Noise properties of grating-based x-ray phase contrast computed tomography
Thomas Köhler1, Klaus Jürgen Engel, Ewald Roessl
1Philips Technologie GmbH Forschungslaboratorien Röntgenstraße, 24-26 D-22335 Hamburg, Germany. thomas.koehler@philips.com
Medical Physics
|October 8, 2011
Summary
This study reveals that grating-based phase contrast imaging offers unique information but has a less efficient noise-resolution trade-off than absorption contrast imaging, potentially limiting low-resolution diagnostic applications.
Area of Science:
- Medical Imaging
- X-ray Physics
- Computational Science
Background:
- Phase contrast imaging offers advantages over conventional absorption contrast imaging.
- Understanding its noise characteristics and energy dependence is crucial for clinical application.
Purpose of the Study:
- To investigate the noise power spectrum of tomographic grating-based phase contrast imaging.
- To determine the energy dependence of the contrast-to-noise ratio (CNR).
Main Methods:
- Simulated tomographic phase contrast imaging of a biological object using wave propagation.
- Monte Carlo simulations to ensure consistent radiation dose across different X-ray energies (25-85 keV).
Main Results:
- Noise power spectrum peaked at low spatial frequencies in reconstructed images.
- Optimal contrast-to-noise ratio observed around 45 keV, independent of material.
- Phase contrast CNR varied compared to absorption contrast, depending on material and energy.
Conclusions:
- Phase contrast imaging provides complementary information to absorption contrast, beneficial for medical use.
- The noise characteristics make the noise-resolution trade-off less efficient than absorption imaging.
- High-resolution imaging is a strength, but limitations in low-resolution scenarios may hinder some clinical applications.
Related Concept Videos
01:10Computed Tomography
Tomography refers to imaging by sections. Computed tomography (CT) is a non-invasive imaging technique that uses computers to analyze several cross-sectional X-rays to reveal minute details about structures in the body.
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
The technique was invented in the 1970s and is based on the principle that as X-rays pass through the body, they are absorbed or reflected at different levels. In the technique, a patient lies on a motorized platform while a computerized axial tomography (CAT) scanner rotates...
01:24X-ray Imaging
German physicist Wilhelm Röntgen (1845–1923) was experimenting with electrical current when he discovered that a mysterious and invisible "ray" would pass through his flesh but leave an outline of his bones on a screen coated with a metal compound. In 1895, Röntgen made the first durable record of the internal parts of a living human: an "X-ray" image (as it came to be called) of his wife’s hand. Scientists worldwide quickly began their own experiments with X-rays, and by 1900, X-ray was widely...
01:26Phase Contrast and Differential Interference Contrast Microscopy
Phase-Contrast Microscopes
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
02:18X-ray Crystallography
The size of the unit cell and the arrangement of atoms in a crystal may be determined from measurements of the diffraction of X-rays by the crystal, termed X-ray crystallography.
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
Diffraction
Diffraction is the change in the direction of travel experienced by an electromagnetic wave when it encounters a physical barrier whose dimensions are comparable to those of the wavelength of the light. X-rays are electromagnetic radiation with wavelengths about as long as the distance between neighboring...
01:27Imaging Studies III: Computed Tomography
DefinitionComputed Tomography (CT) of the genitourinary (GU) tract is a non-invasive imaging modality that utilizes X-rays and computer processing to generate detailed cross-sectional images of the urinary system, encompassing the kidneys, ureters, bladder, and adjacent structures such as the adrenal glands.PurposeCT scans of the GU tract serve several diagnostic and therapeutic purposes, including:Diagnosis of Urinary Tract Diseases: Detects kidney stones, tumors, cysts, and congenital...
01:30Radiological Investigation I: X-ray and CT
Radiological investigations, including X-rays and computed tomography (CT) scans, are critical for diagnosing and evaluating various medical conditions. These imaging techniques provide valuable insights into the body's internal structures, aiding in the detection of abnormalities, assessment of disease progression, and development of treatment strategies. This article delves into two primary radiological investigations, chest X-rays and CT scans, outlining their purpose, procedures, and the...