Virtual CT Image Generation for SPECT PET Dosimetry
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Solution Overview
Problem
Current SPECT/CT and PET/CT protocols for targeted radionuclide therapy face challenges due to poor image resolution, high noise levels, and insufficient anatomical information, leading to uncertainties in image registration and segmentation, and the need for multiple CT scans that increase radiation exposure.
Innovation Solution
The generation of 4-dimensional virtual CT images using motion vectors for registration between SPECT/PET images and a single CT image, allowing for improved dosimetric analysis without the need for multiple CT scans, thereby reducing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple CT scans are performed for dosimetric analysis, then anatomical information and image registration accuracy are improved, but radiation exposure increases
Solution Approach 1:
The patent creates virtual CT images as copies of the single acquired CT image, transformed to different time points using motion vectors derived from SPECT/PET images. This copying approach provides multiple anatomical references without acquiring multiple CT scans, thus maintaining registration accuracy while minimizing radiation exposure
Solution Approach 2:
The patent uses SPECT/PET images as an intermediary to generate motion vectors that transform the single CT image into virtual CT images at different time points. This intermediary approach enables temporal alignment between functional and anatomical images without requiring multiple CT acquisitions
2Loss of information
If sequential CT images are used for dosimetric analysis, then anatomical information is improved, but device complexity and scanning time increase
Solution Approach 1:
The patent separates the anatomical imaging (single CT scan) from the functional imaging (multiple SPECT/PET scans), then uses computational transformation to align them temporally. This segmentation allows each modality to be optimized independently while maintaining their relationship through motion vector transformation
3Object-affected harmful factors
If SPECT/PET images are used alone for dosimetric analysis, then radiation exposure is reduced, but image resolution and anatomical information are insufficient
Solution Approach 1:
The patent merges the advantages of SPECT/PET (low radiation, functional information) with CT (high resolution, anatomical information) by transforming a single CT image into virtual CT images that are temporally aligned with multiple SPECT/PET scans, creating a combined dataset that leverages both modalities' strengths
Data Source
AI summary
The present disclosure provides a system comprising a SPECT or PET device; a CT device; and a computer comprising memory and a processor in communication with the memory, the memory comprising a computer application program for a method of performing dosimetric analysis of an organ. The computer application program is executable by the processor to perform the method. The method comprising receiving single photon emission computed tomography (SPECT) or positron emission tomography (PET) images at time instances, the SPECT or PET images relating to the organ. The method then receives a computed tomography (CT) image at one of the time instances, the CT image relating to the organ. Virtual CT images are then generated at the other time instances based on the received SPECT or PET images and the CT image. An absorbed dose of ionising radiation on the organ can then be measured based on the received SPECT or PET images, the received CT image, and the generated virtual CT images. The method generates the virtual CT images using any one of: SPECT to SPECT (or PET to PET) registration, CT to SPECT (PET) registration, and SPECT (PET) to CT registration.