Photon-Counting Detector Calibration with Movable Attenuation Materials
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Solution Overview
Problem
Existing photon-counting computed tomography (PCCT) systems face challenges in efficiently acquiring calibration data due to the weight and handling difficulties of stepped phantoms used in large irradiation fields, leading to increased time and effort.
Innovation Solution
A calibration device with a holding portion and moving mechanism that moves first and second base substances with different attenuation coefficients between positions within and outside the irradiation field, allowing for easy acquisition of calibration data using a photon-counting detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stepped phantom is used for calibration in a large irradiation field of about 50 cm, then calibration data can be acquired, but the phantom becomes heavy and difficult to handle, and it takes time to acquire calibration data
Solution Approach 1:
The calibration device is divided into multiple independent holding portions, each capable of holding base substances with different attenuation coefficients. These holding portions can be independently positioned within or outside the irradiation field, allowing selective calibration without moving the entire large phantom structure.
Solution Approach 2:
The holding portions are made movable along the body axis direction, enabling dynamic positioning within or outside the irradiation field. This mobility allows the calibration device to adapt its configuration during the calibration process, reducing handling difficulty while maintaining calibration accuracy.
2Measurement precision
If a stepped phantom is used for calibration in a large irradiation field of about 50 cm, then calibration data can be acquired, but it takes time to acquire calibration data of the photon-counting detector
Solution Approach 1:
The calibration device segments the calibration process into multiple independent measurements using different holding portions with different base substances. This allows parallel or sequential calibration without requiring movement of a large entire phantom, significantly reducing the time needed to acquire comprehensive calibration data.
Solution Approach 2:
Multiple holding portions with different base substances are prepared in advance and can be quickly positioned within the irradiation field. This preliminary preparation eliminates the need for time-consuming phantom reconfiguration during the calibration process.
3Measurement precision
If a stepped phantom is used for calibration in a large irradiation field of about 50 cm, then calibration data can be acquired, but the phantom becomes heavy
Solution Approach 1:
The calibration device is segmented into multiple lightweight holding portions rather than using a single large stepped phantom. Each holding portion contains base substances with different attenuation coefficients and can be independently positioned, achieving the same calibration functionality with significantly reduced weight.
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 solution enables efficient and streamlined acquisition of calibration data for photon-counting detectors, reducing the size and weight of the calibration setup while maintaining accuracy.
Implementation Method 1
a photon-counting computed tomography (PCCT) apparatus comprising a photon-counting detector that is a detector adopting a photon-counting method... the photon-counting detector can measure a photon energy, which is an energy of an incident radiation photon
Implementation Method 2
the PCCT apparatus can obtain a medical image in which substances having different compositions are discriminated... for combinations of a plurality of base substances, which are substances having known compositions and thicknesses, a relationship between an output measured by the photon-counting detector and a photon energy is acquired
Data Source
AI summary
Provided are a calibration device, a medical image capturing system, and a calibration method that can easily acquire calibration data of a photon-counting detector. A calibration device is a calibration device that is used to acquire calibration data of a photon-counting detector that outputs an electrical signal corresponding to a photon energy of incident radiation, and includes: a holding portion that holds a first base substance and a second base substance having a larger attenuation coefficient for the radiation than the first base substance; and a moving mechanism that moves the holding portion in a body axis direction of a subject irradiated with the radiation to move each of the first base substance and the second base substance between a position within an irradiation field and a position outside the irradiation field.