Estimation of mean glandular dose for breast tomosynthesis: factors for use with the UK, European and IAEA breast dosimetry protocols.

abstract：:We give an overview of the role of Physics in Medicine and Biology in the development of tomographic reconstruction algorithms. We focus on imaging modalities involving ionizing radiation, CT, PET and SPECT, and cover a wide spectrum of reconstruction problems, starting with classical 2D tomography in the 1970s up to ...

journal_title：Physics in medicine and biology

authors： Defrise M,Gullberg GT

更新日期：2006-07-07 00:00:00

abstract：:To evaluate the effect of approximations in clinical analytical calculations performed by a treatment planning system (TPS) on dosimetric indices in intensity modulated proton therapy. TPS calculated dose distributions were compared with dose distributions as estimated by Monte Carlo (MC) simulations, calculated with ...

journal_title：Physics in medicine and biology

authors： Yepes P,Adair A,Grosshans D,Mirkovic D,Poenisch F,Titt U,Wang Q,Mohan R

更新日期：2018-02-09 00:00:00

abstract：:Peripheral neural stimulation is a major problem in current gradient coil designs. Induced current problems in patients relate directly to gradient strength and modulation frequency. Present designs of gradient coil tend to limit ultra-high-speed imaging methods such as echo-planar imaging (EPI) and echo-volumar imagi...

journal_title：Physics in medicine and biology

authors： Mansfield P,Haywood B

更新日期：2008-04-07 00:00:00

abstract：:Ankylosing spondylitis is a disease characterized by abnormal bone formation (syndesmophyte) at the margins of inter-vertebral disc spaces. Syndesmophyte growth is currently typically monitored by the visual inspection of radiographs. The limitations inherent to the modality (2D projection of a 3D object) and rater (q...

journal_title：Physics in medicine and biology

authors： Tan S,Yao J,Yao L,Ward MM

更新日期：2012-07-21 00:00:00

abstract：:In recent years, optical techniques based on diffusion approximation have demonstrated their ability to gain rich spectral information about bone. However, these methods normally assume homogeneity, while cancellous bone and marrow form a highly heterogeneous two-phase medium. This paper studies the limitations of thi...

journal_title：Physics in medicine and biology

authors： Margallo-Balbás E,Taroni P,Pifferi A,Koolstra JH,v Ruijven LJ,French PJ

更新日期：2010-09-07 00:00:00

abstract：:A photon diffusion model has been developed to calculate the steady-state spatially resolved fluorescence from pencil beam excitation in layered tissue. The model allows the calculation of both the excitation reflectance and the fluorescence escape for an arbitrary continuous depth distribution of tissue optical prope...

journal_title：Physics in medicine and biology

authors： Hyde DE,Farrell TJ,Patterson MS,Wilson BC

更新日期：2001-02-01 00:00:00

abstract：:The signal-to-noise ratio (SNR) in x-ray imaging can be increased using a photon counting detector which could allow for rejecting electronics noise and for weighting x-ray photons according to their energies. This approach, however, was not feasible for a long time because photon counting x-ray detectors with very hi...

journal_title：Physics in medicine and biology

authors： Shikhaliev PM

更新日期：2009-08-21 00:00:00

abstract：:The most advanced delivery technique for proton radiotherapy is active spot scanning. So far, predominantly static targets have been treated with active spot scanning, since mobile targets in combination with dynamic treatment delivery can lead to interplay effects, causing inhomogeneous dose distributions. One way to...

journal_title：Physics in medicine and biology

authors： Knopf AC,Hong TS,Lomax A

更新日期：2011-11-21 00:00:00

abstract：:Managing uncertainty is a major challenge in radiation therapy treatment planning, including uncertainty induced by intrafraction motion, which is particularly important for tumours in the thorax and abdomen. Common methods to account for motion are to introduce a margin or to convolve the static dose distribution wit...

journal_title：Physics in medicine and biology

authors： Chan TC,Bortfeld T,Tsitsiklis JN

更新日期：2006-05-21 00:00:00

abstract：:In recent years, the Monte Carlo method has been used in a large number of research studies in radiation therapy. For applications such as treatment planning, it is essential to validate the dosimetric accuracy of the Monte Carlo simulations in heterogeneous media. The AAPM Report no 105 addresses issues concerning cl...

journal_title：Physics in medicine and biology

authors： Titt U,Sahoo N,Ding X,Zheng Y,Newhauser WD,Zhu XR,Polf JC,Gillin MT,Mohan R

更新日期：2008-08-21 00:00:00

abstract：:The spatial resolution of 2D detector arrays equipped with ionization chambers or diodes, used for the dose verification of IMRT treatment plans, is limited by the size of the single detector and the centre-to-centre distance between the detectors. Optimization criteria with regard to these parameters have been develo...

journal_title：Physics in medicine and biology

authors： Poppe B,Djouguela A,Blechschmidt A,Willborn K,Rühmann A,Harder D

更新日期：2007-05-21 00:00:00

abstract：:Using Monte Carlo simulation of 99Tcm single-photon-emission computed tomography (SPECT), we investigate the effects of tissue-background activity, tumour location, patient size, uncertainty of energy windows, and definition of tumour region on the accuracy of quantification. The dual-energy-window method of correctio...

journal_title：Physics in medicine and biology

authors： Luo JQ,Koral KF,Ljungberg M,Floyd CE Jr,Jaszczak RJ

更新日期：1995-01-01 00:00:00

abstract：:Gel dosimetry based on magnetic resonance imaging (MRI) has previously been shown to provide verification of calculated dose distributions in soft tissue equivalent homogeneous phantoms. This study demonstrates how measurements of dose distribution can also be achieved in a phantom containing porous, lung-equivalent, ...

journal_title：Physics in medicine and biology

authors： Olberg S,Skretting A,Bruland O,Olsen DR

更新日期：2000-10-01 00:00:00

abstract：:Using a statistical (chi-square) test on simulated data and a realistic noise model derived from the system's hardware we study the performance of diffuse optical tomography systems for fluorescence imaging. We compare the predicted smallest size of detectable lesions at various positions in slab and cup geometry and ...

journal_title：Physics in medicine and biology

authors： Ziegler R,Brendel B,Rinneberg H,Nielsen T

更新日期：2009-01-21 00:00:00

abstract：:The implementation of two algorithms for calculating dose distributions for radiation therapy treatment planning of intermediate energy proton beams is described. A pencil kernel algorithm and a depth penetration algorithm have been incorporated into a commercial three dimensional treatment planning system (Helax-TMS,...

journal_title：Physics in medicine and biology

authors： Russell KR,Isacsson U,Saxner M,Ahnesjö A,Montelius A,Grusell E,Dahlgren CV,Lorin S,Glimelius B

更新日期：2000-01-01 00:00:00

abstract：:We propose a regularized least-squares method for reconstructing 2D velocity vector fields within the left ventricular cavity from single-view color Doppler echocardiographic images. Vector flow mapping is formulated as a quadratic optimization problem based on an [Formula: see text]-norm minimization of a cost functi...

journal_title：Physics in medicine and biology

authors： Assi KC,Gay E,Chnafa C,Mendez S,Nicoud F,Abascal JFPJ,Lantelme P,Tournoux F,Garcia D

更新日期：2017-08-11 00:00:00

abstract：:Although radionuclide therapy has been around for a long time, this modality of cancer treatment has been limited mainly to the use of [32P]-phosphate and [131I]-sodium iodide. The last few years, however, have seen an increased interest in this area due to new developments of radionuclides and carrier molecules that ...

journal_title：Physics in medicine and biology

authors： Zweit J

更新日期：1996-10-01 00:00:00

abstract：:Despite the early recognition of the potential of proton imaging to assist proton therapy (Cormack 1963 J. Appl. Phys. 34 2722), the modality is still removed from clinical practice, with various approaches in development. For proton-counting radiography applications such as computed tomography (CT), the water-equival...

journal_title：Physics in medicine and biology

authors： Poludniowski G,Allinson NM,Anaxagoras T,Esposito M,Green S,Manolopoulos S,Nieto-Camero J,Parker DJ,Price T,Evans PM

更新日期：2014-06-07 00:00:00

abstract：:Fluorescence molecular imaging/tomography may play an important future role in preclinical research and clinical diagnostics. Time- and frequency-domain fluorescence imaging can acquire more measurement information than the continuous wave (CW) counterpart, improving the image quality of fluorescence molecular tomogra...

journal_title：Physics in medicine and biology

authors： Lu Y,Zhu B,Shen H,Rasmussen JC,Wang G,Sevick-Muraca EM

更新日期：2010-08-21 00:00:00

abstract：:The objective of this work is to test analytical models to calculate the luminescence efficiency of Al(2)O(3):C optically stimulated luminescence detectors (OSLDs) exposed to heavy charged particles with energies relevant to space dosimetry and particle therapy. We used the track structure model to obtain an analytica...

journal_title：Physics in medicine and biology

authors： Sawakuchi GO,Yukihara EG

更新日期：2012-01-21 00:00:00

abstract：:The external radiation exposure from an overhead plume containing gamma emitting radionuclides can contribute substantial dose to the ground receptor during normal operations as well as accidental release conditions of nuclear facilities. In order to estimate the effective dose conversion coefficients (DCCs) directly,...

journal_title：Physics in medicine and biology

authors： Dey R,Patni HK,Deo Singh K,Kulkarni MS,Anand S

更新日期：2019-08-01 00:00:00

abstract：:There are three ways to determine the spectrum of a clinical photon beam: direct measurement, modelling the source and reconstruction from ion-chamber measurements. We focus on reconstruction because the necessary equipment is readily available and it provides independent confirmation of source models for a given mach...

journal_title：Physics in medicine and biology

authors： Armbruster B,Hamilton RJ,Kuehl AK

更新日期：2004-11-21 00:00:00

abstract：:Calculating the dynamic properties of magnetization of single-domain particles is of great importance for the tomographic imaging modality known as magnetic particle imaging (MPI). Although the assumption of instantaneous thermodynamic equilibrium (Langevin function) after application of time-dependent magnetic fields...

journal_title：Physics in medicine and biology

authors： Weizenecker J

更新日期：2018-01-22 00:00:00

abstract：:We combine two near-infrared diffuse optical techniques to study variations of blood flow, haemoglobin concentration, and blood oxygen saturation in the functioning rat brain. Diffuse correlation spectroscopy (or flowmetry) monitors changes in the cerebral blood flow, without the use of the principles of tracer cleara...

journal_title：Physics in medicine and biology

authors： Cheung C,Culver JP,Takahashi K,Greenberg JH,Yodh AG

更新日期：2001-08-01 00:00:00

abstract：:Remission spectroscopy in living tissues can only be performed because scattering processes induce a pronounced amount of backscattered light. New types of scattering chambers were constructed in order to investigate the angular distribution of light intensities caused by scattering events typical for living tissues. ...

journal_title：Physics in medicine and biology

authors： Frank KH,Kessler M,Appelbaum K,Albrecht HP,Mauch ED

更新日期：1989-12-01 00:00:00

abstract：:A new class of dose calibrator called a micro-dose calibrator, designed to measure radioactivity rates in the range between 1 kBq up to 370 kBq, has been designed and an 8 NaI(Tl)/photo multiplier tube (PMT) module prototype built to evaluate its performance. The design of the micro-dose calibrator is based on the con...

journal_title：Physics in medicine and biology

authors： Adler S,Choyke P

更新日期：2018-09-10 00:00:00

abstract：:The dose distribution near a non-radioactive gold seed under a 6 MV photon beam was measured using radiographic film, water equivalent bolus and solid water slabs. This type of small seed is typically used as a marker in target positional verification using a portal imager for conformal prostate treatment such as inte...

journal_title：Physics in medicine and biology

authors： Chow JC,Grigorov GN

更新日期：2005-09-21 00:00:00

abstract：:DMSA imaging is carried out in nuclear medicine to assess the level of functional renal tissue in patients. This study investigated the use of an artificial neural network to perform diagnostic classification of these scans. Using the radiological report as the gold standard, the network was trained to classify DMSA s...

journal_title：Physics in medicine and biology

authors： Wright JW,Duguid R,McKiddie F,Staff RT

更新日期：2014-04-07 00:00:00

abstract：:Abdominal organ motion may lead to considerable uncertainties in pencil-beam scanning (PBS) proton therapy of pancreatic cancer. Beam gating, where irradiation only occurs in certain breathing phases in which the gating conditions are fulfilled, may be an option to reduce the interplay effect between tumor motion and ...

journal_title：Physics in medicine and biology

authors： Dolde K,Naumann P,Dávid C,Kachelriess M,Lomax AJ,Weber DC,Saito N,Burigo LN,Pfaffenberger A,Zhang Y

更新日期：2019-04-10 00:00:00

abstract：:Focused ultrasound (FUS) phased arrays show promise for non-invasive brain therapy. However, the majority of them are limited to a single transmit/receive frequency and therefore lack the versatility to expose and monitor the treatment volume. Multi-frequency arrays could offer variable transmit focal sizes under a fi...

journal_title：Physics in medicine and biology

authors： Deng L,O'Reilly MA,Jones RM,An R,Hynynen K

更新日期：2016-12-21 00:00:00