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... frequency of infective exacerbations and disease progression[19,20], one must remain cognisant of the radiation dose incurred from this method of assessment[21]. Recent studies have shown that the dose from dose optimised CT scans is equivalent to one-third of one year’s background radiation[22]. P ...
... frequency of infective exacerbations and disease progression[19,20], one must remain cognisant of the radiation dose incurred from this method of assessment[21]. Recent studies have shown that the dose from dose optimised CT scans is equivalent to one-third of one year’s background radiation[22]. P ...
New dimensions in endodontic imaging: Part 2. Cone beam
... skeleton at a considerably lower radiation dose than conventional computed tomography (CT) (Mozzo et al. 1998, Arai et al. 2001). With CBCT, a three-dimensional volume of data is acquired in the course of a single sweep of the scanner, using a simple, direct relationship between sensor and source, w ...
... skeleton at a considerably lower radiation dose than conventional computed tomography (CT) (Mozzo et al. 1998, Arai et al. 2001). With CBCT, a three-dimensional volume of data is acquired in the course of a single sweep of the scanner, using a simple, direct relationship between sensor and source, w ...
Tomographic Imaging on a Cobalt Radiotherapy Machine Matthew Brendon Marsh
... tungsten or depleted uranium, and is exposed by moving the source into alignment with an opening in the shield. Sources are typically replaced after approximately one half-life. Most modern teletherapy equipment does not use radioactive sources. Rather, a particle accelerator– usually a linear accel ...
... tungsten or depleted uranium, and is exposed by moving the source into alignment with an opening in the shield. Sources are typically replaced after approximately one half-life. Most modern teletherapy equipment does not use radioactive sources. Rather, a particle accelerator– usually a linear accel ...
Cine MR angiography of the heart with segmented true fast imaging
... and blood-myocardial signal-to-noise ratio (SNR). With true fast imaging with steadystate precession (FISP) (2– 4), an alternating, large-flip-angle, radio-frequency excitation scheme coupled with a fully balanced gradient waveform is used to recycle steady-state magnetization in long T2 species. Th ...
... and blood-myocardial signal-to-noise ratio (SNR). With true fast imaging with steadystate precession (FISP) (2– 4), an alternating, large-flip-angle, radio-frequency excitation scheme coupled with a fully balanced gradient waveform is used to recycle steady-state magnetization in long T2 species. Th ...
Thomas R. Nelson, Ph.D. Professor of Radiology UC San Diego
... x0 and y0 are the coordinates of the center of a region R with the area F. Then the moments Mij are defined by: Mij = SUM ( (x0 - x)^i (y0 - y)^j ) , where x and y run through all pixels of the region R. If the moments M20, M02 and M11 are normalized to the area, the radii Ra and Rb are ...
... x0 and y0 are the coordinates of the center of a region R with the area F. Then the moments Mij are defined by: Mij = SUM ( (x0 - x)^i (y0 - y)^j ) , where x and y run through all pixels of the region R. If the moments M20, M02 and M11 are normalized to the area, the radii Ra and Rb are ...
December 2012 - University of Iowa Carver College of Medicine
... To change gears, I have a personal appeal to our friends and alumni. Our residents have, for many years, become involved in research activities during their training. And they are required to do so by the Radiology Residency Review Committee. Each resident works under a designated faculty member on ...
... To change gears, I have a personal appeal to our friends and alumni. Our residents have, for many years, become involved in research activities during their training. And they are required to do so by the Radiology Residency Review Committee. Each resident works under a designated faculty member on ...
Standardized volumetric 3D-analysis of SPECT/CT imaging in
... altered metabolic activity it is essential that the reference system is well defined. Further, to overcome the relative position and orientation of the patient to the coordinate system of the scanner, the reference system should be based on anatomic landmarks that are identifiable in subsequent scan ...
... altered metabolic activity it is essential that the reference system is well defined. Further, to overcome the relative position and orientation of the patient to the coordinate system of the scanner, the reference system should be based on anatomic landmarks that are identifiable in subsequent scan ...
evaluation of image-guidance protocols in the treatment of head and
... in the literature for immobilized head-and-neck patients (11). Figure 1 shows the mean systematic error, M; the standard deviation of the systematic error, 冱; and the average random error, , for the residual setup errors after each protocol is applied retrospectively to the daily setup corrections. ...
... in the literature for immobilized head-and-neck patients (11). Figure 1 shows the mean systematic error, M; the standard deviation of the systematic error, 冱; and the average random error, , for the residual setup errors after each protocol is applied retrospectively to the daily setup corrections. ...
77 basic science temel bi̇lgi̇ler susceptibility
... necessary to emphasize the loss of signal intensity caused by any susceptibility effects. The first step is to remove incidental phase variations in the images due to static magnetic field heterogeneities. As a second step, phase mask is created from the MR phase images and multiplied with the magni ...
... necessary to emphasize the loss of signal intensity caused by any susceptibility effects. The first step is to remove incidental phase variations in the images due to static magnetic field heterogeneities. As a second step, phase mask is created from the MR phase images and multiplied with the magni ...
Ultra-Fast Digital Tomosynthesis Reconstruction Using General
... In certain clinical settings, however, CBCT may not be the optimal method for localization because the patient dose is significant (30-32) and acquisition times are long (33-35). In addition, the images may be impossible to acquire for large off-axis patient set-ups, large patients, and/or bulky imm ...
... In certain clinical settings, however, CBCT may not be the optimal method for localization because the patient dose is significant (30-32) and acquisition times are long (33-35). In addition, the images may be impossible to acquire for large off-axis patient set-ups, large patients, and/or bulky imm ...
Single Slice CT Scanner Comparison Report
... Dose efficiency is a term used to describe the quality of a scanner's images relative to the radiation dose to the patient. It can be expressed in a number of ways, ImPACT normally use the 'Q-value', which combines measurements of noise, high contrast resolution, slice thickness and dose to produce ...
... Dose efficiency is a term used to describe the quality of a scanner's images relative to the radiation dose to the patient. It can be expressed in a number of ways, ImPACT normally use the 'Q-value', which combines measurements of noise, high contrast resolution, slice thickness and dose to produce ...
Perfusion magnetic resonance imaging with continuous arterial spin
... resonance imaging (MRI). One class of techniques utilizes electromagnetically labeled arterial blood water as a noninvasive diffusible tracer for blood flow measurements. The electromagnetically labeled tracer has a decay rate of T1, which is sufficiently long to allow perfusion of the tissue and mi ...
... resonance imaging (MRI). One class of techniques utilizes electromagnetically labeled arterial blood water as a noninvasive diffusible tracer for blood flow measurements. The electromagnetically labeled tracer has a decay rate of T1, which is sufficiently long to allow perfusion of the tissue and mi ...
Gastrointestinal Tract scintigraphy and Localization of Active
... At 4 hours after injection Radiolabeled Leukocytes (experimental studies) ...
... At 4 hours after injection Radiolabeled Leukocytes (experimental studies) ...
Iterative model reconstruction - Medical Physics International Journal
... discussed above, as well as the reaction of the human visual perception system to those factors. High noise may obscure the low contrast object in the noise and make it difficult for a human to perceive it. Poor spatial resolution may blur the object and blend it in with the background and poor unif ...
... discussed above, as well as the reaction of the human visual perception system to those factors. High noise may obscure the low contrast object in the noise and make it difficult for a human to perceive it. Poor spatial resolution may blur the object and blend it in with the background and poor unif ...
Institutionen för medicin och hälsa Department of Medical and Health Sciences
... a new MRI technique named synthetic MRI (SyMRI). SyMRI is based on quantitative measurements of data and absolute values of the magnetic properties of the biological tissue can be obtained. The purpose of this master thesis has been to take the development of SyMRI a step further by developing and i ...
... a new MRI technique named synthetic MRI (SyMRI). SyMRI is based on quantitative measurements of data and absolute values of the magnetic properties of the biological tissue can be obtained. The purpose of this master thesis has been to take the development of SyMRI a step further by developing and i ...
Assessment of Lipiodol Deposition and Residual
... Hepatocellular carcinoma (HCC) is primarily an ordinary cause of cancer-related death worldwide, especially in China (1-6). The incidence of HCC keeps the highest in Eastern Asia and Africa, while its frequency has been increased rapidly in western countries and Japan as well (7, 8). Transcatheter a ...
... Hepatocellular carcinoma (HCC) is primarily an ordinary cause of cancer-related death worldwide, especially in China (1-6). The incidence of HCC keeps the highest in Eastern Asia and Africa, while its frequency has been increased rapidly in western countries and Japan as well (7, 8). Transcatheter a ...
Finding Value in Digital Breast Tomosynthesis 29
... in 2015, and that number is expected to reach nearly $1.8 billion by 2022 — an increase of nearly $970 million in just seven years. The growth will largely be driven by increasing use of computed tomography (CT), magnetic resonance imaging (MRI) and angiography procedures, as well as increasing dise ...
... in 2015, and that number is expected to reach nearly $1.8 billion by 2022 — an increase of nearly $970 million in just seven years. The growth will largely be driven by increasing use of computed tomography (CT), magnetic resonance imaging (MRI) and angiography procedures, as well as increasing dise ...
Excite Diffusion Tensor Quick Steps
... one placed before the 180° RF, the other immediately after. This pair of gradients is applied not only for the slice gradient axes, but the readout and the phase gradient axes as well. These six gradients provide the basis of the mathematical expression called Diffusion Tensor. In order to calculate ...
... one placed before the 180° RF, the other immediately after. This pair of gradients is applied not only for the slice gradient axes, but the readout and the phase gradient axes as well. These six gradients provide the basis of the mathematical expression called Diffusion Tensor. In order to calculate ...
Gas Phase UTE MRI of Propane and Propene
... pressures was shown about 15 years ago, with 2-dimensional (2D) images of flowing and static gas and flow velocity maps in pipes and multichannel monolith structures detected using a spin-echo pulse sequence (28, 29). In addition to the low spin density of gases, the rapid diffusion of gases in appl ...
... pressures was shown about 15 years ago, with 2-dimensional (2D) images of flowing and static gas and flow velocity maps in pipes and multichannel monolith structures detected using a spin-echo pulse sequence (28, 29). In addition to the low spin density of gases, the rapid diffusion of gases in appl ...
2011 Rosen et al. J Am Coll Radiol.
... population for acute appendicitis. MRI is desirable due to its lack of ionizing radiation; however, it is limited due to its higher cost, slower acquisition time, and lesser clinical availability. Several small, retrospective studies cite sensitivity of 97%-100% and specificity of 92%-94% [31]; one ...
... population for acute appendicitis. MRI is desirable due to its lack of ionizing radiation; however, it is limited due to its higher cost, slower acquisition time, and lesser clinical availability. Several small, retrospective studies cite sensitivity of 97%-100% and specificity of 92%-94% [31]; one ...
Cardiac MR in clinical routine: the evolving role
... all 11040 consecutive patients who underwent a CMRI procedure between April 2007 and January 2009 in one of the 20 participating sites. Each participating center appointed a senior cardiologist or radiologist as local investigator responsible for the data quality of each individual patient. For qual ...
... all 11040 consecutive patients who underwent a CMRI procedure between April 2007 and January 2009 in one of the 20 participating sites. Each participating center appointed a senior cardiologist or radiologist as local investigator responsible for the data quality of each individual patient. For qual ...
C a t p h a n ® 500 and 600 M a n u a l
... numbers 4 and 5 will have better uniformity than outer slice numbers 1 and 8 because of the scanner x-ray beam geometry. However, if 1 and 8 or 4 and 5 are not similar, this may indicate a problem with the scanner. When assessing a scanner with a step and shoot mode, it is important to cover the ful ...
... numbers 4 and 5 will have better uniformity than outer slice numbers 1 and 8 because of the scanner x-ray beam geometry. However, if 1 and 8 or 4 and 5 are not similar, this may indicate a problem with the scanner. When assessing a scanner with a step and shoot mode, it is important to cover the ful ...
SNM Practice Guideline for Lung Scintigraphy 4.0
... tested and shown to be more accurate than the original PIOPED criteria (19). In an attempt to reduce the number of nondiagnostic studies, the PIOPED II criteria were modified using fewer categories. The performance of the modified PIOPED II criteria was evaluated on the PIOPED II database (20). The ...
... tested and shown to be more accurate than the original PIOPED criteria (19). In an attempt to reduce the number of nondiagnostic studies, the PIOPED II criteria were modified using fewer categories. The performance of the modified PIOPED II criteria was evaluated on the PIOPED II database (20). The ...
Radiation Protection – Chapter 23, Bushberg
... If the scintillator is later heated, the electrons can then fall to their ground state with the emission of light Thermoluminescent (TL) means emitting light when heated ...
... If the scintillator is later heated, the electrons can then fall to their ground state with the emission of light Thermoluminescent (TL) means emitting light when heated ...
The History, Development and Impact of Computed Imaging
... newspapers he approached declined to report about it initially, the editor of an Austrian paper did run the story and the news was then rapidly picked up and reported in papers around the world.54,109 We now understand the X-rays to be electromagnetic radiation emitted by electrons that have much h ...
... newspapers he approached declined to report about it initially, the editor of an Austrian paper did run the story and the news was then rapidly picked up and reported in papers around the world.54,109 We now understand the X-rays to be electromagnetic radiation emitted by electrons that have much h ...
Positron emission tomography
Positron emission tomography (PET) is a nuclear medicine, functional imaging technique that produces a three-dimensional image of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. Three-dimensional images of tracer concentration within the body are then constructed by computer analysis. In modern PET-CT scanners, three dimensional imaging is often accomplished with the aid of a CT X-ray scan performed on the patient during the same session, in the same machine.If the biologically active molecule chosen for PET is fluorodeoxyglucose (FDG), an analogue of glucose, the concentrations of tracer imaged will indicate tissue metabolic activity as it corresponds to the regional glucose uptake. Use of this tracer to explore the possibility of cancer metastasis (i.e., spreading to other sites) is the most common type of PET scan in standard medical care (90% of current scans). However, on a minority basis, many other radioactive tracers are used in PET to image the tissue concentration of other types of molecules of interest. One of the disadvantages of PET scanners is their operating cost.