A set cover approach to fast beam orientation optimization in intensity modulated radiation therapy for total marrow irradiation.

abstract：:To calculate photon spectra for a 10 MV x-ray beam emitted by a medical linear accelerator, we performed numerical analysis using the aluminium transmission data obtained along the central axis of the beam under the narrow beam condition corresponding to a 3x3 cm2 field at a 100 cm distance from the source. We used th...

journal_title：Physics in medicine and biology

authors： Shimozato T,Tabushi K,Kitoh S,Shiota Y,Hirayama C,Suzuki S

更新日期：2007-01-21 00:00:00

abstract：:The combined build-up and attenuation factor, B exp (-mu r), of point isotropic photon sources in a water medium has been calculated using the Monte Carlo method, for energies (20-1500 keV) and distances (1-10 cm) relevant in brachytherapy. For the transport of photons and electrons, up-to-date and self-consistent tot...

journal_title：Physics in medicine and biology

authors： Angelopoulos A,Perris A,Sakellariou K,Sakelliou L,Sarigiannis K,Zarris G

更新日期：1991-06-01 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

abstract：:The National Physical Laboratory (NPL) provides a high-energy photon calibration service using 4-19 MV x-rays and 60Co gamma-radiation for secondary standard dosemeters in terms of absorbed dose to water. The primary standard used for this service is a graphite calorimeter and so absorbed dose calibrations must be con...

journal_title：Physics in medicine and biology

authors： Nutbrown RF,Duane S,Shipley DR,Thomas RA

更新日期：2002-02-07 00:00:00

abstract：:Recent measurements of differential elastic and inelastic neutron scattering from oxygen, nitrogen and calcium at 18 less than En less than 26 MeV are presented and analysed in terms of the optical model. These data, together with earlier measurements of scattering and total cross sections, are used to construct model...

journal_title：Physics in medicine and biology

authors： Islam MS,Finlay RW,Petler JS,Rapaport J,Alarcon R,Wierzbicki J

更新日期：1988-03-01 00:00:00

abstract：:Permanent in vivo verification of IMRT photon beam profiles by a radiation detector with spatial resolution, positioned on the radiation entrance side of the patient, has not been clinically available so far. In this work we present the DAVID system, which is able to perform this quality assurance measurement while th...

journal_title：Physics in medicine and biology

authors： Poppe B,Thieke C,Beyer D,Kollhoff R,Djouguela A,Rühmann A,Willborn KC,Harder D

更新日期：2006-03-07 00:00:00

abstract：:IMRT optimization is an iterative process in which many dose calculations may be necessary. A fast and accurate dose calculation engine is essential for the optimization program to converge to a reliable solution in a reasonable time. Previously we developed a fast dose calculation method for IMRT optimization based o...

journal_title：Physics in medicine and biology

authors： Wu Q

更新日期：2004-10-07 00:00:00

abstract：:Polymer gel dosimetry aims to provide three-dimensional images of radiation therapy dose distributions in irradiated aqueous gels. The first gels required manufacture in an oxygen-free environment, but later the MAGIC formulation was introduced, which could be made in normal atmospheric conditions. Here we report our ...

journal_title：Physics in medicine and biology

authors： Luci JJ,Whitney HM,Gore JC

更新日期：2007-05-21 00:00:00

abstract：:Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the card...

journal_title：Physics in medicine and biology

authors： Du Y,Bhattacharya M,Frey EC

更新日期：2014-06-07 00:00:00

abstract：:Iterative tomographic reconstruction has been established as a viable alternative for data analysis in phase-sensitive x-ray imaging based on the edge-illumination principle. However, previously published approaches did not account for drifts of optical elements during a scan, which can lead to artefacts. Up to now, t...

journal_title：Physics in medicine and biology

authors： Modregger P,Meganck J,Hagen CK,Massimi L,Olivo A,Endrizzi M

更新日期：2019-10-10 00:00:00

abstract：:Computational modeling is an important tool in ultrasound imaging research, but realistic three-dimensional (3D) simulations can exceed the capabilities of serial computers. This paper uses a 3D simulator based on a k-space method that incorporates relaxation absorption and nonreflecting boundary conditions. The simul...

journal_title：Physics in medicine and biology

authors： Daoud MI,Lacefield JC

更新日期：2009-09-07 00:00:00

abstract：:Radiobiological models for estimating normal tissue complication probability (NTCP) are increasingly used in order to quantify or optimize the clinical outcome of radiation therapy. A good NTCP model should fulfill at least the following two requirements: (a) it should predict the sigmoid shape of the corresponding do...

journal_title：Physics in medicine and biology

authors： Adamus-Górka M,Mavroidis P,Brahme A,Lind BK

更新日期：2008-11-21 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：: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：: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：:A number of heating sources are available for minimally invasive thermal therapy of tumours. The purpose of this work was to compare, theoretically, the heating characteristics of interstitial microwave, laser and ultrasound sources in three tissue sites: breast, brain and liver. Using a numerical method, the heating ...

journal_title：Physics in medicine and biology

authors： Skinner MG,Iizuka MN,Kolios MC,Sherar MD

更新日期：1998-12-01 00:00:00

abstract：:The authors have developed an apparatus able to generate ID intensity-modulated beams, using only one moving absorber within the irradiation field. A procedure for deriving optimized absorber-speed profiles in order to produce the desired fluence/dose profiles has been suggested. Experimental tests show that the syste...

journal_title：Physics in medicine and biology

authors： Fiorino C,Lev A,Fusca M,Cattaneo GM,Rudello F,Calandrino R

更新日期：1995-02-01 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：:Most existing spatiotemporal multi-dipole approaches for MEG/EEG source localization assume that the dipoles are active for the full time range being analysed. If the actual time range of activity of sources is significantly shorter than the time range being analysed, the detectability, localization and time-course de...

journal_title：Physics in medicine and biology

authors： Jun SC,George JS,Plis SM,Ranken DM,Schmidt DM,Wood CC

更新日期：2006-05-21 00:00:00

abstract：:Pinhole SPECT is rapidly gaining popularity for imaging laboratory animals using gamma-emitting molecules. Penetration and scattering of gamma radiation in the pinhole edge material can account for a significant fraction of the total number of photons detected, particularly if the pinholes have small diameters. This s...

journal_title：Physics in medicine and biology

authors： van der Have F,Beekman FJ

更新日期：2004-04-21 00:00:00

abstract：:We present the results of utilizing aligned anatomical information from CT images to locally adjust image smoothness during the reconstruction of three-dimensional (3D) whole-body positron emission tomography (PET) data. The ability of whole-body PET imaging to detect malignant neoplasms is becoming widely recognized....

journal_title：Physics in medicine and biology

authors： Comtat C,Kinahan PE,Fessler JA,Beyer T,Townsend DW,Defrise M,Michel C

更新日期：2002-01-07 00:00:00

abstract：:A phantom study for dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer is presented. The measurement method of the secondary standard of the Physikalisch-Technische Bundesanstalt had to be slightly modified in order to be able to measure inside a Foley catheter. The absorbed...

journal_title：Physics in medicine and biology

authors： Anton M,Wagner D,Selbach HJ,Hackel T,Hermann RM,Hess CF,Vorwerk H

更新日期：2009-05-07 00:00:00

abstract：:Several papers have recently addressed the issue of estimating chromophore concentration in optoacoustic imaging (OAI) using multiple wavelengths. The choice of wavelengths obviously affects the accuracy and precision of the estimates. One might assume that the wavelengths that maximize the extinction coefficients of ...

journal_title：Physics in medicine and biology

authors： Modgil D,La Riviére PJ

更新日期：2010-12-07 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：:Ultraviolet (UV) treatment dose is determined by the length of time that a patient spends in a phototherapy cabin. The output from UV fluorescent lamps declines with use and a method is needed to compensate for the change in irradiance and to identify and replace any lamps that fail. The decline in lamp output with ag...

journal_title：Physics in medicine and biology

authors： Amatiello H,Martin CJ

更新日期：2006-01-21 00:00:00

abstract：:Proton therapy is very sensitive to daily density changes along the pencil beam paths. The purpose of this study is to develop and evaluate an automated method for adaptation of IMPT plans to compensate for these daily tissue density variations. A two-step restoration method for 'densities-of-the-day' was created: (1)...

journal_title：Physics in medicine and biology

authors： Jagt T,Breedveld S,van de Water S,Heijmen B,Hoogeman M

更新日期：2017-06-07 00:00:00

abstract：:Many applications in medical imaging include image registration for matching of images from the same or different modalities. In the case of full data sampling, the respective reconstructed images are usually of such a good image quality that standard deformable volume-to-volume (3D-3D) registration approaches can be ...

journal_title：Physics in medicine and biology

authors： Flach B,Brehm M,Sawall S,Kachelrieß M

更新日期：2014-12-21 00:00:00

abstract：:Compromises in the design of a positron emission tomography (PET) insert for a magnetic resonance imaging (MRI) system should minimize the deterioration of image quality in both modalities, particularly when simultaneous demanding acquisitions are performed. In this work, the advantages of using individually read-out ...

journal_title：Physics in medicine and biology

authors： Omidvari N,Topping G,Cabello J,Paul S,Schwaiger M,Ziegler SI

更新日期：2018-05-01 00:00:00

abstract：:A software program, SpekCalc, is presented for the calculation of x-ray spectra from tungsten anode x-ray tubes. SpekCalc was designed primarily for use in a medical physics context, for both research and education purposes, but may also be of interest to those working with x-ray tubes in industry. Noteworthy is the p...

journal_title：Physics in medicine and biology

authors： Poludniowski G,Landry G,DeBlois F,Evans PM,Verhaegen F

更新日期：2009-10-07 00:00:00

abstract：:A multicentre phase II trial of stereotactic body radiotherapy for T1N0M0 non-small cell lung cancer was initiated in Japan as the Japan Clinical Oncology Group trial (JCOG0403). Before starting the trial, a decision was made to evaluate the treatment machine and treatment planning in participating institutions to min...

journal_title：Physics in medicine and biology

authors： Nishio T,Kunieda E,Shirato H,Ishikura S,Onishi H,Tateoka K,Hiraoka M,Narita Y,Ikeda M,Goka T

更新日期：2006-11-07 00:00:00