Biophysical Considerations in the Precision of Quantitative ¹⁸F-FDG PET/CT

As Positron Emission Tomography is increasingly being used as a functional marker of disease states, both adequate image quality and robust quantification are critical components of such imaging studies. A variety of both biological and physical factors affect these qualities in significant ways. As PET technology continues to evolve, an understanding of these effects becomes essential to the continued usefulness of PET in clinical oncology.A detailed investigation of physical elements impacting PET quantification was completed. By directly comparing the results of data sets reconstructed in various ways the true impact of reconstruction settings on quantification was revealed. It was found that changes made to factors such as the number of iterations and subsets per reconstruction or time-of-flight kernel width had a limited impact on PET quantification. However, the addition of a system point spread function correction in the reconstruction algorithm results in significant changes in quantitative measurements. When comparing this state of the art correction method to data including cutting edge time-of-flight data acquisition, further differences in quantitative measurements were found, with time-of-flight data further improving the accuracy with which activity concentrations are recovered. These results show that although there remains a need for improvement in the acquisition and reconstruction of PET data, with each system upgrade the results of PET studies are indeed coming closer to reaching a true estimation of physiological activity distributions. With this in mind, re-evaluation of the PET radiopharmaceutical dose required for adequate and robust imaging was conducted. Simulations of low-count density images showed that reducing the average image count levels by as much as 66% did not significantly impact the clinical usefulness of PET data. Therefore, maintaining current emission scan durations, a significant decrease in the standard amount of administered radioactivity could be implemented.By thoroughly detailing the quantitative impact of improving PET/CT image acquisition and reconstruction methods, it was found that there is potential for decreasing required radioactivity doses in PET/CT imaging. With the current focus on reducing patient radiation exposure in medical imaging procedures, these findings are both timely and critical in terms of the continued utilization of PET/CT imaging in oncology.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Biophysics

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Binzel, Katherine M.

Contributors dc:contributor

• Knopp, Michael

• Biophysics
• Radiology
• positron emission tomography

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1365688391

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1365688391