SPECT/CT Physical Principles and Attenuation Correction*
... the CT acquisition can be found in a stored look-up table in the reconstruction algorithm. The conversion can then be performed using 2 simple linear relationships relating the attenuation coefficient at the desired energy and the measured CT numbers for specific measured tissues. There are numerous ...
... the CT acquisition can be found in a stored look-up table in the reconstruction algorithm. The conversion can then be performed using 2 simple linear relationships relating the attenuation coefficient at the desired energy and the measured CT numbers for specific measured tissues. There are numerous ...
Simple methods to reduce patient dose in a
... For the default technique settings, the dose in the CTDI phantom was 23.7 mGy at the isocentre and 53.3 mGy at the periphery. Using a weighting of 1/3 to 2/3, this results in a weighted CTDI of approximately 45 mGy. This can be compared with a value of 54 mGy reported for the same procedure in the l ...
... For the default technique settings, the dose in the CTDI phantom was 23.7 mGy at the isocentre and 53.3 mGy at the periphery. Using a weighting of 1/3 to 2/3, this results in a weighted CTDI of approximately 45 mGy. This can be compared with a value of 54 mGy reported for the same procedure in the l ...
Fusion of MRIs and CT Scans for Surgical Treatment of
... Results: In 10 children, fusion technique allowed for correct diagnosis and precise localization (hypotympanum, epitympanum, mastoid recess, and attical space) as confirmed by subsequent standard surgery (positive predictive value, 100%). In 3 cases, the surgical approach was adequately determined f ...
... Results: In 10 children, fusion technique allowed for correct diagnosis and precise localization (hypotympanum, epitympanum, mastoid recess, and attical space) as confirmed by subsequent standard surgery (positive predictive value, 100%). In 3 cases, the surgical approach was adequately determined f ...
Actas Urológicas Españolas ACTAS
... 25-30 seconds after contrast administration. This allows for examination of vascular anatomy to detect bleeding and for assessment of early vascular behavior of lesions; b) parenchymal phase, in which kidney medulla is enhanced to the same extent as renal cortex. This occurs within 50-180 seconds of ...
... 25-30 seconds after contrast administration. This allows for examination of vascular anatomy to detect bleeding and for assessment of early vascular behavior of lesions; b) parenchymal phase, in which kidney medulla is enhanced to the same extent as renal cortex. This occurs within 50-180 seconds of ...
Poster Presentation - Research
... The synergistic activity of large neural populations remains largely unexplored in the visual cortex. Hemodynamic metabolic approaches to exploring this activity are based on the fact that energy metabolism (measured as a function of cerebral blood flow and volume change) is coupled to neuronal acti ...
... The synergistic activity of large neural populations remains largely unexplored in the visual cortex. Hemodynamic metabolic approaches to exploring this activity are based on the fact that energy metabolism (measured as a function of cerebral blood flow and volume change) is coupled to neuronal acti ...
Comparison of Radiopharmaceuticals Used in Myocardial Imaging
... This equilibration process has two components washout of 201Tl from the myocardium and new myocardial uptake of 201Tlfrom the blood pool. In myocardium that is ischcmic, the relative amount of thallium in the zone of diminished perfusion is lower than that of the normally perfused mne (indirect prop ...
... This equilibration process has two components washout of 201Tl from the myocardium and new myocardial uptake of 201Tlfrom the blood pool. In myocardium that is ischcmic, the relative amount of thallium in the zone of diminished perfusion is lower than that of the normally perfused mne (indirect prop ...
Dose Management Update for Advocate Healthcare
... Notices (2 of 2) In clinical practice, the use of ASiR-V may reduce CT patient dose depending on the clinical task, patient size, anatomical location, and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image ...
... Notices (2 of 2) In clinical practice, the use of ASiR-V may reduce CT patient dose depending on the clinical task, patient size, anatomical location, and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate dose to obtain diagnostic image ...
Dose issues on multi-slice CT scanners
... operator must decide whether, and if so, by how much, to adjust these settings to take into account variations in patient size. More recently, following concerns about dose levels in CT, particularly to paediatric patients [10], age or weight based tables of exposure settings are often provided as a ...
... operator must decide whether, and if so, by how much, to adjust these settings to take into account variations in patient size. More recently, following concerns about dose levels in CT, particularly to paediatric patients [10], age or weight based tables of exposure settings are often provided as a ...
Informatics in Radiology: Sliding-Thin
... data postprocessing and image display, to gain both high through-plane spatial resolution with minimal partial-volume averaging effects and excellent depiction of low-contrast lesions. In the initial stage of data postprocessing, a secondary “raw” data set is reconstructed from a CT volume data set ...
... data postprocessing and image display, to gain both high through-plane spatial resolution with minimal partial-volume averaging effects and excellent depiction of low-contrast lesions. In the initial stage of data postprocessing, a secondary “raw” data set is reconstructed from a CT volume data set ...
CT Dose Reduction Applications - Journal of the American College
... to determine if a low-kVp protocol is appropriate. Moreover, although it is generally the case that a compensatory increase in mAs is required to reduce image noise, there are no clear clinical guidelines to determine this increase, and there have been very few guidelines in the literature or from C ...
... to determine if a low-kVp protocol is appropriate. Moreover, although it is generally the case that a compensatory increase in mAs is required to reduce image noise, there are no clear clinical guidelines to determine this increase, and there have been very few guidelines in the literature or from C ...
Prospective motion correction of high-resolution magnetic resonance imaging data in children ⁎
... Real-time motion tracking and correction with spiral navigator (SNAV) sequences was performed using the extended Kalman filter (EKF) algorithm (Gelb, 1974) applied to MRI as reported by Dale and colleagues (White et al., 2007, 2010) and as described previously for prospective motion correction in S-N ...
... Real-time motion tracking and correction with spiral navigator (SNAV) sequences was performed using the extended Kalman filter (EKF) algorithm (Gelb, 1974) applied to MRI as reported by Dale and colleagues (White et al., 2007, 2010) and as described previously for prospective motion correction in S-N ...
RT 7
... management of patient motion, and making positional and dosimetric adjustments before and during treatment . The use of such systems will be further disc ussed in Chapter 25 on image-guided radiation therapy (IGRT). ...
... management of patient motion, and making positional and dosimetric adjustments before and during treatment . The use of such systems will be further disc ussed in Chapter 25 on image-guided radiation therapy (IGRT). ...
99mTc-MDP Bone Scan In the Detection of Bone
... information about patients following the administration of a radioactive product. Images are produced of the distribution of the radioactive substance within different organs and systems. This can be compared with normal distribution to diagnose if a medical condition is present and assess its exten ...
... information about patients following the administration of a radioactive product. Images are produced of the distribution of the radioactive substance within different organs and systems. This can be compared with normal distribution to diagnose if a medical condition is present and assess its exten ...
PET-/SPECT-MRI Attenuation Correction using
... Besides the difficulties to combine PET and MRI, it provides several more potential advantages compared to PET-CT as only the high soft-tissue contrast and elimination of additional ionizing radiation. Simultaneous imaging of function and morphology becomes possible, thus, greatly reducing the amoun ...
... Besides the difficulties to combine PET and MRI, it provides several more potential advantages compared to PET-CT as only the high soft-tissue contrast and elimination of additional ionizing radiation. Simultaneous imaging of function and morphology becomes possible, thus, greatly reducing the amoun ...
ACR–SPR–SSR Practice Parameter for the Performance and
... planar or SPECT-alone scans. The main value of SPECT/CT is more of precise anatomical localization of infection and accurate delineation of the infection extent after its diagnosis with planar scintigraphy [45]. Additionally, in patients with contraindications precluding MRI, nuclear medicine imagin ...
... planar or SPECT-alone scans. The main value of SPECT/CT is more of precise anatomical localization of infection and accurate delineation of the infection extent after its diagnosis with planar scintigraphy [45]. Additionally, in patients with contraindications precluding MRI, nuclear medicine imagin ...
Intracoronary MR imaging using a 0.014-inch MR imaging
... intracoronary interventions for decades. However, the limitation with this technique is that the x-ray contrast agent can outline only the vessel lumen. Magnetic resonance imaging (MRI), which provides not only anatomical images of the heart but also functional as well as metabolic information, may ...
... intracoronary interventions for decades. However, the limitation with this technique is that the x-ray contrast agent can outline only the vessel lumen. Magnetic resonance imaging (MRI), which provides not only anatomical images of the heart but also functional as well as metabolic information, may ...
1744 - OPTIMA CT660 - 05.indd
... The Optima CT660 system helps you deliver competent, personalized care that helps fulfill your mission and please your patients. One look at the sleek, modern design tells you this CT system is different. This new-generation, intelligent Volume CT scanner combines the advanced innovations from our Di ...
... The Optima CT660 system helps you deliver competent, personalized care that helps fulfill your mission and please your patients. One look at the sleek, modern design tells you this CT system is different. This new-generation, intelligent Volume CT scanner combines the advanced innovations from our Di ...
3D Imaging Systems - Carestream Dental
... SMV and TMJ images. This scan can even be used to produce a digital model. ...
... SMV and TMJ images. This scan can even be used to produce a digital model. ...
MR Imaging and CT of Vascular Anomalies and Connections in
... the pitch reduces radiation dose by half. A practical standard pitch for single– detector row helical CT in children is 1.5:1 (6). The decision to image with CT versus MR imaging should be based on institutional equipment, scheduling, and availability as well as the patient’s ability to cooperate. T ...
... the pitch reduces radiation dose by half. A practical standard pitch for single– detector row helical CT in children is 1.5:1 (6). The decision to image with CT versus MR imaging should be based on institutional equipment, scheduling, and availability as well as the patient’s ability to cooperate. T ...
NSS-MIC-todd-Poster
... same mean subject dose of 4 cGy. The rationale for the present work is the large slope of the dose versus depth curve (solid red in Fig. 1 for monochromatic protons) at the distal edge of the Bragg peak, producing large image sensitivity to density variations. Experimental results from PSI show that ...
... same mean subject dose of 4 cGy. The rationale for the present work is the large slope of the dose versus depth curve (solid red in Fig. 1 for monochromatic protons) at the distal edge of the Bragg peak, producing large image sensitivity to density variations. Experimental results from PSI show that ...
RAD309
... patient dose for particular examinations. Customize the exposure to patient size: adjust the exposure factors to compensate for changes in patient size (mAs for children examinations) ...
... patient dose for particular examinations. Customize the exposure to patient size: adjust the exposure factors to compensate for changes in patient size (mAs for children examinations) ...
Volumetric High-resolution Computed Tomography of the Lung — a
... of images were obtained by reconstructing the raw data using a high spatial frequency algorithm. These comprised 1.25-mm sections at 10 mm intervals (considered the standard data) and contiguous 0.625-mm thick sections (considered the volumetric data). The volumetric images were reviewed with multip ...
... of images were obtained by reconstructing the raw data using a high spatial frequency algorithm. These comprised 1.25-mm sections at 10 mm intervals (considered the standard data) and contiguous 0.625-mm thick sections (considered the volumetric data). The volumetric images were reviewed with multip ...
Canadian Association of Radiologists Radiation Protection Working
... patient is uniformly exposed, such as fetal radiation exposure, or if the skin entrance dose is monitored for deterministic effects, which may occur in long fluoroscopic procedures or CT perfusion studies. The majority of medical imaging procedures focuses on imaging a specific region of interest (e ...
... patient is uniformly exposed, such as fetal radiation exposure, or if the skin entrance dose is monitored for deterministic effects, which may occur in long fluoroscopic procedures or CT perfusion studies. The majority of medical imaging procedures focuses on imaging a specific region of interest (e ...
Brain Single-Photon Emission CT Physics Principles
... rain single-photon emission computed tomography (SPECT [also abbreviated as SPET]) is a noninvasive technique, which provides 3D functional information with high sensitivity and specificity. As with all nuclear medicine imaging procedures, it is based on the injection of tracer amounts (nano- to pic ...
... rain single-photon emission computed tomography (SPECT [also abbreviated as SPET]) is a noninvasive technique, which provides 3D functional information with high sensitivity and specificity. As with all nuclear medicine imaging procedures, it is based on the injection of tracer amounts (nano- to pic ...
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.