Radiation Medicine Commons^™

Optimal Circulatory Arrest Temperature For Aortic Hemiarch Replacement With Antegrade Brain Perfusion, Laura Seese, Edward P Chen, Vinay Badhwar, Dylan Thibault, Robert H Habib, Jeffrey P Jacobs, Vinod Thourani, Faisal Bakaeen, Sean O'Brien, Oliver K Jawitz, Brittany Zwischenberger, Thomas G Gleason, Ibrahim Sultan, Arman Kilic, Joseph S Coselli, Lars G Svensson, Joanna Chikwe, Danny Chu

Faculty, Staff and Students Publications

Objective: This study sought to identify the optimal temperature for moderate hypothermic circulatory arrest in patients undergoing elective hemiarch replacement with antegrade brain perfusion.

Methods: The Society of Thoracic Surgeons adult cardiac surgery database was queried for elective hemiarch replacements using antegrade brain perfusion for aneurysmal disease (2014-2019). Generalized estimating equations and restricted cubic splines were used to determine the risk-adjusted relationships between temperature as a continuous variable and outcomes.

Results: Elective hemiarch replacement with antegrade brain perfusion occurred in 3898 patients at 374 centers with a median nadir temperature of 24.9°C (first quartile, third quartile = 22.0°C, 27.5°C) and …

Midterm Outcomes Of Aortic Root Surgery In Patients With Marfan Syndrome: A Prospective, Multicenter, Comparative Study, Joseph S Coselli, Irina V Volguina, Scott A Lemaire, Heidi M Connolly, Thoralf M Sundt, Dianna M Milewicz, Harry C Dietz, Hiruni S Amarasekara, Susan Y Green, Qianzi Zhang, Hartzell V Schaff, D Craig Miller

Faculty, Staff and Students Publications

Objective: The objective of this study was to compare midterm outcomes of aortic valve-replacing root replacement (AVR) and aortic valve-sparing root replacement (AVS) operations in patients with Marfan syndrome.

Methods: Patients who met strict Ghent diagnostic criteria for Marfan syndrome and who underwent either AVR or AVS between March 1, 2005 and December 31, 2010 were enrolled in a 3-year follow-up prospective, multicenter, international registry study; the study was subsequently amended to include 20-year follow-up. Enrollees were followed clinically and echocardiographically.

Results: Of the 316 patients enrolled, 77 underwent AVR and 239 underwent AVS; 214 gave reconsent for 20-year follow-up. …

A Novel Method For Measuring The Burden Of Breast Cancer In Neighborhoods, Russell K. Mcintire, Hee-Soon Juon, Scott W. Keith, Nicole L. Simone, Dexter Waters, Eleanor Lewis, Charnita Zeigler-Johnson

College of Population Health Faculty Papers

Community-based breast cancer prevention efforts often focus on women who live in the same neighborhoods, as they tend to have similar demographic characteristics, health behaviors, and environmental exposures; yet little research describes methods of selecting neighborhoods of focus for community-based cancer prevention interventions. Studies frequently use demographics from census data, or single breast cancer outcomes (e.g., mortality, morbidity) in order to choose neighborhoods of focus for breast cancer interventions, which may not be optimal. This study presents a novel method for measuring the burden of breast cancer among neighborhoods that could be used for selecting neighborhoods of focus. In this …

Modelling Radiation Cancer Treatment With A Death-Rate Term In Ordinary And Fractional Differential Equations, Nicole Wilson, Corina S Drapaca, Heiko Enderling, Jimmy J Caudell, Kathleen P Wilkie

Faculty, Staff and Student Publications

Fractional calculus has recently been applied to the mathematical modelling of tumour growth, but its use introduces complexities that may not be warranted. Mathematical modelling with differential equations is a standard approach to study and predict treatment outcomes for population-level and patient-specific responses. Here, we use patient data of radiation-treated tumours to discuss the benefits and limitations of introducing fractional derivatives into three standard models of tumour growth. The fractional derivative introduces a history-dependence into the growth function, which requires a continuous death-rate term for radiation treatment. This newly proposed radiation-induced death-rate term improves computational efficiency in both ordinary and …

Pocketnet: A Smaller Neural Network For Medical Image Analysis, Adrian Celaya, Jonas A Actor, Rajarajesawari Muthusivarajan, Evan Gates, Caroline Chung, Dawid Schellingerhout, Beatrice Riviere, David Fuentes

Faculty, Staff and Student Publications

Medical imaging deep learning models are often large and complex, requiring specialized hardware to train and evaluate these models. To address such issues, we propose the PocketNet paradigm to reduce the size of deep learning models by throttling the growth of the number of channels in convolutional neural networks. We demonstrate that, for a range of segmentation and classification tasks, PocketNet architectures produce results comparable to that of conventional neural networks while reducing the number of parameters by multiple orders of magnitude, using up to 90% less GPU memory, and speeding up training times by up to 40%, thereby allowing …

An Untrained Deep Learning Method For Reconstructing Dynamic Mr Images From Accelerated Model-Based Data, Kalina P Slavkova, Julie C Dicarlo, Viraj Wadhwa, Sidharth Kumar, Chengyue Wu, John Virostko, Thomas E Yankeelov, Jonathan I Tamir

Faculty, Staff and Student Publications

PURPOSE: To implement physics-based regularization as a stopping condition in tuning an untrained deep neural network for reconstructing MR images from accelerated data.

METHODS: The ConvDecoder (CD) neural network was trained with a physics-based regularization term incorporating the spoiled gradient echo equation that describes variable-flip angle data. Fully-sampled variable-flip angle k-space data were retrospectively accelerated by factors of R = {8, 12, 18, 36} and reconstructed with CD, CD with the proposed regularization (CD + r), locally low-rank (LR) reconstruction, and compressed sensing with L1-wavelet regularization (L1). Final images from CD + r training were evaluated at the "argmin" of …

Commentary: Through Thick And Thin, Jonathan C Hong, Joseph S Coselli

Faculty, Staff and Students Publications

No abstract provided.

Commentary: There Is More Than One Way To Skin A Cat, Joseph S Coselli, Jonathan C Hong

Faculty, Staff and Students Publications

No abstract provided.

Hemangioblastoma With Late Leptomeningeal Metastasis: A Case Report, Spencer J. Poiset, Aneesh Reddy, Catherine M. Tucker, Lawrence C. Kenyon, Kevin D. Judy, Wenyin Shi

Department of Radiation Oncology Faculty Papers

BACKGROUND: Hemangioblastoma of the central nervous system is an uncommon benign neoplasm, with about 25% of cases in patients with von Hippel-Lindau disease. The incidence of metastasis is rare, particularly in patients without von Hippel-Lindau disease. We report a case of hemangioblastoma with leptomeningeal dissemination as a late recurrence.

CASE PRESENTATION: A 65-year-old Caucasian man with a history of World Health Organization grade I hemangioblastoma of the cerebellar vermis underwent gross total resection in 1997. In early 2018, he developed intracranial recurrences with diffuse leptomeningeal disease of the entire spine. The patient underwent resection of intracranial recurrence, followed by palliative …

Safety Of Nivolumab Added To Chemoradiation Therapy Platforms For Intermediate And High-Risk Locoregionally Advanced Head And Neck Squamous Cell Carcinoma: Rtog Foundation 3504, Maura L Gillison, Robert L Ferris, Jonathan Harris, A Dimitrios Colevas, Loren K Mell, Christina Kong, Richard C Jordan, Kevin L Moore, Minh-Tam Truong, Claudia Kirsch, Arnab Chakravarti, Dukagjin M Blakaj, David A Clump, James P Ohr, John F Deeken, Michael F Gensheimer, Nabil F Saba, Jennifer A Dorth, David I Rosenthal, Rom S Leidner, Randall J Kimple, Mitchell Machtay, Walter J Curran, Pedro Torres-Saavedra, Quynh Thu Le

Faculty, Staff and Student Publications

PURPOSE: Programmed death-1 immune checkpoint blockade improves survival of patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC), but the benefits of addition to (chemo)radiation for newly diagnosed patients with HNSCC remain unknown.

METHODS AND MATERIALS: We evaluated the safety of nivolumab concomitant with 70 Gy intensity modulated radiation therapy and weekly cisplatin (arm 1), every 3-week cisplatin (arm 2), cetuximab (arm 3), or alone for platinum-ineligible patients (arm 4) in newly diagnosed intermediate- or high-risk locoregionally advanced HNSCC. Patients received nivolumab from 2 weeks prior to radiation therapy until 3 months post-radiation therapy. The primary endpoint was dose-limiting …

Physician Perspectives On Telemedicine In Radiation Oncology, Sean Maroongroge, Brian De, Kristina D Woodhouse, Roland L Bassett, Percy Lee, Elizabeth S Bloom, Grace L Smith, Steven J Frank, Jing Li, George Perkins, Prajnan Das, Albert C Koong, Benjamin D Smith, Chenyang Wang

Faculty, Staff and Student Publications

PURPOSE: Telemedicine enthusiasm and uptake in radiation oncology rapidly increased during the COVID-19 pandemic, but it is unclear if and how telemedicine should be used after the COVID-19 public health emergency ends is unclear. Herein, we report on our institution's provider experience after the mature adoption of telemedicine.

METHODS AND MATERIALS: We distributed a survey to all radiation oncology attending physicians at our institution in October 2021 to assess satisfaction, facilitators, and barriers to telemedicine implementation. We performed quantitative and qualitative analyses to characterize satisfaction and identify influencing factors whether telemedicine is employed. We calculated the average proportion of visits …

Vidutolimod In Combination With Atezolizumab With And Without Radiation Therapy In Patients With Programmed Cell Death Protein 1 Or Programmed Death-Ligand 1 Blockade-Resistant Advanced Nsclc, Marcelo V Negrao, Vassiliki A Papadimitrakopoulou, Andrew C Price, Alda L Tam, Muhammad Furqan, Sandeep T Laroia, Erminia Massarelli, Jose Pacheco, John V Heymach, Anne S Tsao, Gary V Walker, Lalit Vora, David Mauro, Heather Kelley, James E Wooldridge, Arthur M Krieg, Jiaxin Niu

Faculty, Staff and Student Publications

INTRODUCTION: Vidutolimod, a CpG-A TLR9 agonist, was investigated in a phase 1b study (CMP-001-003; ClinicalTrials.gov, NCT03438318) in combination with atezolizumab with and without radiation therapy (RT) in patients with advanced NSCLC.

METHODS: Patients with progressive disease after anti-programmed cell death protein 1 or programmed death-ligand 1 therapy received either vidutolimod and atezolizumab (part A) or vidutolimod, atezolizumab, and RT (part B). The primary objective was to evaluate the safety of vidutolimod and atezolizumab with and without RT. Key secondary end point was best objective response rate per Response Evaluation Criteria in Solid Tumors, version 1.1.

RESULTS: Between March 28, 2018, …

Circulating Neutrophils And Tumor-Associated Myeloid Cells Function As A Powerful Biomarker For Response To Chemoradiation In Locally Advanced Cervical Cancer, Olsi Gjyshi, Adam Grippin, Lauren Andring, Anuja Jhingran, Lilie L Lin, Julianna Bronk, Patricia J Eifel, Melissa M Joyner, Jagannadha K Sastry, Kyoko Yoshida-Court, Travis N Solley, Tatiana Cisneros Napravnik, Madison P O'Hara, Venkatesh L Hegde, Lauren E Colbert, Ann H Klopp

Faculty, Staff and Student Publications

PURPOSE: The immune system's role in mediating the cytotoxic effects of chemoradiotherapy remains not completely understood. The integration of immunotherapies into treatment will require insight into features and timing of the immune microenvironment associated with treatment response. Here, we investigated the role of circulating neutrophils and tumor-associated myeloid cells (TSAMs) as potential agents and biomarkers for disease-related outcomes in locally advanced cervical cancer (LACC).

MATERIAL AND METHODS: Hematologic parameters for two LACC patient cohorts, a retrospective clinical and a prospective translational cohort, were obtained at baseline, weekly during chemoradiotherapy for the retrospective cohort, biweekly during chemoradiotherapy for the prospective cohort, …

Carbon Fiber-Reinforced Polyetheretherketone Spinal Implants For Treatment Of Spinal Tumors: Perceived Advantages And Limitations, Christopher Alvarez-Breckenridge, Romulo De Almeida, Ali Haider, Matthew Muir, Justin Bird, Robert North, Laurence Rhines, Claudio Tatsui

Faculty, Staff and Student Publications

PURPOSE: Carbon-fiber reinforced polyetheretherketone (CFRP)-based spinal implants are an alternative to titanium, offering less image artifact as their metallic counterparts while maintaining similar biomechanical and biocompatibility properties. Its use in the management of spinal tumors has been reported, however the perceived advantages related to improved imaging quality, radiation treatment planning, and detection of tumor recurrence have not been fully assessed.

METHODS: We performed a retrospective review of medical records amongst oncologic patients treated at MD Anderson Cancer Center with CFRP implants. Histology, tumor location, construct features, time of follow-up, adjuvant radiation, recurrences, overall survival, and hardware-related complications were recorded.

RESULTS: …

Commentary: Is The Glass Half Full Or Half Empty?, Monika Halas, Joseph S Coselli

Faculty, Staff and Students Publications

No abstract provided.

Commentary: A Little Help From The Bench To Cut Risk Of Paraplegia?, Monika Halas, Joseph S Coselli

Faculty, Staff and Students Publications

No abstract provided.

Multisite Detection Of Tn1549-Mediated Vanb Vancomycin Resistance In Multidrug-Resistant Enterococcus Faecalis St6 In Texas And Florida, Shelby R Simar, Truc T Tran, Kirsten B Rydell, Diana Panesso, German A Contreras, Jose M Munita, Renzo O Cifuentes, Lilian M Abbo, Pranoti Sahasrabhojane, An Q Dinh, Dierdre B Axell-House, Tor Savidge, Samuel A Shelburne, Blake M Hanson, Cesar A Arias

Faculty, Staff and Student Publications

In the United States, vanB-mediated resistance in enterococci is rare. We characterized three sequence type (ST) 6, vancomycin-resistant Enterococcus faecalis isolates causing bacteremia in unique patients in spatiotemporally distinct settings. Isolates were recovered between 2018 and 2020 in two cities in the United States (Houston, TX; Miami, FL). The isolates harbored the vanB operon on a chromosomally located Tn1549 transposon, and epidemiological data suggested multiple introductions of the vanB gene cluster into ST6 E. faecalis.

Radiation Therapy For Retroperitoneal Sarcomas: A Strass-Ful Situation, Ahsan S Farooqi, B Ashleigh Guadagnolo, Devarati Mitra, Andrew J Bishop

Faculty, Staff and Student Publications

Locoregional recurrence (LRR) is the predominant pattern of relapse and often the cause of death in patients with retroperitoneal sarcomas (RPS). As a result, reducing LRR is a critical objective for RPS patients. However, unlike soft tissue sarcomas (STS) of the superficial trunk and extremity where the benefits of radiation therapy (RT) are well-established, the role of RT in the retroperitoneum remains controversial. Historically, preoperative or postoperative RT, either alone or in combination with intraoperative radiation (IORT), was commonly justified for RPS based on extrapolation from the superficial trunk and extremity STS literature. However, long-awaited results were recently published from …

Determination Of Kinetic Parameters For Bone Turnover In Chronic Kidney Disease With Hemodialysis Patients Using Dynamics 18f-Naf Pet/Ct Imaging, Viyada Sanoesan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Bone turnover measurement using 18F-NaF PET/CT serves as a valuable imaging biomarker for studying bone metabolism at various sites of skeleton. This study aimed to determine the kinetic parameters (Ki–Patlak) for bone turnover prediction as a non-invasive biomarker from dynamic 18F-NaF PET/CT in chronic kidney disease (CKD) patients with hemodialysis. Moreover, we aimed to investigate whether Ki–Patlak derived from shortened scan time can provide a prediction equivalent to that obtained from routine dynamic scan. Twenty-seven Thai CKD patients on hemodialysis (48 scans) from December 2021 to December 2023 were recruited. After intravenous injection of 18F-NaF of 133±39.3 MBq, dynamic PET/CT …

Analysis Of Biologically Effective Dose For Retroactive Yttrium-90 Trans-Arterial Radioembolization Treatment Optimization, Mj Lindsey

CMC Senior Theses

Trans-arterial radioembolization (TARE) is a protracted modality of radiation therapy where radionuclides labeled with Yttrium-90 (⁹⁰Y) are inserted inside a patient's hepatic artery to treat hepatocellular carcinoma (HCC). While TARE has been shown to be a clinically effective and safe treatment, there is little understanding of the radiobiological relationship between absorbed dose and tissue response, and thus there is no dosimetric standard for treatment planning. The Biologically Effective Dose (BED) formalism, derived from the Linear-Quadratic model of radiobiology, is used to weigh the absorbed dose by the time pattern of delivery. BED is a virtual dose that can …

Accuracy Of 177lu Quantification For Dosimetry Calculation Using 12-Swiveling Czt Detectors Spect/Ct Camera, Panattha Damthongsen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Recently, the 12-cadmium zinc telluride (CZT) based digital detectors SPECT/CT system has been introduced for advanced technology in nuclear medicine instrument, which outperforms conventional cameras. Moreover, the voxel S value-based dosimetry is important and offers more accurate in personalized dosimetry treatment using targeted radionuclide therapy. This study aimed to determine the accuracy of 177Lu quantification through an IEC/NEMA phantom study and to evaluate total-body dosimetry in patients undergoing 177Lu therapy using 12-swiveling digital CZT detectors SPECT/CT camera. The NEMA/IEC body phantom inserted with six fillable spheres (10-, 13-, 17-, 22-, 28-, and 37-mm inner diameter), filled with 177Lu solution of …

Impact Of Contrast Agent Administration On Water Equivalent Diameter For Ssde Calculation In Chest Ct Angiography Examination, Nuttanit Kaewsan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to determine the impact of intravenous contrast enhancement on the calculation of water equivalent diameter (Dw) for size-specific dose estimate (SSDE) in chest CT angiography (CTA) using different calculation methods in non-contrast and arterial phase images. A cohort of 231 adult patients who underwent chest CT angiography at King Chulalongkorn Memorial Hospital (KCMH) were included. The 3D Slicer image computing software was used to automatically draw the ROI in each axial CT image to measure area and mean CT number. The Dw values were calculated following the American Association of Physicists in Medicine (AAPM) Report No.220 utilizing …

Improving Radiotherapy Workflow: Evaluation And Implementation Of Deep Learning Auto-Segmentation In A Multi-User Environment, And Development Of Automatic Contour Quality Assurance System, Jingwei Duan

Theses and Dissertations--Radiation Medicine

Radiotherapy is a frequently used therapeutic modality for cancer patients. Accurately contouring of tumors and organs at risk (OARs) is critical for developing optimal treatment plans in radiotherapy, especially after the implementation of Intensity-modulated radiation therapy (IMRT) and Stereotactic Body Radiation Therapy (SBRT). The manual contouring process is time-consuming and suffers from inter-observer variations. However, manual contouring is often hindered by laborious clinical duties, leading to reduced effectiveness, and increased segmentation errors due to fatigue. Additionally, online adaptive radiation therapy(ART), which has been shown to benefit patient outcomes, places higher demands on contouring and quality assurance (QA) speed.

Recently, deep …

Evaluation Of Patient Radiation Dose And Risk Of Cancer From Ct Examinations, Saowapark Poosiri

Chulalongkorn University Theses and Dissertations (Chula ETD)

Computed Tomography (CT) examinations have been increasingly requested and become the major sources of patient exposure. The cancer risk from CT scans is contingent upon the amount of organ absorbed dose. This study aims to evaluate the cumulative effective doses (CED) and risk of cancer incidence and mortality from recurrent CT examinations in a single day. The patient data at aged 15 to 75 years old performed CT examinations during the period of five years from January 2018 to December 2022 were collected from two academic centers. The CED and organ doses were evaluated using Radimetrics™ Enterprise Platform from Monte …

Characterization Of A Solid-State Detector For Dosimetry In The Diagnostic Energy Range With Verification Via Monte Carlo Estimation Of Average Breast Dose In Mammography, Areej Aljabal

Theses and Dissertations

This dissertation aims to develop a simplified QA metric for estimating radiation dose in mammography. This metric, the Mid-Breast Dose (MDB) Index, maybe be proposed as an alternative dose index, consistent with average glandular dose (AGD), for routine QA. MBD was obtained using “Phantom mid-point Air Kerma (AK) measurement” for conventional mammography. The advantage of this method is that MBD can be measured directly without requiring multiple conversion factors. The accuracy of clinical measurements in computing the MBD was assessed by comparing it with the AGD estimated by the Dance formalism experimentally and Monte Carlo simulation.

MBD methodology relies on …

Characterization And Investigation Of Cold Atmospheric Plasma And Its Effects On Cancer Cell Biology, Thomas M. Ritrosky

Theses and Dissertations

Modern cancer treatment uses radiation therapy in over 50% of patient cases. It is an e↵ective way of treating tumors because the mechanisms of cell killing are well known through the damage that ionizing radiation does to DNA. The amount of radiation can be tracked through measuring the dose of the clinical photon or electron beam used. However, there are limitations in the usage of radiation therapy, for example, a tumor can create hypoxic areas that become radioresistant leading to complete ine↵ectiveness of further radiation treatment. This project looks into the application of cold atmospheric plasma as an adjuvant therapy …

A Learning Health System For Radiation Oncology, Rishabh Kapoor

Theses and Dissertations

The proposed research aims to address the challenges faced by clinical data science researchers in radiation oncology accessing, integrating, and analyzing heterogeneous data from various sources. The research presents a scalable intelligent infrastructure, called the Health Information Gateway and Exchange (HINGE), which captures and structures data from multiple sources into a knowledge base with semantically interlinked entities. This infrastructure enables researchers to mine novel associations and gather relevant knowledge for personalized clinical outcomes.

The dissertation discusses the design framework and implementation of HINGE, which abstracts structured data from treatment planning systems, treatment management systems, and electronic health records. It utilizes …

Comparison Of Modified Formalism Output And Trs-398 Absorbed Dose To Water In Electron Beams Reference Dosimetry In Multiple Radiotherapy Centers, Yasumon Thinka

Chulalongkorn University Theses and Dissertations (Chula ETD)

The study aimed to investigate the feasibility and efficacy of utilizing modified calibration with cylindrical chambers for reference dosimetry in electron beam radiotherapy, challenging the recommendation of using plane-parallel chambers in low-energy electron beams by IAEA's TRS-398 and AAPM's TG-51 standards. Data collection involved six radiotherapy centers in Bangkok using Varian linear accelerators, with chambers including the IBA FC65-G, PTW 30013 cylindrical chambers, and PPC40, Roos plane-parallel chambers. Results of dose comparison between modified and TRS-398 protocols fell within ±2%. For low-energy electron beams, percent dose discrepancies ranged from -1.57% to 0.91%, and from -0.37% to 0.91% for high-energy. The …

Characteristics Of Two-Dimensional Ionization Chamber Array For Patient-Specific Quality Assurance In Pencil Beam Scanning Proton Therapy, Nuttida Rawiwan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Proton therapy is an advanced technique that uses positive particles in external treatment. It can spare normal tissue and increase tumor control probability. In radiotherapy, patient-specific quality assurance is an important part, but according to protons’ characteristics, especially finite range, it is challenging to do verification because when the density has changed the finite range will have drastic changes. Although the two-dimensional ionization chamber array is used for patient-specific quality assurance in pencil beam scanning proton therapy, most studies investigate the IBA MatriXX as the dosimetry device, and few studies explored the PTW OCTAVIUS 1500XDR. This research aims to determine …

Determination Of The Surface Dose Correction Factors For Various Detectors In Proton Scanning Therapy, Pakjira Saruang

Chulalongkorn University Theses and Dissertations (Chula ETD)

Proton therapy delivers tumors doses precisely but concerns about skin toxicity due to energy dispersion beyond the Bragg peak remain. Accurate surface dose measurement is crucial for calculating the radiation dose patients receive. Studying factors that improve measurement accuracy is essential, as current methods are challenging and often inaccurate. This research aims to determine the surface dose correction factors (Scf) for various detectors in spot scanning beam proton therapy and study the effect of surface dose according to various clinical factors. The PTW Advanced Markus, PTW Roos chamber and IBA FC65-G Farmer chamber were utilized to measure the surface dose …