{"id":{"repo_id":"buffalo","oai_identifier":"oai:ubir.buffalo.edu:10477/86747"},"canonical_url":"https://search.dev.ndltd.org/etd/buffalo/oai:ubir.buffalo.edu:10477/86747","repository":{"repo_id":"buffalo","name":"Buffalo","base_url":"https://ubir.buffalo.edu/oai/request"},"display":{"title":"Monte-Carlo Calculations for Patient and Staff Dose Management during Fluoroscopically-Guided Procedures","abstract":"Ph.D.","abstract_html":"Ph.D.","abstract_has_math":false,"creators":["Guo, Chao; 0000-0001-5878-0757"],"institution":"State University of New York at Buffalo","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Bednarek, Daniel","Radiology"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-02-21T21:44:41Z","date_published":"2025-02-21T21:44:41Z","updated_at":"2026-07-27T19:05:37Z","subjects":["medical imaging"],"languages":["eng"],"rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10477/86747","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Bednarek, Daniel","Radiology"]},{"key":"dc:creator","label":"Author","values":["Guo, Chao; 0000-0001-5878-0757"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-02-21T21:44:41Z","2020"]},{"key":"dc:publisher","label":"Institution","values":["State University of New York at Buffalo"]},{"key":"dc:type","label":"Dc Type","values":["Text","Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["medical imaging"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/10477/86747"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Ph.D.","Fluoroscopically-guided interventional procedures are widely used in the hospital. These employ X-ray based imaging techniques that provide real-time imaging. Our group previously developed the Dose Tracking System (DTS) to monitor the patient's skin dose during long interventional procedures; however, radiation dose is a concern not only for the patient but also for the personnel in the procedure room. In recent years, the number and types of fluoroscopically-guided procedures have increased dramatically. The NCRP has estimated that 17 million interventional fluoroscopic procedures were performed in 2006. In order to improve the radiation safety for staff during the procedure, we developed a new system called the Scattered Radiation Display System (SDS), which could help personnel in the room to know their dose level in real-time and to avoid high-scatter regions or to add adequate shielding during the procedure to reduce their dose. The work of this dissertation develops the groundwork for the SDS, which provides a color-coded display of the scattered radiation distribution in the fluoroscopic procedure room for feedback to staff. By using Monte Carlo simulations and physical measurements, we were able to determine the distribution of radiation scattered from the patient and how this distribution changes with different exposure parameters and phantoms. Between CAU 30 to CRA 30 degree, at eye level, Caudal results in 20 % higher dose for exposure in the chest region compared to the abdominal region. In general, for both CRA/CAU and LAO/RAO angles, the chest region produces higher scatter than the abdomen at eye level, and less below the table. EGSnrc Monte Carlo software was used to simulate the fluoroscopically-guided procedures, using the specifications of the Canon (Toshiba) Infinix Bi-plane C-arm fluoroscopic system (BLA-900A). BEAMnrc and DOSXYZnrc were used to accurately determine the scattered radiation distribution within the procedure room. BEAMnrc created the phase-space files with different beam specifications including different filters, beam field sizes, and beam energies. These phase-space files are used in DOSXYZnrc to simulate the scattering within the patient. For comparisons, 3D scattered radiation distributions were created using different phantoms in the simulations including a 30 cm diameter cylindrical and a 30 cm wide super-ellipse water phantom, and the Zubal anthropomorphic computational phantom. Monte Carlo simulations take a long time to run, especially when calculating the low level scattered radiation dose in the room. To reduce the number of required simulations for each parameter change, an interpolation method was developed to determine intermediate distributions. This method helps save a considerable amount of simulation time without a significant loss of accuracy. The fine angular and horizontal-plane interpolations typically had better than 5% agreement with the MC simulation, while for coarse interpolation, the difference increased up to 15% but was typically less than 10%. Interpolation saves not only the MC simulation time to create each distribution for the library, but also the memory requirements and the time to read those distributions into the SDS. During a fluoroscopically-guided interventional procedure, the beam is not always centered on the patient center-line and thus scattered radiation distributions were also determined with lateral shifts in the head, chest, and abdomen regions for different projection angles. This considerably improved the potential accuracy of the scattering distribution used for the SDS, since the distributions become asymmetric with lateral shifts of the patient with reduced scatter in the direction of patient movement. Scatter dose per patient entrance dose was calculated in both vertical and horizontal planes to develop 3D volumes of scattered radiation dose distributions. The simulation volume covered 3 m (length) × 3 m (width) × 2 m (height), and the distributions in region outside this volume are obtained by extrapolation using \"inverse square law\" to cover the entire procedure room. In addition to determining scattering radiation distributions for the SDS, the patient's eye lens dose was also calculated using Monte Carlo software to provide look-up-tables (LUT) of values for the dose tracking system (DTS). The lens dose was calculated for both eyes as a function of technical and geometric exposure factors and as a function of the x, y and z shifts of the beam isocenter from the center of the head. These calculations help improve the accuracy of patient eye lens dose estimation with the DTS. We have successfully generated libraries of room scattering radiation dose distributions and eye lens dose LUT's using the Monte Carlo method to provide effective dose management for staff and patient by allowing real-time estimation of dose during fluoroscopically-guided procedures.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Monte-Carlo Calculations for Patient and Staff Dose Management during Fluoroscopically-Guided Procedures"]}]}],"canonical_facts":{"dc:contributor":["Bednarek, Daniel","Radiology"],"dc:creator":["Guo, Chao; 0000-0001-5878-0757"],"dc:date":["2025-02-21T21:44:41Z","2020"],"dc:description":["Ph.D.","Fluoroscopically-guided interventional procedures are widely used in the hospital. These employ X-ray based imaging techniques that provide real-time imaging. Our group previously developed the Dose Tracking System (DTS) to monitor the patient's skin dose during long interventional procedures; however, radiation dose is a concern not only for the patient but also for the personnel in the procedure room. In recent years, the number and types of fluoroscopically-guided procedures have increased dramatically. The NCRP has estimated that 17 million interventional fluoroscopic procedures were performed in 2006. In order to improve the radiation safety for staff during the procedure, we developed a new system called the Scattered Radiation Display System (SDS), which could help personnel in the room to know their dose level in real-time and to avoid high-scatter regions or to add adequate shielding during the procedure to reduce their dose. The work of this dissertation develops the groundwork for the SDS, which provides a color-coded display of the scattered radiation distribution in the fluoroscopic procedure room for feedback to staff. By using Monte Carlo simulations and physical measurements, we were able to determine the distribution of radiation scattered from the patient and how this distribution changes with different exposure parameters and phantoms. Between CAU 30 to CRA 30 degree, at eye level, Caudal results in 20 % higher dose for exposure in the chest region compared to the abdominal region. In general, for both CRA/CAU and LAO/RAO angles, the chest region produces higher scatter than the abdomen at eye level, and less below the table. EGSnrc Monte Carlo software was used to simulate the fluoroscopically-guided procedures, using the specifications of the Canon (Toshiba) Infinix Bi-plane C-arm fluoroscopic system (BLA-900A). BEAMnrc and DOSXYZnrc were used to accurately determine the scattered radiation distribution within the procedure room. BEAMnrc created the phase-space files with different beam specifications including different filters, beam field sizes, and beam energies. These phase-space files are used in DOSXYZnrc to simulate the scattering within the patient. For comparisons, 3D scattered radiation distributions were created using different phantoms in the simulations including a 30 cm diameter cylindrical and a 30 cm wide super-ellipse water phantom, and the Zubal anthropomorphic computational phantom. Monte Carlo simulations take a long time to run, especially when calculating the low level scattered radiation dose in the room. To reduce the number of required simulations for each parameter change, an interpolation method was developed to determine intermediate distributions. This method helps save a considerable amount of simulation time without a significant loss of accuracy. The fine angular and horizontal-plane interpolations typically had better than 5% agreement with the MC simulation, while for coarse interpolation, the difference increased up to 15% but was typically less than 10%. Interpolation saves not only the MC simulation time to create each distribution for the library, but also the memory requirements and the time to read those distributions into the SDS. During a fluoroscopically-guided interventional procedure, the beam is not always centered on the patient center-line and thus scattered radiation distributions were also determined with lateral shifts in the head, chest, and abdomen regions for different projection angles. This considerably improved the potential accuracy of the scattering distribution used for the SDS, since the distributions become asymmetric with lateral shifts of the patient with reduced scatter in the direction of patient movement. Scatter dose per patient entrance dose was calculated in both vertical and horizontal planes to develop 3D volumes of scattered radiation dose distributions. The simulation volume covered 3 m (length) × 3 m (width) × 2 m (height), and the distributions in region outside this volume are obtained by extrapolation using \"inverse square law\" to cover the entire procedure room. In addition to determining scattering radiation distributions for the SDS, the patient's eye lens dose was also calculated using Monte Carlo software to provide look-up-tables (LUT) of values for the dose tracking system (DTS). The lens dose was calculated for both eyes as a function of technical and geometric exposure factors and as a function of the x, y and z shifts of the beam isocenter from the center of the head. These calculations help improve the accuracy of patient eye lens dose estimation with the DTS. We have successfully generated libraries of room scattering radiation dose distributions and eye lens dose LUT's using the Monte Carlo method to provide effective dose management for staff and patient by allowing real-time estimation of dose during fluoroscopically-guided procedures.","**To request an accessible version of the file(s) associated with this item, contact library@buffalo.edu. Please include the item's persistent URL [http://hdl.handle.net/. . .] in your request.**"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/10477/86747"],"dc:language":["eng"],"dc:publisher":["State University of New York at Buffalo"],"dc:rights":["Users of works found in University at Buffalo Institutional Repository (UBIR) are responsible for identifying and contacting the copyright owner for permission to reuse. University at Buffalo Libraries do not manage rights for copyright-protected works and cannot assist with permissions.","Copyright retained by author."],"dc:subject":["medical imaging"],"dc:title":["Monte-Carlo Calculations for Patient and Staff Dose Management during Fluoroscopically-Guided Procedures"],"dc:type":["Text","Dissertation"]},"updated_at":"2026-07-27T19:05:37Z"}