Radiology Commons^™

Determination Of Field Output Correction Factors Of Radiophoto Luminescent Glass Dosimeter In 6 Mv Small Photon Beams, Sumalee Yabsantia

Chulalongkorn University Theses and Dissertations (Chula ETD)

The objective of this study was to determine the field output correction factors of radiophotoluminescent glass dosimeter (RPLGD) for 6 MV photon beams by using Monte Carlo (MC) simulation. The ratios of absorbed dose of water and RPLGD were calculated using egs_chamber code for 6 MV, 90-cm SSD, 10-cm depth, and field size range from 0.5 × 0.5 to 10 × 10 cm2. Then the field output correction factors of RPLGD in perpendicular and parallel orientations were determined. Also, the volume averaging correction factors were discovered for supporting our results. Moreover, the comparison of measurement field output factors of RPLGD …

Patient-Specific Organ Dose Calculated By Dose Tracking Software Based On Monte Carlo Simulation In Pediatric Abdominal Ct, Yuparak Innan

Chulalongkorn University Theses and Dissertations (Chula ETD)

This study aimed to determine the patient-specific organ doses using Radimetrics dose tracking software in pediatric abdominal CT at Praram9 Hospital. The organ doses were measured using the anthropomorphic Rando phantom inserted with radiophotoluminescent glass dosimeters (RPLGDs) to verify the organ doses calculated by Radimetrics program. The retrospective data were collected from pediatric abdominal CT 164 studies (78 patients), age range 0-15 years-old), who underwent single phase abdominal CT at Praram9 Hospital. The tube voltages ranged between 80 and 135 kVp were adjusted according to the size and age of patients, and rotation time 0.35-0.5 sec. All patients were acquired …

The Study Of Local Diagnostic Reference Levels At Unit Of Vascular And Interventional Radiology, King Chulalongkorn Memorial Hospital, Kornkamol Prajamchuea

Chulalongkorn University Theses and Dissertations (Chula ETD)

Interventional Radiology (IR) procedures are minimally invasive surgery using angiographic equipment which the patients and staffs may receive high radiation dose. DRLs, based on 75th percentile of the median dose for a sample of standard sized of patients, are an effective tool for optimization of protection in the medical exposure of patients for diagnostic and interventional procedures (ICRP Publication 135, 2017). The objective of this study is to establish the local DRLs distribution of patient radiation dose and related parameters in interventional radiology procedures in standard-sized of Thai patients. Local DRLs of radiation dose and related parameters of patients (45-75kg …

Evaluation Of Patient Doses From 177lu-Psma In Metastases Prostate Cancer Treatment At King Chulalongkorn Memorial Hospital, Kotchakorn Chatachot

Chulalongkorn University Theses and Dissertations (Chula ETD)

177Lu-PSMA I&T has increasingly used for targeted radionuclide therapy of metastatic castration-resistant prostate cancer (mCRPC). Dosimetric calculation, therefore, is critical to achieve the optimal therapeutic activity while sparing side effects to the normal tissues. The purpose of this study was to determine the radiation dosimetry for metastases prostate cancer patients treated by 177Lu-PSMA I&T at King Chulalongkorn Memorial Hospital (KCMH). Whole-body planar images were acquired in eight patients (12 treatment cycles) at immediately, 4 and 24 h after 177Lu-PSMA I&T injection (range 4.36 to 8.58 GBq). Region of interests (ROIs) were manually contoured on the whole-body, liver, spleen, urinary bladder, …

Synthesis Of Radioluminescent Caf2:Ln Core, Mesoporous Silica Shell Nanoparticles For Use In X-Ray Based Theranostics, Hayden Winter, Megan J. Neufeld, Lydia Makotamo, Conroy Sun, Andrea M. Goforth

Chemistry Faculty Publications and Presentations

X-ray radiotherapy is a common method of treating cancerous tumors or other malignant lesions. The side effects of this treatment, however, can be deleterious to patient quality of life if critical tissues are affected. To potentially lower the effective doses of radiation and negative side-effects, new classes of nanoparticles are being developed to enhance reactive oxygen species production during irradiation. This report presents the synthesis and radiotherapeutic efficacy evaluation of a new nanoparticle formulation designed for this purpose, composed of a CaF₂ core, mesoporous silica shell, and polyethylene glycol coating. The construct was additionally doped with Tb and Eu …

Intervention For Cognitive Reserve Enhancement In Delaying The Onset Of Alzheimer's Symptomatic Expression (Increase), A Randomized Controlled Trial: Rationale, Study Design, And Protocol, Daniela C. Moga, Brooke F. Beech, Erin L. Abner, Frederick A. Schmitt, Riham H. El Khouli, Ashley I. Martinez, Lynne Eckmann, Mark Huffmyer, Rosmy George, Gregory A. Jicha

Pharmacy Practice and Science Faculty Publications

BACKGROUND: The course of Alzheimer's disease (AD) includes a 10-20-year preclinical period with progressive accumulation of amyloid β (Aβ) plaques and neurofibrillary tangles in the absence of symptomatic cognitive or functional decline. The duration of this preclinical stage in part depends on the rate of pathologic progression, which is offset by compensatory mechanisms, referred to as cognitive reserve (CR). Comorbid medical conditions, psychosocial stressors, and inappropriate medication use may lower CR, hastening the onset of symptomatic AD. Here, we describe a randomized controlled trial (RCT) designed to test the efficacy of a medication therapy management (MTM) intervention to reduce inappropriate …

Chloroquine Induction Par-4 And Treatment Of Cancer, Vivek M. Rangnekar

Radiation Medicine Faculty Patents

Described herein are methods for treating cancer in a subject in need thereof by administering chloroquine, or a salt or prodrug thereof, optionally with another agent that promotes Par-4 production to induce prostate apoptosis response-4 (Par-4) production by host cells, particularly non-cancerous host cells, to promote apoptosis in cancer cells, including androgen insensitive prostate cancer cells.

Feasibility Of Diffusion And Probabilistic White Matter Analysis In Patients Implanted With A Deep Brain Stimulator., J. Muller, M. Alizadeh, L. Li, S. Thalheimer, C. Matias, M. Tantawi, J. Miao, M. D. Silverman, V. Zhang, G. Yun, V. Romo, F. B. Mohamed, C. Wu

Department of Neurosurgery Faculty Papers

Deep brain stimulation (DBS) for Parkinson's disease (PD) is an established advanced therapy that produces therapeutic effects through high frequency stimulation. Although this therapeutic option leads to improved clinical outcomes, the mechanisms of the underlying efficacy of this treatment are not well understood. Therefore, investigation of DBS and its postoperative effects on brain architecture is of great interest. Diffusion weighted imaging (DWI) is an advanced imaging technique, which has the ability to estimate the structure of white matter fibers; however, clinical application of DWI after DBS implantation is challenging due to the strong susceptibility artifacts caused by implanted devices. This …

Sarcoidosis Of The Mandibular Condyle: A Rare Disease That Can Mimic Malignancy, Chad Sloan, Ben Lacrosse, Lei Yu, Alexander Braun, Scott Lauer, Timothy Donovan, John Baker, Jason Untrauer

Graduate Medical Education Research Journal

Sarcoidosis can involve any of the organs, however intraosseous involvement is rare and ranges from 5 to 15%, with lesions of the mandible being even rarer – currently with few known cases reported. Intraosseous lesions involving the mandible have been noted to be asymptomatic or associated with chronic jaw pain. Additionally, mandibular involvement can present as a lytic bone lesion mimicking osseous malignancy. Chronic polyarthritis is commonly associated with the progression of sarcoidosis and intraosseous involvement has been considered a late-stage sequelae. We report a case of biopsy-proven sarcoidosis within the mandibular condyle in an asymptomatic 56-year-old Caucasian female who …

Evolution Of Acute Ischemic Stroke Treatment As Supported By Clinical Trials, Savya S. Shukla, Brian F. Baigorri Md, Roberto I. Fourzali Md, Yafell Serulle Md

Radiology

No abstract provided.

A Multiple Comparison Study That Test The Validity Of Varian’S Rapidplan For Prostate Cancer Cases Based On Models Built From Outside Institution., La'rone Reid

Masters Projects

In radiation oncology treatment planning techniques and outcomes can differ from one institution to the next. With knowledge-based planning (KBP) the experience of larger institutions could help smaller institutions who may not have the opportunity to encounter certain types of cancer cases. However, this scenario is only true if the KBP software is consistent with its algorithmic output. Varian's KBP software called Rapid Plan (RP) will be analyzed for algorithmic consistency. This study investigates the validity and consistency of RP models from two different radiation oncology institutions, and compare data to determine RP quality, and consistency when planning prostate cancer …

Automatic Exposure Control During Computed Tomography Scans Of The Head: Effects On Dose And Image Quality, Stephen D. Osborne

Electronic Theses and Dissertations

Automatic exposure control (AEC) is effective at reducing potentially harmful radiation doses without sacrificing image quality for many types of computed tomography (CT) scans. However, there is a need for more information regarding the use of AEC for CT head scans. This study was conducted at Johnson County Community Hospital in Mountain City, TN. Preexisting adult CT head scans (n)60 were randomly selected to form 2 stratified samples, (n)30 each. One sample used a standard protocol, and the other used a protocol with a mA-modulated AEC system, Siemens CARE Dose 4D. Causal-comparative analyses were conducted, and …

Cultural Diversity In Healthcare [Radiologic Technology], Lorena Maldonado, Theresa Licari

Open Educational Resources

The Cultural Diversity in Healthcare assignment is designed for the SCX 101 Patient care course. This assignment was first implemented in 2011 and has undergone significant revisions in the past few years from individual presentation to collaborative group presentation in 2013 and the connection to the Health Science First Year Seminar (HSF) assignment in 2018. The most recent revisions made were through the Center for Teaching and Learning (CTL) workshop on Global Learning in Fall 2018. Feedback from the CTL seminar led to the inclusion of the Learning Objectives of the assignment and prompts that direct students to relate their …

Standardized Reporting In Pancreatic Protocol Ct: Implementation Across 3 Community Hospitals, Jacob L. Miller, Kevin Carr, James Banks, Nisha Mani

Radiology

No abstract provided.

Mr Perfusion Imaging, Techniques And Role In Differentiating Radiation Necrosis And Tumor Recurrence, Raima Zakaria, Fatima Mubarak, Muhammad Shahzad Shamim

Department of Radiology

High grade brain tumours are treated with surgery, chemotherapy and radiation therapy and despite such aggressive treatment, can recur in a short span of time. MRI scan has been the conventional diagnostic modality to diagnose recurrence, although at times it becomes difficult for the neuroradiologists to differentiate between tumour recurrence and radiation necrosis. Herein lies the emergent need to explore the efficacy of functional imaging to assist in this diagnostic challenge. Recent studies have sought to do so with promising implications, which we have attempted to summarize in this review.

Percutaneous Venoplasty For Central Venous Stenosis: Effect On Patient's Symptoms And Patency Of Arteriovenous Accesses, Zia Ur Rehman, Abdul Hakeem Memon, Raza Sayani, Nida Zahid

Department of Surgery Docs

Objective: To determine symptomatic relief and patency rate of arteriovenous (AV) fistulae and grafts after venoplasty in patients with central venous stenosis (CVS) on hemodialysis.
Study Design: Case series.
Place and Duration of Study: The Aga Khan University Hospital, Karachi, from January 2012 to December 2017.
Methodology: The data of patients who had one session of successful venoplasty for CVS were reviewed. The outcomes measured were symptomatic recovery and improvement in the patency of AV accesses. Symptomatic recovery was termed 'complete', when there was complete symptomatic relief after venoplasty; and 'partial' when the procedure was technically successful, but symptoms were …

Outpatient Facility-Based Order Variation In Combined Imaging., Adam C. Powell, Yan Wang, Gary L. Smith, James W. Long, Uday U. Deshmukh, David P. Friedman, Christopher G. Roth, Baskaran Sundaram

Department of Radiology Faculty Papers

OBJECTIVE: Combined computed tomography (CT) occurs when one anatomical area is simultaneously imaged both without and with contrast, or two overlapping anatomical areas are imaged concurrently. While this has been studied in a Traditional Medicare population, it has not been studied in other populations subject to prior authorization. This study explores between-facility variation in ordering and receiving orders to render combined CT in a mixed commercial and Medicare Advantage population.

METHODS: Orders for CT abdomen (without/with contrast), CT thorax (without/with contrast), and concurrent CT brain and sinus authorized by a prior authorization company from 2013-2017, pertaining to patients with commercial …

Changes In Ventricular Depolarisation Vectors During Exercise Caused By Regional Myocardial Ischaemia, Cameruddin Vellani, Satwat Hashmi, Sadia Mahmud, Mohammad Yusuf, Safia Awan, Khawar Kazmi

Section of Cardiology

Research at the Aga Khan University for several years has been directed to find a reliable, low-cost, portable, non-invasive method for identification of coronary artery disease, its location and extent. A new method has been devised to measure the magnitude and direction of cardiac electrical vectors in three perpendicular planes during physical exercise to identify reduction in myocardial excitability as the electrophysiological marker of hypoxia. This report shows that changes in electrical forces due to exercise-induced regional hypoxia serve as indicators of reversible myocardial ischaemia. Changes in the magnitude and direction of vectors at stages of the Bruce protocol were …

Chemical Structure Of Fe–Ni Nanoparticles For Efficient Oxygen Evolution Reaction Electrocatalysis, Prashant Acharya, Zachary J. Nelson, Mourad Benamara, Ryan H. Manso, Sergio I. Perez Bakovic, Mojtaba Abolhassani, Sungsik Lee, Benjamin Reinhart, Jingyi Chen, Lauren F. Greenlee

Chemical Engineering Faculty Publications and Presentations

Bimetallic iron–nickel-based nanocatalysts are perhaps the most active for the oxygen evolution reaction (OER) in alkaline electrolytes. Recent developments in literature have suggested that the ratio of iron and nickel in Fe–Ni thin films plays an essential role in the performance and stability of the catalysts. In this work, the metallic ratio of iron to nickel was tested in alloy bimetallic nanoparticles. Similar to thin films, nanoparticles with iron–nickel atomic compositions where the atomic iron percentage is ≤50% outperformed nanoparticles with iron–nickel ratios of >50%. Nanoparticles of Fe20Ni80, Fe50Ni50, and Fe80Ni20 compositions were evaluated and demonstrated to have overpotentials of …

Value Of Elastography In Differentiating Benign From Malignant Breast Lesions Keeping Histopathology As Gold Standard, Faryal Farooq, Syed Mubarak, Shaista Shaukat, Noman Khan, Kahkashan Jafar, Tariq Mahmood, Muhammad Arif Saeed

Department of Radiology

Background: Breast cancer is the most common cancer in females, both in developed and developing countries. Pakistan has the highest breast cancer incidence rate in Asia. Guidelines recommend screening for detecting breast cancer with mammography and ultrasonography (US). Shear-wave elastography (SWE) is a newer technique that can aid additional characterization of breast lesions.
Objective: The aim of this study was to determine the diagnostic accuracy of breast ultrasound elastography in differentiating benign from malignant breast lesions using histology diagnosis as the gold standard.
Materials and methods: The study was conducted at the Abbasi Shaheed Hospital and Jinnah Post Graduate Medical …