Stopping power and ranges of low-energy protons in tissue-equivalent gas.

abstract：:This paper describes the development and characterization of a fully automated in vitro cell irradiator using an electronic brachytherapy source to perform radiation sensitivity bioassays. This novel irradiator allows complex variable dose and dose rate schemes to be delivered to multiple wells of 96-well culture plat...

journal_title：Physics in medicine and biology

authors： Fowler TL,Fulkerson RK,Micka JA,Kimple RJ,Bednarz BP

更新日期：2014-03-21 00:00:00

abstract：:Ultrasound may provide a quantitative technique for the characterization of cartilage changes typical of early osteoarthrosis. In this study, specific changes in bovine articular cartilage were induced using collagenase and chondroitinase ABC, enzymes that selectively degrade collagen fibril network and digest proteog...

journal_title：Physics in medicine and biology

authors： Töyräs J,Rieppo J,Nieminen MT,Helminen HJ,Jurvelin JS

更新日期：1999-11-01 00:00:00

abstract：:Dynamic contrast enhanced MRI (DCE-MRI) and pharmacokinetic models have been used to measure tumour permeability (K(trans)) and leakage volume (ve) in numerous studies. The construction of pharmacokinetic models describing such tissue properties relies on defining the blood plasma concentration of contrast agent with ...

journal_title：Physics in medicine and biology

authors： Ahearn TS,Staff RT,Redpath TW,Semple SI

更新日期：2004-05-21 00:00:00

abstract：:The ion recombination is examined in parallel-plate ionization chambers in scanning proton beams at the Danish Centre for Particle Therapy and the Skandion Clinic. The recombination correction factor k s is investigated for clinically relevant energies between 70 MeV and 244 MeV for dose rates below 400 Gy min-1 in ai...

journal_title：Physics in medicine and biology

authors： Christensen JB,Almhagen E,Stolarczyk L,Liszka M,Hernandez GG,Bassler N,Nørrevang O,Vestergaard A

更新日期：2020-06-05 00:00:00

abstract：:Beam hardening is inevitable due to the polychromatic X-ray spectrum and energy-dependent attenuation coefficients of materials, leading to the underestimation of artifacts arising from projection data, especially on metal regions. State-of-the-art research on beam-hardening artifacts is based on a numerical method th...

journal_title：Physics in medicine and biology

authors： Hur J,Kim D,Shin YG,Lee H

更新日期：2021-01-26 00:00:00

abstract：:The architecture of multi-layer imagers (MLIs) can be exploited to provide megavoltage spectral imaging (MVSPI) for specific imaging tasks. In the current work, we investigated bone suppression and gold fiducial contrast enhancement as two clinical tasks which could be improved with spectral imaging. A method based on...

journal_title：Physics in medicine and biology

authors： Myronakis M,Hu YH,Fueglistaller R,Wang A,Baturin P,Huber P,Morf D,Star-Lack J,Berbeco R

更新日期：2018-05-10 00:00:00

abstract：:We have developed an x-ray imaging system for in vivo four-dimensional computed tomography (4DCT) of small animals for pre-clinical lung investigations. Our customized laboratory facility is capable of high resolution in vivo imaging at high frame rates. Characterization using phantoms demonstrate a spatial resolution...

journal_title：Physics in medicine and biology

authors： Preissner M,Murrie RP,Pinar I,Werdiger F,Carnibella RP,Zosky GR,Fouras A,Dubsky S

更新日期：2018-04-20 00:00:00

abstract：:A theoretical analysis and numerical solutions are presented for viscosity-dominated flow through a uniform, highly distensible tube with a slit-shaped cross section undergoing peristalsis. At flow rates below an intrinsic upper limit to the peristaltic carrying capacity of the tube, provided that there is always at l...

journal_title：Physics in medicine and biology

authors： Griffiths DJ

更新日期：1987-07-01 00:00:00

abstract：:Accurate scatter correction is especially important for high-resolution 3D positron emission tomographies (PETs) such as high-resolution research tomograph (HRRT) due to large scatter fraction in the data. To address this problem, a fully 3D iterative scatter-corrected ordered subset expectation maximization (OSEM) in...

journal_title：Physics in medicine and biology

authors： Kim KS,Ye JC

更新日期：2011-08-07 00:00:00

abstract：:As a prerequisite for clinical treatments it was necessary to characterize the Elekta 1.5 T MRI-linac 7 MV FFF radiation beam. Following acceptance testing, beam characterization data were acquired with Semiflex 3D (PTW 31021), microDiamond (PTW 60019), and Farmer-type (PTW 30013 and IBA FC65-G) detectors in an Elekta...

journal_title：Physics in medicine and biology

authors： Woodings SJ,Bluemink JJ,de Vries JHW,Niatsetski Y,van Veelen B,Schillings J,Kok JGM,Wolthaus JWH,Hackett SL,van Asselen B,van Zijp HM,Pencea S,Roberts DA,Lagendijk JJW,Raaymakers BW

更新日期：2018-04-19 00:00:00

abstract：:In robotic radiosurgery, it is necessary to compensate for systematic latencies arising from target tracking and mechanical constraints. This compensation is usually achieved by means of an algorithm which computes the future target position. In most scientific works on respiratory motion prediction, only one or two a...

journal_title：Physics in medicine and biology

authors： Ernst F,Dürichen R,Schlaefer A,Schweikard A

更新日期：2013-06-07 00:00:00

abstract：:A modified sector-integration method is presented that can predict the output factors of irregular shaped electron fields even in the case of extended source to surface distance (SSD). The model takes as input measured output factors for circular inserts of various radii. These circular fields were measured at SSDs of...

journal_title：Physics in medicine and biology

authors： Choi DR,Wolters J,Mason D,Baillie A

更新日期：2000-11-01 00:00:00

abstract：:The origin of the differences in the refractive index observed between normal and tumor tissues using terahertz spectroscopy has been described quantitatively. To estimate water content differences in tissues, we prepared fresh and paraffin-embedded samples from rats. An approximately 5% increase of water content in t...

journal_title：Physics in medicine and biology

authors： Yamaguchi S,Fukushi Y,Kubota O,Itsuji T,Ouchi T,Yamamoto S

更新日期：2016-09-21 00:00:00

abstract：:Acidic drinks and foodstuffs can demineralize dental hard tissues, leading to a pathological condition known as dental erosion, which is of increasing clinical concern. The first step in enamel dissolution is a demineralization of the outer few micrometres of tissue, which results in a softening of the structure. The ...

journal_title：Physics in medicine and biology

authors： Barbour ME,Shellis RP

更新日期：2007-02-21 00:00:00

abstract：:Subharmonic contrast imaging promises to improve ultrasound-imaging quality by taking advantage of an increased contrast to tissue signal. However, acoustic pressures beyond the subharmonic generation threshold using common ultrasound pulses may induce significant contrast microbubble destruction. In this work, a chir...

journal_title：Physics in medicine and biology

authors： Zhang D,Gong Y,Gong X,Liu Z,Tan K,Zheng H

更新日期：2007-09-21 00:00:00

abstract：:Component-based normalization is a method used to compensate for the sensitivity of each of the lines of response acquired in positron emission tomography. This method consists of modelling the sensitivity of each line of response as a product of multiple factors, which can be classified as time-invariant, time-varian...

journal_title：Physics in medicine and biology

authors： Belzunce MA,Reader AJ

更新日期：2016-05-07 00:00:00

abstract：:Intensity modulated proton radiotherapy (IMPT) can reduce the dose to critical structures by optimizing the distribution and intensity of individual pencil beams. The IMPT can be delivered by dynamically scanning a pencil beam with variable intensity and energy across the tumor target volume. The lateral penumbra of a...

journal_title：Physics in medicine and biology

authors： Safai S,Bortfeld T,Engelsman M

更新日期：2008-03-21 00:00:00

abstract：:The accurate determination of mean ionization potential (I m) has the potential to reduce range uncertainty based margins and therefore allow for more focal treatments in proton radiotherapy. Many methods have been proposed to reduce uncertainty in I m and stopping power ratios (SPR), each with varying degrees of accu...

journal_title：Physics in medicine and biology

authors： Sudhyadhom A

更新日期：2017-10-27 00:00:00

abstract：:The purpose of this work is the clinical commissioning of a recently developed in vivo range verification system (IRVS) for treatment of prostate cancer by anterior and anterior oblique proton beams. The IRVS is designed to perform a complete workflow for pre-treatment range verification and adjustment. It contains sp...

journal_title：Physics in medicine and biology

authors： Hoesl M,Deepak S,Moteabbed M,Jassens G,Orban J,Park YK,Parodi K,Bentefour EH,Lu HM

更新日期：2016-04-21 00:00:00

abstract：:This paper evaluates results of a survey of electrostimulation models of myelinated nerve. Participants were asked to determine thresholds of excitation for 18 cases involving different characteristics of the neuron, the stimulation waveform, and the electrode arrangement. Responses were received from 7 investigators ...

journal_title：Physics in medicine and biology

authors： Reilly JP

更新日期：2016-06-21 00:00:00

abstract：:Depth-dose distributions were calculated for thermal and epithermal neutron fluence and capture gamma ray dose rates using a two-dimensional neutron-coupled gamma-ray transport code (DOT 3.5) for gadolinium neutron capture therapy. The results show that (i) a capture gamma-ray dose rate of 10 Gy h-1 was obtained with ...

journal_title：Physics in medicine and biology

authors： Matsumoto T

更新日期：1992-01-01 00:00:00

abstract：:Beta emitting 106Ru-applicators are used to treat choroidal melanoma. In order to improve the accuracy and simplify the dosimetry of these applicators, the suitability of using a p-type silicon semiconductor detector has been investigated. The detector is calibrated in a low energy electron beam. An important property...

journal_title：Physics in medicine and biology

authors： Lax I

更新日期：1991-07-01 00:00:00

abstract：:A single photon absorptiometry method to measure the arterial concentration of injected iodinated contrast agent was developed. A prototype absorptiometry unit was built which consists of either a square or circular cross section acrylic (polymethylmethacrylate) cuvette connected to an arterial catheter at one end and...

journal_title：Physics in medicine and biology

authors： Yeung WT,Lee TY,Del Maestro RF,Kozak R,Bennett JD,Brown T

更新日期：1992-09-01 00:00:00

abstract：:The convergence rates of the fast Padé transform (FPT) and the fast Fourier transform (FFT) are compared. These two estimators are used to process a time-signal encoded at 4 T by means of one-dimensional magnetic resonance spectroscopy (MRS) for healthy human brain. It is found systematically that at any level of trun...

journal_title：Physics in medicine and biology

authors： Belkić D,Belkić K

更新日期：2005-09-21 00:00:00

abstract：:The present note addresses the development of a lung tumor position predictor to be used in dynamic tumor tracking radiotherapy, abbreviated as DTT-RT. As there exists 50-500 ms positioning lag in the control of the multi-leaf collimator (MLC) of commercial medical linear accelerators, prediction of future lung tumor ...

journal_title：Physics in medicine and biology

authors： Jiang K,Fujii F,Shiinoki T

更新日期：2019-10-31 00:00:00

abstract：:Existing studies have suggested some debate on whether the quality of radiation that delivers dose outside of the primary field of a radiotherapy photon beam can be considered the same as that inside the primary field. We used a Monte Carlo approach to simulate the electron fluence differential in energy inside a wate...

journal_title：Physics in medicine and biology

authors： Kirkby C,Field C,MacKenzie M,Syme A,Fallone BG

更新日期：2007-06-21 00:00:00

abstract：:A leaf-setting algorithm is developed for generating arbitrary beam intensity profiles in discrete levels using dynamic multileaf collimators (DMLCs). The algorithm starts with the algebraic expression for the area under the beam profile. It is shown that the coefficients in this expression can be transformed into the...

journal_title：Physics in medicine and biology

authors： Ma L,Boyer AL,Xing L,Ma CM

更新日期：1998-06-01 00:00:00

abstract：:Finding fluence maps for intensity-modulated radiation therapy (IMRT) can be formulated as a multi-criteria optimization problem for which Pareto optimal treatment plans exist. To account for the dose-per-fraction effect of fractionated IMRT, it is desirable to exploit radiobiological treatment plan evaluation criteri...

journal_title：Physics in medicine and biology

authors： Hoffmann AL,den Hertog D,Siem AY,Kaanders JH,Huizenga H

更新日期：2008-11-21 00:00:00

abstract：:Tumour blood flow is one of the important factors limiting the efficacy of radiation therapy (hypoxic radioresistance), chemotherapy (drug delivery) and thermal therapy (heat dissipation) in treating cancer. The modification of tumour blood flow has been an area of intense investigation. In the current study, the arte...

journal_title：Physics in medicine and biology

authors： Purdie TG,Lee TY

更新日期：2003-04-07 00:00:00

abstract：:The purpose of this study was to determine the performance of a single lutetium oxy-orthosilicate (LSO) crystal layer High Resolution Research Tomograph (HRRT) positron emission tomography (PET) scanner. The HRRT is a high resolution PET scanner designed for human brain and small animal imaging. The scanner consists o...

journal_title：Physics in medicine and biology

authors： Boellaard R,Buijs F,de Jong HW,Lenox M,Gremillion T,Lammertsma AA

更新日期：2003-02-21 00:00:00