Radiation Medicine Commons^™

Mri-Based Radiomics Model From Mesorectal Fat To Predict Perirectal Lymph Node Status And Extramural Venous Invasion In Colorectal Cancer Patients, Yaniga Swaengdee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Colorectal cancer (CRC) is the third most common cancer worldwide and the incidence rate is rising in Asia. Perirectal lymph node metastasis (PLN) and extramural venous invasion (EMVI) are common and associated with poor prognosis in CRC patients. While total mesorectal excision is the gold standard for confirming PLN and EMVI, MRI is keys modality for staging. Radiomics, a technique that extracts quantitative features from medical images, allows for the development of predictive models for PLN and EMVI. This study aimed to build and evaluate a predictive model based on mesorectal fat radiomics from MRI images to improve PLN and …

Varian Halcyon Cone Beam Computed Tomography Dose Measurement By Radiophotoluminescent Glass Dosimeter, Kantida Jittrakool

Chulalongkorn University Theses and Dissertations (Chula ETD)

Cone beam computed tomography (CBCT) is widely used as the primary imaging method in image-guided radiation therapy. The Varian Halcyon system (Varian Medical Systems, Palo Alto, CA, USA) requires daily imaging prior to each patient’s treatment. This study focuses on comparing the radiation doses to normal organs across all available kV-CBCT protocols on the Varian Halcyon system. Radiophotoluminescent glass dosimeters (RPLGD) were used to measure doses, placed inside an Alderson Rando phantom positioned at specific anatomical sites including the head, thorax, breast, and pelvis. CBCT scans were performed using preset protocols, with no modifications to parameters. The average organ dose …

Dosimetric Comparison Between Volumetric Modulated Arc Therapy On Truebeam And Halcyon Of Boost Plan For Total Body Irradiation, Wanwanut Jaihow

Chulalongkorn University Theses and Dissertations (Chula ETD)

Total Body Irradiation (TBI) is a special treatment technique aimed at immunosuppression. The purpose of this study was to compare the dosimetric results of volumetric modulated arc therapy (VMAT) plans of TBI treatment between TrueBeam and Halcyon treatment machines. Eight TBI patients were planned by 6 MV of two lateral opposing with extended SAD technique to 5 meters to receive the prescribed dose of 1200 cGy in 6 fractions at head and legs. A single fraction boosts up the dose ranging from shoulder to mid-thigh. Plans were optimized and calculated in the Eclipse treatment planning system using VMAT by TrueBeam …

Local Diagnostic Reference Level At Nuclear Medicine Centers In Thailand And Myanmar, Yin Moe Aye

Chulalongkorn University Theses and Dissertations (Chula ETD)

Diagnostic reference level (DRL) has been an effective and practical tool in the optimization of radiation protection in medical exposure to patients. Local DRL represents the median value, or 50th percentile, of the quantity distribution of common nuclear medicine examinations. This study aims to establish LDRL at NM centers in Thailand and Myanmar. Methods: The demographic data of adult patients with body weight 45-75kg, radiation metric parameters including radiopharmaceutical administered activity (MBq), Volumetric CT dose index (CTDIvol, mGy), dose length product (DLP, mGy. cm), and scan length (cm), of SPECT, SPECT/CT, and PET/CT imaging were retrospectively collected from January 2023 …

Evaluating Dosimetric Accuracy Of Aaa And Axb Algorithms In Lung Stereotactic Body Radiation Therapy, May Thu Htet

Chulalongkorn University Theses and Dissertations (Chula ETD)

The accuracy of dose calculation in heterogeneous media is heavily influenced by the choice of dose calculation algorithm. This study aimed to compare the dosimetric performance of the Anisotropic Analytical Algorithm (AAA) and Acuros XB (AXB) in stereotactic body radiotherapy (SBRT) for lung cancer. Twenty-four lung cancer patients were divided into two groups: free breathing (FB) and deep inspiration breath hold (DIBH). For each patient, three half-arc volumetric modulated arc therapy (VMAT) plans were generated using 6 MV flattening filter-free (FFF) beams, prescribing 50 Gy in five fractions to the planning target volume (PTV), using the Eclipse Treatment Planning System. …

Tumor Prognosis In Nasopharyngeal Carcinoma Using Deep Transfer Learning With Radimagenet From Ct Images, Parida Petiraksakul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Nasopharyngeal carcinoma (NPC) is a common malignant tumor in Southeast Asia. It is characterized by complex anatomical features and aggressive behavior. Accurate prognosis prediction plays a crucial role in the optimization of treatment strategies and improvement of patient outcomes. Although recent advances in deep learning, particularly convolutional neural networks (CNNs), have demonstrated promising results in medical image analysis, the limited availability of annotated medical imaging datasets remains a significant challenge. Transfer learning (TL), particularly using domain-specific pretrained datasets, such as RadImageNet, offers a practical solution to this limitation. This study aimed to evaluate the effectiveness of deep transfer learning models …

Cbct Perceptions Of Radiology Leaders In The Midwest Dental Schools: A Qualitative Study, Tenzin Dadul

Dissertations

Problem

The integration of Cone Beam Computed Tomography (CBCT) in dental education is hindered by a lack of formal training among radiology leaders, insufficient institutional support, and financial constraints. Despite the proven efficacy of CBCT in enhancing diagnostic accuracy and treatment planning, its adoption in pre-doctoral curricula remains limited. This gap in education poses significant challenges for dental graduates, who are increasingly expected to utilize advanced imaging technologies in clinical practice.

Purpose of Study

This qualitative study aimed to explore the perceptions of radiology leaders in Midwest dental schools regarding the integration of CBCT education into pre-doctoral curricula. The objectives …

Developing Radiosensitizers To Enhance Radiotherapy In Treating Gastroenteropancreatic Neuroendocrine Tumor, Zeta Chow

Theses and Dissertations--Clinical and Translational Science

Gastroenteropancreatic Neuroendocrine Tumor (GEP-NET) is a heterogeneous group of malignancies arising from multipotent neuroendocrine stem cells in the gastrointestinal tract. The incidence of GEP-NET continues to rise, possibly due to the advancement of imaging and biomarkers available for diagnosis. However, even though the majority of patients are diagnosed with low-grade and localized disease, a significant percentage of patients present with advanced-stage metastatic disease with poor prognosis in months to a few years. These advanced-stage GEP-NET patients can also present with a variety of debilitating symptoms that significantly impact their quality of life. The role of palliative-intent surgery is limited, and …

Evidence Of Direct Interaction Between Cisplatin And The Caspase-Cleaved Prostate Apoptosis Response-4 Tumor Suppressor, Krishna K. Raut, Samjhana Pandey, Gyanendra Kharel, Steven M. Pascal

Chemistry & Biochemistry Faculty Publications

Prostate apoptosis response-4 (Par-4) tumor suppressor protein has gained attention as a potential therapeutic target owing to its unique ability to selectively induce apoptosis in cancer cells, sensitize them to chemotherapy and radiotherapy, and mitigate drug resistance. It has recently been reported that Par-4 interacts synergistically with cisplatin, a widely used anticancer drug. However, the mechanistic details underlying this relationship remain elusive. In this investigation, we employed an array of biophysical techniques, including circular dichroism spectroscopy, dynamic light scattering, and UV–vis absorption spectroscopy, to characterize the interaction between the active caspase-cleaved Par-4 (cl-Par-4) fragment and cisplatin. Additionally, elemental analysis was …

Racial Disparities In Thoracic Aortic Surgery: Myth Or Reality?, Ourania Preventza, Elizabeth Akpan-Smart, Khan Lubna, Katherine Simpson, Lorraine Cornwell, Sydney Schmitt, Hiruni S Amarasekara, Scott A Lemaire, Joseph S Coselli

Faculty, Staff and Students Publications

Objective: We examined the relationship between Black or White race and adverse outcomes in patients who underwent surgery of the ascending aorta, aortic root, or aortic arch at our center.

Methods: We analyzed 2335 consecutive patients who identified as Black (n = 217, 9.3%) or White (n = 2118, 90.7%) and underwent proximal aortic surgery. Patient zip codes were used to determine community socioeconomic (CSE) characteristics. The composite adverse outcome comprised mortality, persistent neurologic injury, and renal failure necessitating dialysis at discharge. We performed multivariable analysis, Kaplan-Meier analysis, and propensity score matching adjusted for CSE factors.

Results: Median follow-up time …

Prediction The Dose Distributions Of Prostate Cancer Patients Using Deep Learning, Pumipat Chaikamthorn

Chulalongkorn University Theses and Dissertations (Chula ETD)

Volumetric Modulated Arc Therapy (VMAT) is one of the advanced modalities in recent radiotherapy. It uses the inverse treatment planning system for optimization and dose calculation. However, this approach is a trial-and-error process, which takes a long time. An accurate deep-learning model that can predict the dose would solve this issue. This approach can save more treatment planning time, by guiding the planners to the optimum dose while maintaining the plan quality. The 40 previously treated prostate cancer plans were collected the volumetric information of PTV and OARs, overlapping volume, and the dosimetric information. The regression deep learning model, which …

Optimal Dual-Time-Point Dynamic 68ga-Psma-11 Pet/Ct Protocols For Parametric Imaging Generation In Prostate Cancer Patients, Paphawarin Burasothikul

Chulalongkorn University Theses and Dissertations (Chula ETD)

Globally, prostate cancer is the second most common cancer for men. Prostate cancer patients presenting metastasis exhibit a poor prognosis, consequently leading to diminished survival rates. Thus, 68Ga-PSMA-11 PET/CT examination plays a critical role in prostate cancer diagnosis. Parametric imaging techniques offer the potential to improve the accuracy of quantification analysis in PET/CT diagnosis, but their effectiveness is constrained by lengthy acquisition protocols. This study developed optimal dual-time-point (DTP) parametric imaging using shortened dynamic 68Ga-PSMA-11 PET/CT scans in prostate cancer patients and investigated the feasibility of parametric images in terms of image quality by comparing them with a routine standardized …

Reporting Quality Of Endoscopic Colorectal Cancer Screening Randomized Controlled Trials: Adherence To Recommendations And Interventions, Fouad Jaber, Khalid Ahmed, Osama Hamid, Willie Mohammed Johnson, Saqr Alsakarneh, Abubaker O Abdalla, Yazan Abboud, Mouhand Mohamed, Dushyant Singh Dahiya, Shifa Umar, Mohamed Abdallah, Mohammad Bilal, Aasma Shaukat

Faculty, Staff and Student Publications

BACKGROUND AND AIMS: In 2013, the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) steering group published recommendations to standardize reporting quality in randomized controlled trials (RCTs). We aim to assess adherence to SPIRIT reporting guidelines in RCTs on endoscopic colorectal cancer (CRC) screening and participants' adherence to trial protocols.

METHODS: We searched databases for RCTs evaluating flexible sigmoidoscopy or colonoscopy for CRC screening published in English language through September 2023. Each eligible study was evaluated using the 8 core SPIRIT statement areas, totaling 51 points. Each item received 1 point if it met the criteria and 0 points if …

Clinical Acceptability Of Automatically Generated Lymph Node Levels And Structures Of Deglutition And Mastication For Head And Neck Radiation Therapy, Sean Maroongroge, Abdallah Sr Mohamed, Callistus Nguyen, Jean Guma De La Vega, Steven J Frank, Adam S Garden, Brandon G Gunn, Anna Lee, Lauren Mayo, Amy Moreno, William H Morrison, Jack Phan, Michael T Spiotto, Laurence E Court, Clifton D Fuller, David I Rosenthal, Tucker J Netherton

Faculty, Staff and Student Publications

BACKGROUND AND PURPOSE: Auto-contouring of complex anatomy in computed tomography (CT) scans is a highly anticipated solution to many problems in radiotherapy. In this study, artificial intelligence (AI)-based auto-contouring models were clinically validated for lymph node levels and structures of swallowing and chewing in the head and neck.

MATERIALS AND METHODS: CT scans of 145 head and neck radiotherapy patients were retrospectively curated. One cohort (n = 47) was used to analyze seven lymph node levels and the other (n = 98) used to analyze 17 swallowing and chewing structures. Separate nnUnet models were trained and validated using the separate …

A Look-Up-Table Development To Facilitate Ct Simulation Of Mr-Linac Treatment, Neil Hughes, Travis C Salzillo, Sastry Vedam, Tze Yee Lim, Xin Wang, He Wang, Mustefa Mohammedsaid, Clifton D Fuller, Jihong Wang, Jinzhong Yang

Faculty, Staff and Student Publications

While current MR-Linac (MRL) treatment workflows utilize a large table overlay during CT simulation to convert indexing between the two machines, we developed a look-up-table (LUT) as an alternative approach. After populating the LUT, index conversion factors were verified at three separate table locations. The resultant root-mean-square isocenter shifts on the MRL were 0.04/0.08 cm, 0.08/0.07 cm, and 0.09/0.08 cm with/without using the table overlay during simulation in the lateral, longitudinal, and vertical directions, respectively, which is within registration tolerance. Clinical implementation of the LUT has resulted in a more efficient MRL treatment workflow while maintaining accurate patient setup.

Harnessing Uncertainty In Radiotherapy Auto-Segmentation Quality Assurance, Kareem A Wahid, Jaakko Sahlsten, Joel Jaskari, Michael J Dohopolski, Kimmo Kaski, Renjie He, Enrico Glerean, Benjamin H Kann, Antti Mäkitie, Clifton D Fuller, Mohamed A Naser, David Fuentes

Faculty, Staff and Student Publications

One of the key contributions of this study is the reappropriation of standard DL outputs as a quality indicator to identify cases that clinicians should review further. The authors achieve this by applying an empirically derived threshold to the softmax output of their DL network, computing the mean of the thresholded score map (termed the HiS metric), and correlating it with standard geometric quality indices. When juxtaposed with a mean entropy — a commonly used measure of model output uncertainty — HiS consistently demonstrated a stronger correlation with the geometric indices, suggesting its superior ability to stratify cases needing additional …

Comparative Analysis Of Rectum Delineation: Inter-Observer Agreement Among Treatment Planners Versus Auto Segmentation In A Single Institution, Haley Douglas

Masters Projects

Abstract

Introduction

The past 20 years have seen a continuous rise in the cancer patient population, resulting in staffing shortages, longer wait times for patients, and potentially lower-quality care. Artificial intelligence has been incorporated into the healthcare system and has provided ease with understaffing. Using AI technology to delineate structures can reduce planning time and variation between planners. The objective of this research is to assess the level of consistency in the rectum boundary delineation performed by different dosimetrists working at a single institution, as compared to the performance of the AutoContour software. This analysis will help determine the efficacy …

Stereotactic Mr-Guided On-Table Adaptive Radiation Therapy (Smart) For Borderline Resectable And Locally Advanced Pancreatic Cancer: A Multi-Center, Open-Label Phase 2 Study, Michael Chuong, Percy Lee, Daniel Low, Joshua Kim, Kathryn Mittauer, Michael Bassetti, Carri Glide-Hurst, Ann Raldow, Yingli Yang, Lorraine Portelance, Kyle Padgett, Bassem Zaki, Rongxiao Zhang, Hyun Kim, Lauren Henke, Alex Price, Joseph Mancias, Christopher Williams, John Ng, Ryan Pennell, M Raphael Pfeffer, Daphne Levin, Adam Mueller, Karen Mooney, Patrick Kelly, Amish Shah, Luca Boldrini, Lorenzo Placidi, Martin Fuss, Parag Jitendra Parikh

Department of Radiation Oncology Faculty Papers

BACKGROUND AND PURPOSE: Radiation dose escalation may improve local control (LC) and overall survival (OS) in select pancreatic ductal adenocarcinoma (PDAC) patients. We prospectively evaluated the safety and efficacy of ablative stereotactic magnetic resonance (MR)-guided adaptive radiation therapy (SMART) for borderline resectable (BRPC) and locally advanced pancreas cancer (LAPC). The primary endpoint of acute grade ≥ 3 gastrointestinal (GI) toxicity definitely related to SMART was previously published with median follow-up (FU) 8.8 months from SMART. We now present more mature outcomes including OS and late toxicity.

MATERIALS AND METHODS: This prospective, multi-center, single-arm open-label phase 2 trial (NCT03621644) enrolled 136 …

Identification Of Ct-Based Non-Invasive Radiomic Biomarkers For Overall Survival Prediction In Oral Cavity Squamous Cell Carcinoma, Xiao Ling, Gregory S. Alexander, Jason Molitoris, Jinhyuk Choi, Lisa Schumaker, Ranee Mehra, Daria A. Gaykalova, Lei Ren

Department of Radiation Oncology Faculty Papers

This study addresses the limited non-invasive tools for Oral Cavity Squamous Cell Carcinoma (OSCC) survival prediction by identifying Computed Tomography (CT)-based biomarkers to improve prognosis prediction. A retrospective analysis was conducted on data from 149 OSCC patients, including CT radiomics and clinical information. An ensemble approach involving correlation analysis, score screening, and the Sparse-L1 algorithm was used to select functional features, which were then used to build Cox Proportional Hazards models (CPH). Our CPH achieved a 0.70 concordance index in testing. The model identified two CT-based radiomics features, Gradient-Neighboring-Gray-Tone-Difference-Matrix-Strength (GNS) and normalized-Wavelet-LLL-Gray-Level-Dependence-Matrix-Large-Dependence-High-Gray-Level-Emphasis (HLE), as well as stage and alcohol usage, …

Targeted Gene Expression Profiling Predicts Meningioma Outcomes And Radiotherapy Responses, William C Chen, Abrar Choudhury, Mark W Youngblood, Mei-Yin C Polley, Calixto-Hope G Lucas, Kanish Mirchia, Sybren L N Maas, Abigail K Suwala, Minhee Won, James C Bayley, Akdes S Harmanci, Arif O Harmanci, Tiemo J Klisch, Minh P Nguyen, Harish N Vasudevan, Kathleen Mccortney, Theresa J Yu, Varun Bhave, Tai-Chung Lam, Jenny Kan-Suen Pu, Lai-Fung Li, Gilberto Ka-Kit Leung, Jason W Chan, Haley K Perlow, Joshua D Palmer, Christine Haberler, Anna S Berghoff, Matthias Preusser, Theodore P Nicolaides, Christian Mawrin, Sameer Agnihotri, Adam Resnick, Brian R Rood, Jessica Chew, Jacob S Young, Lauren Boreta, Steve E Braunstein, Jessica Schulte, Nicholas Butowski, Sandro Santagata, David Spetzler, Nancy Ann Oberheim Bush, Javier E Villanueva-Meyer, James P Chandler, David A Solomon, C Leland Rogers, Stephanie L Pugh, Minesh P Mehta, Penny K Sneed, Mitchel S Berger, Craig M Horbinski, Michael W Mcdermott, Arie Perry, Wenya Linda Bi, Akash J Patel, Felix Sahm, Stephen T Magill, David R Raleigh

Faculty, Staff and Student Publications

Surgery is the mainstay of treatment for meningioma, the most common primary intracranial tumor, but improvements in meningioma risk stratification are needed and indications for postoperative radiotherapy are controversial. Here we develop a targeted gene expression biomarker that predicts meningioma outcomes and radiotherapy responses. Using a discovery cohort of 173 meningiomas, we developed a 34-gene expression risk score and performed clinical and analytical validation of this biomarker on independent meningiomas from 12 institutions across 3 continents (N = 1,856), including 103 meningiomas from a prospective clinical trial. The gene expression biomarker improved discrimination of outcomes compared with all other systems …