Radiology Commons^™

Moderated Neutron Detector For Accumulated Ambient Dose Equivalent In Proton Therapy, Tanawat Tawonwong

Chulalongkorn University Theses and Dissertations (Chula ETD)

The Varian ProBeam compact was installed at Her Royal Highness Princess Maha Chakri Sirindhorn Proton Center. Since 2017, the project has started at the King Chulalongkorn Memorial Hospital and after 4 years, during Covid19 pandemic, the 1st patient treatment received proton therapy on August, 2021. The radiation safety of the center was accomplished through firstly, the shielding calculation and secondary, the radiation survey at the milestone points such as cyclotron installation and 1st Beam ON at the treatment room. The only one WENDI-II dosimeter was used in radiation survey. The main purpose of this study is to validate the in-house …

Baselines Of Daily Quality Assurance For Proton Pencil Beam Scanning Using The Sphinx Compact, Tanapat Tiajaroen

Chulalongkorn University Theses and Dissertations (Chula ETD)

Quality assurance (QA) is a systematic process used to determine whether the product meets specified requirements. The American Association of Physicists in Medicine (AAPM) published a comprehensive proton therapy machine QA in TG-224 to provide confidence in use. King Chulalongkorn Memorial Hospital (KCMH) recently operated the first proton therapy center in Thailand, and the data of daily QA are not available or established. This study aims to apply the control chart for establishing the baselines of daily QA for the proton pencil beam scanning system using the Sphinx Compact detector. The Sphinx Compact was used to perform the proton daily …

Determination Of Field Output Correction Factors In Elongated Small Field Photon Beams, Mananchaya Vimolnoch

Chulalongkorn University Theses and Dissertations (Chula ETD)

IAEA along with AAPM have published a code of practice TRS 483 for small field dosimetry. The field correction output factors of various detectors were introduced to correct detector response changes in relative dosimetry. However, the publication of TRS 483 has focused on symmetry field sizes, the correction factors for elongated small fields are not included in the protocol. The overall objective of this work is to determine the field output correction factor in elongated small field. The correction factors of IBA CC01, Sun nuclear EDGE, and Exradin W2 PSD for 6 MV photon beam were determined using Monte Carlo …

A Deep Learning U-Net For Detecting And Segmenting Liver Tumors, Vidhya Cardozo

Theses and Dissertations

Visualization of liver tumors on simulation CT scans is challenging even with contrast-enhancement, due to the sensitivity of the contrast enhancement to the timing of the CT acquisition. Image registration to magnetic resonance imaging (MRI) can be helpful for delineation, but differences in patient position, liver shape and volume, and the lack of anatomical landmarks between the two image sets makes the task difficult. This study develops a U-Net based neural network for automated liver and tumor segmentation for purposes of radiotherapy treatment planning. Non-contrast simulation based abdominal CT axial scans of 52 patients with primary liver tumors were utilized. …

Development Of Fully Balanced Ssfp And Computer Vision Applications For Mri-Assisted Radiosurgery (Mars), Jeremiah Sanders

Dissertations and Theses (Open Access)

Prostate cancer is the second most common cancer in men and the second-leading cause of cancer death in men. Brachytherapy is a highly effective treatment option for prostate cancer, and is the most cost-effective initial treatment among all other therapeutic options for low to intermediate risk patients of prostate cancer. In low-dose-rate (LDR) brachytherapy, verifying the location of the radioactive seeds within the prostate and in relation to critical normal structures after seed implantation is essential to ensuring positive treatment outcomes.

One current gap in knowledge is how to simultaneously image the prostate, surrounding anatomy, and radioactive seeds within the …

Adjuvant Therapy In Adrenocortical Carcinoma: Reflections And Future Directions, Sara Bedrose, Marilyne Daher, Lina Altameemi, Mouhammed Amir Habra

Faculty, Staff and Students Publications

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with high risk of recurrence despite macroscopically complete surgical resection. The main predictors of ACC recurrence include advanced disease stage, incomplete surgical resection, cortisol production, certain genetic alterations, and high proliferation rate (Ki-67 proliferation index). Mitotane has been the mainstay adjuvant therapy of ACC. However, the use of mitotane is based on retrospective and occasionally conflicting evidence. As mitotane levels can take a few months before reaching therapeutic levels, there is an emerging practice of combining platinum-based chemotherapy with mitotane in the adjuvant setting. Retrospective data indicate that radiotherapy is an …

The Labeling Of 99mtc-Psma-Hbed-Cc For Prostate Cancer Imaging, Benchamat Phromphao

Chulalongkorn University Theses and Dissertations (Chula ETD)

Prostate cancer (PCa) is the second most common cancer and the fifth leading cause of death worldwide in 2018 (1). Initially, PCa diagnosis is based on Prostate Specific Antigen (PSA) blood test, which is low sensitivity and low specificity, and sonography guided needle biopsy, which is invasive. Therefore, molecular imaging recently enrolls as an important technique in PCa diagnosis using some small molecules which are well developed to bind to overexpressed Prostate Specific Membrane Antigen (PSMA). The small molecules, for example PSMA-HBED-CC, PSMA I&T, can be chelated with Ga-68 for diagnostic purpose using positron emission tomography (PET) scan. Even though …

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 …

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, …

Surface And Build-Up Region Dose Measurement In Head And Neck Region Using Radio - Photoluminescent Glass Dosimeter, Sonam Choki

Chulalongkorn University Theses and Dissertations (Chula ETD)

The use of commercially available radio-photoluminescent glass dosimeter (RPLGD) for radiation measurement has increased in recent years. It has been shown to have superior dosimetric characteristics as compared to other dosimeters. The purpose of this research is to evaluate the suitability of the GD-302M glass dosimeter for surface and build-up region dose measurement in head and neck region. The glass dosimeter was analyzed for its dosimetric properties in photon beam. Then, the study was performed for surface and build-up region dose comparison between EBT3 film and RPLGD in solid water phantom at 0, 2, 3, 5, 10 and 15mm depths …

Development And Dosimetric Verification Of 3d Customized Bolus In Radiotherapy, Nichakan Chatchumnan

Chulalongkorn University Theses and Dissertations (Chula ETD)

Bolus is a tissue equivalent material that is commonly used to reduce the skin-sparing effect in radiotherapy. The commercial flat bolus cannot form perfect contact with the irregular surface of the patient's skin, resulting in an air gap, especially in irregular surface shape. The purpose of this study was to evaluate the feasibility of two types of silicone rubber bolus, RA-00AB, and RA-05AB that were made as to the fabricated flat and 3D customized bolus using 3D printing technology. The 1 cm thick boluses were made from two types of silicone rubber solutions. The point dose and planar dose differences …

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 …

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 …

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 …

Following The Growth Of Sarah's Baby: An Ipe Activity For Medical Nutrition & Diagnostic Sonography Students, Tanya M. Custer, Megan Timmerman, Cynthia M. Schmidt, Teresa L. Hartman, Harlan Sayles, Kathryn Wampler, Lea Lambing, Kim Michael

Posters and Presentations: Medical Imaging & Therapeutic Sciences

Objectives: Interprofessional education (IPE) involves collaborative learning among students from different professions. While acceptance of these types of activities is increasing, there are opportunities to expand the number of health care professions involved in IPE. The purpose of this study was to explore student perceptions and outcomes after participation in a Diagnostic Medical Sonography (DMS) and Medical Nutrition Education (MNE) interprofessional education activity centered around a clinical case study on fetal growth. Subjects & Methods: The IPE activity was administered to four student cohorts from academic years to 2015-2016 to 2018-2019. Participants included 66 students (n=39 DMS and n=27 MNE). …

Retrospective Evaluation Of Weight Loss In Maine Medical Center Cancer Institute (Mmcci) Patients Receiving Radiation Treatment For Head And Neck Cancer, Julian Johnson, David Debartolo-Stone, Jessica Moore, Ruth Hanselman, Stephen Tyzik, Suneela Nayak, Amy Sparks

Operations Transformation

Treatment for head and neck cancer often results in weight loss as a side effect. One option to mitigate this weight loss is placement of a percutaneous endoscopic gastrostomy (PEG) tube placement. Radiation oncologists at a academic tertiary medical center discuss the option of PEG placement during patient consultation.

A retrospective evaluation of weight loss in patients receiving radiation was conducted over a two-year period. The goal of this data collection was to create a standard for oncology consultations regarding PEG tube placement.

Baseline metrics and a root cause analysis drove subsequent data collection steps. After analyzing the raw data, …

Scintillation Event Localization In Novel Hemi-Ellipsoid Detector For Spect, Hanif R. Soysal

LSU Master's Theses

A high sensitivity Cardiac SPECT system using hemi-ellipsoid crystals with pinhole collimation was previously proposed by Dey et al. To investigate detector resolution for this design, the scintillation light spread on a monolithic hemi-ellipsoidal CsI crystal was simulated using Geant4 Monte Carlo. The expected distribution of scintillation light on the outer surface of the crystal from photoelectric absorption events was obtained from the simulations for selected points inside the crystal. Two sets of simulations were performed. For the first set, a look-up table (LUT) of 12 points was created and each point mapped to its expected light distribution—four points at …

Mindful Meditation Practice For Imaging Professionals, Tanya M. Custer, Kim Michael

Posters and Presentations: Medical Imaging & Therapeutic Sciences

Although a career in medical imaging is very fulfilling and rewarding, research shows that health care professionals are becoming more prone to burnout. The healthcare environment can be face-paced, stressful and demanding. Burnout syndrome results from emotional exhaustion that causes depersonalization and decreased professional accomplishment.1-3 Burnout can have a negative impact not only on the individual, but the environment as well. Decreased patient satisfaction and increased errors are both associated with burnout in the healthcare setting.2

Mindfulness can be defined as the awareness that emerges through paying attention on purpose, in the present moment, and non-judgmentally to the unfolding of …

Survival And Treatment Outcomes Of Metaplastic Breast Carcinoma: Single Tertiary Care Center Experience In Pakistan, Zarka Samoon, Madiha Beg, Romana Idress, Adnan Jabbar

Department of Radiation Oncology

Background: Metaplastic breast carcinoma (MBC) is a rare disease with incidence of less than 1%. MBC present with a larger tumor size, less number of nodes involved, mostly undifferentiated triple negative tumors. We aimed to determine progression-free and overall survival and reported hospital-based incidence of MBC.
Material and Methods: A retrospective closed Cohort study elicited data of 42 patients with MBC from January 2008 to December 2013; followed till August 2016. Kaplan-Meier method was applied to compute overall and progression-free survival analysis. Cox Proportional hazard ratios were computed to assess associations between survival and independent variables.
Results: Hospital-based incidence of …

Measurement Of The Whole Body, Eye Lens And Extremity Occupational Exposures In Nuclear Medicine Staff At King Chulalongkorn Memorial Hospital, Siriwan Sisai

Chulalongkorn University Theses and Dissertations (Chula ETD)

Due to the epidemiology evidence of cataract and eye lens opacity, ICRP Publication 118 in 2012, recommended the new eye lens dose limit of occupational exposure at 20 mSv/year, averaged over 5-year periods, no single year exceeding 50 mSv. For the public eye lens dose limit is 15 mSv/year. After ICRP changed the eye lens dose limit, many reports on eye lens dose measurement using thermoluminescent dosimeter (TLD) from interventional radiologists and interventional cardiologists were published. Few reports on eye lens dose measurement in nuclear medicine (NM) personnel were found. The primary objective of this study is to measure whole …

A Feasibility Study Of Diffusion Weighted Imaging And Parametric Response Map Analysis For Treatment Response Prediction In Nasopharyngeal Cancer, Titiya Jirawatwanith

Chulalongkorn University Theses and Dissertations (Chula ETD)

Diffusion-weighted imaging (DWI) is an MRI technique which provides functional information of tissue by detecting microscopic motion of water molecules. The change of apparent diffusion coefficient (ADC) derived from DWI was used as an imaging biomarker for treatment response prediction in cancers. However, it was based on whole-tumor analysis which did not reflect heterogeneity within the tumor. To overcome this limitation, a new method called parametric response map (PRM) analysis was proposed to evaluate response by quantifying voxel-wise changes in ADC. Here we investigated the use of PRM analysis on ADC from DWI as an imaging biomarker for treatment response …

Dosimetric Comparison Between Single And Double Isocenters Volumetric Arc Therapy For Stereotactic Radiotherapy With Multiple Targets, Wai Lwin Lwin Kyaw

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this study was to evaluate the dosimetric effects between single isocenter (SI) and double isocenters (DI) VMAT SRT of multiple brain metastases. There are two parts of study, which were experimental for energy selection, technique comparison and clinical part to use appropriate technique. As the first part, three lesions with 3 cm distance apart and 1 cm size for all lesions were created as standard plan by varying energy. Twelve VMAT SRT plans by varying energy with 6 MV, 10 MV, 6 FFF and 10 FFF were planned on simulated three lesions of CT image. 18 VMAT …

A Custom Radiopaque Thermoresponsive Chemotherapy-Loaded Hydrogel For Intratumoural Injection: An In Vitro And Ex Vivo Assessment Of Imaging Characteristics And Material Properties, Seóna M. Rossi, Timothy E. Murray, John Cassidy, Michael J. Lee, Helena M. Kelly

Articles

Purpose Thermoresponsive hydrogels are gels which have different properties at varying temperatures. The objective of this study was to assess the material characteristics, imaging properties and chemotherapeutic drug release profile of a novel radiopaque thermoresponsive hydrogel in vitro, which is liquid at room temperature but solidifies at body temperature, to determine potential suitability for intratumoural delivery. Materials and Methods An iodinated radiopaque thermoresponsive hydrogel was formulated using iodixanol at a range of concentrations and assessed for sol–gel transition, radiopacity and imaging using CT and US. A lead formulation containing iodixanol at a concentration of 9.22% weight by weight (w/w, g …

Clinical Audit To Assess Delays In Chemotherapy Administration At Daycare Oncology Center At A Tertiary Care Hospital In Karachi, Pakistan, Arifa Arifa Aziz, Zarka Samoon, Afsheen Feroz, Nadia Ayoub, Safia Awan, Madhia Beg

Department of Radiation Oncology

Aim: There were delays reported by patients in chemotherapy administration in daycare oncology. Therefore, we decided to audit all processes which are involved in chemotherapy administration. The objective was to improve our service by decreasing the time between admission and initiation of chemotherapy and identify the reasons for delays. Materials and Methods: The audit was conducted in three parts. In Review I, audit tool was developed and information documented of 109 patients receiving chemotherapy at daycare center from April 14 to May 13, 2015. Five processes were assessed out of which delay in initial assessment by the nurse was the …

Prognostic Factors For Elderly Patients Treated With Stereotactic Body Radiation Therapy For Pancreatic Adenocarcinoma, Philip A. Sutera, Mark E. Bernard, Hong Wang, Dwight E. Heron

Radiation Medicine Faculty Publications

Introduction: Pancreatic ductal adenocarcinoma (PDAC) commonly presents later in life with a median age at diagnosis of 70 years. Unfortunately, elderly patients are significantly underrepresented in clinical trials. Stereotactic body radiation therapy (SBRT) is a promising treatment modality in this population as it has demonstrated excellent local control with minimal toxicity. We aimed to determine prognostic factors associated with outcomes in elderly patients treated with SBRT.

Materials and Methods: Elderly patients older than 70 treated with SBRT for PDAC at our institution, from 2004 to 2014 were included. Our primary endpoints included overall survival (OS) and local-progression-free survival (LPFS). Secondary …

Open Book Testing In Health Science Education: Student Perceptions And Outcomes In Ultrasound Physics, Kim Michael, Tanya M. Custer

Posters and Presentations: Medical Imaging & Therapeutic Sciences

Objectives: The purpose of this study was to investigate the use of open book exams (OBE) in the education of imaging students and to assess the beliefs and perceptions of the students in regard to the use of open book testing.

Subjects & Methods: Study participants included twenty-seven sonography students enrolled in an academic health sciences center. OBE was implemented in two ultrasound physics courses. Data was collected through focus groups & exam outcomes. Creswell’s procedure for data analysis & representation was followed.

Results: Overall outcomes showed no statistically significant difference between exam grades for the different cohorts with the …

Discriminating Radiation Injury From Recurrent Tumor With [18f]Parpi And Amino Acid Pet In Mouse Models, Patrick L. Donabedian, Susanne Kossatz, John A. Engelbach, Stephen A. Jannetti, Brandon Carney, Robert J. Young, Wolfgang A. Weber, Joel R. Garbow, Thomas Reiner

Publications and Research

Background

Radiation injury can be indistinguishable from recurrent tumor on standard imaging. Current protocols for this differential diagnosis require one or more follow-up imaging studies, long dynamic acquisitions, or complex image post-processing; despite much research, the inability to confidently distinguish between these two entities continues to pose a significant dilemma for the treating clinician. Using mouse models of both glioblastoma and radiation necrosis, we tested the potential of poly(ADP-ribose) polymerase (PARP)-targeted PET imaging with [¹⁸F]PARPi to better discriminate radiation injury from tumor.

Results

In mice with experimental radiation necrosis, lesion uptake on [¹⁸F]PARPi-PET was similar to …

Tmsotf Assisted Synthesis Of 2’-Deoxy-2’-[18f] Fluoro-Β-D-Arabinofuranosylcytosine ([18f] Fac), Kishore K. Gangangari, John L. Humm, Steven M. Larson, Naga Vara Kishore Pillarsetty

Publications and Research

[¹⁸F]FAC (2’-deoxy-2’-[¹⁸F]fluoro-β-D-arabinofuranosylcytosine, 1) is a versatile probe for imaging deoxycytidine kinase (dCK) expression levels in vivo. dCK is responsible for phosphorylation of deoxycytidine (dC, 2) and other nucleoside analogs, plays a key role in immune activation and has demonstrated to be one of the key enzymes in activating nucleoside based drugs including gemcitabine. Reported synthesis of [¹⁸F]FAC is high yielding but is quite challenging requiring bromination using HBr and careful drying of excess HBr which is critical for successful synthesis. Here in we report a simplified trimethylsilyl trifluoromethanesulfonate (TMSOTf) assisted synthesis …

Bezoar: Imaging Findings & Case Study Of A Rare Pathology, Tanya M. Custer, Kim Michael

Posters and Presentations: Medical Imaging & Therapeutic Sciences

A bezoar is a hard, indigestible mass of material that forms within the alimentary canal, most commonly the stomach.1 Bezoars are classified according to composition. The most common type of bezoar is a phytobezoar composed of indigestible food fibers that occur in fruits & vegetables, including celery, pumpkin, prunes, raisins, & sunflower-seed shells. Other common types of bezoars include trichobezoars, composed of hair, & pharmacobezoars, made of undissolved medications.

A number of risk factors have been associated with bezoar development. Patients who have undergone gastric surgery, such as partial gastrectomy, are at an increased risk of developing a bezoar due …

The Interprofessional Academy Of Educators: Inclusive, Collaborative, Innovative, Tanya M. Custer, Kim Michael

Posters and Presentations: Medical Imaging & Therapeutic Sciences

Issue to be addressed: To elevate the educational mission of the institution, UNMC established the Interprofessional Academy of Educators in 2016. Designed by educators for educators, this interprofessional community strives to improve health professions education by encouraging curricular innovation, supporting educational scholarship & offering mentorship for early career and seasoned educators.

Method: The inaugural class included a unique blend of medical scholars from 8 Colleges, 2 Institutes, Academic Affairs, IT Services, and Library Sciences. Members span a 500-mile wide campus. Eight SIGs foster interprofessional collaboration & scholarship. An academically diverse leadership team of five oversees the Academy.