Search results for " Medical imaging"
showing 10 items of 1067 documents
Compartmental analysis of dynamic nuclear medicine data: Models and identifiability
2016
Compartmental models based on tracer mass balance are extensively used in clinical and pre-clinical nuclear medicine in order to obtain quantitative information on tracer metabolism in the biological tissue. This paper is the first of a series of two that deal with the problem of tracer coefficient estimation via compartmental modelling in an inverse problem framework. Specifically, here we discuss the identifiability problem for a general n-dimension compartmental system and provide uniqueness results in the case of two-compartment and three-compartment compartmental models. The second paper will utilize this framework in order to show how non-linear regularization schemes can be applied t…
Comparison of Iodine Quantification and Conventional Attenuation Measurements for Differentiating Small, Truly Enhancing Renal Masses From High-Atten…
2019
OBJECTIVE. The purpose of this study is to determine whether iodine quantification techniques from contrast-enhanced dual-energy CT (DECT) data allow equal differentiation of small enhancing renal masses from high-attenuation (> 20 HU of unenhanced attenuation) nonenhancing lesions, compared with conventional attenuation measurements. MATERIALS AND METHODS. A total of 220 nonconsecutive patients (mean [± SD] age, 66 ± 13 years; 130 men and 90 women) with 265 high-attenuation renal lesions (mean attenuation, 54 ± 33 HU; 91 enhancing lesions) were included. Each patient underwent single-energy unenhanced CT followed by DECT during the nephrographic phase using one of four different high-en…
Semiautomatic detection of myocardial contours in order to investigate normal values of the left ventricular trabeculated mass using MRI
2015
Purpose To propose, assess, and validate a semiautomatic method allowing rapid and reproducible measurement of trabeculated and compacted left ventricular (LV) masses from cardiac magnetic resonance imaging (MRI). Materials and Methods We developed a method to automatically detect noncompacted, endocardial, and epicardial contours. Papillary muscles were segmented using semiautomatic thresholding and were included in the compacted mass. Blood was removed from trabeculae using the same threshold tool. Trabeculated, compacted masses and ratio of noncompacted to compacted (NC:C) masses were computed. Preclinical validation was performed on four transgenic mice with hypertrabeculation of the LV…
Surface brachytherapy: Joint report of the AAPM and the GEC-ESTRO Task Group No. 253.
2020
The surface brachytherapy Task Group report number 253 discusses the common treatment modalities and applicators typically used to treat lesions on the body surface. Details of commissioning and calibration of the applicators and systems are discussed and examples are given for a risk-based analysis approach to the quality assurance measures that are necessary to consider when establishing a surface brachytherapy program.
Structured Reporting in Clinical Routine.
2018
The radiology report is the key component in the communication between radiologists and referring clinicians. Traditionally, reports are written as free text. Several studies have shown that structured reporting using dedicated report templates has a number of advantages compared to conventional reports. Therefore, many radiological societies have recommended the implementation of structured reporting in clinical routine. In the meantime, collections of freely available templates have been presented and software solutions for structured reporting have been made commercially available. These allow for quality improvements in the written radiology report as they ensure that all relevant clin…
Supplement 2 for the 2004 update of the AAPM Task Group No. 43 Report: Joint recommendations by the AAPM and GEC-ESTRO
2017
Since publication of the 2004 update to the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (TG-43U1) and its 2007 supplement (TG-43U1S1), several new low-energy photon-emitting brachytherapy sources have become available. Many of these sources have satisfied the AAPM prerequisites for routine clinical purposes and are posted on the Brachytherapy Seed Registry managed jointly by the AAPM and the Imaging and Radiation Oncology Core Houston Quality Assurance Center (IROC Houston). Given increasingly closer interactions among physicists in North America and Europe, the AAPM and the Groupe Europeen de Curietherapie-European Society for Radiotherapy & Oncology (GEC…
Atypical epithelial hyperplasia of the breast: state of the art.
2016
International audience; Introduction: Atypical epithelial hyperplasia (AEH) of the breast is considered benign histological lesions with breast cancer risk. This review focuses on clinical signification and management of AEH that remains controversial. Areas covered: A review of published studies was performed using medline database. In this review, we fully describe the current evidence available. In particular, we describe 1) data from immunohistochemistry and molecular studies that suggest AEH is a precursor of breast cancer; 2) epidemiological studies demonstrate low rate of breast cancer in women with AEH; 3) surgical excision is necessary after diagnosis of AEH, such as lobular carcin…
Protecting sensitive patient groups from imaging using ionizing radiation: effects during pregnancy, in fetal life and childhood
2019
The frequency of imaging examinations requiring radiation exposure in children (especially CT) is rapidly increasing. This paper reviews the current evidence in radiation protection in pediatric imaging, focusing on the recent knowledge of the biological risk related to low doses exposure. Even if there are no strictly defined limits for patient radiation exposure, it is recommended to try to keep doses as low as reasonably achievable (the ALARA principle). To achieve ALARA, several techniques to reduce the radiation dose in radiation-sensitive patients groups are reviewed. The most recent recommendations that provide guidance regarding imaging of pregnant women are also summarized, and the…
Occupational Exposure to Extremely Low-Frequency Magnetic Fields and Risk of Amyotrophic Lateral Sclerosis : Results of a Feasibility Study for a Poo…
2021
Bioelectromagnetics 42(4), 271-283 (2021). doi:10.1002/bem.22335
Quantification of Radiation Biomarkers in Leukocytes of Breast Cancer Patients Treated with Different Modalities of 3D-CRT or IMRT
2016
The goal of this study was to determine whether the quantification of radiation biomarkers in peripheral leukocytes of 111 breast cancer patients after adjuvant treatment with different modalities of three-dimensional conformal radiation therapy (3D-CRT) or intensity-modulated radiation therapy (IMRT) revealed any difference in the patients' radiation burden by out-of-field doses and an associated risk of second malignancies. Whole-breast radiation therapy was performed by 3D-CRT using either a hard wedge (n = 32) or a virtual wedge (n = 49) at dose rates of 3 and 6 Gy per min each. Patients receiving additional radiotherapy to lymph nodes were treated by 3D-CRT (n = 21) or IMRT (n = 9). DN…