Functional studies of the lung using radioactive nuclides
Functional studies of the lung using radioactive nuclides
The measurement of regional pulmonary ventilation using the radioactive gas xenon-133 is severely limited by the physical characteristics of this nuclide. The object of this thesis is to examine the theoretical criteria which govern the measurement of regional ventilation, by the method of clearance of radioactive gas from the lungs using a gamma camera system, in order that the nuclide xenon-127 can be considered as an alternative.Assessment is made of the statistical accuracy of the data obtained from such a study, and a mathematical expression is derived which relates the maximum count rate, its maximum proportionate rate of change and the maximum permissible statistical error to the maximum possible number of regions of interest, assumed square and of equal size, in a uniform field of radioactivity. Furthermore, in order to optimise the count rate, the total geometrical spatial resolution of the camera system must be matched to the number of regions of interest (the 'dynamic spatial resolution') which, as the derived expression shows, is proportional to the count rate. However, the count rate is related to both the total geometrical spatial resolution of the camera system, in terms of collimator design parameters, and to the quantity of radioactivity administered.Detailed consideration is, therefore, given to the calculation of absorbed dose from possible gaseous radionuclides. The fundamental criteria of collimator design are also examined. A new theory, geometrically based, is developed and used in the manufacture of a collimator of optimum characteristics. A new handling and dispensing technique for inert gas radionuclides is presented, which improves efficiency and safety; factors which are of particular importance when using xenon-127.Finally, a technique, based upon these considerations and using xenon127, has been used for the study of regional ventilation in three normal subjects. The results of these studies are discussed and a comparison made with an alternative technique using the continuous breathing of the short half-life gas krypton-81m.
University of Southampton
1976
Goddard, Brian Arthur
(1976)
Functional studies of the lung using radioactive nuclides.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The measurement of regional pulmonary ventilation using the radioactive gas xenon-133 is severely limited by the physical characteristics of this nuclide. The object of this thesis is to examine the theoretical criteria which govern the measurement of regional ventilation, by the method of clearance of radioactive gas from the lungs using a gamma camera system, in order that the nuclide xenon-127 can be considered as an alternative.Assessment is made of the statistical accuracy of the data obtained from such a study, and a mathematical expression is derived which relates the maximum count rate, its maximum proportionate rate of change and the maximum permissible statistical error to the maximum possible number of regions of interest, assumed square and of equal size, in a uniform field of radioactivity. Furthermore, in order to optimise the count rate, the total geometrical spatial resolution of the camera system must be matched to the number of regions of interest (the 'dynamic spatial resolution') which, as the derived expression shows, is proportional to the count rate. However, the count rate is related to both the total geometrical spatial resolution of the camera system, in terms of collimator design parameters, and to the quantity of radioactivity administered.Detailed consideration is, therefore, given to the calculation of absorbed dose from possible gaseous radionuclides. The fundamental criteria of collimator design are also examined. A new theory, geometrically based, is developed and used in the manufacture of a collimator of optimum characteristics. A new handling and dispensing technique for inert gas radionuclides is presented, which improves efficiency and safety; factors which are of particular importance when using xenon-127.Finally, a technique, based upon these considerations and using xenon127, has been used for the study of regional ventilation in three normal subjects. The results of these studies are discussed and a comparison made with an alternative technique using the continuous breathing of the short half-life gas krypton-81m.
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Published date: 1976
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Local EPrints ID: 462360
URI: http://eprints.soton.ac.uk/id/eprint/462360
PURE UUID: 14bba697-cd7a-4dda-b09f-e9a05761f99a
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Date deposited: 04 Jul 2022 19:06
Last modified: 04 Jul 2022 19:06
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Author:
Brian Arthur Goddard
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