Izabella Barreto

University of Florida | UF · College of Medicine, Department of Radiology

Because ionizing radiation is widely used in medical imaging and in military, industry, and commercial applications, programmatic management and advancement in knowledge is needed, especially related to the health effects of low-dose radiation. The U.S. Congress in partnership with the U.S. Department of Energy called on the National Academies of S...

A production facility shutdown related to containment measures during the COVID-19 pandemic has resulted in a global shortage of iodinated contrast media. This article describes the strategies implemented at one large U.S. health system to maintain care continuity during the ongoing shortage. The strategies have included attempts to procure additio...

Background Children with craniosynostosis may undergo multiple computed tomography (CT) examinations for diagnosis and post-treatment follow-up, resulting in cumulative radiation exposure. Objective To reduce the risks associated with radiation exposure, we evaluated the compliance, radiation dose reduction and clinical image quality of a lower-do...

Objectives The purpose of this study was to compare the effectiveness of metal artifact reduction using Single Energy Metal Artifact Reduction (SEMAR) and Dual Energy CT (DECT). Materials and methods Six cadavers containing metal implants in the head, neck, abdomen, pelvis, and extremities were scanned with Standard, SEMAR, and DECT protocols on a...

Purpose: We compare the effect of tube current modulation (TCM) and fixed tube current (FTC) on size-specific dose estimates (SSDE) and image quality in lung cancer screening with low-dose CT (LDCT) for patients of all sizes. Methods: Initially, 107 lung screening examinations were performed using FTC, which satisfied the Centers for Medicare &...

Purpose The global cancer burden and mortality rates are increasing, with significant disparities in access to care in low- and middle-income countries (LMICs). This study aimed to identify radiology and radiation therapy needs in LMICs from the perspective of departmental and institutional leaders. Methods and Materials A survey was developed and...

The American Association of Physicists in Medicine began the Medical Physics Leadership Academy Journal Club in the fall of 2020. The initiative was launched to provide a forum for medical physicists to learn about leadership topics using published material, discuss and reflect on the material, and consider incorporating the discussed skills into t...

Magnetic particle imaging (MPI) is a novel biomedical imaging modality that allows non-invasive, tomographic, and quantitative tracking of the distribution of superparamagnetic iron oxide nanoparticle (SPION) tracers. While MPI possesses...

Objective: To estimate the minimum iodine concentrations detectable in simulated vessels of various diameters for both subtraction computed tomography (CT) and dual-energy CT systems. Methods: Fillable tubes (diameters: 1, 3, and 5 mm) were filled with a variety of iodine concentrations (range: 0-20 mg/ml), placed in the center of 28-mm cylindri...

A body of studies has proposed to obtain high-quality images from low-dose and noisy Computed Tomography (CT) scans for radiation reduction. However, these studies are designed for population-level data without considering the variation in CT devices and individuals, limiting the current approaches' performance, especially for ultra-low-dose CT ima...

Purpose This is a multi-institutional report on inter-observer and inter-instrument variation in the calibration of the absorbed dose rate for a planar ³²P beta emitting brachytherapy source. Measurement accuracy is essential since the dose profile is steep and the source is used for the treatment of tumors that are located in close proximity to he...

Hyperintense reperfusion marker (HARM) on post-contrast magnetic resonance imaging (MRI) fluid attenuated inversion recovery (FLAIR) represents gadolinium contrast extravasation in the setting of acute ischemic stroke and is a common finding after revascularization therapies. Clinically, it is a marker of blood brain barrier (BBB) disruption, predi...

Purpose: Most clinical computed tomography (CT) protocols use helical scanning; however, the traditional method for CTDIvol measurement replaces the helical protocol with an axial scan, which is not easily accomplished on many scanners and may lead to unmatched collimation settings and bowtie filters. This study assesses whether CTDIvol can be acc...

The purpose of this study was to investigate the frequency and impact of vertical mis‐centering on organ doses in computed tomography (CT) exams and evaluate the effect of a commercially available positioning compensation system (PCS). Mis‐centering frequency and magnitude was retrospectively measured in 300 patients examined with chest‐abdomen‐pel...

Objective: To compare organ specific radiation dose and image quality in kidney stone patients scanned with standard CT reconstructed with filtered back projection (FBP-CT) to those scanned with low dose CT reconstructed with iterative techniques (IR-CT). Materials and methods: Over a one-year study period, adult kidney stone patients were retro...

Purpose: To assess the effects of tube current modulation (TCM) on radiation dose indices and image quality as a function of patient size in lung cancer screening CT with a 16‐slice CT scanner. Methods: Initially, 107 lung screening examinations were performed using a fixed tube current that satisfied the U.S. Centers for Medicare & Medicaid Servi...

Purpose: To determine the effect of patient off‐centering on organ doses in computed tomography (CT) and evaluate the impact of an automatic centering technology. Methods: With IRB approval, clinical off‐centering was measured in 300 patients examined with chest‐abdomen‐pelvis CT. Four cadavers were scanned on a 320‐slice CT scanner, with the tabl...

Purpose: To evaluate size‐specific dose estimates (SSDE) as a function of patient size for adults examined with low‐dose lung cancer screening CT. Methods: With institutional‐review‐board approval, data was retrospectively collected for 388 adult patients examined with lung cancer screening CT during a one‐year period. Patients were examined on fo...

Purpose: To characterize the response of Optically Stimulated Luminescent Dosimeters (OSLDs) in a simulated fluoroscopy beam. Methods: OSLD response to various energies, scatter, time, tube current, angulation, and dose rate were assessed. The half‐value layers (HVL) of typical clinical beams in a fluoroscopic system driven by automatic brightness...

Rationale and Objectives Implementation of low dose computed tomography (LDCT) lung cancer screening programs has followed the demonstration of reduced lung cancer mortality in the National Lung Screening Trial and subsequent consensus screening recommendations. Here we aim to assess the initial results of a screening program at an academic medical...

Purpose: Tube current modulation (TCM) in helical CT is not typically used for head exams due to the head’s cylindrical shape. Because it is difficult to determine whether TCM has the potential to reduce CT dose while maintaining image quality using phantoms, we approach this question using cadavers. Methods: Five cadavers were scanned using a rout...

Purpose: Efforts to optimize scan protocol should consider both dose and clinical image quality. This is made possible with postmortem subjects, whose brains are similar to patients, allowing for an investigation of ideal scan parameters. The purpose of this work is to reduce dose for head CT protocols for 3 indications commonly examined in childre...

SPS Undergraduate Research & Outreach Abstract

Purpose:To develop new proton tissue equivalent materials (PTEM), urethane and fiberglass based, for proton therapy calibration and dosimetry studies. Existing tissue equivalent plastics are applicable only for x-rays because they focus on matching mass attenuation coefficients. This study aims to create new plastics that match mass stopping powers...

Purpose:To optimize adult head CT protocol by reducing dose to an appropriate level while providing CT images of diagnostic quality. Methods:Five cadavers were scanned from the skull base to the vertex using a routine adult head CT protocol (120 kVp, 270 mA, 0.75 s rotation, 0.5 mm × 32 detectors, 70.8 mGy CTDIvol) followed by seven reduced-dose p...

Purpose:This retrospective study analyzes the exposure history of emergency department (ED) patients undergoing head and cervical spine trauma computed tomography (CT) studies. This study investigated dose levels received by trauma patients and addressed any potential concerns regarding radiation dose issues. Methods:Under proper IRB approval, a co...

Purpose:The imaging of pregnant patients is medically necessary in certain clinical situations. The purpose of this work was to directly measure uterine doses in a cadaver scanned with CT protocols commonly performed on pregnant patients in order to estimate fetal dose and assess potential risk. Method:One postmortem subject was scanned on a 320-sl...

BACKGROUND Over the past three decades, utilization of medical imaging has risen tremendously, thus, placing patients at increased risk for associated harmful effects. Ordering providers may not be intimately familiar with ALARA and the ACR Appropriateness Criteria. The Emergency Department is responsible for approximately 30% of all medical imagin...

PURPOSE The National Lung Screening Trial (NLST) and the United States Preventative Services Task Force (USPSTF) have recommended using low-dose computed tomography for early detection of lung cancer. Direct measurements in post-mortem subjects were carried out to determine organ doses that would be experienced by patients undergoing a lung cancer...

To determine the quantitative effect of adipose tissue shielding on organ dose measurements in computed tomography (CT) and model the effects with organ dose equations. The post-mortem dose measurement methodology established in house was utilized to perform organ dose measurements on subjects of varying body habitus for a clinically standardized c...

PURPOSE To measure pediatric organ doses and assess clinical image quality in a cadaver scanned with pediatric protocols on a clinical CT scanner. METHODS Organ doses were measured in the thoracic and abdominal regions of a small sized cadaver by inserting optically stimulated luminescent dosimeters (OSLDs) into various organs. The subject's effec...

Purpose: New radiation dose reduction technologies are emerging constantly in the medical imaging field. The latest of these technologies, iterative reconstruction (IR) in CT, presents the ability to reduce dose significantly and hence provides great opportunity for CT protocol optimization. However, without effective analysis of image quality, th...

To introduce and investigate effective diameter ratios as a new patient metric for use in computed tomography protocol selection as a supplement to patient-specific size parameter data. The metrics of outer effective diameter and inner effective diameter were measured for 7 post-mortem subjects scanned with a standardized chest/abdomen/pelvis (CAP)...

INTRODUCTION AND OBJECTIVES: Methods commonly used to reduce patient radiation exposure, such as standard Filtered Back Projection CT (FBP CT), may still result in significant image noise and decreased image quality. Adaptive Iterative Dose Reduction (AIDR), a CT image reconstruction algorithm, has been touted to lower patient radiation dose while...