Summary
UCLA researchers have developed a low-dose CT scanning system that uses pulsed X-ray emission at selected rotation angles combined with advanced reconstruction algorithms to maintain image quality while reducing radiation exposure by factors of ~4–8× compared to continuous CT protocols.
Background
Computed tomography (CT) is widely used in medicine (e.g. perfusion CT, angiography), but continuous X-ray emission throughout the scan leads to substantial radiation dose to patients. Dynamic CT protocols (multiple time frames) multiply dose exposure. Conventional methods to lower dose often degrade image quality or temporal resolution. A method is needed to deliver substantially reduced radiation dose while preserving both spatial and temporal fidelity in CT imaging.
Innovation
The patented system modulates X-ray emission such that the CT source is intermittently pulsed (turned on/off rapidly) according to a predefined sequence of rotation angles of the CT gantry, rather than emitting continuously. During the “off” periods, no X-rays are emitted, reducing dose. To compensate, image reconstruction algorithms (including view sharing, iterative or constrained reconstructions) weave in data across frames and angles (e.g. using KWIC or projection-view sharing) to reconstruct high fidelity images. The system also permits selection of nonuniform projection angle sequences (e.g. angle-bisect / bit-reverse, golden ratio, pseudo-random), optimized for temporal/spatial sampling, and hardware that supports high-speed switching (on the order of milliseconds) of the X-ray source via pulsed control or shutters.
Advantages
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Significant dose reduction (4–8× or more) while preserving image quality
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Maintains both spatial and temporal resolution, enabling dynamic CT scans (e.g. perfusion) that were previously limited by dose constraints.
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Flexible control over projection angle scheduling (angle-bisect, golden-ratio, pseudo-random) to optimize reconstruction and sampling.
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Compatible with conventional CT hardware augmented with a pulse generator / shutter / beam gating mechanism.
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Allows clinicians to trade off dose vs scan speed or temporal sampling automatically or adaptively.
Potential Applications
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CT perfusion imaging (brain, heart), where multiple time-resolved scans are needed
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CT angiography (dynamic vessel enhancement studies)
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Dynamic contrast-enhanced CT protocols in oncology (e.g. tumor perfusion)
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Any clinical CT scanning where reducing radiation dose is critical (pediatric, repeat imaging)
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Research or preclinical CT systems seeking dose-efficient dynamic imaging
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Low-dose CT in resource-limited settings where minimizing exposure is especially important
Patent / Record
US 10,772,579 B2 — Systems and Methods for Reducing Radiation Dose in CT
Systems and Methods for Reducing Radiation Dose in CT (US10772579B2) Google Patents