skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The criteria for measuring average density by x-ray attenuation: The role of spatial resolution

Abstract

It is well known that the attenuation of X-rays as they pass through a material can be used to quantify the amount of matter in their path. This is the basis for the gamma ray densitometer which can measure the amount of material on a moving conveyor belt. It is also the rationale for using X-rays for medical imaging as the attenuation can discriminate between tissue of different density and composition, yielding images of great diagnostic utility. Spatial resolution is obviously important with regard to detecting small features. However, it is less obvious that it plays an important role in obtaining quantitative information from the X-ray transmission data since the spatial resolution of the instrument can affect the accuracy of those measurements. This problem is particularly severe in the case of computed tomography where the accuracy of the reconstruction is dependent on the accuracy of the initial projection data. It should be noted that spatial resolution is not a concern for the case where the material is uniform. Here uniform is defined by small variations related to either the scale size of the resolution element in the detector, or to the size of a collimated X-ray beam. However, if themore » material has non-homogeneous composition or changes in density on the scale size of the systems spatial resolution, then there can be effects that will compromise the transmission data before it is acquired and these errors can not be corrected by any subsequent data processing. A method is presented for computing the density measurement error which parameterizes the effect in terms of the actual modulation on the face of the detector and the attenuation in the material. For cases like stacks of lead plates the errors can exceed 80%.« less

Authors:
Publication Date:
Research Org.:
Knolls Atomic Power Lab., Niskayuna, NY (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
754940
Report Number(s):
KAPL-P-000315; K99098
TRN: US0003547
DOE Contract Number:  
AC12-76SN00052
Resource Type:
Conference
Resource Relation:
Conference: Twenty-sixth Annual Review of Progress in Quantitative Nondestructive Evaluation, Montreal, Quebec (CA), 07/29/1999; Other Information: PBD: 29 Jul 1999
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; X RADIATION; ATTENUATION; ERRORS; DENSITY; MEASURING METHODS; COMPUTERIZED TOMOGRAPHY; SPATIAL RESOLUTION

Citation Formats

Friedman, W. The criteria for measuring average density by x-ray attenuation: The role of spatial resolution. United States: N. p., 1999. Web.
Friedman, W. The criteria for measuring average density by x-ray attenuation: The role of spatial resolution. United States.
Friedman, W. 1999. "The criteria for measuring average density by x-ray attenuation: The role of spatial resolution". United States. https://www.osti.gov/servlets/purl/754940.
@article{osti_754940,
title = {The criteria for measuring average density by x-ray attenuation: The role of spatial resolution},
author = {Friedman, W},
abstractNote = {It is well known that the attenuation of X-rays as they pass through a material can be used to quantify the amount of matter in their path. This is the basis for the gamma ray densitometer which can measure the amount of material on a moving conveyor belt. It is also the rationale for using X-rays for medical imaging as the attenuation can discriminate between tissue of different density and composition, yielding images of great diagnostic utility. Spatial resolution is obviously important with regard to detecting small features. However, it is less obvious that it plays an important role in obtaining quantitative information from the X-ray transmission data since the spatial resolution of the instrument can affect the accuracy of those measurements. This problem is particularly severe in the case of computed tomography where the accuracy of the reconstruction is dependent on the accuracy of the initial projection data. It should be noted that spatial resolution is not a concern for the case where the material is uniform. Here uniform is defined by small variations related to either the scale size of the resolution element in the detector, or to the size of a collimated X-ray beam. However, if the material has non-homogeneous composition or changes in density on the scale size of the systems spatial resolution, then there can be effects that will compromise the transmission data before it is acquired and these errors can not be corrected by any subsequent data processing. A method is presented for computing the density measurement error which parameterizes the effect in terms of the actual modulation on the face of the detector and the attenuation in the material. For cases like stacks of lead plates the errors can exceed 80%.},
doi = {},
url = {https://www.osti.gov/biblio/754940}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jul 29 00:00:00 EDT 1999},
month = {Thu Jul 29 00:00:00 EDT 1999}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: