Monte Carlo simulation to evaluate the contamination in an energy modulated carbon ion beam for hadron therapy delivered by cyclotron.

abstract：:A mathematical procedure, using Fourier deconvolution, is described whereby diffusion-free proximity functions can be obtained from cloud-chamber data. Such non-diffused distributions can be used to obtain further microdosimetric and nanodosimetric quantities hitherto not available from experiments, thus making the cl...

journal_title：Physics in medicine and biology

authors： Zaider M,Minerbo GN

更新日期：1988-11-01 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：:Pulsed nuclear magnetic resonance imaging (NMRI) apparatus has developed very quickly. On the other hand, the development of apparatus for pulsed electron paramagnetic resonance imaging (EPRI) has been very slow. This fact is due to the extremely reduced relaxation times of the paramagnetic probes. EPR linewidths are ...

journal_title：Physics in medicine and biology

authors： Di Giuseppe S,Placidi G,Brivati JA,Alecci M,Sotgiu A

更新日期：1999-06-01 00:00:00

abstract：:Determining a multidimensional velocity field within microscale opaque fluid flows is needed in areas such as microfluidic devices, biofluid mechanics and hemodynamics research in animal studies. The ultrasonic particle image velocimetry (EchoPIV) technique is appropriate for measuring opaque flows by taking advantage...

journal_title：Physics in medicine and biology

authors： Qian M,Niu L,Wang Y,Jiang B,Jin Q,Jiang C,Zheng H

更新日期：2010-10-21 00:00:00

abstract：:A novel meshless reconstruction algorithm for digital tomosynthesis (DT) is presented and assessed against experimental data. The algorithm does not require a three-dimensional grid or mesh allocation and performs a slice-by-slice reconstruction where each slice position can be chosen at runtime. The methodology is ba...

journal_title：Physics in medicine and biology

authors： Soloviev VY,Renforth KL,Dirckx CJ,Wells SG

更新日期：2020-04-20 00:00:00

abstract：:An important challenge in real-world biomedical applications of x-ray phase contrast imaging (XPCI) techniques is the efficient use of the photon flux generated by an incoherent and polychromatic x-ray source. This efficiency can directly influence dose and exposure time and ideally should not affect the superior cont...

journal_title：Physics in medicine and biology

authors： Saghamanesh S,Aghamiri SM,Kamali-Asl A,Yashiro W

更新日期：2017-09-01 00:00:00

abstract：:In the real-time tumor-tracking radiotherapy system, fluoroscopy is used to determine the real-time position of internal fiducial markers. The pattern recognition score (PRS) ranging from 0 to 100 is computed by a template pattern matching technique in order to determine the marker position on the fluoroscopic image. ...

journal_title：Physics in medicine and biology

authors： Miyamoto N,Ishikawa M,Bengua G,Sutherland K,Suzuki R,Kimura S,Shimizu S,Onimaru R,Shirato H

更新日期：2011-08-07 00:00:00

abstract：:Magnetic Particle Imaging (MPI) is a promising medical imaging technique for visualizing the three-dimensional distribution of tracer materials, specifically iron oxide nanoparticles (IONP). The optimization of magnetic nanoparticles (MNP) plays an essential role to improve the image resolution and sensitivity of imag...

journal_title：Physics in medicine and biology

authors： Arsalani S,Loewa N,Kosch O,Radon P,Baffa O,Wiekhorst F

更新日期：2020-11-23 00:00:00

abstract：:This study presents a new approach to accurately account for the medium-dependent effect in model-based dose calculations for kilovoltage (kV) x-rays. This approach is based on the hypothesis that the correction factors needed to convert dose from model-based dose calculations to absorbed dose-to-medium depend on both...

journal_title：Physics in medicine and biology

authors： Pawlowski JM,Ding GX

更新日期：2011-07-07 00:00:00

abstract：:The goal of this study was to assess the impact of set-up uncertainty on compliance with the objectives and constraints of an intensity modulated radiation therapy protocol for early stage cancer of the oropharynx. As the convolution approach to the quantitative study of set-up uncertainties cannot accommodate either ...

journal_title：Physics in medicine and biology

authors： Ploquin N,Song W,Lau H,Dunscombe P

更新日期：2005-08-07 00:00:00

abstract：:A special parallel-plate ionization chamber was developed. The motivation for the construction of this new chamber was mainly to fulfil the need of a reference system for computed tomography standard beams in the Calibration Laboratory of IPEN. However, the chamber was tested also in standard radiation beams of mammog...

journal_title：Physics in medicine and biology

authors： Maia AF,Caldas LV

更新日期：2005-08-21 00:00:00

abstract：:The class of non-rigid registration methods proposed in the framework of PDE-constrained large deformation diffeomorphic metric mapping is a particularly interesting family of physically meaningful diffeomorphic registration methods. Inexact Gauss-Newton-Krylov optimization has shown an excellent numerical accuracy an...

journal_title：Physics in medicine and biology

authors： Hernandez M

更新日期：2019-01-07 00:00:00

abstract：:IMRT delivery follows a planned leaf sequence, which is optimized before treatment delivery. However, it is hard to model real-time variations, such as respiration, in the planning procedure. In this paper, we propose a negative feedback system of IMRT delivery that incorporates real-time optimization to account for i...

journal_title：Physics in medicine and biology

authors： Lu W,Chen M,Ruchala KJ,Chen Q,Langen KM,Kupelian PA,Olivera GH

更新日期：2009-07-21 00:00:00

abstract：:Mean glandular dose is the quantity used for dosimetry in mammography and depends on breast-related characteristics, such as thickness and density, and on the x-ray spectrum used for breast imaging. This work aims to present an experimentally-based method to derive polyenergetic normalized glandular dose coefficients ...

journal_title：Physics in medicine and biology

authors： Santos JC,Tomal A,de Barros N,Costa PR

更新日期：2019-05-10 00:00:00

abstract：:A simple and fast, but sensitive TLD method for the measurement of energy and homogeneity of therapeutically used electron beams has been developed and tested. This method is based on the fact that when small thicknesses of high-Z absorbers such as lead are interposed in the high-energy electron beams, the transmitted...

journal_title：Physics in medicine and biology

authors： Pradhan AS,Quast U,Sharma PK

更新日期：1994-09-01 00:00:00

abstract：:We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961-71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in t...

journal_title：Physics in medicine and biology

authors： Palmans H,Vatnitsky SM

更新日期：2016-09-07 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：:To increase the scanning speed of cone-beam CT, a scanning configuration with three pairs of x-ray sources and panel detectors was proposed. In this paper, we apply the M-line-based backprojected filtration algorithm to this scanning configuration and propose a fast implementation for this algorithm. Compared with exi...

journal_title：Physics in medicine and biology

authors： Zhao Y,Zhu Y,Zhang P

更新日期：2010-12-07 00:00:00

abstract：:Radiotherapy and particle therapy treatment planning require accurate knowledge of the electron density and elemental composition of the tissues in the beam path to predict the local dose deposition. We describe a method for the analysis of dual energy computed tomography (DECT) images that provides the electron densi...

journal_title：Physics in medicine and biology

authors： van Abbema JK,van Goethem MJ,Greuter MJ,van der Schaaf A,Brandenburg S,van der Graaf ER

更新日期：2015-05-07 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：:The use of deformable image registration methods in the context of adaptive radiotherapy leads to uncertainties in the simulation of the administered dose distributions during the treatment course. Evaluation of these methods is a prerequisite to decide if a plan adaptation will improve the individual treatment. Curre...

journal_title：Physics in medicine and biology

authors： Teske H,Bartelheimer K,Meis J,Bendl R,Stoiber EM,Giske K

更新日期：2017-06-21 00:00:00

abstract：:A recently described, computer aided method of attenuation analysis has been applied to free-air chamber measurements of the attenuation by up to 30mm A1 of the exposure rate of a narrow beam of X-radiation excited at a thick W target in a Be window tube by constant potentials of 60, 80, 100, 120 and 140 kV. It has ...

journal_title：Physics in medicine and biology

authors： Soole BW

更新日期：1977-03-01 00:00:00

abstract：:Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that ...

journal_title：Physics in medicine and biology

authors： Nasr AT,Alexander K,Schreiner LJ,McAuley KB

更新日期：2015-06-21 00:00:00

abstract：:Although field area and object thickness are important parameters in comparisons of techniques for optimal reduction of scattered radiation to the image, they are in practice seldom varied. For this reason, we suggest that contrast degradation (CDF) and contrast improvement (CIF) factors be more frequently used and ap...

journal_title：Physics in medicine and biology

authors： Carlsson GA,Carlsson CA,Nielsen B,Persliden J

更新日期：1986-07-01 00:00:00

abstract：:The effects of radiation damage, tumour repopulation and cell sublethal damage repair and the possibility of extracting information about the model parameters describing them are investigated in this work. Previously published data on two different cultured cell lines were analysed with the help of a tumour control pr...

journal_title：Physics in medicine and biology

authors： Stavrev P,Weldon M,Warkentin B,Stavreva N,Fallone BG

更新日期：2005-07-07 00:00:00

abstract：:We report a simulation study on diffuse reflective optical computed tomography, in which continuous-wave sources and detectors are placed on the plane surface of a semi-infinite body. We adopted a simple Tikhonov regularization in the inverse problem and demonstrated the feasibility of three-dimensional reconstruction...

journal_title：Physics in medicine and biology

authors： Endoh R,Suzuki A,Fujii M,Nakayama K

更新日期：2004-05-21 00:00:00

abstract：:Diffuse optical tomography is an imaging technique whereby spatial maps of absorption and scattering coefficients are derived from the characteristics of multiply scattered light transmitted through the object. The system described here used four intensity-modulated light sources and measurements of the intensity and ...

journal_title：Physics in medicine and biology

authors： Pogue BW,Patterson MS,Jiang H,Paulsen KD

更新日期：1995-10-01 00:00:00

abstract：:A Monte Carlo computational model of a fluoroscopic imaging chain was used for deriving optimal technique factors for paediatric fluoroscopy. The optimal technique was defined as the one that minimizes the absorbed dose (or dose rate) in the patient with a constraint of constant image quality. Image quality was assess...

journal_title：Physics in medicine and biology

authors： Tapiovaara MJ,Sandborg M,Dance DR

更新日期：1999-02-01 00:00:00

abstract：:A dynamic-contrast-enhanced magnetic resonance imaging (DCE-MRI) dataset consists of many imaging frames, often acquired both before and after contrast injection. Due to the length of time spent acquiring images, patient motion is likely and image re-alignment or registration is required before further analysis such a...

journal_title：Physics in medicine and biology

authors： Melbourne A,Hipwell J,Modat M,Mertzanidou T,Huisman H,Ourselin S,Hawkes DJ

更新日期：2011-12-21 00:00:00

abstract：:Treatment plans optimized for intensity modulated proton therapy (IMPT) may be sensitive to range variations. The dose distribution may deteriorate substantially when the actual range of a pencil beam does not match the assumed range. We present two treatment planning concepts for IMPT which incorporate range uncertai...

journal_title：Physics in medicine and biology

authors： Unkelbach J,Chan TC,Bortfeld T

更新日期：2007-05-21 00:00:00