CT Scanner Table Speed Control for Scanning Region

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Solution Overview

Problem

In multi-slice computed tomography, the increased speed of patient tables required for faster scanning reduces the available scanning region due to longer acceleration and braking distances, leading to image quality deterioration and limitations in detector width, especially with wide detectors and high examination speeds.

Innovation Solution

A method where the patient table is moved through a measurement region with time-resolved recording of projections, varying the number of slices contributing to the recording during phases of variable speed to maintain a constant pitch factor, allowing projection recording during acceleration and braking phases, and using a diaphragm device to dynamically adjust detector rows for optimal scanning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the table feed d is increased to reduce scanning time, then productivity is improved, but the available scanning region is reduced due to longer acceleration and braking distances

Engineering Contradiction:

Improvescanning speedVSAvoidavailable scanning region

Core Design Contradiction:

ProductivityVSLength of moving object

Solution Approach 1:

The patent applies variable table feed during the scan, using higher feed rates in the middle scanning region and lower feed rates during acceleration and braking phases. This dynamic adjustment allows the system to achieve high productivity in the main scanning region while reducing the impact of acceleration and braking distances, thereby preserving the available scanning region.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the table feed parameter dynamically during the scanning process. By adjusting the table feed based on the scanning phase (acceleration, constant speed, braking), the system optimizes both productivity and the effective scanning region, resolving the contradiction between scanning speed and available scanning length.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the number of detector rows is increased to improve image quality, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improveimage qualityVSAvoiddetector width

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the detector rows into different groups that can be independently controlled and activated. By selectively using only the necessary number of detector rows for each scanning phase and region, the system achieves high measurement precision where needed while avoiding the complexity of continuously using all detector rows, thus resolving the contradiction between image quality and device complexity.

Inventive Principle:

Principle #1Segmentation

3Length of moving object

If projection recording is performed during acceleration and braking phases to enlarge scanning region, then the scanning region is enlarged, but image reconstruction becomes more difficult

Engineering Contradiction:

Improvescanning regionVSAvoidimage reconstruction

Core Design Contradiction:

Length of moving objectVSDevice complexity

Solution Approach 1:

The patent uses dynamic table feed adjustment during acceleration and braking phases, maintaining a substantially constant pitch factor by coordinating table movement with detector row selection. This dynamic control enables projection recording during variable speed phases while keeping the data suitable for standard image reconstruction algorithms, thus resolving the contradiction between enlarging scanning region and simplifying image reconstruction.

Inventive Principle:

Principle #15Dynamics

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 enlarges the available scanning region, simplifies image reconstruction, reduces unnecessary radiation dose, and optimizes signal-to-noise ratio by allowing partial projection recording during acceleration and braking phases, thereby improving image quality and reducing scanning time.

Implementation Method 1

at least one radiation source and a detector simultaneously executes a multiplicity of rotations. The beam of radiation of the radiation source thereby scans the object to be examined in the shape of a spiral

Methodology Applied

Scientific EffectX-Ray: X-Ray

Implementation Method 2

a detector array, opposite the focus, which supplies output data which represent the attenuation of the beams upon passage through an examination object

Methodology Applied

Scientific EffectX-Ray detection: X-Ray

Data Source

PatentUS9402587B2Method for recording projections during a spiral scan, method for imaging and multi-slice computed tomography device

Publication Date: 2016.08.02 SIEMENS HEALTHINEERS AG

AI summary

In an embodiment, a method includes at least moving a patient table through a measurement region of the computed tomography device, the movement of the patient having at least one phase of variable speed during the projection recording, time-solved determination or recording of the patient table position, time-resolved recording of projections of at least one part of an examination object moving with the table, the number of the slices contributing to the recording being varied during the at least one phase of variable speed of the patient table as a function of the table speed in such a way that the quotient formed from the current table speed divided by the number of the slices contributing to the recording is constant so that the pitch factor is kept constant during the projection recording, and time-resolved determination or recording of the number or slices contributing to the projection recording.