Search results for "030218 nuclear medicine & medical imaging"
showing 10 items of 1054 documents
AUTOMATIC DETECTION OF SMALL SPHERICAL LESIONS USING MULTISCALE APPROACH IN 3D MEDICAL IMAGES
2013
International audience; Automated detection of small, low level shapes such as circular/spherical objects in images is a challenging computer vision problem. For many applications, especially microbleed detection in Alzheimer's disease, an automatic pre-screening scheme is required to identify potential seeds with high sensitivity and reasonable specificity. A new method is proposed to detect spherical objects in 3D medical images within the multi-scale Laplacian of Gaussian framework. The major contributions are (1) breaking down 3D sphere detection into 1D line profile detection along each coordinate dimension, (2) identifying center of structures by normalizing the line response profile …
Helical Tomotherapy® is a safe and feasible technique for total scalp irradiation
2017
Angiosarcoma of the scalp is a rare aggressive tumor that affects elderly patients. Chemoradiation is the treatment of choice for multicentric and extensive disease. The shape of the scalp represents a dosimetric challenge in terms of achieving a homogeneous concave dose distribution with coverage of the entire target volume and an acceptable organs-at-risk sparing. We report a case of an 81-year-old man with a multifocal angiosarcoma of the scalp treated with Helical TomoTherapy® (Accuray Inc., Sunnyvale, CA, USA) intensity modulated radiotherapy. This technique allows precise and daily verifiable coverage of the target keeping the dose to the organs at risk within the constraints.
FIRST experiment: Fragmentation of Ions Relevant for Space and Therapy
2013
International audience; Nuclear fragmentation processes are relevant in different fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at SIS accelerator of GSI laboratory in Darmstadt, has been designed for the measurement of different ions fragmentation cross sections at different energies between 100 and 1000 MeV/nucleon. The experiment is performed by an international collaboration made of institutions from Germany, France, Italy and Spain. The experimental apparatus is partly based on an already existing setup made of the …
MR Thermometry Data Correlate with Pathological Response for Soft Tissue Sarcoma of the Lower Extremity in a Single Center Analysis of Prospectively …
2020
Background: There is a strong biologic rationale for using locoregional hyperthermia in soft tissue sarcoma and a randomized trial reported significant improvements with hyperthermia. The aim of this study was to describe the opportunities of magnetic resonance (MR)-based thermometry in a cohort of soft tissue sarcoma patients undergoing combined radiotherapy and locoregional hyperthermia. Patients and Methods: For eleven evaluable patients, tumor volume (VTu) and a separate volume for temperature analysis with reliable temperature distribution (Vtherm) were contoured for every hyperthermia treatment (103 therapies). Temperature data were recorded for all tumors and were correlated with cli…
Ultrasound hyperthermia induces apoptosis in head and neck squamous cell carcinoma: an in vitro study
2016
Background Hyperthermia is considered an efficient complement in the treatment of head and neck squamous cell carcinoma (HNSCC). Hyperthermia induces cell apoptosis in a temperature- and time-dependent manner. However, the molecular mechanism of hyperthermia remains unclear. The aim of this study was to investigate the mechanism of apoptosis induced by ultrasound hyperthermia in HNSCC cell lines HN-30 and HN-13. Material and Methods We examined the dynamic changes of early apoptosis and secondary necrosis in HN-30 and HN-13 cells treated by hyperthermia at 42°C for 10 min. We further examined mitochondrial membrane potential in vitro by ultrasound hyperthermia for different heating temperat…
Moderate hypofractionated helical tomotherapy for localized prostate cancer: preliminary report of an observational prospective study.
2019
Objective: To report preliminary findings of a phase II study exploring the clinical outcomes of moderate hypofractionated radiotherapy performed with helical tomotherapy (HT) using computed tomography–magnetic resonance imaging–based planning for localized prostate cancer. Methods: The phase II prospective study received ethics approval from our institutional ethics committee. A dose of 60 Gy/20 fractions for low–intermediate risk prostate cancer by means of HT was explored. Primary endpoints of the study were acute and late gastrointestinal (GI) and genitourinary (GU) toxicities. Secondary endpoints were quality of life and biochemical-free survival. Results: A total of 35 patients were i…
A novel framework for MR image segmentation and quantification by using MedGA
2019
BACKGROUND AND OBJECTIVES: Image segmentation represents one of the most challenging issues in medical image analysis to distinguish among different adjacent tissues in a body part. In this context, appropriate image pre-processing tools can improve the result accuracy achieved by computer-assisted segmentation methods. Taking into consideration images with a bimodal intensity distribution, image binarization can be used to classify the input pictorial data into two classes, given a threshold intensity value. Unfortunately, adaptive thresholding techniques for two-class segmentation work properly only for images characterized by bimodal histograms. We aim at overcoming these limitations and…
Computer-Assisted Approaches for Uterine Fibroid Segmentation in MRgFUS Treatments: Quantitative Evaluation and Clinical Feasibility Analysis
2019
Nowadays, uterine fibroids can be treated using Magnetic Resonance guided Focused Ultrasound Surgery (MRgFUS), which is a non-invasive therapy exploiting thermal ablation. In order to measure the Non-Perfused Volume (NPV) for treatment response assessment, the ablated fibroid areas (i.e., Region of Treatment, ROT) are manually contoured by a radiologist. The current operator-dependent methodology could affect the subsequent follow-up phases, due to the lack of result repeatability. In addition, this fully manual procedure is time-consuming, considerably increasing execution times. These critical issues can be addressed only by means of accurate and efficient automated Pattern Recognition ap…
Failed Total Hip Arthroplasty: Diagnostic Performance of Conventional MRI Features and Locoregional Lymphadenopathy to Identify Infected Implants.
2020
Background Very little has been published about the diagnostic performance of MRI in total hip arthroplasty (THA) infection. Purpose To determine the diagnostic performance of conventional MRI features and of new lymph nodal indices to identify infection in patients with failed THA. Study type Retrospective. Population In all, 119 patients (66 females; age 66.9 ± 12.4 years) with failed THA. Field strength/sequences Metal artifact reduction sequence (MARS) protocol including short tau inversion recovery and turbo spin-echo T1 - and T2 -weighted sequences at 1.5T. Assessment Patients underwent pelvis MRI prior to failed THA revision. MRIs were reviewed to identify periprosthetic bone destruc…
Benchmarking Wilms’ tumor in multisequence MRI data: why does current clinical practice fail? Which popular segmentation algorithms perform well?
2019
Wilms' tumor is one of the most frequent malignant solid tumors in childhood. Accurate segmentation of tumor tissue is a key step during therapy and treatment planning. Since it is difficult to obtain a comprehensive set of tumor data of children, there is no benchmark so far allowing evaluation of the quality of human or computer-based segmentations. The contributions in our paper are threefold: (i) we present the first heterogeneous Wilms' tumor benchmark data set. It contains multisequence MRI data sets before and after chemotherapy, along with ground truth annotation, approximated based on the consensus of five human experts. (ii) We analyze human expert annotations and interrater varia…