Brendan Hill - School of Physics
... polymer gel was subsequently shown to be useful for both radiotherapy and diagnostic dosimetry with high spatial resolution being achieved when imaged with MRI in the relevant clinical dose ranges [14]. In addition to the MRI evaluation of polymer gels other evaluation modalities such as optical tom ...
... polymer gel was subsequently shown to be useful for both radiotherapy and diagnostic dosimetry with high spatial resolution being achieved when imaged with MRI in the relevant clinical dose ranges [14]. In addition to the MRI evaluation of polymer gels other evaluation modalities such as optical tom ...
A Guide to CT Radiation Dose Management
... Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Fundamentals of Scanning Parameters and Radiation Dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ...
... Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Fundamentals of Scanning Parameters and Radiation Dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ...
X-ray-based attenuation correction for positron emission
... Transmission of photons through any material can be characterized by the linear attenuation coefficient , which depends on the photon energy E and the atomic number Z of the material. The linear attenuation coefficient can be defined as the probability per unit pathlength that the photon will inter ...
... Transmission of photons through any material can be characterized by the linear attenuation coefficient , which depends on the photon energy E and the atomic number Z of the material. The linear attenuation coefficient can be defined as the probability per unit pathlength that the photon will inter ...
The management of imaging dose during image-guided
... increasing steadily with the introduction of more imaging procedures to the treatment process. However, much of this exposure is only qualitatively monitored, and some is not monitored at all. Aird maintains that because this cumulative extra-target dose has a negative biological effect even within ...
... increasing steadily with the introduction of more imaging procedures to the treatment process. However, much of this exposure is only qualitatively monitored, and some is not monitored at all. Aird maintains that because this cumulative extra-target dose has a negative biological effect even within ...
The management of imaging dose during image-guided
... increasing steadily with the introduction of more imaging procedures to the treatment process. However, much of this exposure is only qualitatively monitored, and some is not monitored at all. Aird maintains that because this cumulative extra-target dose has a negative biological effect even within ...
... increasing steadily with the introduction of more imaging procedures to the treatment process. However, much of this exposure is only qualitatively monitored, and some is not monitored at all. Aird maintains that because this cumulative extra-target dose has a negative biological effect even within ...
article in press - The EndoExperience
... Ludlow et al. shows a good overall reproducibility (2.5% variation between repeated identical examinations), although some specific TLD locations showed a large variation [11]. It is clear that effective dose estimations are dependent on many factors which are not standardised, such as the phantom i ...
... Ludlow et al. shows a good overall reproducibility (2.5% variation between repeated identical examinations), although some specific TLD locations showed a large variation [11]. It is clear that effective dose estimations are dependent on many factors which are not standardised, such as the phantom i ...
Patient and Staff Radiological Protection in Cardiology
... adults. They also have a longer potential lifespan than do adults, so they have more time to develop possible radiation related sequelae. Deterministic effects (e.g., skin injury) are due to injury in populations of cells, characterised by a threshold dose and an increase in the incidence and severi ...
... adults. They also have a longer potential lifespan than do adults, so they have more time to develop possible radiation related sequelae. Deterministic effects (e.g., skin injury) are due to injury in populations of cells, characterised by a threshold dose and an increase in the incidence and severi ...
Influence of Horizontal Condylar Angle and X
... surrounding alveolar bone, which is useful in obtaining general information about a patient’s oral health status. Panoramic radiographs also give information about the integrity of structures related to teeth such as maxillary sinus and mandibular condyle [1]. Panoramic radiographs are used very fre ...
... surrounding alveolar bone, which is useful in obtaining general information about a patient’s oral health status. Panoramic radiographs also give information about the integrity of structures related to teeth such as maxillary sinus and mandibular condyle [1]. Panoramic radiographs are used very fre ...
Reducing Radiation Dose to the Female Breast During
... make the world free of illness. The rest of us will write you epic poems and staple them together into a booklet.” Daniel Handler, Adverbs ...
... make the world free of illness. The rest of us will write you epic poems and staple them together into a booklet.” Daniel Handler, Adverbs ...
1 - Portfoliocommunities
... a low negative charge. This counteracts the divergence of the negatively charged electrons. Focusing them toward the target of the anode ...
... a low negative charge. This counteracts the divergence of the negatively charged electrons. Focusing them toward the target of the anode ...
radiation medicine qa
... as a 27-year-old after a serious illness, I thought about what I wanted to do Prof. Wilhelm Hammer, in my future professional life. 1885-1949, inventor of the relay-based Hammer doseI considered qualifying as a meter and founder of PTW university lecturer. But in the end, fate would have it that I m ...
... as a 27-year-old after a serious illness, I thought about what I wanted to do Prof. Wilhelm Hammer, in my future professional life. 1885-1949, inventor of the relay-based Hammer doseI considered qualifying as a meter and founder of PTW university lecturer. But in the end, fate would have it that I m ...
Measurements of void fraction distribution in cavitating pipe flow
... at the vapor–liquid boundary layer, harder radiation such as xrays is needed for these measurements which are not scattered at the gas–liquid interface. Over the past few years, much effort has been put into this field of cavitation research. By examining a cavitating flow with x-rays, a quantitativ ...
... at the vapor–liquid boundary layer, harder radiation such as xrays is needed for these measurements which are not scattered at the gas–liquid interface. Over the past few years, much effort has been put into this field of cavitation research. By examining a cavitating flow with x-rays, a quantitativ ...
Radiation Dose and Image Quality in Computed
... the use of automatic exposure control (AEC) and fixed tube current (FTC) techniques using a head and body phantom in a Siemens emotion 16-slice multidetector computed tomography (MDCT) scanner. The head and body phantoms were scanned with AEC activated and with FTC for routine head, chest, abdomen a ...
... the use of automatic exposure control (AEC) and fixed tube current (FTC) techniques using a head and body phantom in a Siemens emotion 16-slice multidetector computed tomography (MDCT) scanner. The head and body phantoms were scanned with AEC activated and with FTC for routine head, chest, abdomen a ...
Energy Subtraction Methods as an Alternative to Conventional X
... mask and contrasted images which cause motion artifacts. An alternative approach, known as dual-energy or energy subtraction angiography (ESA) is one that exploits the iodine kedge by acquiring images with a low and high kV in rapid succession. The idea for ESA is to bring the benefits of DSA to car ...
... mask and contrasted images which cause motion artifacts. An alternative approach, known as dual-energy or energy subtraction angiography (ESA) is one that exploits the iodine kedge by acquiring images with a low and high kV in rapid succession. The idea for ESA is to bring the benefits of DSA to car ...
Dose and image quality for a cone-beam C-arm
... Cone-beam C-arm imaging has entered clinical routine for neuro-interventional applications permitting the visualization of detailed cerebral vasculature.1–3 With new improvements in detector technology, image reconstruction, and image correction algorithms,4–8 three-dimensional 共3D兲 cone-beam C-arm ...
... Cone-beam C-arm imaging has entered clinical routine for neuro-interventional applications permitting the visualization of detailed cerebral vasculature.1–3 With new improvements in detector technology, image reconstruction, and image correction algorithms,4–8 three-dimensional 共3D兲 cone-beam C-arm ...
Reduction of CT dose for CT-based PET attenuation correction
... One important goal of quantitative imaging using positron emission tomography (PET) combined with X-ray computed tomography (CT) is to accurately measure a tumor's characteristics both before and during therapy to determine as early as possible the efficacy of the treatment. The transmission CT scan ...
... One important goal of quantitative imaging using positron emission tomography (PET) combined with X-ray computed tomography (CT) is to accurately measure a tumor's characteristics both before and during therapy to determine as early as possible the efficacy of the treatment. The transmission CT scan ...
Managing Patient Dose in Multi-Detector Computed Tomography
... The selection of image quality parameters in AEC systems is not a straightforward process. There is lack of consensus on how image quality is to be specified; with the result that there are significant differences in the ways different companies achieve exposure control. It is important that users a ...
... The selection of image quality parameters in AEC systems is not a straightforward process. There is lack of consensus on how image quality is to be specified; with the result that there are significant differences in the ways different companies achieve exposure control. It is important that users a ...
CONE BEAM COMPUTED TOMOGRAPHY THREE-DIMENSIONAL RECONSTRUCTION FOR EVALUATION OF THE MANDIBULAR CONDYLE
... X-Ray X-rays were an accidental discovery made by Wilhelm Conrad Roentgen on November 8, 1885.20 ...
... X-Ray X-rays were an accidental discovery made by Wilhelm Conrad Roentgen on November 8, 1885.20 ...
evaluation of a diffraction-enhanced imaging (dei)
... LAURA FAULCONER: Evaluation of a Diffraction-Enhanced Imaging (DEI) Prototype and Exploration of Novel Applications for Clinical Implementation of DEI (Under the direction of Etta Pisano) Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visuali ...
... LAURA FAULCONER: Evaluation of a Diffraction-Enhanced Imaging (DEI) Prototype and Exploration of Novel Applications for Clinical Implementation of DEI (Under the direction of Etta Pisano) Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visuali ...
Anniversary Paper: Development of x
... Image artifacts also occupied an important body of early research. The deleterious effect of the polychromatic spectrum of conventional x-ray sources on CT image quality— the so-called beam hardening effect—was recognized and described early in this era, along with a number of correction algorithms. ...
... Image artifacts also occupied an important body of early research. The deleterious effect of the polychromatic spectrum of conventional x-ray sources on CT image quality— the so-called beam hardening effect—was recognized and described early in this era, along with a number of correction algorithms. ...
Electromagnetic Tracking for Medical Imaging
... Respiratory motion has significant effects on abdominal and lung tumor position, and the uncertainty of the motion increases the treatment volume of the target due to a blurred tissue margin [1]. Respiratory correlated CT, which is obtained by oversampling images over the breathing cycles based on a ...
... Respiratory motion has significant effects on abdominal and lung tumor position, and the uncertainty of the motion increases the treatment volume of the target due to a blurred tissue margin [1]. Respiratory correlated CT, which is obtained by oversampling images over the breathing cycles based on a ...
Cone beam computed tomography: Adding three dimensions to
... found to be 51.5% by Weine et al.[19] They had stated that the difficulty to detect the extra canal with intraoral radiograph could result in an unexplained failure of the treatment. CBCT helps in confirming the presence of MB2 [Figure 3] and also determining its internal anatomy in relation to mesiob ...
... found to be 51.5% by Weine et al.[19] They had stated that the difficulty to detect the extra canal with intraoral radiograph could result in an unexplained failure of the treatment. CBCT helps in confirming the presence of MB2 [Figure 3] and also determining its internal anatomy in relation to mesiob ...
CT scanner automatic exposure control systems
... mainly due to the wide range of available tube current settings, typically from around 50 to 500 mA on a modern scanner. In addition, variations in rotation time are restricted by the need to perform most scans within a limited time frame, such as a single patient breath hold. All CT scanners have a ...
... mainly due to the wide range of available tube current settings, typically from around 50 to 500 mA on a modern scanner. In addition, variations in rotation time are restricted by the need to perform most scans within a limited time frame, such as a single patient breath hold. All CT scanners have a ...
Characterization of the homogeneous tissue mixture approximation
... adipose and glandular tissue as obtained from BCT images of the specimens and the corresponding homogeneous tissue mixture approximation, finding no significant difference between these two groups.29 However, as mentioned, that study compared the average breast dose, not the mean glandular dose, inc ...
... adipose and glandular tissue as obtained from BCT images of the specimens and the corresponding homogeneous tissue mixture approximation, finding no significant difference between these two groups.29 However, as mentioned, that study compared the average breast dose, not the mean glandular dose, inc ...
communicating radiation risks in paediatric imaging
... and communication experts. Subsequent revisions of the document were made based on feedback collected through a number of workshops held in different regions of the world. This document is intended to serve as a communication tool about known or potential radiation risks associated with paediatric i ...
... and communication experts. Subsequent revisions of the document were made based on feedback collected through a number of workshops held in different regions of the world. This document is intended to serve as a communication tool about known or potential radiation risks associated with paediatric i ...
X-ray
X-radiation (composed of X-rays) is a form of electromagnetic radiation. Most X-rays have a wavelength ranging from 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz (3×1016 Hz to 3×1019 Hz) and energies in the range 100 eV to 100 keV. X-ray wavelengths are shorter than those of UV rays and typically longer than those of gamma rays. In many languages, X-radiation is referred to with terms meaning Röntgen radiation, after Wilhelm Röntgen, who is usually credited as its discoverer, and who had named it X-radiation to signify an unknown type of radiation. Spelling of X-ray(s) in the English language includes the variants x-ray(s), xray(s) and X ray(s).X-rays with photon energies above 5–10 keV (below 0.2–0.1 nm wavelength) are called hard X-rays, while those with lower energy are called soft X-rays. Due to their penetrating ability, hard X-rays are widely used to image the inside of objects, e.g., in medical radiography and airport security. As a result, the term X-ray is metonymically used to refer to a radiographic image produced using this method, in addition to the method itself. Since the wavelengths of hard X-rays are similar to the size of atoms they are also useful for determining crystal structures by X-ray crystallography. By contrast, soft X-rays are easily absorbed in air and the attenuation length of 600 eV (~2 nm) X-rays in water is less than 1 micrometer.There is no universal consensus for a definition distinguishing between X-rays and gamma rays. One common practice is to distinguish between the two types of radiation based on their source: X-rays are emitted by electrons, while gamma rays are emitted by the atomic nucleus. This definition has several problems; other processes also can generate these high energy photons, or sometimes the method of generation is not known. One common alternative is to distinguish X- and gamma radiation on the basis of wavelength (or equivalently, frequency or photon energy), with radiation shorter than some arbitrary wavelength, such as 10−11 m (0.1 Å), defined as gamma radiation.This criterion assigns a photon to an unambiguous category, but is only possible if wavelength is known. (Some measurement techniques do not distinguish between detected wavelengths.) However, these two definitions often coincide since the electromagnetic radiation emitted by X-ray tubes generally has a longer wavelength and lower photon energy than the radiation emitted by radioactive nuclei.Occasionally, one term or the other is used in specific contexts due to historical precedent, based on measurement (detection) technique, or based on their intended use rather than their wavelength or source.Thus, gamma-rays generated for medical and industrial uses, for example radiotherapy, in the ranges of 6–20 MeV, can in this context also be referred to as X-rays.