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EP-4736804-A2 - METHODS AND SYSTEMS FOR HIGH PERFORMANCE AND VERSATILE MOLECULAR IMAGING

EP4736804A2EP 4736804 A2EP4736804 A2EP 4736804A2EP-4736804-A2

Abstract

Improved imaging devices and methods. A portable SPECT imaging device may co-register with imaging modalities such as ultrasound. Gamma camera panels including gamma camera sensors may be connected to a mechanical arm. A coded aperture mask may be placed in front of a gamma-ray photon sensor and used to construct a high-resolution three-dimensional map of radioisotope distributions inside a patient, which can be generated by scanning the patient from a reduced range of directions around the patient and with radiation sensors placed in close proximity to this patient. Increased imaging sensitivity and resolution is provided. The SPECT imaging device can be used to guide medical interventions, such as biopsies and ablation therapies, and can also be used to guide surgeries.

Inventors

  • MIHAILESCU, LUCIAN
  • Cosma, Andrei Claudiu
  • QUINLAN, MICHAEL

Assignees

  • Siemens Medical Solutions USA, Inc.

Dates

Publication Date
20260506
Application Date
20200409

Claims (15)

  1. An imaging system comprising: a gamma-ray photon sensor with energy and position resolution sensing capability, the sensor providing positions of photon interactions; a coded aperture mask placed in front of the sensor, wherein the mask comprises mask pixel elements shaped as bifrustums, wherein a physical space between bifrustum mask pixel elements that have a common edge is partially or completely occupied by a material, and wherein the mask creates an imaging field of view in front of the sensor; at least one processor; and a memory operatively coupled with the sensor and the processor, the memory storing instructions for execution by the at least one processor that cause the processor to: create a first projected photon interaction point on a plane of reference; retrieve photon attenuation coefficients stored in the memory for the first projected interaction point for directions towards the imaging field of view; create a second projected photon interaction point on a plane of reference; retrieve photon attenuation coefficients stored in the memory for the second projected interaction point for directions towards the imaging field of view; and reconstruct an image of a gamma-ray source using the retrieved attenuation coefficients for the first and second photon interactions.
  2. The imaging system of claim 1, wherein the sensor provides the position of the photon interaction with resolution better than 4 millimeters (mm) in all three dimensions.
  3. The imaging system of claim 1, wherein the coded aperture mask is made out a material of density higher than 10 grams per cubic centimeter (g/cc), or wherein mask pixel elements are shaped as bifrustums that have at least a side face making an angle larger than 3 degrees with respect to the normal on the bifrustum base.
  4. The imaging system of claim 1, wherein creating the first projected photon interaction point on the plane of reference comprises projecting a position of a first photon interaction onto the plane of reference.
  5. The imaging system of claim 1, wherein the mask pixel elements are shaped as bifrustums that have at least a side face making an angle larger than 5 degrees with respect to the normal on the bifrustum base, or wherein the bifrustum mask pixel elements have a base selected from a group containing: a rectangular base, a triangular base, a hexagonal base.
  6. The imaging system of claim 1, wherein the shape of bifrustum mask pixel elements is approximated by mask pixel elements with curved side faces, or wherein the coded aperture mask expands across multiple planes.
  7. The imaging system of claim 1, further comprising one or more photon attenuating shields at directions around the sensor not covered by the coded aperture mask.
  8. The imaging system of claim 1, wherein the coded aperture mask is built of multiple layers stacked together to approximate the bifrustum shaping of the mask pixels, or wherein the coded aperture mask has an opening fraction, defined as fraction of the area of the of mask pixel elements to the total area of the mask, to span from 0.1% to 70%.
  9. A method comprising: based on a first photon interaction detected by a gamma-ray photon sensor, creating a first projected photon interaction point on a first plane of reference, wherein the gamma-ray photon sensor has energy and position resolution sensing capability, the gamma-ray photon sensor providing the position of photon interactions, wherein a coded aperture mask is placed in front of the gamma-ray photon sensor, wherein the mask comprises mask pixel elements shaped as bifrustums, wherein a physical space between bifrustum mask pixel elements that have a common edge is partially or completely occupied by a material, and wherein the mask creates an imaging field of view in front of the sensor; retrieving photon attenuation coefficients stored in a memory for the first projected interaction photon point for directions towards the imaging field of view; creating a second projected photon interaction point on a second plane of reference; retrieving photon attenuation coefficients stored in the memory for the second projected photon interaction point for directions towards the imaging field of view; and reconstructing an image of a gamma-ray source using the retrieved attenuation coefficients for the first and second photon interactions.
  10. The method of claim 9, wherein the mask has an adjustable geometry.
  11. The method of claim 10, further comprising adjusting the mask from a first configuration to a second configuration to alter one or more of: the imaging field of view, a distance between the mask and the gamma-ray photon sensor, an opening fraction of the mask, a collimation of the mask, or a focusing power of the mask.
  12. A coded aperture mask for an imaging system, the mask comprising: a photon-attenuating material defining a plurality of mask pixel elements configured to permit gamma-ray photons to pass therethrough; and the plurality of mask pixel elements shaped as bifrustums, wherein a physical space between bifrustum mask pixel elements that have a common edge is partially or completely occupied by the photon-attenuating material.
  13. The coded aperture mask of claim 12, wherein mask pixel elements are shaped as bifrustums that have at least a side face making an angle larger than 3 degrees with respect to the normal on the bifrustum base.
  14. The coded aperture mask of claim 12, wherein the bifrustum mask pixel elements have a base selected from a group containing: a rectangular base, a triangular base, a hexagonal base.
  15. The coded aperture mask of claim 12, wherein the shape of bifrustum mask pixel elements is approximated by mask pixel elements with curved side faces, or wherein the coded aperture mask is built of multiple layers stacked together to approximate the bifrustum shaping of the mask pixels.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the benefit and priority of U.S. Application No. 62/831,504, filed on April 9, 2019, entitled "Methods And Systems For High Performance Spect Imaging," and U.S. Application No. 62/836,514, filed on April 19, 2019, entitled "Methods And Systems For Portable Spect And Ultrasound Imaging," the contents of which are herein incorporated by reference in their entirety for all purposes. FIELD OF THE INVENTION This invention relates to the architecture of gamma cameras and their use along other co-registered medical imaging modalities, such as ultrasound systems, to enable new, high performance and versatile imaging systems for diagnostic imaging, guidance of medical intervention, such as percutaneous biopsies and ablation therapies, and for surgical guidance. BACKGROUND Single Photon Emission Computer Tomography (SPECT) by itself, or in combination with Computer Tomography (CT) (SPECT/CT), is a primary molecular imaging modality used for medical diagnostic imaging. Most commonly, SPECT imaging devices comprise an array of gamma-ray sensors that either surround the body of the patient, or orbit around the patient. During the imaging scan the patient most commonly lays on a table, and for some cardiac imaging systems, may sit on a custom built chair. Parallel hole collimators are commonly used in front of the detector array to constrain the direction gamma-ray photons can take before interacting with the position sensitive sensors. This creates parallel projections of the distribution of the gamma-ray emitting isotopes inside the patient. A computer program is used to reconstruct this distribution in 3D by using analytical or iterative image reconstruction algorithms. Embodiments provide improved methods and systems for SPECT imaging. BRIEF SUMMARY Embodiments relate to systems and methods for Single Photon Emission Computer Tomography (SPECT) imaging. Some embodiments provide a portable Single Photon Emission Computer Tomography (SPECT) imaging system to scan a patient. The system comprises a SPECT controller unit, where the controller unit includes a computer. The system further comprises a mechanical jointed arm connected to the controller unit. The jointed arm can be positioned to a desired location by a user through applying direct force. The system further comprises at least one gamma camera panel connected to the jointed arm. The gamma camera panel comprises gamma camera sensors with position and energy sensing resolution. The gamma camera panel may provide an imaging field of view that is larger than 15 degrees. The system further comprises a camera mounted in such a way as to observe an overall area of a patient. The system further comprises at least one processor and a memory operatively coupled with the at least one processor, the camera, and the gamma camera sensors. The memory has instructions for execution by the at least one processor that cause the at least one processor to read a first gamma-ray photon sensing event received from the gamma camera sensors. The processor further provides a first position and orientation of the gamma camera panel with respect to a body of the patient. The processor further co-registers the first gamma-ray photon sensing event to the body of the patient using the first position and orientation. The processor further reads a second gamma-ray photon sensing event received from the gamma sensors. The processor further provides a second position and orientation of the gamma camera panel with respect to the body of the patient. The processor further co-registers the second gamma-ray photon sensing event to the body of the patient using the second position and orientation. And the processor reconstructs a 3D distribution of gamma-ray emitting radioisotopes inside the patient by using first and second co-registered sensing events. Some embodiments provide a real-time multi-modality portable Single Photon Emission Computer Tomography (SPECT) imaging system to scan a patient. The system comprises a SPECT controller unit, where the unit comprises a computer. The system further comprises a mechanical jointed arm connected to the controller unit, where the jointed arm can be positioned to a desired location by a user through applying direct force. The system further comprises at least one gamma camera panel connected to the jointed arm. The gamma camera panel comprises gamma camera sensors with position and energy sensing resolution. The system further comprises an ultrasound probe positionable in such a way as to have a field of view that at least partially overlaps with the gamma camera field of view. The system further comprises a tracking system able to provide information about the relative position of the ultrasound probe with respect to the gamma camera. The system further comprises a visualization device. The system further comprises at least one processor and a memory operatively coupled with the gamma