Monte Carlo- versus pencil-beam-/collapsed-cone-dose calculation in a heterogeneous multi-layer phantom.

abstract：:Enabling automated pipelines, image analysis and big data methodology in cancer clinics requires thorough understanding of the data. Automated quality assurance steps could improve the efficiency and robustness of these methods by verifying possible data biases. In particular, in head and neck (H&N) computed-tomograph...

journal_title：Physics in medicine and biology

authors： Welch ML,McIntosh C,Purdie TG,Wee L,Traverso A,Dekker A,Haibe-Kains B,Jaffray DA

更新日期：2020-01-10 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：:Reference dosimetry of photon fields is a well-established subject and currently available protocols (such as the IAEA TRS-398 and AAPM TG-51) provide methods for converting the ionization chamber (IC) reading into dose to water, provided reference conditions of charged particle equilibrium (CPE) are fulfilled. But th...

journal_title：Physics in medicine and biology

authors： Pena J,Sánchez-Doblado F,Capote R,Terrón JA,Gómez F

更新日期：2006-03-21 00:00:00

abstract：:Over the last two years we have evaluated paediatric patient doses in projection radiography derived from exposure level (EL) in computed radiography (CR) in a large university hospital. Entrance surface air kerma (ESAK) for 3501 paediatric examinations was calculated from the EL, which is a dose index parameter relat...

journal_title：Physics in medicine and biology

authors： Vano E,Martinez D,Fernandez JM,Ordiales JM,Prieto C,Floriano A,Ten JI

更新日期：2008-06-21 00:00:00

abstract：:The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This proced...

journal_title：Physics in medicine and biology

authors： Walters EB,Panda K,Bankson JA,Brown E,Cody DD

更新日期：2004-09-07 00:00:00

abstract：:The aim of the present work was to implement the kinetics of cisplatin into a previously developed tumour growth model and to simulate the combined cisplatin-radiotherapy treatment with the emphasis on time sequencing and scheduling of drug and radiation. An investigation into whether the effect of cisplatin-radiation...

journal_title：Physics in medicine and biology

authors： Marcu L,Bezak E,Olver I

更新日期：2006-08-07 00:00:00

abstract：:An open-ended coaxial probe is often used for investigating the dielectric properties of biological tissues. The present study indicates that in addition to the probe size, the penetration of the electromagnetic (EM) fields of an open-ended coaxial probe in contact with the skin is dependent on the applied frequency b...

journal_title：Physics in medicine and biology

authors： Alanen E,Lahtinen T,Nuutinen J

更新日期：1999-07-01 00:00:00

abstract：:The beam quality correction factor k Q for megavoltage photon beams has been calculated for eight PTW (Freiburg, Germany) ionization chambers (Farmer chambers PTW30010, PTW30011, PTW30012, and PTW30013, Semiflex 3D chambers PTW31021, PTW31010, and PTW31013, and the PinPoint 3D chamber PTW31016). Simulations performed ...

journal_title：Physics in medicine and biology

authors： Giménez-Alventosa V,Giménez V,Ballester F,Vijande J,Andreo P

更新日期：2020-10-07 00:00:00

abstract：:In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in...

journal_title：Physics in medicine and biology

authors： von Voigts-Rhetz P,Anton M,Vorwerk H,Zink K

更新日期：2016-02-07 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：:This paper contains the recommendations of the high dose rate (HDR) brachytherapy working party of the UK Institute of Physics and Engineering in Medicine (IPEM). The recommendations consist of a Code of Practice (COP) for the UK for measuring the reference air kerma rate (RAKR) of HDR (192)Ir brachytherapy sources. I...

journal_title：Physics in medicine and biology

authors： Bidmead AM,Sander T,Locks SM,Lee CD,Aird EG,Nutbrown RF,Flynn A,IPEM Working Party.

更新日期：2010-06-07 00:00:00

abstract：:This work applies a previously developed analytical algorithm to the reconstruction problem in a rotating multi-segment slant-hole (RMSSH) SPECT system. The RMSSH collimator has greater detection efficiency than the parallel-hole collimator with comparable spatial resolution at the expense of limited common volume-of-...

journal_title：Physics in medicine and biology

authors： Huang Q,Xu J,Tsui BM,Gullberg GT

更新日期：2009-07-07 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：:In electron beam dosimetry using parallel-plate chambers solid phantoms are sometimes necessary. To obtain the dose to water from the ionization obtained in the solid phantom, fluence correction factors and perturbation factors have to be applied. In this study fluence factors in a perturbation free geometry have been...

journal_title：Physics in medicine and biology

authors： Nilsson B,Montelius A,Andreo P,Johansson J

更新日期：1997-11-01 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：:Proton computed tomography (pCT) promises to reduce or even eliminate range uncertainties inherent in the conversion of Hounsfield units into relative stopping power (RSP) for proton therapy treatment planning. This is of particular interest for proton irradiation studies in animal models due to the high precision req...

journal_title：Physics in medicine and biology

authors： Meyer S,Bortfeldt J,Lämmer P,Englbrecht FS,Pinto M,Schnürle K,Würl M,Parodi K

更新日期：2020-08-13 00:00:00

abstract：:In elastography we have previously developed a tracking and correction method that estimates the axial and lateral strain components along and perpendicular to the compressor/scanning axis following an externally applied compression. However, the resulting motion is a three-dimensional problem. Therefore, in order to ...

journal_title：Physics in medicine and biology

authors： Konofagou EE,Ophir J

更新日期：2000-06-01 00:00:00

abstract：:Dose to water (Dw) determination in clinical high-energy photon beams with ionization chambers calibrated in terms of absorbed dose to water has been proposed as an alternative to ionization chamber dosimetry based on air kerma calibrations. Dw in the clinical beam is derived using a kappaQ factor that scales the abso...

journal_title：Physics in medicine and biology

authors： Palmans H,Mondelaers W,Thierens H

更新日期：1999-03-01 00:00:00

abstract：:Monte Carlo simulation of radiation transport is considered to be one of the most accurate methods of radiation therapy dose calculation. With the rapid development of computer technology, Monte Carlo based treatment planning for radiation therapy is becoming practical. A basic requirement for Monte Carlo treatment pl...

journal_title：Physics in medicine and biology

authors： Ma CM,Jiang SB

更新日期：1999-12-01 00:00:00

abstract：:Complex intra-fractional motion and deformation of the liver significantly impacts the accuracy of delivered dose in radiotherapy. It limits margin reduction, dose escalation and normal tissue sparing. A critical component of motion management is to accurately reconstruct tumor motion. In this study, we developed a si...

journal_title：Physics in medicine and biology

authors： Chi Y,Shen C,Li B,Zhang Y,Yang M,Folkert M,Jia X

更新日期：2019-11-21 00:00:00

abstract：:Two dosimetry protocols based on absorbed dose to water have recently been implemented: TG-51 and TRS-398. These protocols use different beam-quality indices: %dd(10)x and TPR20,10. The effect of electron contamination in measurements of %dd(10)x has been proposed as a disadvantage of the TG-51. For actual measurement...

journal_title：Physics in medicine and biology

authors： Lopez Medina A,Teijeiro A,Salvador F,Medal D,Vazquez J,Salgado M,Carrion MC

更新日期：2004-01-07 00:00:00

abstract：:A new hybrid imaging-treatment modality, the MRI-Linac, involves the irradiation of the patient in the presence of a strong magnetic field. This field acts on the charged particles, responsible for depositing dose, through the Lorentz force. These conditions require a dose calculation engine capable of taking into con...

journal_title：Physics in medicine and biology

authors： Hissoiny S,Raaijmakers AJ,Ozell B,Després P,Raaymakers BW

更新日期：2011-08-21 00:00:00

abstract：:The design, construction and use of a large-scale field-cycled proton-electron double-resonance imaging (FC-PEDRI) imager is described. The imager is based on a whole-body sized, vertical field, 59 mT permanent magnet. Field cycling is accomplished by the field compensation method, and uses a secondary, resistive magn...

journal_title：Physics in medicine and biology

authors： Lurie DJ,Foster MA,Yeung D,Hutchison JM

更新日期：1998-07-01 00:00:00

abstract：:In treatment planning we depend upon accurate knowledge of geometric and range uncertainties. If the uncertainty model is inaccurate then the plan will produce under-dosing of the target and/or overdosing of OAR. We aim to provide a method for which centre and site-specific population range uncertainty due to inter-fr...

journal_title：Physics in medicine and biology

authors： Holloway SM,Holloway MD,Thomas SJ

更新日期：2017-12-19 00:00:00

abstract：:This paper presents a compressed sensing (CS)-inspired reconstruction method for limited-angle computed tomography (CT). Currently, CS-inspired CT reconstructions are often performed by minimizing the total variation (TV) of a CT image subject to data consistency. A key to obtaining high image quality is to optimize t...

journal_title：Physics in medicine and biology

authors： Chen Z,Jin X,Li L,Wang G

更新日期：2013-04-07 00:00:00

abstract：:An experimental determination of the energy correction factor for alanine/paraffin pellets in the 192Ir spectrum at varying distances from the source is presented. Alanine dosimeters were irradiated in water under full scatter conditions with a high dose rate (HDR) 192Ir source (Flexisource), using a dedicated holder....

journal_title：Physics in medicine and biology

authors： Schaeken B,Cuypers R,Goossens J,Van den Weyngaert D,Verellen D

更新日期：2011-10-21 00:00:00

abstract：:Reducing radiation dose in dual energy computed tomography (DECT) is highly desirable but it may lead to excessive noise in the filtered backprojection (FBP) reconstructed DECT images, which can inevitably increase the diagnostic uncertainty. To obtain clinically acceptable DECT images from low-mAs acquisitions, in th...

journal_title：Physics in medicine and biology

authors： Zhang H,Zeng D,Lin J,Zhang H,Bian Z,Huang J,Gao Y,Zhang S,Zhang H,Feng Q,Liang Z,Chen W,Ma J

更新日期：2017-07-07 00:00:00

abstract：:Blood was withdrawn from the ante-cubital vein of five normal volunteers and the erythrocytes were washed and resuspended in isotonic saline. The rate of descent of the erythrocyte-saline boundary was measured every hour for a period of at least 4 h for different suspended cell concentrations. The velocity of this bou...

journal_title：Physics in medicine and biology

authors： Smallwood RH,Tindale WB,Trowbridge EA

更新日期：1985-02-01 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：:A Gaussian convolution kernel K is deduced as a Green's function of a Lie operator series. The deconvolution of a Gaussian kernel is developed by the inverse Green's function K(-1). A practical application is the deconvolution of measured profiles Dm(x) of photons and protons with finite detector size to determine the...

journal_title：Physics in medicine and biology

authors： Ulmer W,Kaissl W

更新日期：2003-03-21 00:00:00