field-programmable gate array (FPGA) front-end, used as the central element of the front-end module, is configured to configure ASICs, adjust HV circuits, read temperature data from temperature sensors, read serial data from multiple ASICs and arrange them into data streams, and communicate with a DAQ via a connector used to receive external configuration commands and transmit digitized event data from the ASICs, wherein each FPGA is connected to multiple ASICs for control and data acquisition, and A serializer circuit, each dedicated to a specific FPGA, is used to serialize data from the FPGA according to a serial protocol and transmit it to the DAQ. A USB 3.0 connector-compatible cable, rated to operate at >15V and >3A, is used to connect the front-end board to the DAQ board. It has two serializer channels, two sets of I / O pins for configuration and control, and two RST channels. A module including a connecting cable with two clock channels and two power channels, receiving event data from the front-end board via a serialization protocol, converting the data back into a fixed-size sequence of events in its original bitstream, and sending this data to the FPGA-DAQ via a deserializer. The DAQ board includes an FPGA-DAQ as its central element, which receives serialized event data from multiple serializer inputs, arranges it in separate FIFO buffers to ensure uniform acquisition from all read sources, sends an RST signal to the ASIC in response to a request from user software via USB connection, receives user requests and configuration settings for the front-end board including ASIC configuration, high voltage settings, clock settings, and FPGA-front-end acquisition settings, and forwards the configurable settings via dedicated input / output lines of the connection cable (USB3.0). The system includes a power supply circuit that receives an external input of 5V to 15V and 0 to 6A from a dedicated DC power supply unit and sends the power line via a connecting cable to supply power to the regulator and the HV circuit on the front-end board; a regulator 15→3.3V circuit that receives an input voltage in the range of 5 to 15V and outputs a voltage of 1.8V to supply power to the onboard electronic equipment; an FTDI bridge chip that forms an interface between the FPGA-DAQ and a communication hub that hosts an external computer or user interface software, and is used to communicate configuration settings transmitted by the host and to transmit received events from the FPGA-DAQ to the host computer; and a communication hub, which is an electronic system that interacts with a set of multiple sensors and connects them to a single computer (or central processing unit).

[0011] Computer (or CPU, central processing unit) The CPU connects to all other major units in the system by issuing control signals, receiving data from each unit, and processing the received data to generate appropriate responses for each of the major units. The CPU also includes several instances of pre-loaded imaging plans, enabling it to function as a state machine that interacts and generates responses based on the placement of a human patient. For any short time interval, the CPU inputs information from the perception unit, compares it to the imaging plan, calculates the target position of the robotic arm, and issues commands to the robotic unit. The CPU performs image reconstruction and co-registration with the patient's existing CT images or another highly matched DICOM image. The CPU transmits the currently registered image to the imaging unit for real-time monitoring.

[0012] Reconstruction technology Polygonal reconstruction involves subsequent steps for forward and back projection of each separate data point corresponding to a different angle. The basis space is defined by coordinate axes, as shown in the diagram of the entire system. Each rotated direction is reconstructed by reorienting the image from the previous angle to the current angle, ultimately returning to the basis space. Iterative reconstruction is performed according to the algorithm shown below.

[0013]

number

[0014] For each iteration of the MLEM reconstruction, all sub-iterations of L are performed.

[0015] Between each sub-iteration, the image from the previous step is rotated to the current sub-iteration, this rotated image is forward-projected, divided by measurement data for its angle, and then back-projected. This result is multiplied by the i-th pixel of the rotated image from the previous sub-iteration and normalized by the system response matrix.

[0016] Revision of restricted angles The compact system described in this invention has a limited field of view. The reconstruction technique developed in this invention makes it possible to obtain a larger field of view. The detection unit is rotated to three distinct angles, each shifted by 120 degrees, around the patient's head to cover the area of ​​the brain. The detection system is then shifted in the direction of the rotation axis to acquire data from different regions. By performing three rotations and two axial positionings, the entire area of ​​the brain can be imaged. By combining different combinations of rotations and sections, images for various cases can be obtained.

[0017] The detector needs to be moved. For systems with a limited field of view, the following operations are performed: Rotate the detector system around the y-axis to cover a wider field of view. Move the detector system axially along the y-axis to cover a wider field of view. Adjust the distance between detector modules along the x-axis to address different biological regions as desired.

[0018] Approach to reconstruction The reconstruction technique involves subsequent steps for forward and back projection of each separate data point corresponding to a different angle. The basis space is defined by coordinate axes, as shown in the diagram of the entire system. Each rotated direction is used to reconstruct the image, which is then reoriented in the basis space and reconstructed iteratively.

[0019] [ka]

[0020] Perceptual unit The depth sensor is part of an imaging subsystem with time-of-flight capability to generate a 3D point cloud of space containing objects. Its primary purpose is to capture the position and orientation of the patient subject. The proximity sensor is an infrared radiation source-detector module that generates a corresponding signal depending on the distance from the object to the sensor. The temperature sensor records the ambient temperature at various locations around the imaging system. The output of this system keeps the detector system running. The output of this system is also useful for updating the settings of the detector system. For DAQ perception, the data acquisition unit for the perception subsystem receives data from various components, holds and arranges the data, and transmits it to the CPU. It also receives calibration commands from the CPU and calibrates the sensors within the perception unit.

[0021] User interface and video unit The terminal is the component where the user inputs variables related to the current imaging plan. The viewer is a screen for monitoring the 3D image of the patient as seen by the perception unit. The viewer consists of markings that help guide the patient to stay in the most desirable position and orientation. The visualization unit, as a module, displays the reconstructed and re-registered images of the patient in real time.

[0022] Robot unit The 6-axis robotic arm is a 6-axis robotic arm that holds a sensor module via a C-shaped connecting arm, receives input from the CPU regarding its final position, velocity, and placement, and is connected to the end of the distance adjustment arm. The height adjustment arm is a single-axis platform whose vertical height is adjustable based on input from the CPU. This arm is placed on the ground or on a table with a fixed base and is connected to the distance adjustment arm. The distance adjustment arm is a single-axis platform whose horizontal arm is adjustable based on input from the CPU. This arm is connected to the top of the height adjustment arm. The end of this arm is used to connect to the 6-axis robotic arm.

[0023] The present invention is further described as follows:

[0024] Explanation of the system's small size The detector system design presented for the "detection system" allows the resulting system to be small and modular. This small size is achieved through our design choices in the detection system, which enable early digitization of information in the data flow. Using the described design, a 512-channel module was developed with a form factor of 104mm × 52mm × 60mm. Within this rectangular structure are two electronic boards: 512 channels of inorganic scintillate crystal, a SiPM sensor, and front-end electronics that interact with the 512 sensitive channels of the detector, transmitting information to the DAQ module via a USB cable. To maintain a small form factor, the sensitive area of ​​the detector must occupy the largest proportion of the module's total area within the sensitive field of view. This design ensures high signal reliability while keeping the detector compact.

[0025] In order to achieve the above, 1. The sensor and corresponding readout electronic circuitry are placed on two sides of the same board, thereby minimizing the area required. 2. The area occupied by the readout electronics for a predetermined number of channels (512 in the implemented example) is smaller than the area occupied by the sensors. 3. Heat is dissipated within the sensitive field of view with only a minimal increase in the total area of ​​the detector. 4. The SiPM is thermally isolated from the heat-generating readout circuit. 5. To minimize heat dissipation, switching regulators are selected over linear regulators in the front-end module. 6. Shorter lead wires from the SiPM (sensor) channel to the input of the readout ASIC ensure lower capacitance and higher signal quality. 7. Each ASIC is provided with its own dedicated power supply circuit, and each sensor array ensures that the readout circuit achieves maximum isolation. 8. All mechanical components must be designed to be connected to a heat conduction frame, which is the central mechanical structure for the module.

[0026] Description of mechanical and thermal design The mechanical device, including the robotic unit, is designed to support a sensitive detector with heavy LYSO crystals, a readout electronics board, and a thermal system that manages heat dissipation. The system generates 45 watts of power and is originally designed to dissipate the heat generated within the system, keeping it at a stable temperature within 1°C. An aluminum plate is fabricated to fit between the narrow spaces of the two electronics boards and is thermally bonded to the ASIC by thermal paste. This plate is screwed to an external mechanical plate and also bonded by thermal paste. The external mechanical plate is perpendicular to the plane of the sensitive detector and readout electronics and has a flattened arm that projects away from the detector. A heatsink of a conventional design is then bonded to the external mechanical plate by thermal paste and mechanically secured with screws. A backplane with an electric fan directs air into the heatsink to dissipate the heat generated from the ASIC and conducted to the heatsink. This design allows for maintaining a compact size and enables the system to be scaled up without losing sensitive area.

[0027] The present invention offers several advantages: its compact and portable design maximizes the ratio of the sensitive area to the total area of ​​the field of view; the electronic components are miniaturized through the design of the electronic components; the proportion of the sensitive area is maintained at a high level through the thermal design; the need for an external cooling system is eliminated, thereby making the invention compact and portable; the mechanical design ensures compactness and portability through the combination of a central mechanical frame that contributes to both mechanical and thermal purposes; motion blur is corrected by R&Perception, thereby aiding in coregistration without the need for separate CT hardware; the patient is freed from restraint on the examination table or other restraints; and images can be acquired at many unusual angles.

[0028] As shown in Figures 1(a), 1(b), and 1(c), the real-time adaptable, portable, and compact positron emission tomography (PET) system 100 according to the present invention is A front-end readout includes at least one small, handheld gamma-ray detector module 1101 for processing signals to convert gamma rays into visible light, convert visible light into analog electrical signals, and output serialized data; at least one connection cable 1102 for connecting to at least one detector unit; and at least one detector unit 110 including a DAQ unit 1103 for data acquisition to serialize and restore data and to proceed with configuration. A computer 120 connected to at least one detector unit, a robot unit 130, a user interface and imaging unit 150, and a perception unit 140, which receives data from each unit, processes the received data to generate an appropriate response for each unit, and issues control signals. A robot unit 130 connected to a CPU for mechanically holding, positioning, and orienting each of the at least one detector unit, including a C-shaped arm holder 131 for holding at least one detector unit 110, a multi-axis robotic arm 132 connected to the C-shaped arm holder 131 for receiving input from a computer for final position, velocity, and positioning, a height adjustment arm 134 for adjusting the vertical height based on input from the computer, and a distance adjustment arm 133 for horizontally adjusting the distance of the at least one detector unit 110 and the center of the detector and the multi-axis arm 132 from two angularly moving platforms, and a computer-connected controller 135 for controlling the positioning of the multi-axis robotic arm, height adjustment arm, and distance adjustment arm to a suitable location for acquiring images. A perception unit 140 equipped with sensors for calibration using 1D, 2D, or 3D standard reference signals to align coordinates with the robot unit and capture the position and orientation of the patient to be detected, and The imaging module 150 includes a user interface and viewer screen 151 for the user to input variables for the current imaging plan and for displaying reconstructed and co-registered images of the patient to be detected in real time.

[0029] In the robot unit 130 of the real-time adaptable portable and compact positron emission tomography (PET) system according to the present invention, the multi-axis robotic arm is for setting rotation around the y-axis, translation along the y-axis, and distance adjustment along the x-axis, and the multi-axis robotic arm 132 is a combination of a 6-axis arm or two angular motion platforms. Referring again to Figure 1, the robot unit 130 further comprises at least one mechanical frame 170 provided for connecting to a readout board from at least one detector module 110 and providing conduction paths for heat dissipation, and for mounting lower components including a PCB, FPGA front end, serializer and DAQ board, including crystals, SiPMs and ASICs, in order, and the unit further comprises a chair with neck support (not shown) for the patient to sit in. Figure 9 shows an exploded view of the main units of the detector unit included in the PET system.

[0030] In the real-time adaptable, portable, and compact positron emission tomography (PET) system of the present invention, the sensing unit 140 is for tracking patient movement and guiding a multi-axis robotic arm to orient at least one detector unit 110, and for achieving motion correction and acquiring a predetermined subset by maintaining a constant relative orientation between the imaging module and the patient.

[0031] In the PET system 100 of the present invention, the user interface and imaging unit 150 further include a screen 151 for viewing.

[0032] As shown in Figure 3, in the real-time adaptable, portable, and compact positron emission tomography (PET) system of the present invention, a communication hub 160 is provided for connecting to multiple detector units and a computer, when used. In addition, as shown in Figure 6, the perception unit further comprises a depth-sensing camera, a safety proximity camera, and a temperature sensor for monitoring ambient temperature.

[0033] As shown in Figures 4 and 5, the compact, handheld gamma-ray detector module 1101 for a positron emission tomography (PET) system 100 or a single-photon emission tomography (SPECT) imaging system comprises: multiple scintillate crystals 11011 that detect and convert gamma photons emitted from the patient being detected into visible light; multiple photodetectors 11012, which are silicon photomultipliers (SiPMs) for converting the visible light into analog or digital electrical signals; a reading unit 11013, which is an application-specific integrated circuit (ASIC) for reading the analog or digital signals from each of the photodetectors to capture the arrival time and energy of the detected gamma-ray events; and a field-programmable gate array for constructing and reading the data from the reading unit. The detector comprises a configurable integrated circuit 11014 which may be the front end of an FPGA, a data serializer which may be a serializer for serializing configured data, a plurality of printed circuit boards (PCBs) provided for housing electronic components in such a way as to minimize the total volume enclosed by themselves, as shown in Figures 10(a) and 10(b) and Table 1, and a holding means 170 which has minimal wiring to facilitate movement of the detector, thereby maximizing the sensitive area and minimizing the total volume of the detector module by mechanically holding components which also act as means for dissipating heat in the detector module, as shown in Figure 1(b), and thus not being constrained by external static structures for mechanical, power, thermal, or signal flow requirements.

[0034] In the detector module 1101 of the present invention, the holding means is a heat sink or a fan.

[0035] In the detector module of the present invention, the scintillate crystal 11011 is coupled with one or more photodetectors, which are SiPM arrays, in a one-to-one, one-to-many, or many-to-one arrangement that maximizes light transmission.

[0036] According to the detector module, each pixel of the SiPM11013 array is connected one-to-one or many-to-one to an input channel of a reading means for reading signals from the photodetector. The reading means is an ASIC with a timing resolution in the range of 1 picosecond to 10 nanoseconds that digitizes the time and energy information of each gamma-ray event and emits the data generated on its input channel via a high-speed interface.

[0037] In the detector module of the present invention, the configurable integrated circuit 11014 is an FPGA that configures and reads data from one or more ASICs, sets up a photodetector, reads a temperature sensor, and sends data to a data acquisition (DAQ) unit, wherein a gamma-ray detection crystal 11011 bonded to a photodetector device 11012 is connected to one side of the PCB by an inter-board connector, and the PCB includes a reading means 11013 for reading the photodetector and an inter-board connector on the other side, minimizing the distance from the photodetector to the reading means to read the photodetector to which the photodetector is connected, and is configurable integrated. Circuit 11014 is soldered to one side of the PCB, the PCB includes an inter-board connector and a non-high-power device for clock generation / distribution and data serialization on the other side, the two PCBs are stacked via the inter-board connector, the PCBs enclose a minimal cumulative volume, the ratio of the volume of the PCB assembly to the sensitive area is <15 mm with respect to a given sensitive area of ​​the detector module, the retaining means 170 for mechanically holding the components of the detector module is a thermally conductive metal enclosure that includes the entire elements of the detector module and connects them to achieve thermal stability, the retaining means is, The SiPM is isolated from the PCB, which further comprises a subunit for conductively dissipating heat from the means for reading the SiPM and transferring it to a retaining means for mechanically holding the components of the detector module. ii. It is connected to a subunit (not shown) to hold the crystal element, iii. Houses a heatsink (not shown) and a subunit (not shown) for housing a fan. iV ensures that the iV-sensitive plane has the minimum area so that the ratio of the sensitive area to the mainframe area is >85%.

[0038] Furthermore, the detector module of the present invention further comprises a detector unit 110 including at least one detector module 1101, at least one cable 1101 for transmitting power, structuring information, and transmitting serial data from the detector module to at least one interface electronic board connected to a central data processing unit comprising a deserializer 11031, an FPGA 11032, a communication chip 11033 or an FTDI bridge chip, a clock 11016 for generating a clock signal and sending it to at least one detector module 1101, and a power supply (not shown) for providing power to at least one detector module, and a communication hub 160 (as shown in Figure 3) for connecting to a plurality of interface electronic boards.

[0039] Furthermore, as shown in Figure 1(a), the PET imaging system or SPECT system according to the present invention, in which the system identifies the patient's position and positions itself to sequentially scan one or more target organs along one or more positions and directions for each organ, comprises a detector unit 110 for detecting and capturing gamma photon information, a perception unit 140 for mapping the view around the imaging system, a robotic unit 130 for holding and positioning sensitive elements of the detector unit, a computer 120 or central processing unit (CPU) connected to all elements of the imaging system for controlling and processing information, and a user interface and imaging unit 150 for receiving user commands and displaying any selected information.

[0040] Referring to Figure 1 and Figures 2-4, the detector unit 110 includes at least one detector module, the at least one detector module comprising at least one scintillate crystal 11011 for converting gamma photons into visible light, a plurality of photodetectors 11012 for converting visible light into analog or digital electrical signals, reading means 11013 for reading the analog or digital signals from each of the photodetectors to capture the arrival time and energy of detected gamma-ray events, at least one of the following electronic components: a configurable integrated circuit 11014, a high-voltage (HV) power supply unit having coarse and fine adjustment units, a clock circuit, and a data serializer, a plurality of PCBs designed to minimize the total volume enclosed by themselves for housing the electronic components, and holding means 170 for mechanically holding components that also act as means for dissipating heat in the detector module, thereby maximizing the sensitive area and minimizing the total volume of the detector module.

[0041] In the imaging system according to the present invention, the robot unit 130 is a six-axis or multi-axis robotic arm that achieves any possible localization and orientation of a detector module within a predetermined volume, and the robot unit 130 comprises a six-axis robotic arm, a height-adjusting arm, a distance-adjusting arm that extends the reach of the six-axis robotic arm, and a vertical-adjusting arm for a sensing unit, and as shown in Figure 1(b), the robot unit 130 further comprises a C-shaped arm holder for holding at least one detector module at the end of the C-shaped arm, and a connector to the rest of the robot unit in the center of the C-shaped arm, and as shown in Figure 5, the sensing unit 140 comprises a depth-sensing RGBd camera and a temperature sensor for monitoring ambient temperature, and the sensing unit 150 tracks the patient's movement and components of the imaging system and provides signals to a computer for estimation and guidance of the robot unit in real time.

[0042] According to the present invention, a computer or central processing unit 120 estimates a precise map of computed tomography (CT) images taken from an existing image database that can be physically correlated to a given patient from sensory unit data relating to the patient, and as a result, the reconstructed PET image can be projected onto the CT image.

[0043] In this invention, the user interface and imaging unit 150 are used by the user to input settings related to the current imaging plan and to display reconstructed and correlated images of the patient to be detected in real time.

[0044] Furthermore, the present invention provides a polygonal image reconstruction method comprising multiple iterations, each including multiple stages corresponding to different angular positions of a detector, wherein the reconstruction at each stage utilizes information from other angular projections during the reconstruction, and a fully reconstructed image including information from all angular projections is achieved, which is referenced to a base space having fixed coordinate axes corresponding to one of the preferred angular arrangements.

[0045] In the multi-angle image reconstruction method used in PET systems, each angular direction is reconstructed by reorienting the image from the previous angle to the current angle. Furthermore, because several target regions exist within multiple angular fields of view (FOV), this causes changes in sensitivity between different target regions. Therefore, at the end of each iteration, the image is rotated back to the basis space, and iterative reconstruction is performed according to the following algorithm.

[0046] [ka] (In the formula, i represents the pixel number, j represents the LOR (Low-Range) line, k represents the number of repetitions from 1 to N. L is the total number of rotation angles θ1...θ L This represents, l represents a sub-repetition of the angle in the range of 0 to L-1. α is, When l=0, α=1. For l>0, α=0 It is defined as, JPEG2026515870000008.jpg1094MLEM reconstruction. For each iteration, all L sub-iterations are performed. Between each sub-iteration, the image from the previous step is rotated to the current sub-iteration. The rotated image is forward-projected, divided by the measured data for its angle, then back-projected. The result is multiplied by the i-th pixel of the rotated image from the previous sub-iteration, normalized by the system response matrix, and each rotation direction is reconstructed separately, then rotated into basis space and summed. The summed image is then normalized again to the target. The PET system is an angle-limited PET data system that involves steps involving multiple iterations of reconstruction, each iteration consisting of many stages for forwarding the image into the detector space and returning to the image space for various projections into each separate dataset of the detector space, each belonging to a different acquisition corresponding to a given detector positioning angle, related to detecting the area, the basis space is defined by coordinate axes, and the images reconstructed in each projection are rotated and integrated to achieve a complete image of the target.

[0047] As shown in Figure 7, the channel threshold has been modified and calibrated for the absolute energy of gamma rays, and the standard radiation is shown on the left. 22 Sample 16-channel energy spectra for intrinsic activity from Na sources and crystals are shown. On the right are standards for all 1024 channels after calibration for precise energy prediction. 22 The energy spectrum for the Na source is shown. An energy resolution of 8% FWHM was achieved.

[0048] Figure 8 shows the time resolution measured as the full width at half maximum of the time delay histogram between the reference channel and all 512 channels of the module, exhibiting a simultaneous clock time-spanning resolution of 282 ps FWHM.

[0049] Figure 9 is an exploded view of the main units of the detector unit included in the PET system of the present invention, and Table 1, which lists the lower components held within the metal frame 170 by their reference numerals, is as follows.

[0050] [Table 1]

Claims

1. A compact, handheld gamma-ray detector module for a positron emission tomography (PET) system or a single-photon emission tomography (SPECT) imaging system, Multiple scintillate crystals that detect gamma photons emitted from the patient being detected and convert them into visible light, Multiple photodetectors, which are silicon photomultipliers (SiPMs), for converting the aforementioned visible light into analog or digital electrical signals, A reading means, which is an application-specific IC (ASIC), for reading the analog or digital signals from each of the aforementioned photodetectors and capturing the arrival time and energy of the detected gamma-ray event, A configurable integrated circuit which may be a front-end for a field-programmable gate array (FPGA) for composing and reading data from the aforementioned reading means, A data serializer, which may be a serializer, for serializing the configured data, Multiple printed circuit boards (PCBs) are provided to house electronic components in a manner that minimizes the total volume enclosed by them, A retaining means with minimal wiring to facilitate the movement of the detector, which maximizes the sensitive area and minimizes the total volume of the detector module by mechanically holding components that also act as means of dissipating heat within the detector module, thereby freeing the detector from constraints of external static structures for mechanical, power, thermal, or signal flow requirements, A small, handheld gamma-ray detector module equipped with [feature / feature].

2. The detector module according to claim 1, wherein the holding means is a heat sink or a fan.

3. The detector module according to claim 1, wherein the scintillate crystal is coupled with a plurality of photodetectors, which are SiPM arrays, in a one-to-one, one-to-many, or many-to-one arrangement that maximizes light transmission.

4. The detector module according to claim 3, wherein each pixel of the SiPM array is connected one-to-one or many-to-one to an input channel of a reading means for reading signals from the photodetector, and the reading means is an ASIC having a timing resolution in the range of 1 picosecond to 10 nanoseconds, which digitizes the time and energy information of each gamma-ray event and emits the data generated in the input channel via a high-speed interface.

5. The detector module according to claim 4, wherein the configurable integrated circuit is an FPGA that configures and reads data from one or more ASICs, sets the light detector, reads the temperature sensor, and sends the data to a data acquisition (DAQ) unit.

6. The detector module according to claim 3, wherein the scintillate crystal bonded to the photodetector is connected to one side of the PCB by an inter-board connector, the PCB includes the reading means for reading the photodetector and the inter-board connector on the other side, and the distance from the photodetector to the reading means to which the photodetector is connected is minimized.

7. The detector module according to claim 1, wherein the configurable integrated circuit is soldered to one side of the PCB, and the PCB includes on the other side an inter-board connector and a non-high-power device for clock generation / distribution and data serialization.

8. The detector module according to claim 1, wherein the two PCBs are stacked via an inter-board connector, the PCBs enclose a minimum cumulative volume, and the ratio of the volume of the PCB assembly to the sensitive area is <15 mm with respect to a predetermined sensitive area of ​​the detector module.

9. The retaining means for mechanically holding the components of the detector module is a thermally conductive metal enclosure that includes the entire elements of the detector module and is connected to the entire elements of the detector module to achieve thermal stability, and the retaining means is i. The SiPM is isolated from the PCB, which further comprises a subunit for conductively extracting the heat from the means for reading the SiPM and transmitting it to the holding means for mechanically holding the components of the detector module. ii. Connected to the aforementioned subunit to hold the crystal element, iii A subunit for housing a heatsink and a fan, i. The detector module according to claim 3, wherein the sensitive plane has the minimum area so that the ratio of the sensitive area to the area of ​​the mainframe is >85%.

10. At least one detector module, A cable for transmitting power, structuring information, and transmitting serial data from the detector module to at least one interface electronic board connected to a central data processing unit comprising a deserializer, FPGA, communication chip or FTDI bridge chip, a clock for generating and sending a clock signal to the at least one detector module, and a power supply for providing power to the at least one detector module, and Communication hub for connecting to multiple interface electronic boards The detector module according to claim 1, further comprising a detector unit including the following.

11. An imaging system for use in a PET imaging system or SPECT, which identifies the patient's position and positions itself to sequentially scan one or more target organs along one or more positions and directions for each organ, A detector unit for detecting and capturing information from gamma photons. A perception unit for mapping the view around the imaging system. A robot unit for holding and positioning the sensitive element of the aforementioned detection unit. A computer or central processing unit (CPU) connected to all elements of the imaging system for controlling and processing the information, and A user interface and visualization unit for receiving user commands and displaying arbitrarily selected information. An imaging system equipped with the following features.

12. The detector unit includes at least one detector module, and the at least one detector module is Multiple scintillate crystals for converting gamma photons into visible light, Multiple photodetectors for converting visible light into analog or digital electrical signals, Reading means for reading the analog or digital signals from each of the aforementioned photodetectors to capture the arrival time and energy of the detected gamma-ray event, At least one of the following electronic components: a configurable integrated circuit, a high-voltage (HV) power supply unit having a coarse adjustment unit and a fine adjustment unit, a clock circuit, and a data serializer. Multiple PCBs designed to minimize the total volume enclosed by themselves for housing electronic components, and, A holding means for mechanically holding components that also act as means for dissipating heat within the detector module, thereby maximizing the sensitive area and minimizing the total volume of the detector module. The imaging system according to claim 11, comprising:

13. The imaging system according to claim 11, wherein the robot unit is a six-axis robotic arm that achieves any possible localization and orientation of the detector module within a predetermined volume.

14. The imaging system according to claim 11, wherein the robot unit comprises a six-axis robot arm or a plurality of axes, a height adjustment arm, a distance adjustment arm for extending the reach of the six-axis robot arm, and a vertical height adjustment arm for the perception unit.

15. The imaging system according to claim 11, wherein the robot unit further comprises a C-shaped arm holder for holding at least one detector module at the end of a C-shaped arm, and a connector in the center of the C-shaped arm to the remainder of the robot unit.

16. The imaging system according to claim 11, wherein the perception unit comprises an RGBd camera for sensing depth and a temperature sensor for monitoring ambient temperature.

17. The imaging system according to claim 11, wherein the perception unit tracks the patient's movements and the components of the imaging system, makes estimations, and provides signals to the computer for guiding the robot unit in real time.

18. The imaging system according to claim 11, wherein the computer or the central processing unit estimates a precise map of the CT images taken from an existing image database that can be physically correlated to a predetermined patient from the data of the perceptual unit relating to the patient, and as a result projected onto the computed tomography (CT) images, the reconstructed PET images.

19. The imaging system according to claim 11, wherein the user interface and the imaging unit are used by the user to input settings related to the current imaging plan and to display reconstructed and co-registered images of the patient to be detected in real time.

20. A polygonal image reconstruction method for use in a PET system, comprising multiple iterations, each including multiple stages corresponding to different angular positions of a detector, wherein the reconstruction at each stage utilizes information from other angular projections during the reconstruction, and a fully reconstructed image containing information from all angular projections is achieved, which is referenced to a base space having fixed coordinate axes corresponding to one of the preferred angular arrangements.

21. Each angular direction is reconstructed by reorienting the image from the previous angle to the current angle, and because several target regions exist within the field of view (FOV) at multiple angles, this causes changes in sensitivity between different target regions. At the end of each iteration, the image is rotated back to the basis space, and iterative reconstruction is performed according to the following algorithm. 【Chemistry 1】 (In the formula, i represents the pixel number, j represents the LOR (Low-Round) clock line, k represents the number of repetitions from 1 to N. L is the total number of rotation angles θ １ …θ Ｌ This represents, l represents a sub-repetition of the angle in the range of 0 to L-1. α is, When l = 0, α = 1. For l > 0, α = 0 It is defined as, 【change】 For each iteration of the MLEM reconstruction, all L sub-iterations are performed, and between each sub-iteration, the image from the previous step is rotated to the current sub-iteration, the rotated image is forward-projected, divided by the measured data for its angle, then back-projected, the result is multiplied by the i-th pixel of the rotated image from the previous sub-iteration, and normalized by the system response matrix. A polygonal image reconstruction method for use in the PET system according to claim 20, wherein each rotation direction is reconstructed separately, then rotated in base space and added together, and the added image is then normalized again, causing a variation in sensitivity between different regions of the target, depending on the number of projections to which the region belongs.

22. A polygonal image reconstruction method for use in the PET system according to claim 21, wherein the PET system is an angle-limited PET data system and comprises steps comprising multiple iterations of reconstruction, each iteration further comprising many steps of returning to an image space for various projections of the detector space to each separate dataset, each projection of the detector space to each separate dataset, each projection belonging to different acquisitions corresponding to a given positioning angle of a detector relating to forwarding an image into detector space and detecting an area, the basis space being defined by coordinate axes, and the images reconstructed in each projection being rotated and integrated to achieve a complete image of the target.

Images