Browsing Masteruppsatser / Medicinsk strålningsvetenskap by Title
Now showing items 12-31 of 35
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Deep Neural Networks for Noise Reduction and Bias Removal in MR Diffusion Signal
(2022-03-22)The purpose of this study is to assess the potential of deep neural networks, trained by unsupervised learning, for diffusion weighted imaging (DWI) data modeling and denoising. DWI data were modeled by a biexponential ... -
DEFORMABLE IMAGE REGISTRATION OF SPINE MAGNETIC RESONANCE IMAGES WITH ELASTIX FOR DETAILED CHARACTERIZATION OF DISC LOADING BEHAVIORS
(2021-05-10)Purpose: This work aimed to develop an optimized strategy for registration of spine magnetic resonance (MR) images acquired with and without spinal loading, as well as evaluate the quality of the registration strategy ... -
DEVELOPMENT, VALIDATION AND APPLICATION OF A METHOD FOR DETERMINATION OF METABOLITE CONCENTRATIONS WITH PRECLINICAL MAGNETIC RESONANCE SPECTROSCOPY
(2021-05-10)Background: Information on the metabolic content in tissue has diagnostic and prognostic value when examining for example cancer and diseases of the brain. MR spectroscopy is a non-invasive method that allows quantification ... -
Effects of reconstruction parameters on the image quality and quantification of PET images from PET/MRI and PET/CT systems
(2022-03-09)Aim: To study how reconstruction parameters affect the positron emission tomography (PET) image quality and quantitative results for the different lesion to background radioactivity ratios in three different PET ... -
ENVIRONMENTAL RADIOLOGICAL STUDIES OF KVARNTORPSHÖGEN Dose and Radiological Risk Assessments for Humans and Biota
(2021-04-06)Background: The pile Kvarntorpshögen and the lakes Surpölen and Norrtorpssjön are the remains of an industry which mined and processed oil shales to extract oil during World War II. The pile mainly consists of shale ... -
Establishment of a deep learning algorithm for dosimetry of radiopharmaceuticals
(2022-01-13)Purpose: The aim of this study was to introduce a volumetric convolutional neural network for segmentation of the kidneys in SPECT images and to apply it in the dosimetry of radiopharmaceuticals of this organ, in order ... -
ESTIMATION OF RADIATION EXPOSURE FROM NATURALLY OCCURRING RADIONUCLIDES IN FOOD AND FOODSTUFF
(2022-01-13)Purpose: The main purpose of this study was to provide an estimation of the committed effective dose received by the Swedish population from naturally occurring radionuclides (NORM) in the diet. This study was also ... -
Evaluating aperture shape controller (ASC) in modulated radiation treatments
(2023-09-28)To decrease aperture complexity, the aperture shape controller (ASC) is a recently introduced function in Eclipse external beam planning (Varian Medical Systems, Palo Alto, USA). ASC works within the photon optimizer, ... -
Evaluation of deep learning image reconstruction for brain- and abdominal CT - A visual grading characteristics study
(2022-05-04)Computed tomography (CT) is a common medical imaging method today. There are different ways of reconstructing the images from a CT examination. The standard method is the filtered back projection (FBP). However, a disadvantage ... -
EVALUATION OF RADIATION DOSES USING CONE BEAM COMPUTED TOMOGRAPHY IN ENDOVASCULAR AORTIC REPAIR AND SCOLIOSIS PROCEDURES
(2021-04-06)Purpose: The study includes the two areas, vascular surgery and orthopedics, and focuses on endovascular aortic aneurysm repair (EVAR) and scoliosis procedures. EVAR procedures contribute to a high radiation dose to ... -
Evaluation of the DXA radiation environment at Sahlgrenska University Hospital
(2022-05-18)Purpose: The aims of this work were to evaluate the radiation environment in the dual-energy X-ray absorptiometry (DXA) rooms at Sahlgrenska University Hospital, estimate personnel doses, determine legal requirements for ... -
Evaluation of the iterative kilovoltage cone-beam computed tomography reconstruction method for the Varian TrueBeam system
(2022-03-18)Introduction: Radiotherapy is used to treat patients with various types of cancer, where linear accelerators produce the radiation beam used for the treatment. Before each treatment fraction, the patient needs to be ... -
Evaluation of whole-body bone scans performed using a gamma camera with Cadmium Zinc Telluride detector
(2022-01-13)The bone scan is a common nuclear medicine imaging procedure that is mainly used for evaluating several oncological patient groups. A radioactive tracer, 99mTc -labelled diphosphonate, is injected intravenously and ... -
FETAL DOSE ESTIMATION IN ABDOMINAL AND PELVIC CT EXAMINATIONS
(2021-05-10)Purpose: The purpose of this is study was to compare different methods for estimating the fetal dose, how much the different methods differ from each other and on which dose levels the fetal doses are estimated to. ... -
Measuring natural hemispheric asymmetry in the brain: quantifying the Yakovlevian torque phenomenon
(2022-01-13)Background: Just by a cursory examination, the two hemispheres of the human brain may appear as mirror images of one another. Yet, the left and right sides exhibit profound differences in anatomy. One of the most obvious ... -
Models for estimating radiation dose and LAR from radioactive fallout: extended dose algorithms for the computational tool LARCalc
(2022-09-09)Today, emergency preparedness is needed against both nuclear reactor accidents and nuclear weapons fallout. Both scenarios can lead to exposure of ionizing radiation. Upon exposure, radionuclides will incur a radiation ... -
Monte Carlo evaluation of static and dynamic 6FFF treatments - Evaluation of dose distributions calculated with AAA, Acuros XB, and Collapsed Cone (RayStation and DoseCheck)
(2023-02-23)There are several benefits to removing the standard flattening filter and using so-called flattening filter free (FFF) treatments in external radiation therapy with photons. The main advantage is the possibility of ... -
Optimization of MP2RAGE sequence parameters for head and neck T1-mapping and OE-MRI
(2022-05-04)Cancer is the collective name for more than 200 types of diseases that annually causes the death of 8.8 million people, cancer in the head and neck (H&N) accounts for 330.000 of these. It has been shown that hypoxic tumors ... -
osimetric impact of system spe cific geometric distortion on head and neck treatment plans in MRI only based radiation therapy
(2022-01-13)Background/ purpose: Because of the superior soft tissue contrast, in comparison with computed tomography (CT) data, magnetic resonance imaging (MRI) is of high interest to include in a larger extent in the ra diation ... -
Preprocessing for intravoxel incoherent motion analysis in the brain - Signal drift correction
(2023-04-17)Diffusion magnetic resonance imaging (dMRI) is a diagnostic imaging technique that is sensitized to the movement of water molecules in tissues. Intravoxel incoherent motion (IVIM) analysis can be used to estimate blood ...