Radiology Commons^™

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 Mesh Characteristics In Mesh-Based Phase Imaging, Desiree Caryl D'Moore

Legacy Theses & Dissertations (2009 - 2024)

Mammographic screening has played a pivotal role in reducing mortality rates associated with breast cancer. Despite an overall decline of breast cancer death rates of 43% from 1989 through 2020, breast cancer remains a predominant form of invasive cancer among women. Conventional X-ray imaging used in mammography can yield limited contrast when it comes to substances with similar X-ray attenuation, such as that between benign and cancerous tissue. Mesh-based X-ray phase imaging allows for higher contrast and resolution in similar-density materials. This thesis aims to explore characteristics of the mesh used in this kind of system.To investigate the significance of …

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 …

Standard Deviations Of Mr Signal Intensities Show A Consistent Trend During Imaging Follow-Ups For Glioblastoma Patients When Corrected For Non-Biological Heterogeneity Due To Hardware And Software Variation, Subhendra N. Sarkar, Rafael Rojas, Evans Lespinasse, Xiangfu Zhang, Ruth Zeron

Publications and Research

Introduction

Glioblastoma multiforme (GBM) has a poor prognosis in spite of advanced MRI guided treatments today. Routine MRI using conventional T₁ or advanced permeability based MRI of GBM often does not adequately represent changing tumor phases or overall survival. In this work, region of interest (ROI) based tissue MR standard deviation (SD) is demonstrated as an important MRI variable that could be a potential biomarker of GBM heterogeneity and radioresistance.

Materials and methods

MRI characterization is often qualitative and lacks reproducibility. Using standardized MRI phantoms we have normalized retrospective records of 12 radioresistant GBM patients that underwent radiation therapy …

Prevalence And Clinical Significance Of Unsuspected Intracranial Findings In Patients Undergoing Oncological Whole Body 18f- Fluorodeoxyglucose (Fdg) Pet Ct Imaging., Diana Kerubo Nyamieri

Master of Medicine in Imaging and Diagnostic Radiology

Background: 18F –fluoro-2-deoxyglucose (18F-FDG PET), an imaging modality that provides metabolic information of cancers, is integral in the diagnostic workup of many malignancies. Most oncological FDG PET scans are acquired from the base of the skull to the upper thighs, as lesions that take up FDG are usually within this field of view. Routine inclusion of brain within the field of view of all oncological 18FDG PET/CT studies leads to increase of both time of acquisition and radiation dose (albeit marginal) delivered by the CT component of the study, therefore one can debate if addition brain in oncological 18FDG PET-CT …

Effect Of Aromatase Inhibitors On Bone Mineral Density In Black African Women With Breast Cancer, Dayib Said Buthul

Master of Medicine in Imaging and Diagnostic Radiology

Introduction: Aromatase inhibitors (AIs) are a commonly used type of endocrine therapy for post-menopausal women with breast cancer. In clinical trials with a predominant Caucasian population, it has been shown to cause reduction in bone mineral density of up to 1.5% and 3.2% in total hip and 2.6% and 4% in lumbar spine after 1 and 2 years of AI therapy respectively. Previous studies have shown that black women tend to have higher bone mineral density reserve compared to Caucasians. To the best of our knowledge no study has described the effect of AIs on bone mineral density in black …

A Comparison Of Robotically Assisted Needle Guidance Via The Piga Ct System And Conventional Ct For Percutaneous Lung Biopsies, Virender Malik, K Uday Bhanu, Dhanalakshmi B

Journal of Medicine in Scientific Research

Objective

The aim was to compare the speed, radiation exposure, needle adjustments, diagnostic efficacy, and complication rate using manual guidance and robotically assisted needle guidance via the PIGA computed tomography (CT) system for percutaneous lung biopsy.

Methods

A randomized interventional trial was conducted from September 2020 to March 2021 on 30 patients requiring lung biopsies for suspected malignancy. Random allocation of the 30 patients was done in group A (robot-assisted CT scan) and group B (conventional manual CT scan). The outcomes were compared with respect to the total procedural duration, time taken in the navigation of needle insertion, needle manipulations, …

Predictive Digital Twin For Optimizing Patient-Specific Radiotherapy Regimens Under Uncertainty In High-Grade Gliomas, Anirban Chaudhuri, Graham Pash, David A Hormuth, Guillermo Lorenzo, Michael Kapteyn, Chengyue Wu, Ernesto A B F Lima, Thomas E Yankeelov, Karen Willcox

Faculty, Staff and Student Publications

We develop a methodology to create data-driven predictive digital twins for optimal risk-aware clinical decision-making. We illustrate the methodology as an enabler for an anticipatory personalized treatment that accounts for uncertainties in the underlying tumor biology in high-grade gliomas, where heterogeneity in the response to standard-of-care (SOC) radiotherapy contributes to sub-optimal patient outcomes. The digital twin is initialized through prior distributions derived from population-level clinical data in the literature for a mechanistic model's parameters. Then the digital twin is personalized using Bayesian model calibration for assimilating patient-specific magnetic resonance imaging data. The calibrated digital twin is used to propose optimal …

Head And Neck Radiation Therapy Patterns Of Practice Variability Identified As A Challenge To Real-World Big Data: Results From The Learning From Analysis Of Multicentre Big Data Aggregation (Lambda) Consortium, Amanda Caissie, Michelle Mierzwa, Clifton David Fuller, Murali Rajaraman, Alex Lin, Andrew Macdonald, Richard Popple, Ying Xiao, Lisanne Vandijk, Peter Balter, Helen Fong, Heping Xu, Matthew Kovoor, Joonsang Lee, Arvind Rao, Mary Martel, Reid Thompson, Brandon Merz, John Yao, Charles Mayo

Faculty, Staff and Student Publications

PURPOSE: Outside of randomized clinical trials, it is difficult to develop clinically relevant evidence-based recommendations for radiation therapy (RT) practice guidelines owing to lack of comprehensive real-world data. To address this knowledge gap, we formed the Learning from Analysis of Multicenter Big Data Aggregation consortium to cooperatively implement RT data standardization, develop software solutions for data analysis, and recommend clinical practice change based on real-world data analyzed. The first phase of this "Big Data" study aimed at characterizing variability in clinical practice patterns of dosimetric data for organs at risk (OARs) that would undermine subsequent use of large-scale, electronically aggregated …

Dose Escalation For Pancreas Sbrt: Potential And Limitations Of Using Daily Online Adaptive Radiation Therapy And An Iterative Isotoxicity Automated Planning Approach, Dong Joo Rhee, Sam Beddar, Joseph Abi Jaoude, Gabriel Sawakuchi, Rachael Martin, Luis Perles, Cenji Yu, Yulun He, Laurence E Court, Ethan B Ludmir, Albert C Koong, Prajnan Das, Eugene J Koay, Cullen Taniguichi, Joshua S Niedzielski

Faculty, Staff and Student Publications

PURPOSE: To determine the dosimetric limitations of daily online adaptive pancreas stereotactic body radiation treatment by using an automated dose escalation approach.

METHODS AND MATERIALS: We collected 108 planning and daily computed tomography (CT) scans from 18 patients (18 patients × 6 CT scans) who received 5-fraction pancreas stereotactic body radiation treatment at MD Anderson Cancer Center. Dose metrics from the original non-dose-escalated clinical plan (non-DE), the dose-escalated plan created on the original planning CT (DE-ORI), and the dose-escalated plan created on daily adaptive radiation therapy CT (DE-ART) were analyzed. We developed a dose-escalation planning algorithm within the radiation treatment …

Oncology-Specific Radiation Dose And Image Noise Reference Levels In Adult Abdominal-Pelvic Ct, Moiz Ahmad, Xinming Liu, Ajaykumar C Morani, Dhakshinamoorthy Ganeshan, Marcus R Anderson, Ehsan Samei, Corey T Jensen

Faculty, Staff and Student Publications

OBJECTIVES: To provide our oncology-specific adult abdominal-pelvic CT reference levels for image noise and radiation dose from a high-volume, oncologic, tertiary referral center.

METHODS: The portal venous phase abdomen-pelvis acquisition was assessed for image noise and radiation dose in 13,320 contrast-enhanced CT examinations. Patient size (effective diameter) and radiation dose (CTDI

RESULTS: The noise reference level was 11.25 HU with a reference range of 10.25-12.25 HU. The dose reference level at a median effective diameter of 30.7 cm was 26.7 mGy with a reference range of 19.6-37.0 mGy. Dose increased with patient size; however, image noise remained approximately constant within …

Advances In The Management Of Spinal Metastases: What The Radiologist Needs To Know, Sarah M Bahouth, Debra N Yeboa, Amol J Ghia, Claudio E Tatsui, Christopher A Alvarez-Breckenridge, Thomas H Beckham, Andrew J Bishop, Jing Li, Mary Frances Mcaleer, Robert Y North, Laurence D Rhines, Todd A Swanson, Wang Chenyang, Behrang Amini

Faculty, Staff and Student Publications

Spine is the most frequently involved site of osseous metastases. With improved disease-specific survival in patients with Stage IV cancer, durability of local disease control has become an important goal for treatment of spinal metastases. Herein, we review the multidisciplinary management of spine metastases, including conventional external beam radiation therapy, spine stereotactic radiosurgery, and minimally invasive and open surgical treatment options. We also present a simplified framework for management of spinal metastases used at The University of Texas MD Anderson Cancer Center, focusing on the important decision points where the radiologist can contribute.

Verification Of Proton Range Predictions In Proton Treatment Planning Using X-Ray Ct Or Proton Ct Imaging, Nicholas S. Yee

Graduate Research Theses & Dissertations

The objective of this paper is to compare the range errors for two treatment plans; one using x-ray CT and the other using proton CT for calculating dose distributions in an animal tissue phantom. We shot 150 MeV proton beam through a meat phantom to a film stack to measure the exponential drop of dose at the Bragg peak until zero dose remained. Plotting the depth dose curves and performing gamma analyses are two ways to quantify the proton range errors when comparing them to depth dose curves from film measurements in the phantom. The depth dose curves give us …

Uncovering The Role Of Fat-Infiltrated Axillary Lymph Nodes In Obesity-Related Diseases With Statistical And Machine Learning Analyses, Qingyuan Song

Dartmouth College Ph.D Dissertations

The link between obesity and pathogenesis is a complex and multifaceted area of research that is yet to be fully understood. Ample evidence exists to demonstrate the direct relationship between excessive internal fat and various health conditions such as cancer, and metabolic and cardiovascular diseases. The infiltration of ectopic fat into axillary lymph nodes, observable on breast cancer screening images, has been shown to be correlated with body mass index (BMI) in women undergoing screening. This study aimed to explore the relationship between fat-infiltrated axillary lymph nodes (FIN) and obesity-related diseases, with the goal of evaluating the clinical value of …

Diagnostic Dilemma: Schwannoma Or Ganglion Cyst, Karthik Ks, Prakash M, Gurumurthy B, Sujanatheja Js, Pramod Bm, Punith N

Digital Journal of Clinical Medicine

Schwannomas are rare, slow growing benign tumors of peripheral nerve sheath originating from Schwann cells surrounding the nerve associated with delayed presentation of pain and paresthesia. Their incidence being 5% of all upper extremity tumors. They may be a part of neurofibromatosis called schwannomatosis with multiple peripheral schwannomas. We present a case of solitary schwannomas from the peripheral nerves probably superficial branch of median nerve mistaken initially for ganglion cyst.

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 …

Association Of The Bb Genotype Of The Abo Gene With The Risk Of Acute Myocardial Infarction In Hospital-Based Study, Farzana Abubakar Yousuf, Iqbal Azam Syed, Asal Khan Tareen, Khawar A. Kazmi, Jibran Sualeh Muhammad, Mohammad Perwaiz Iqbal

Department of Biological & Biomedical Sciences

Objectives: The ABO gene locus has been identified to be associated with myocardial infarction in patients with coronary heart disease. The primary focus of this hospital-based study was to explore the relationship of ABO blood groups and ABO genotypes with acute myocardial infarction (AMI) in Karachi, Pakistan.
Methods: In a comparative cross-sectional study, an equal number of adult AMI patients and healthy controls (n=275 in each group; age range 30-70 years, both males and females) were recruited from the Aga Khan University and NICVD, Karachi, with informed consent. The blood samples were analyzed for ABO blood groups and other biomarkers. …

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 …

Alignment And Range Verification In Proton Therapy Using Proton Radiography And Proton Ct, Joseph Piet

Graduate Research Theses & Dissertations

Protons are used in radiation therapy to lower doses to healthy tissues by utilizing their Bragg peak. Protons can be used both in imaging and treatment. One of the uses of protons in imaging we tested is its use to align patients using a single beam's eye proton radiograph (pRad). By using a beam's eye pRad, and comparing the water equivalent thickness (WET) to proton digitally reconstructed radiographs (pDRRs), we show that we can measure the best alignment on six axes, three translational and three rotational. This is done by defining a cost function, chi squared, which quantifies the misalignment …