Stationary Transmission Source for Continuous Bed Motion PET Scanners
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Solution Overview
Problem
Current PET scanner designs face challenges in attenuation correction due to the need for additional CT scanning hardware and radiation shielding, especially when using rotating or moveable transmission sources, which reduce the field of view and increase complexity.
Innovation Solution
A stationary tube within the PET scanner is used to introduce a positron-emitting radioisotope during patient scanning, allowing for continuous bed motion and simultaneous generation of transmission information, which is then withdrawn after the scan, eliminating the need for additional CT hardware and reducing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a rotating or moveable transmission source is used, then the PET scanner configuration is more compact, but the field of view is reduced and radiation shielding is required
Solution Approach 1:
A stationary tube acts as an intermediary structure that holds the radiotracer in place during the scan. The tube is positioned within the detector array and remains fixed while the patient bed moves continuously, eliminating the need for rotating mechanisms while maintaining compact configuration and full field of view coverage
2Volume of moving object
If a rotating or moveable transmission source is used, then the PET scanner configuration is more compact, but radiation shielding is required to protect patients and personnel
Solution Approach 1:
The radiotracer is extracted from a shielded storage container and temporarily placed in a stationary tube only during the scan duration. After scanning, the radiotracer is removed and returned to shielded storage. This extraction approach minimizes radiation exposure time for patients and personnel while maintaining compact scanner configuration without requiring permanent shielding structures
Solution Approach 2:
The radiotracer is introduced into the stationary tube periodically - only during the brief duration of each scan - and then removed. This periodic introduction and removal of the radiotracer reduces cumulative radiation exposure while maintaining system compactness
3Measurement precision
If CT scanning hardware is integrated for attenuation correction, then attenuation correction accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The PET detector array serves multiple functions: it detects both the radiotracer emitted by the patient and the transmission signal from the radiotracer in the stationary tube. This multi-functionality eliminates the need for separate CT hardware while maintaining attenuation correction accuracy through transmission scans performed simultaneously with patient imaging
Solution Approach 2:
The transmission scan function is merged with the patient scan function by using the same PET detector array for both purposes. The radiotracer in the stationary tube provides transmission data for attenuation correction while the patient undergoes imaging, combining two functions into one integrated process without additional hardware
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 approach enables accurate attenuation correction without additional CT hardware, improves image quality, and reduces radiation exposure, while maintaining a compact and efficient PET scanner configuration.
Implementation Method 1
a radiotracer is injected into the patient. As the radioisotope in the radiotracer undergoes positron emission decay (also known as positive beta decay), it emits the antimatter counterpart of electrons
Implementation Method 2
As the positrons lose energy, they ultimately encounter and annihilate with electrons, usually producing a pair of annihilation (gamma) photons moving in opposite directions
Implementation Method 3
a narrow tube that includes radioactive material... a pump device fluidly connected to the receiving end, wherein the pump device introduces a positron-emitting radioisotope into the tube
Data Source
AI summary
A method for generating transmission information in a time-of-flight positron emission tomography (PET) scanner having a patient tunnel and a plurality of PET detector rings. The PET scanner uses continuous bed motion to move a patient bed and patient through the patient tunnel. The patient receives a positron-emitting radioisotope dose prior to undergoing a PET scan. The method includes storing a positron-emitting radioisotope in a radiation shielded container. The method also includes moving the radioisotope into a stationary vessel located adjacent to the PET detectors and within a field of view of the PET scanner at substantially the same time that the patient receives the radioisotope dose to form a stationary transmission source wherein transmission information is generated while the bed undergoes continuous bed motion. Further, the method includes withdrawing the radioisotope from the vessel when the PET scan is complete and storing the radioisotope in the container.