Delivery time comparison for intensity-modulated radiation therapy with/without flattening filter: a planning study.

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：:This paper concerns the robustness of discrete wavelet transform (DWT) compression in terahertz pulsed imaging (TPI). TPI datasets consist of terahertz time-domain series which are sampled at each 'pixel' of the image, leading to file sizes which are typically of the order of several megabytes (MB) per image. This mak...

journal_title：Physics in medicine and biology

authors： Handley JW,Fitzgerald AJ,Berry E,Boyle RD

更新日期：2002-11-07 00:00:00

abstract：:Characterization of both malignant and benign lesions in the female breast is presented as the result of a clinical study that involved more than 190 subjects in the framework of the OPTIMAMM European project. All the subjects underwent optical mammography, by means of a multi-wavelength time-resolved mammograph, in t...

journal_title：Physics in medicine and biology

authors： Spinelli L,Torricelli A,Pifferi A,Taroni P,Danesini G,Cubeddu R

更新日期：2005-06-07 00:00:00

abstract：:The function of the placenta is challenging to characterize and as a result is understudied, despite the growing awareness of the impact of the placental environment on human health and development. Medical imaging has the potential to improve our ability to screen for diseases associated with placental insufficiency,...

journal_title：Physics in medicine and biology

authors： Wu C,Bayer CL

更新日期：2018-07-09 00:00:00

abstract：:In dynamic renal scintigraphy, the main interest is the radiopharmaceutical redistribution as a function of time. Quality control (QC) of renal procedures often relies on phantom experiments to compare image-based results with the measurement setup. A phantom with a realistic anatomy and time-varying activity distribu...

journal_title：Physics in medicine and biology

authors： Brolin G,Gleisner KS,Ljungberg M

更新日期：2013-05-21 00:00:00

abstract：:Inverse treatment planning in intensity modulated particle therapy (IMPT) with scanned carbon-ion beams is currently based on the optimization of RBE-weighted dose to satisfy requirements of target coverage and limited toxicity to organs-at-risk (OARs) and healthy tissues. There are many feasible IMPT plans that meet ...

journal_title：Physics in medicine and biology

authors： Burigo LN,Ramos-Méndez J,Bangert M,Schulte RW,Faddegon B

更新日期：2019-01-04 00:00:00

abstract：:While megavoltage cone-beam computed tomography (CBCT) using an electronic portal imaging device (EPID) provides many advantages over kilovoltage (kV) CBCT, clinical adoption is limited by its high doses. Multi-layer imager (MLI) EPIDs increase DQE(0) while maintaining high resolution. However, even well-designed, hig...

journal_title：Physics in medicine and biology

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

更新日期：2018-01-30 00:00:00

abstract：:Non-pure positron emitters, with their long half-lives, allow for the tracing of slow biochemical processes which cannot be adequately examined by the commonly used short-lived positron emitters. Most of these isotopes emit high-energy cascade gamma rays in addition to positron decay that can be detected and create a ...

journal_title：Physics in medicine and biology

authors： Lin HH,Chuang KS,Chen SY,Jan ML

更新日期：2016-03-07 00:00:00

abstract：:Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct ra...

journal_title：Physics in medicine and biology

authors： Boussion N,Hatt M,Lamare F,Bizais Y,Turzo A,Cheze-Le Rest C,Visvikis D

更新日期：2006-04-07 00:00:00

abstract：:Proton CT nowadays aims at improving hadron therapy treatment planning by mapping the stopping power of materials. In order to optimize a spatial resolution of the reconstructed images, the most likely path (MLP) of each proton can be computed. We investigated the errors in the computation of this path due to the conf...

journal_title：Physics in medicine and biology

authors： Bopp C,Rescigno R,Rousseau M,Brasse D

更新日期：2014-12-07 00:00:00

abstract：:Analytic solutions to the time-dependent multiregion bioheat equation are evaluated numerically for cartesian and spherical models. Principle and alternate branch contributions to the solutions are examined. The calculations include a parametric investigation and analyses of temperature behaviour in idealised upper th...

journal_title：Physics in medicine and biology

authors： Durkee JW Jr,Antich PP,Lee CE

更新日期：1990-07-01 00:00:00

abstract：:The sensitivity and detection limit for measurements of the concentration of cadmium in the kidney cortex of man in vivo have been investigated using the technique of X-ray fluorescence. An 11 GB1 241Am source was used to generate the characteristic K alpha X-rays of cadmium. The variation in the sensitivity for the d...

journal_title：Physics in medicine and biology

authors： Ahlgren L,Mattsson S

更新日期：1981-01-01 00:00:00

abstract：:Radiotherapy treatment planning is associated with uncertainties. Examples are uncertainties in the tumour location due to organ movement or the inter/intra observer variability in target definition. Different approaches to incorporate uncertainties into IMRT optimization have been proposed. In this note, we point out...

journal_title：Physics in medicine and biology

authors： Unkelbach J,Oelfke U

更新日期：2006-12-07 00:00:00

abstract：:In radiotherapy with photon beams, the use of dynamic wedges, which are obtained by the movement of one of the jaws, offers an increasing flexibility relative to the traditional use of metal wedges. But it is a disadvantage for the measurement of absorbed dose distributions, because the absorbed dose at each measureme...

journal_title：Physics in medicine and biology

authors： Storchi P,Woudstra E,Verlinde P,Johansson KA,Samuelsson A

更新日期：1998-06-01 00:00:00

abstract：:Area laser lathing and trephination of donor corneas is used to produce different types of grafts for human transplantation. 193 nm (ArF excimer) laser radiation is used, since this is known to give a non-thermal laser-tissue interaction with a minimal zone of tissue damage. To guarantee the highest degree of flexibil...

journal_title：Physics in medicine and biology

authors： Homolka P,Biowski R,Kaminski S,Barisani T,Husinsky W,Bergmann H,Grabner G

更新日期：1999-05-01 00:00:00

abstract：:The purpose of this paper for four-dimensional (4D) computed tomography (CT) is threefold. (1) A new spatiotemporal model is presented from the matrix perspective with the row dimension in space and the column dimension in time, namely the robust PCA (principal component analysis)-based 4D CT model. That is, instead o...

journal_title：Physics in medicine and biology

authors： Gao H,Cai JF,Shen Z,Zhao H

更新日期：2011-06-07 00:00:00

abstract：:The purpose of this work is to model electron contamination in clinical photon beams and to commission the source model using measured data for Monte Carlo treatment planning. In this work, a planar source is used to represent the contaminant electrons at a plane above the upper jaws. The source size depends on the di...

journal_title：Physics in medicine and biology

authors： Yang J,Li JS,Qin L,Xiong W,Ma CM

更新日期：2004-06-21 00:00:00

abstract：:Refraction contrast of simple objects obtained using diffraction enhanced imaging (DEI) was studied and compared to conventional radiographic contrast. Lucite cylinders and nylon wires were imaged using monochromatic synchrotron radiation at the National Synchrotron Light Source (http://nslsweb. nsls.bnl.gov/nsls/Defa...

journal_title：Physics in medicine and biology

authors： Kiss MZ,Sayers DE,Zhong Z

更新日期：2003-02-07 00:00:00

abstract：:Exploiting the field response of magnetic tracers, magnetic particle imaging (MPI) allows direct, local quantification of the tracer concentration in bulk structures. Here, we investigated the use of characteristic field response functions to spatially resolve the absolute concentration of multiple nanoparticle specie...

journal_title：Physics in medicine and biology

authors： Han SH,Cho E,Lee DK,Cho G,Kim YR,Cho H

更新日期：2014-11-07 00:00:00

abstract：:Monte Carlo (MC) algorithms are recognized as the most accurate methodology for patient dose assessment. For intensity-modulated radiation therapy (IMRT) delivered with dynamic multileaf collimators (DMLCs), accurate dose calculation, even with MC, is challenging. Accurate IMRT MC dose calculations require inclusion o...

journal_title：Physics in medicine and biology

authors： Siebers JV,Keall PJ,Kim JO,Mohan R

更新日期：2002-09-07 00:00:00

abstract：:Biomedical fibre-optic sensors are attractive for the measurement of physical, chemical and biochemical parameters and for spectral measurements directly performed on the patient. An overview of fibre-optic sensors for in vivo monitoring is given, with particular attention paid to the advantages that these sensors are...

journal_title：Physics in medicine and biology

authors： Mignani AG,Baldini F

更新日期：1997-05-01 00:00:00

abstract：:Charge-coupled devices (CCDs) coupled to scintillation crystals can be used for high-resolution imaging with x-rays and gamma rays. When the CCD images can be read out fast enough, the energy and interaction position of individual gamma quanta can be estimated by a real-time image analysis of the scintillation light f...

journal_title：Physics in medicine and biology

authors： Heemskerk JW,Westra AH,Linotte PM,Ligtvoet KM,Zbijewski W,Beekman FJ

更新日期：2007-04-21 00:00:00

abstract：:Assessment of image quality for digital x-ray mammography systems used in European screening programs relies mainly on contrast-detail CDMAM phantom scoring and requires the acquisition and analysis of many images in order to reduce variability in threshold detectability. Part II of this study proposes an alternative ...

journal_title：Physics in medicine and biology

authors： Monnin P,Marshall NW,Bosmans H,Bochud FO,Verdun FR

更新日期：2011-07-21 00:00:00

abstract：:Techniques for reducing computation time in 3D photon dose calculations are addressed with specific emphasis given to the convolution/superposition approach. A single polyenergetic superposition model calculating absorbed dose per incident photon fluence (Gy cm2) was developed in terms of TERMA and a total energy depo...

journal_title：Physics in medicine and biology

authors： Aspradakis MM,Redpath AT

更新日期：1997-08-01 00:00:00

abstract：:In the IAEA TRS-381 protocol, k(cel) and p(cel) account for the central electrode perturbation during the air kerma chamber calibration and the in-phantom measurements. The values of these correction factors are based mainly on Monte Carlo simulations. In the present work experimental data on k(cel) and p(cel) for the...

journal_title：Physics in medicine and biology

authors： Palm A,Mattsson O

更新日期：1999-05-01 00:00:00

abstract：:The aim of this study was to measure entrance skin doses on patients undergoing cone-beam computed tomography (CBCT) examinations, to establish conversion factors between skin and organ doses, and to estimate cancer risk from CBCT exposures. 266 patients (age 8-83) were included, involving three imaging centres. CBCT ...

journal_title：Physics in medicine and biology

authors： Pauwels R,Cockmartin L,Ivanauskaité D,Urbonienė A,Gavala S,Donta C,Tsiklakis K,Jacobs R,Bosmans H,Bogaerts R,Horner K,SEDENTEXCT Project Consortium.

更新日期：2014-07-21 00:00:00

abstract：:The most advanced delivery technique for proton radiotherapy is active spot scanning. So far, predominantly static targets have been treated with active spot scanning, since mobile targets in combination with dynamic treatment delivery can lead to interplay effects, causing inhomogeneous dose distributions. One way to...

journal_title：Physics in medicine and biology

authors： Knopf AC,Hong TS,Lomax A

更新日期：2011-11-21 00:00:00

abstract：:It seems likely that long term patency of small bore vascular prostheses is dependent upon, among other things, the mechanical properties of their walls. Arteries are visco-elastic but there is no accurate method of measuring the visco-elasticity of arterial substitutes in vivo. The most successful vascular substitute...

journal_title：Physics in medicine and biology

authors： Chapman BL,Charlesworth D

更新日期：1983-09-01 00:00:00

abstract：:This work aims to develop, implement and validate a Monte Carlo (MC)-based independent dose calculation (IDC) framework to perform patient-specific quality assurance (QA) for multi-leaf collimator (MLC)-based CyberKnife® (Accuray Inc., Sunnyvale, CA) treatment plans. The IDC framework uses an XML-format treatment plan...

journal_title：Physics in medicine and biology

authors： Mackeprang PH,Vuong D,Volken W,Henzen D,Schmidhalter D,Malthaner M,Mueller S,Frei D,Stampanoni MFM,Dal Pra A,Aebersold DM,Fix MK,Manser P

更新日期：2017-12-19 00:00:00

abstract：:Methods based on magnetic resonance imaging for the measurement of three-dimensional distributions of radiation dose are highly developed. However, relatively little work has been done on optical computed tomography (OCT). This paper describes a new OCT scanner based on a broad beam light source and a two-dimensional ...

journal_title：Physics in medicine and biology

authors： Doran SJ,Koerkamp KK,Bero MA,Jenneson P,Morton EJ,Gilboy WB

更新日期：2001-12-01 00:00:00