Relative determination of W-values for alpha particles in tissue-equivalent and other gases.

abstract：:Dual-energy x-ray absorptiometry (DXA) is widely applied for estimating body fat. The percentage of body mass as fat (%fat) is predicted from a DXA-estimated R(ST) value defined as the ratio of soft tissue attenuation at two photon energies (e.g., 40 keV and 70 keV). Theoretically, the R(ST) concept depends on the mas...

journal_title：Physics in medicine and biology

authors： Wang Z,Heymsfield SB,Chen Z,Zhu S,Pierson RN

更新日期：2010-05-07 00:00:00

abstract：:Doxorubicin (Dox) is a well-established chemotherapeutic agent, however it has limited efficacy in treating brain malignancies due to the presence of the blood-brain barrier (BBB). Recent preclinical studies have demonstrated that focused ultrasound induced BBB disruption (BBBD) enables efficient delivery of Dox to th...

journal_title：Physics in medicine and biology

authors： Nhan T,Burgess A,Lilge L,Hynynen K

更新日期：2014-10-21 00:00:00

abstract：:A semi-empirical theory has been derived that relates the aluminum equivalence of various materials used in diagnostic radiology to their attenuation coefficients. The dependence of the aluminum hardness (AHE) and attenuation (AAE) equivalent on the beam quality is described in terms of effective energy. This 'aluminu...

journal_title：Physics in medicine and biology

authors： Nagel HD

更新日期：1986-12-01 00:00:00

abstract：:The dosimetric measurement and modeling of small radiation treatment fields (<2 × 2 cm2) are difficult to perform and prone to error. Measurements of small fields are often adversely influenced by the properties of the detectors used to make them. The dosimetric properties of small fields have been difficult to accura...

journal_title：Physics in medicine and biology

authors： Hundertmark B,Sterpin E,Mackie T

更新日期：2011-06-21 00:00:00

abstract：:In order (i) to evaluate the dose uncertainty of the mouthpiece in daily use during intensity-modulated radiotherapy of patients with head and neck cancer, and (ii) to present a system for in vivo dosimetry of the oral mucosa, we equipped the mouthpiece with alanine dosimeter probes for in vivo dosimetry. The aim was ...

journal_title：Physics in medicine and biology

authors： Wagner D,Anton M,Vorwerk H

更新日期：2011-03-07 00:00:00

abstract：:Measurements have been made using an air sampler to measure airborne radioactivity produced during the routine handling of large activities of technetium-99m, iodine-125 and iodine-131. The results indicate that 99Tcm can be safely handled in environments without direct exhaust of the ventilated air but that 125I and ...

journal_title：Physics in medicine and biology

authors： Eadie AS,Horton PW,Hilditch TE

更新日期：1980-11-01 00:00:00

abstract：:Monte Carlo simulation was used to calculate correction factors for output factor (OF), percentage depth-dose (PDD), and off-axis ratio (OAR) measurements with the CyberKnife M6 System. These include the first such data for the InCise MLC. Simulated detectors include diodes, air-filled microchambers, a synthetic micro...

journal_title：Physics in medicine and biology

authors： Francescon P,Kilby W,Noll JM,Masi L,Satariano N,Russo S

更新日期：2017-02-07 00:00:00

abstract：:An algorithm for dynamic multileaf-collimator (dMLC) tracking of a target performing a known a priori, rigid-body motion during volumetric modulated arc therapy (VMAT), has been experimentally validated and applied to investigate the potential of the Agility (Elekta AB, Stockholm, Sweden) multileaf-collimator (MLC) fo...

journal_title：Physics in medicine and biology

authors： Davies GA,Clowes P,Bedford JL,Evans PM,Webb S,Poludniowski G

更新日期：2013-07-07 00:00:00

abstract：:At low and intermediate frequencies, the strength of the induced electric field is used as dosimetric quantity for human protection in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. To compute the induced electric field, numerical methods based on anatomically realistic voxel mo...

journal_title：Physics in medicine and biology

authors： Soldati M,Laakso I

更新日期：2020-01-10 00:00:00

abstract：:It has been reported that acoustic waves are generated when a high-energy pulsed proton beam is deposited in a small volume within tissue. One possible application of proton-induced acoustics is to get real-time feedback for intra-treatment adjustments by monitoring such acoustic waves. A high spatial resolution in ul...

journal_title：Physics in medicine and biology

authors： Kipergil EA,Erkol H,Kaya S,Gulsen G,Unlu MB

更新日期：2017-06-21 00:00:00

abstract：:Voxel phantoms are human models based on computed tomographic or magnetic resonance images obtained from high-resolution scans of a single individual. They consist of a huge number of volume elements (voxels) and are at the moment the most precise representation of the human anatomy. The purpose of this paper is to in...

journal_title：Physics in medicine and biology

authors： Petoussi-Henss N,Zanki M,Fill U,Regulla D

更新日期：2002-01-07 00:00:00

abstract：:Users of nuclear and atomic data for biomedical purposes often have difficulty in identifying the most up-to-date and appropriate sources of such data. The biomedical Subcommittee of the UK Nuclear Data Committee have prepared a list of recommended data sources available at the beginning of 1978 on radioactive decay s...

journal_title：Physics in medicine and biology

authors： Holt PD

更新日期：1979-01-01 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：:The aim of the study is to determine PTV margin for inter-observer variability in the volumetric modulated arc therapy (VMAT) prostate radiotherapy with high-dose volumetric CT (HDVCT) and conventional helical CT (CCT) for planning. Secondly to investigate the impact of geometric (PTV expansion) and dosimetric (confor...

journal_title：Physics in medicine and biology

authors： Cho YB,Alasti H,Kong V,Catton C,Berlin A,Chung P,Bayley A,Jaffray D

更新日期：2019-03-14 00:00:00

abstract：:Although it is known that obesity has a profound effect on x-ray computed tomography (CT) image quality and patient organ dose, quantitative data describing this relationship are not currently available. This study examines the effect of obesity on the calculated radiation dose to organs and tissues from CT using newl...

journal_title：Physics in medicine and biology

authors： Ding A,Mille MM,Liu T,Caracappa PF,Xu XG

更新日期：2012-05-07 00:00:00

abstract：:Novel methods are presented which allow the estimation of the effect of stereotactic fiducial marker localization on target localization in a stereotactic surgery planning program based on the integration of image data from various modalities. The results of simulations are presented. A method for the evaluation of th...

journal_title：Physics in medicine and biology

authors： Lemieux L,Jagoe R

更新日期：1994-11-01 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：: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：:Finite element (FE) modeling provides a useful tool to understand the mechanical behavior of complex tissues, such as cancers, in a variety of testing conditions. Although a number of numerical and analytical models for cancerous tumors are retrievable in the literature, none of these models is capable of completely d...

journal_title：Physics in medicine and biology

authors： Islam MT,Reddy JN,Righetti R

更新日期：2018-10-24 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：:In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 microm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity....

journal_title：Physics in medicine and biology

authors： Osterås BH,Hole EO,Olsen DR,Malinen E

更新日期：2006-12-21 00:00:00

abstract：:In this paper the propagation of a UWB pulse into a layered model of the human body is studied to characterize absorption and reflection of the UWB signal due to the different body tissues. Several time behaviours for the incident UWB pulse are considered and compared with reference to the feasibility of breath and he...

journal_title：Physics in medicine and biology

authors： Cavagnaro M,Pittella E,Pisa S

更新日期：2013-12-21 00:00:00

abstract：:A parametric model for the x-ray linear attenuation coefficient is used to describe the compositional dependence of Hounsfield numbers measured by medical CT scanners. Measurements with materials of known density and composition, that span and evenly sample the compositional range of tissues, are written as linear sim...

journal_title：Physics in medicine and biology

authors： Midgley SM

更新日期：2014-12-07 00:00:00

abstract：:Arc-therapy is a dose delivery technique regularly applied in photon radiation therapy, and is currently subject of great interest for proton therapy as well. In this technique, proton beams are aimed at a tumor from different continuous ranges of incident directions (so called "arcs"). This technique can potentially ...

journal_title：Physics in medicine and biology

authors： Nesteruk KP,Bolsi A,Lomax AJ,Meer D,van de Water S,Schippers JM

更新日期：2021-01-26 00:00:00

abstract：:This paper introduces a novel compartmental model describing the excretion of 18F-fluoro-deoxyglucose (FDG) in the renal system and a numerical method based on the maximum likelihood for its reduction. This approach accounts for variations in FDG concentration due to water re-absorption in renal tubules and the increa...

journal_title：Physics in medicine and biology

authors： Garbarino S,Caviglia G,Sambuceti G,Benvenuto F,Piana M

更新日期：2014-05-21 00:00:00

abstract：:Measuring spin-spin relaxation times (T2) by quantitative MR imaging represents a potentially efficient tool to evaluate the physicochemical properties of various media. However, noise in MR images is responsible for uncertainties in the determination of T2 relaxation times, which limits the accuracy of parametric tis...

journal_title：Physics in medicine and biology

authors： Gensanne D,Josse G,Lagarde JM,Vincensini D

更新日期：2006-06-07 00:00:00

abstract：:Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrome...

journal_title：Physics in medicine and biology

authors： Gherase MR,Mader JE,Fleming DE

更新日期：2010-09-21 00:00:00

abstract：:Preclinical positron emission tomography, combined with magnetic resonance imaging (PET/MRI), is increasingly used as a tool to simultaneously characterize functional processes in vivo. Many emerging preclinical applications, however, are limited by PET detection sensitivity, especially when generating short imaging f...

journal_title：Physics in medicine and biology

authors： Selfridge AR,Cherry SR,Judenhofer MS

更新日期：2018-12-06 00:00:00

abstract：:The purpose of this study was to develop a method to simulate breathing motion induced interplay effects for volumetric modulated arc therapy (VMAT), to verify the proposed method with measurements, and to use the method to investigate how interplay effects vary with different patient- and machine specific parameters....

journal_title：Physics in medicine and biology

authors： Edvardsson A,Nordström F,Ceberg C,Ceberg S

更新日期：2018-04-19 00:00:00

abstract：:Coronary computed tomography angiography (cCTA) is a commonly used imaging modality for the evaluation of coronary artery disease. cCTA is generally reconstructed in multiple cardiac phases because different coronary arteries may be better visualized in some phases than in others due to the periodic cardiac motion. We...

journal_title：Physics in medicine and biology

authors： Hadjiiski L,Zhou C,Chan HP,Chughtai A,Agarwal P,Kuriakose J,Kazerooni E,Wei J,Patel S

更新日期：2014-08-21 00:00:00