Continuous kV Beam Acquisition for Cone-Beam CT
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Solution Overview
Problem
Conventional cone-beam computed tomography (CBCT) with pulsed beam acquisition limits the duty cycle of the radiation source to 30-40 percent, reducing the frame rate of the detector and causing measurement inaccuracies due to the 'tail effect' of beam output.
Innovation Solution
A CBCT method and system with continuous kilovoltage (kV) beam acquisition, where the radiation source continuously irradiates the subject with a cone beam from multiple angles, and the area detector reads out data during continuous irradiation, allowing for a 100 percent duty cycle and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pulsed beam acquisition is used in CBCT, then the radiation source can operate with sequential emission and detection, but the duty cycle is limited to 30-40 percent and the frame rate is reduced
Solution Approach 1:
The patent implements continuous beam operation where the radiation source continuously emits x-rays during the entire detection period, eliminating the sequential on-off pulsing. This allows the detector to continuously acquire projection data without interruption, achieving a 100% duty cycle and maximizing the productive utilization of both the radiation source and detector throughout the scanning period.
2Ease of operation
If pulsed beam acquisition is used in CBCT, then emission and detection are operated sequentially, but the maximally possible frame rate of the detector is reduced
Solution Approach 1:
The continuous beam operation enables the detector to continuously read out projection data at its maximum possible frame rate without being constrained by beam pulsing intervals. The detector operates at full capacity throughout the entire acquisition period, significantly increasing the frame rate compared to pulsed operation where the detector must wait for beam emission cycles.
3Loss of time
If short pulsed beams are used in CBCT, then acquisition time is reduced, but the tail effect causes measurement inaccuracy and imaging artifacts
Solution Approach 1:
The continuous beam eliminates the tail effect entirely by maintaining a steady, uninterrupted x-ray output without the abrupt on-off transitions characteristic of pulsed beams. This continuous operation ensures that the beam intensity remains stable throughout the acquisition period, preventing the formation of tail-induced artifacts and ensuring high measurement precision without requiring short pulses.
4Object-generated harmful factors
If pulsed beam operation is used in CBCT, then the beam can be turned off between pulses, but the duty cycle is significantly limited
Solution Approach 1:
The continuous beam operation maintains constant x-ray emission throughout the entire scanning period, achieving a 100% duty cycle where the radiation source is productively utilized without interruption. This eliminates the idle time between pulses inherent in pulsed operation, maximizing the productivity and efficiency of the radiation source while maintaining precise control over the continuous output.
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
The continuous kV beam acquisition increases the duty cycle of the radiation source to 100 percent, enabling faster acquisition of projection data and improved image quality, with reduced aliasing artifacts and increased effective detection speed of the area detector.
Implementation Method 1
a radiation source emits x-rays into a portion of a subject from a plurality of angles
Implementation Method 2
a detector detects the radiation transmitted through the portion of the subject to acquire projection data
Data Source
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AI summary
A cone-beam computed tomography (CBCT) method uses a continuous beam and an area detector to carry out fast acquisition of projection data. The acquired projection data are then reconstructed to generate tomographic images. In acquisition of the projection data, a radiation source (102) continuously irradiates a subject (112) with a cone beam (116) of radiation from a plurality of angles and an area detector (104) continuously reads out data. A CBCT system including a source operable to produce a cone beam of radiation and an area detector movable in synchrony with the source to rapidly acquire projection data for CBCT construction is also disclosed.