Optimizing functional parameter accuracy for breath-hold DCE-MRI of liver tumours.

abstract：:To evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy. Twenty-five prostate patients underwent CT and MR simulation scans in treatment position on a 3T MR scanner. A commercially available MR protocol was used that included a T2w turbo spin-echo sequence for soft-tissue contrast and ...

journal_title：Physics in medicine and biology

authors： Tyagi N,Fontenla S,Zhang J,Cloutier M,Kadbi M,Mechalakos J,Zelefsky M,Deasy J,Hunt M

更新日期：2017-04-21 00:00:00

abstract：:Irreversible electroporation (IRE) is a minimally invasive tumor therapy using pulsed electric field with high intensity while the important tissues such as blood vessel, bile duct, and nerve are preserved. In addition to ablation area, reversible electroporation (RE) region is also generated using needle electrodes f...

journal_title：Physics in medicine and biology

authors： Lv Y,Tang X,Peng W,Cheng X,Chen S,Yao C

更新日期：2020-10-14 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：:Elastography, which uses ultrasound to image the tissue strain that results from an applied displacement, can display tumours and heat-ablated tissue with high contrast. However, its application to liver in vivo may be problematic due to the presence of respiratory and cardiovascular sources of displacement. The aim o...

journal_title：Physics in medicine and biology

authors： Kolen AF,Miller NR,Ahmed EE,Bamber JC

更新日期：2004-09-21 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：:This paper presents two methods for absorbed dose determination with ionization chambers at short distance from 60Co and 192Ir brachytherapy sources. The methods are modifications of the Bragg-Gray and large cavity principles given in the IAEA code of practice for high- and medium-energy photon beams. A non-uniformity...

journal_title：Physics in medicine and biology

authors： Tölli H,Johansson KA

更新日期：1998-11-01 00:00:00

abstract：:It has been demonstrated that gas-filled microbubble contrast agents, based on their volume changes, can serve as pressure probes in an MR field. It was recently reported that such an MR-based pressure measurement with microbubbles at 1.5 T must make use of microbubbles that have a volumetric magnetic susceptibility d...

journal_title：Physics in medicine and biology

authors： Dharmakumar R,Plewes DB,Wright GA

更新日期：2005-10-21 00:00:00

abstract：:Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry ...

journal_title：Physics in medicine and biology

authors： Afsharpour H,Landry G,D'Amours M,Enger S,Reniers B,Poon E,Carrier JF,Verhaegen F,Beaulieu L

更新日期：2012-06-07 00:00:00

abstract：:This work aims at developing a generic virtual source model (VSM) preserving all existing correlations between variables stored in a Monte Carlo pre-computed phase space (PS) file, for dose calculation and high-resolution portal image prediction. The reference PS file was calculated using the PENELOPE code, after the ...

journal_title：Physics in medicine and biology

authors： Chabert I,Barat E,Dautremer T,Montagu T,Agelou M,Croc de Suray A,Garcia-Hernandez JC,Gempp S,Benkreira M,de Carlan L,Lazaro D

更新日期：2016-07-21 00:00:00

abstract：:By analyzing the radiobiological model, and the equations derived from the model, it is shown that the main results of the article 'The influence of dose heterogeneity on tumor control probability in fractionated radiation therapy' by Wiklund et al (2011 Phys. Med. Biol. 56 7585-600) are valid only under the condition...

journal_title：Physics in medicine and biology

authors： Grusell E

更新日期：2013-09-21 00:00:00

abstract：:Over the last decade, the performance of benchtop x-ray fluorescence computed tomography (XFCT) systems has been significantly enhanced through hardware and software optimizations. Recent studies have indicated the need of energy-resolving pixelated/array detectors in the x-ray detection component to further improve t...

journal_title：Physics in medicine and biology

authors： Moktan H,Ahmed MF,Jayarathna S,Deng L,Cho SH

更新日期：2020-08-31 00:00:00

abstract：:Diffusion tensor - magnetic resonance electrical impedance tomography (DT-MREIT) is an imaging modality to obtain low-frequency anisotropic conductivity distribution employing diffusion tensor imaging (DTI) and magnetic resonance electrical impedance tomography (MREIT) techniques. DT-MREIT is based on the linear relat...

journal_title：Physics in medicine and biology

authors： Sadighi M,Sisman M,Acikgoz BC,Eroglu HH,Eyuboglu BM

更新日期：2021-01-20 00:00:00

abstract：:The elastic and hyperelastic properties of biological soft tissues have been of interest to the medical community. There are several biomedical applications where parameters characterizing such properties are critical for a reliable clinical outcome. These applications include surgery planning, needle biopsy and brach...

journal_title：Physics in medicine and biology

authors： O'Hagan JJ,Samani A

更新日期：2009-04-21 00:00:00

abstract：:Evidence that some lung tumors change shape during respiration is derived from respiratory gated CT data by statistical shape modeling and image manipulation. Some tumors behave as rigid objects while others show systematic shape changes. Two views of lung motion are presented to allow analysis of the results. In the ...

journal_title：Physics in medicine and biology

authors： Kyriakou E,McKenzie DR

更新日期：2012-02-21 00:00:00

abstract：:Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B. The purpose of this study is to system...

journal_title：Physics in medicine and biology

authors： Pojtinger S,Dohm OS,Kapsch RP,Thorwarth D

更新日期：2018-06-07 00:00:00

abstract：:Scattered doses, e.g. neutron doses in proton therapy, are of concern in radiation therapy. Although measured data are the gold standard, Monte Carlo simulations allow a more realistic consideration of patient anatomy via whole-body phantoms. When calculating neutron doses with Monte Carlo techniques, the dose can be ...

journal_title：Physics in medicine and biology

authors： Jarlskog CZ,Paganetti H

更新日期：2008-09-07 00:00:00

abstract：:Dose calculations were performed for a tissue phantom irradiated by uniform circular beams of negative pions with an assumed gaussian momentum distribution. The mean momentum of the pions was varied from 104.4 to 171.5 MeV/c (mean range 5-20 cm in unit-density tissue) and the momentum spread from 0 to 5% of the mean. ...

journal_title：Physics in medicine and biology

authors： Hamm RN,Wright HA,Turner JE

更新日期：1979-05-01 00:00:00

abstract：:We study the treatment plan optimization problem for volumetric modulated arc therapy (VMAT). We propose a new column-generation-based algorithm that takes into account bounds on the gantry speed and dose rate, as well as an upper bound on the rate of change of the gantry speed, in addition to MLC constraints. The alg...

journal_title：Physics in medicine and biology

authors： Peng F,Jia X,Gu X,Epelman MA,Romeijn HE,Jiang SB

更新日期：2012-07-21 00:00:00

abstract：:An accurate, low noise estimate of photon attenuation in the subject is required for quantitative microPET studies of molecular tracer distributions in vivo. In this work, several transmission-based measurement techniques were compared, including coincidence mode with and without rod windowing, singles mode with two d...

journal_title：Physics in medicine and biology

authors： Lehnert W,Meikle SR,Siegel S,Newport D,Banati RB,Rosenfeld AB

更新日期：2006-08-21 00:00:00

abstract：:This work presents an improvement of the VIPARnd ('nd' stands for 'normoxic, double', or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N'-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composit...

journal_title：Physics in medicine and biology

authors： Kozicki M,Jaszczak M,Maras P,Dudek M,Cłapa M

更新日期：2017-02-07 00:00:00

abstract：:Iterative image reconstruction algorithms have the potential to produce low noise images. Early stopping of the iteration process is problematic because some features of the image may converge slowly. On the other hand, there may be noise build-up with increased number of iterations. Therefore, we examined the stabili...

journal_title：Physics in medicine and biology

authors： Chlewicki W,Hermansen F,Hansen SB

更新日期：2004-10-21 00:00:00

abstract：:Dynamic modulation can be affected by inaccuracies when the required acceleration is larger than the highest allowed by the mechanical characteristics of the whole apparatus. In this study, inertia effects have been investigated with regard to the single absorber 1D modulation, analysing primarily how the acceleration...

journal_title：Physics in medicine and biology

authors： Corletto D,Broggi S,Fiorino C,Mangili P,Calandrino R,Lev A,Gennari D,Rudello F

更新日期：1999-11-01 00:00:00

abstract：:This study aims to develop a computer-aided diagnosis (CADx) scheme for classification between malignant and benign lung nodules, and also assess whether CADx performance changes in detecting nodules associated with early and advanced stage lung cancer. The study involves 243 biopsy-confirmed pulmonary nodules. Among ...

journal_title：Physics in medicine and biology

authors： Gong J,Liu JY,Sun XW,Zheng B,Nie SD

更新日期：2018-02-05 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：:Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and radiotracer guided surgery. Statistical methods of position reconstruction, which are p...

journal_title：Physics in medicine and biology

authors： Morozov A,Alves F,Marcos J,Martins R,Pereira L,Solovov V,Chepel V

更新日期：2017-05-07 00:00:00

abstract：:Single monochromator charge-coupled device (CCD) array spectroradiometers have the advantage of ease of use and speed compared with double grating instruments. Their inherently inferior stray-light rejection, however, can critically affect their accuracy in phototherapy and research-related dosimetry applications. Thi...

journal_title：Physics in medicine and biology

authors： Coleman A,Sarkany R,Walker S

更新日期：2008-09-21 00:00:00

abstract：:In recent years there has been a large amount of research into the potential use of radiation sensitive gels for three-dimensional verification of clinical radiotherapy doses. In this paper we report the use of a MAGIC gel dosimeter (Fong et al 2001 Phys. Med. Biol. 46 3105) for the verification of a specific patient'...

journal_title：Physics in medicine and biology

authors： Trapp JV,Partridge M,Hansen VN,Childs P,Bedford J,Warrington AP,Leach MO,Webb S

更新日期：2004-05-07 00:00:00

abstract：:Reliable treatment planning of highly conformal scanned ion beam therapy demands accurate tools for the determination and characterization of the individual pencil-like beams building up the integral dose delivery and related mixed radiation field. At present, clinically practicable inverse treatment planning systems ...

journal_title：Physics in medicine and biology

authors： Parodi K,Mairani A,Brons S,Hasch BG,Sommerer F,Naumann J,Jäkel O,Haberer T,Debus J

更新日期：2012-06-21 00:00:00

abstract：:This paper addresses fundamental issues that underlie the interpretation of images acquired from turbid tissues by optical-coherence tomography (OCT). The attenuation and backscattering properties of freshly excised rat arteries and their dependence on the focusing and collection optics of the OCT system were measured...

journal_title：Physics in medicine and biology

authors： Schmitt JM,Knüttel A,Yadlowsky M,Eckhaus MA

更新日期：1994-10-01 00:00:00

abstract：:There is a need to verify the accuracy of general purpose Monte Carlo codes like EGSnrc, which are commonly employed for investigations of dosimetric problems in radiation therapy. A number of experimental benchmarks have been published to compare calculated values of absorbed dose to experimentally determined values....

journal_title：Physics in medicine and biology

authors： Renner F,Wulff J,Kapsch RP,Zink K

更新日期：2015-10-07 00:00:00