Hybrid positron emission tomography imaging techniques such as PET/CT and PET/MR have undergone significant developments over the last two decades and have played increasingly more important roles both in research and in the clinic. A unique advantage PET has over other clinical imaging modalities is its capability of accurate quantification. However, as the most critical component of PET quantification, attenuation correction in hybrid PET systems is challenged in several different aspects, including the spatial- temporal mismatch between the PET emission images and the associated attenuation images provided by the complementary modality, and the difficulty in bone identification in the MR-based attenuation correction approaches. These problems, if left unaddressed, can limit the potential of the hybrid PET systems.
This research developed solutions to overcome the spatial-temporal mismatch in PET/CT and PET/MR, and established the requirements for bone identification in PET/MR. An automatic registration algorithm based on a modified fuzzy c-means clustering method and gradient correlation was developed and validated to perform automatic registration in cardiac PET/CT data of different breathing protocols. A free- breathing MR protocol and post-process algorithm were developed to provide MR-based attenuation images that also match the temporal resolution of PET and were evaluated in a feasibility study. The relationship between the sensitivity of bone identification in attenuation images and PET quantification of bone lesions uptake was evaluated in a simulated study using data from 18F-sodium fluoride PET/CT exams.
","abstract_html":"<p>Hybrid positron emission tomography imaging techniques such as PET/CT and PET/MR have undergone significant developments over the last two decades and have played increasingly more important roles both in research and in the clinic. A unique advantage PET has over other clinical imaging modalities is its capability of accurate quantification. However, as the most critical component of PET quantification, attenuation correction in hybrid PET systems is challenged in several different aspects, including the spatial- temporal mismatch between the PET emission images and the associated attenuation images provided by the complementary modality, and the difficulty in bone identification in the MR-based attenuation correction approaches. These problems, if left unaddressed, can limit the potential of the hybrid PET systems.</p> <p>This research developed solutions to overcome the spatial-temporal mismatch in PET/CT and PET/MR, and established the requirements for bone identification in PET/MR. An automatic registration algorithm based on a modified fuzzy c-means clustering method and gradient correlation was developed and validated to perform automatic registration in cardiac PET/CT data of different breathing protocols. A free- breathing MR protocol and post-process algorithm were developed to provide MR-based attenuation images that also match the temporal resolution of PET and were evaluated in a feasibility study. The relationship between the sensitivity of bone identification in attenuation images and PET quantification of bone lesions uptake was evaluated in a simulated study using data from 18F-sodium fluoride PET/CT exams.</p>","abstract_has_math":false,"creators":["Ai, Hua Asher"],"institution":null,"degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation (PhD)","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Richard Wendt III, Ph.D.","Jim Bankson, Ph.D.","Michele Guindani, Ph.D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-08-01T07:00:00Z","date_published":"2015-08-01T07:00:00Z","updated_at":"2026-07-24T05:49:30Z","subjects":["PET","PET/CT","PET/MR","attenuation correction","automatic registration","average CT","average MR","MR-based attenuation correction","Medical Biophysics","Medicine and Health Sciences","Other Physics"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.library.tmc.edu/utgsbs_dissertations/604","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Richard Wendt III, Ph.D.","Jim Bankson, Ph.D.","Michele Guindani, Ph.D."]},{"key":"dc:creator","label":"Author","values":["Ai, Hua Asher"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2016-07-20T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation (PhD)"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["PET","PET/CT","PET/MR","attenuation correction","automatic registration","average CT","average MR","MR-based attenuation correction","Medical Biophysics","Medicine and Health Sciences","Other Physics"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://digitalcommons.library.tmc.edu/utgsbs_dissertations/604"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Hybrid positron emission tomography imaging techniques such as PET/CT and PET/MR have undergone significant developments over the last two decades and have played increasingly more important roles both in research and in the clinic. A unique advantage PET has over other clinical imaging modalities is its capability of accurate quantification. However, as the most critical component of PET quantification, attenuation correction in hybrid PET systems is challenged in several different aspects, including the spatial- temporal mismatch between the PET emission images and the associated attenuation images provided by the complementary modality, and the difficulty in bone identification in the MR-based attenuation correction approaches. These problems, if left unaddressed, can limit the potential of the hybrid PET systems.
This research developed solutions to overcome the spatial-temporal mismatch in PET/CT and PET/MR, and established the requirements for bone identification in PET/MR. An automatic registration algorithm based on a modified fuzzy c-means clustering method and gradient correlation was developed and validated to perform automatic registration in cardiac PET/CT data of different breathing protocols. A free- breathing MR protocol and post-process algorithm were developed to provide MR-based attenuation images that also match the temporal resolution of PET and were evaluated in a feasibility study. The relationship between the sensitivity of bone identification in attenuation images and PET quantification of bone lesions uptake was evaluated in a simulated study using data from 18F-sodium fluoride PET/CT exams.
"]},{"key":"dc:title","label":"Title","values":["Improving Attenuation Correction In Hybrid Positron Emission to mography"]}]}],"canonical_facts":{"dc:contributor":["Richard Wendt III, Ph.D.","Jim Bankson, Ph.D.","Michele Guindani, Ph.D."],"dc:creator":["Ai, Hua Asher"],"dc:date.available":["2016-07-20T07:00:00Z"],"dc:description.abstract":["Hybrid positron emission tomography imaging techniques such as PET/CT and PET/MR have undergone significant developments over the last two decades and have played increasingly more important roles both in research and in the clinic. A unique advantage PET has over other clinical imaging modalities is its capability of accurate quantification. However, as the most critical component of PET quantification, attenuation correction in hybrid PET systems is challenged in several different aspects, including the spatial- temporal mismatch between the PET emission images and the associated attenuation images provided by the complementary modality, and the difficulty in bone identification in the MR-based attenuation correction approaches. These problems, if left unaddressed, can limit the potential of the hybrid PET systems.
This research developed solutions to overcome the spatial-temporal mismatch in PET/CT and PET/MR, and established the requirements for bone identification in PET/MR. An automatic registration algorithm based on a modified fuzzy c-means clustering method and gradient correlation was developed and validated to perform automatic registration in cardiac PET/CT data of different breathing protocols. A free- breathing MR protocol and post-process algorithm were developed to provide MR-based attenuation images that also match the temporal resolution of PET and were evaluated in a feasibility study. The relationship between the sensitivity of bone identification in attenuation images and PET quantification of bone lesions uptake was evaluated in a simulated study using data from 18F-sodium fluoride PET/CT exams.
"],"dc:identifier":["https://digitalcommons.library.tmc.edu/utgsbs_dissertations/604"],"dc:subject":["PET","PET/CT","PET/MR","attenuation correction","automatic registration","average CT","average MR","MR-based attenuation correction","Medical Biophysics","Medicine and Health Sciences","Other Physics"],"dc:title":["Improving Attenuation Correction In Hybrid Positron Emission to mography"],"thesis:degree_level":["Dissertation (PhD)"],"thesis:degree_name":["Doctor of Philosophy (PhD)"]},"updated_at":"2026-07-24T05:49:30Z"}