Dual-Modality SPECT CT Gantry Design
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Solution Overview
Problem
Dual-modality imaging systems, combining Single Photon Emission Computed Tomography (SPECT) and Computed Tomography (CT) modalities, face challenges due to increased footprint and complexity, leading to patient discomfort and image registration issues caused by larger CT detectors and longer patient travel distances.
Innovation Solution
A dual-modality imaging system design where SPECT and CT detector units are positioned adjacent to each other within a common bore, allowing for reduced gantry size and FOV gap, enabling simultaneous image acquisition without patient repositioning and minimizing table travel length, thus reducing claustrophobia and image distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate gantries are used for SPECT and CT imaging, then imaging functionality is achieved, but system footprint and space requirements increase
Solution Approach 1:
The patent combines SPECT and CT imaging systems into a single integrated gantry structure, where both detector arrays are mounted on the same rotating framework. This merging approach maintains dual-modality imaging functionality while significantly reducing the overall system footprint and eliminating the need for separate gantries.
Solution Approach 2:
The integrated gantry is designed to perform multiple imaging functions (SPECT and CT) simultaneously or sequentially using a single structural platform. The universal design allows the same mechanical structure to support both nuclear medicine detectors and x-ray imaging components, optimizing space utilization.
2Area of moving object
If CT detector size is increased to provide higher field of view, then CT imaging coverage is improved, but NM detector displacement increases causing patient discomfort
Solution Approach 1:
The patent resolves the spatial conflict by arranging SPECT and CT detector arrays in different dimensional orientations within the gantry. The detectors are positioned at different radial distances and angular positions, allowing both large FOV coverage and close patient proximity without direct interference in the same spatial dimension.
Solution Approach 2:
The system employs dynamic positioning where detector arrays can be adjusted radially and angularly during operation. This allows the system to optimize the balance between field of view requirements and patient proximity needs, reducing discomfort while maintaining imaging quality.
3Length of moving object
If increased travel length is used to accommodate larger detector arrays, then detector coverage is improved, but patient movement and image registration issues increase
Solution Approach 1:
By merging SPECT and CT acquisition into a single synchronized scanning process within the same gantry rotation, the system eliminates the need for separate patient positioning and table movements. Both modalities acquire data simultaneously over the same anatomical region, ensuring automatic spatial alignment and eliminating registration issues.
Solution Approach 2:
The integrated system maintains continuous scanning action where both SPECT and CT data are acquired in an uninterrupted sequence during a single gantry rotation. This continuous acquisition process prevents patient movement between separate scans and ensures consistent anatomical coverage for accurate image registration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the FOV gap between SPECT and CT modalities to less than 50 cm, allowing for continuous image acquisition along at least 120 cm of the patient's length, improving image overlap and reducing patient table sagging, thereby enhancing imaging efficiency and comfort.
Implementation Method 1
SPECT imaging systems, such as Nuclear Medicine (NM) imaging systems, use radioactive isotopes injected into the patient and multiple detectors or detector heads to measure emitted photons
Implementation Method 2
CT imaging systems typically include an x-ray source and a detector. In operation, the x-ray source and the detector are rotated around an object to be imaged such that an angle at which an x-ray beam intersects the object changes. A group of x-ray attenuation measurements, or projection data, from a detector at one gantry angle
Data Source
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AI summary
A medical imaging system is provided that includes a first gantry having a plurality of first detector units coupled within a bore of the first gantry such that the first detector units form a first field of view (FOV) of the first gantry. The first detector units are configured to acquire SPECT data. Further, the medical imaging system includes a second gantry having a plurality of second detector units coupled within a bore of the second gantry such that the second detector units form a second FOV of the second gantry. The second detector units are configured to acquire x-ray CT data. The second gantry is positioned adjacent to the first gantry. The medical imaging system also includes a patient table movable through the bores and a controller unit configured to control a rotation speed of the first detector units and the second detector units around the examination axis.