{"id":{"repo_id":"buffalo","oai_identifier":"oai:ubir.buffalo.edu:10477/78041"},"canonical_url":"https://search.dev.ndltd.org/etd/buffalo/oai:ubir.buffalo.edu:10477/78041","repository":{"repo_id":"buffalo","name":"Buffalo","base_url":"https://ubir.buffalo.edu/oai/request"},"display":{"title":"Enhancement of the Real-Time Dose Tracking System for Interventional Fluoroscopic Procedures through Monte Carlo Investigations","abstract":"Ph.D.","abstract_html":"Ph.D.","abstract_has_math":false,"creators":["Xiong, Zhenyu"],"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":2018,"date_issued":"2018-06-28T20:33:03Z","date_published":"2018-06-28T20:33:03Z","updated_at":"2026-07-27T19:05:07Z","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/10477/78041","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":["Xiong, Zhenyu"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2018-06-28T20:33:03Z","2018","2018-05-16 11:48:57"]},{"key":"dc:publisher","label":"Institution","values":["State University of New York at Buffalo"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation","Text"]}]},{"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/10477/78041"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Ph.D.","Fluoroscopically-guided neuro-interventional procedures are increasingly used in the treatment of various vascular lesions. They provide important benefits to public health, but the use of ionizing radiation usually require a long time and patients can receive relatively high dose, thus the inherent risks that must be evaluated and minimized. We have previously developed a dose tracking system (DTS) to provide a real-time color-coded 3D-mapping of skin dose. The purpose of this work is to add the capability to determine more organ dose such as eye lens dose to the DTS software through Monte Carlo methods. The Toshiba Infinix C-Arm System was modeled in BEAMnrc/EGSnrc Monte Carlo code and patient organ and effective doses were calculated in DOSxynrc/EGSnrc for CBCT and interventional procedures. We have successfully produced a library of lens dose values based on a series of Monte Carlo simulation to quickly determine the lens dose for a given set of conditions. Also, organ and effective dose for long interventional procedures can be routinely calculated using exposure event log files. Effective dose and most organ doses calculated with PCXMC closely match those calculated with EGSnrc. Data grouping, which can be done automatically, makes the calculation time with PCXMC on a standard PC acceptable. The method we have developed provides real- time updates of lens dose with acceptable accuracy and expands the dose information that can be provided by the DTS software. To evaluate the effect of patient head size on radiation dose to radiosensitive organs, such as the eye lens, brain and spinal cord, X-ray projections from different angles, CBCT scans, and neuro-interventional procedures were simulated on a computational head phantom for the range of head sizes in the adult population and for different pediatric ages. The difference of left-eye lens dose between the mean head size and the mean ±1 standard deviation (SD) ranges from 20% to 300% for projection angles of 0°to 90°RAO. Dose for all organs increases with decreasing head size for the same reference point air kerma. These results will allow size-specific dose estimates to be made using software such as our dose tracking system (DTS). Several patient dose reduction techniques were developed and the effect of them were also evaluated. To reduce the dose to the patient while maintaining visualization of the entire field of view, a Cu attenuator with a circular aperture for the region of interest (ROI) has been developed. The dependence of dose reduction on the ROI attenuator thickness, the opening size of the ROI, the axial beam position and the location of the different organs for both neuro and thoracic imaging was evaluated. The results showed a reduction in most organ doses of 45%-70% and in effective dose of 46%-66% compared to the dose in a CBCT scan and in an interventional procedure without the ROI attenuator. Also, the use of small lead shields placed over the temple region of the head can substantially reduce the dose to the patient’s eye lens. The presence of the lead shields are not expected to compromise image quality significantly in neuro imaging procedures. A method was developed to determine the skin dose distribution for x-ray beams by convolving the backscatter point-spread-function (PSF) with the primary-dose distribution to generate the backscatter distribution that, when added to the primary dose, gives the total dose distribution. The variation of the backscatter PSF with different parameters in beam energies, soft-tissue thickness above bone, bone thickness and entrance beam angles, as well as for different locations on the head phantom were investigated. The results of this study can be used to improve the accuracy of dose calculation when using PSF convolution in the DTS."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Enhancement of the Real-Time Dose Tracking System for Interventional Fluoroscopic Procedures through Monte Carlo Investigations"]}]}],"canonical_facts":{"dc:contributor":["Bednarek, Daniel","Radiology"],"dc:creator":["Xiong, Zhenyu"],"dc:date":["2018-06-28T20:33:03Z","2018","2018-05-16 11:48:57"],"dc:description":["Ph.D.","Fluoroscopically-guided neuro-interventional procedures are increasingly used in the treatment of various vascular lesions. They provide important benefits to public health, but the use of ionizing radiation usually require a long time and patients can receive relatively high dose, thus the inherent risks that must be evaluated and minimized. We have previously developed a dose tracking system (DTS) to provide a real-time color-coded 3D-mapping of skin dose. The purpose of this work is to add the capability to determine more organ dose such as eye lens dose to the DTS software through Monte Carlo methods. The Toshiba Infinix C-Arm System was modeled in BEAMnrc/EGSnrc Monte Carlo code and patient organ and effective doses were calculated in DOSxynrc/EGSnrc for CBCT and interventional procedures. We have successfully produced a library of lens dose values based on a series of Monte Carlo simulation to quickly determine the lens dose for a given set of conditions. Also, organ and effective dose for long interventional procedures can be routinely calculated using exposure event log files. Effective dose and most organ doses calculated with PCXMC closely match those calculated with EGSnrc. Data grouping, which can be done automatically, makes the calculation time with PCXMC on a standard PC acceptable. The method we have developed provides real- time updates of lens dose with acceptable accuracy and expands the dose information that can be provided by the DTS software. To evaluate the effect of patient head size on radiation dose to radiosensitive organs, such as the eye lens, brain and spinal cord, X-ray projections from different angles, CBCT scans, and neuro-interventional procedures were simulated on a computational head phantom for the range of head sizes in the adult population and for different pediatric ages. The difference of left-eye lens dose between the mean head size and the mean ±1 standard deviation (SD) ranges from 20% to 300% for projection angles of 0°to 90°RAO. Dose for all organs increases with decreasing head size for the same reference point air kerma. These results will allow size-specific dose estimates to be made using software such as our dose tracking system (DTS). Several patient dose reduction techniques were developed and the effect of them were also evaluated. To reduce the dose to the patient while maintaining visualization of the entire field of view, a Cu attenuator with a circular aperture for the region of interest (ROI) has been developed. The dependence of dose reduction on the ROI attenuator thickness, the opening size of the ROI, the axial beam position and the location of the different organs for both neuro and thoracic imaging was evaluated. The results showed a reduction in most organ doses of 45%-70% and in effective dose of 46%-66% compared to the dose in a CBCT scan and in an interventional procedure without the ROI attenuator. Also, the use of small lead shields placed over the temple region of the head can substantially reduce the dose to the patient’s eye lens. The presence of the lead shields are not expected to compromise image quality significantly in neuro imaging procedures. A method was developed to determine the skin dose distribution for x-ray beams by convolving the backscatter point-spread-function (PSF) with the primary-dose distribution to generate the backscatter distribution that, when added to the primary dose, gives the total dose distribution. The variation of the backscatter PSF with different parameters in beam energies, soft-tissue thickness above bone, bone thickness and entrance beam angles, as well as for different locations on the head phantom were investigated. The results of this study can be used to improve the accuracy of dose calculation when using PSF convolution in the DTS."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/10477/78041"],"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":["Enhancement of the Real-Time Dose Tracking System for Interventional Fluoroscopic Procedures through Monte Carlo Investigations"],"dc:type":["Dissertation","Text"]},"updated_at":"2026-07-27T19:05:07Z"}