A low cost method for hard x-ray grating interferometry.

abstract：:The relative stopping power (RSP) uncertainty is the largest contributor to the range uncertainty in proton therapy. The purpose of this work was to develop a systematic method that yields accurate and patient-specific RSPs by combining (1) pre-treatment x-ray CT and (2) daily proton radiography of the patient. The me...

journal_title：Physics in medicine and biology

authors： Collins-Fekete CA,Brousmiche S,Hansen DC,Beaulieu L,Seco J

更新日期：2017-08-03 00:00:00

abstract：:In this paper, the influence of a dynamic variation in the ambient pressure on the subharmonic response of phospholipid-coated microbubbles was investigated. The ambient pressure in water was modulated by a 2.5 kHz acoustic wave with a peak amplitude of 15 kPa. We investigated the fundamental and subharmonic emissions...

journal_title：Physics in medicine and biology

authors： Faez T,Renaud G,Defontaine M,Calle S,de Jong N

更新日期：2011-10-07 00:00:00

abstract：:The bone mineral density (BMD), ultrasound velocity (UV) and attenuation were examined in sixteen matched sets of human patellae and calcanei. For the sixteen calcanei, BMD was strongly correlated with all ultrasound parameters. Calcaneal UV appeared to be inferior to attenuation in the ability to predict BMD. For the...

journal_title：Physics in medicine and biology

authors： Han SM,Davis J

更新日期：1997-10-01 00:00:00

abstract：:Kilovoltage intratreatment monitoring (KIM) is a novel real-time localization modality where the tumor position is continuously measured during intensity modulated radiation therapy (IMRT) or intensity modulated arc therapy (IMAT) by a kilovoltage (kV) x-ray imager. Adding kV imaging during therapy adds radiation dose...

journal_title：Physics in medicine and biology

authors： Ng JA,Booth J,Poulsen P,Kuncic Z,Keall PJ

更新日期：2013-09-07 00:00:00

abstract：:In order to enable a detailed analysis of radio frequency (RF) absorption in the human middle and inner ear organs, a numerical model of these organs was developed at a spatial resolution of 0.1 mm, based on a real human tissue sample. The dielectric properties of the liquids (perilymph and endolymph) inside the bony ...

journal_title：Physics in medicine and biology

authors： Schmid G,Uberbacher R,Samaras T,Jappel A,Baumgartner WD,Tschabitscher M,Mazal PR

更新日期：2007-04-07 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 this study, two computational phantoms of the newborn patient were used to assess individual organ doses and effective doses delivered during head, chest, abdomen, pelvis, and torso examinations using the Siemens SOMATOM Sensation 16 helical multi-slice computed tomography (MSCT) scanner. The stylized phantom used ...

journal_title：Physics in medicine and biology

authors： Staton RJ,Lee C,Lee C,Williams MD,Hintenlang DE,Arreola MM,Williams JL,Bolch WE

更新日期：2006-10-21 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：:Optical experiments are described for measuring the attenuation characteristics of breast tissues at visible and near-infrared wavelengths. Total attenuation coefficients post mortem were measured directly in thin tissue sections. They are usually within the range from 10 to 30 mm-1, are rather higher in fat than in f...

journal_title：Physics in medicine and biology

authors： Key H,Davies ER,Jackson PC,Wells PN

更新日期：1991-05-01 00:00:00

abstract：:This study evaluates the performance of the Bruker positron emission tomograph (PET) insert combined with a BioSpec 70/30 USR magnetic resonance imaging (MRI) scanner using the manufacturer acceptance protocol and the NEMA NU 4-2008 for small animal PET. The PET insert is made of 3 rings of 8 monolithic LYSO crystals ...

journal_title：Physics in medicine and biology

authors： Gsell W,Molinos C,Correcher C,Belderbos S,Wouters J,Junge S,Heidenreich M,Vande Velde G,Rezaei A,Nuyts J,Cawthorne C,Cleeren F,Nannan L,Deroose CM,Himmelreich U,González Martínez AJ

更新日期：2020-06-26 00:00:00

abstract：:Accurate real-time prediction of respiratory motion is desirable for effective motion management in radiotherapy for lung tumor targets. Recently, nonparametric methods have been developed and their efficacy in predicting one-dimensional respiratory-type motion has been demonstrated. To exploit the correlation among v...

journal_title：Physics in medicine and biology

authors： Ruan D,Keall P

更新日期：2010-06-07 00:00:00

abstract：:The aim of this study was to develop a model exploiting artificial neural networks (ANNs) to correlate dosimetric and clinical variables with late rectal bleeding in prostate cancer patients undergoing radical radiotherapy and to compare the ANN results with those of a standard logistic regression (LR) analysis. 718 m...

journal_title：Physics in medicine and biology

authors： Tomatis S,Rancati T,Fiorino C,Vavassori V,Fellin G,Cagna E,Mauro FA,Girelli G,Monti A,Baccolini M,Naldi G,Bianchi C,Menegotti L,Pasquino M,Stasi M,Valdagni R

更新日期：2012-03-07 00:00:00

abstract：:In dual energy x-ray absorptiometry (DXA) the photon attenuation is assumed to be similar in soft tissue overlying, adjacent to and inside the measured bone. In the calcaneal dual energy x-ray laser (DXL) technique, this assumption is not needed as attenuation by soft tissues at the local bone site is determined by co...

journal_title：Physics in medicine and biology

authors： Hakulinen MA,Saarakkala S,Töyräs J,Kröger H,Jurvelin JS

更新日期：2003-06-21 00:00:00

abstract：:Geometric and penetration responses of a multihole focusing collimator to a point source have been determined using a digital computer and a ray tracing technique. Results are presented as point and line spread functions for collimated rays and penetrating rays, and as plane sensitivities and modulation transfer funct...

journal_title：Physics in medicine and biology

authors： Jahns MJ

更新日期：1981-01-01 00:00:00

abstract：:Most commonly in radiation therapy, treatments are delivered in a co-planar geometry. Numerous advantages have been reported of adding non-coplanar beams to the treatment plan. The aim of this study was to compare current state-of-the-art VMAT and CyberKnife treatment plans to that of a novel linac design developed at...

journal_title：Physics in medicine and biology

authors： Schüler E,Wang L,Loo BW,Maxim PG

更新日期：2019-06-20 00:00:00

abstract：:In brachytherapy, plans are routinely calculated using the AAPM TG43 formalism which considers the patient as a simple water object. An accurate modeling of the physical processes considering patient heterogeneity using Monte Carlo simulation (MCS) methods is currently too time-consuming and computationally demanding ...

journal_title：Physics in medicine and biology

authors： Lemaréchal Y,Bert J,Falconnet C,Després P,Valeri A,Schick U,Pradier O,Garcia MP,Boussion N,Visvikis D

更新日期：2015-07-07 00:00:00

abstract：:Time-of-flight (TOF) positron emission tomography (PET) technology has recently regained popularity in clinical PET studies for improving image quality and lesion detectability. Using TOF information, the spatial location of annihilation events is confined to a number of image voxels along each line of response, there...

journal_title：Physics in medicine and biology

authors： Mehranian A,Kotasidis F,Zaidi H

更新日期：2016-02-07 00:00:00

abstract：:All particle beam scanning systems are subject to dose delivery errors due to errors in position, energy and intensity of the delivered beam. In addition, finite scan speeds, beam spill non-uniformities, and delays in detector, detector electronics and magnet responses will all contribute errors in delivery. In this p...

journal_title：Physics in medicine and biology

authors： Coutrakon G,Wang N,Miller DW,Yang Y

更新日期：2010-12-07 00:00:00

abstract：:Two different classifiers, an artificial neural network (ANN) and a hybrid system (one step rule-based method followed by an artificial neural network) have been investigated to merge computer-extracted features in the task of differentiating between malignant and benign masses. A database consisting of 65 cases (38 m...

journal_title：Physics in medicine and biology

authors： Huo Z,Giger ML,Metz CE

更新日期：1999-10-01 00:00:00

abstract：:The aim of this study was to investigate the utility of consistency metrics, such as inverse consistency, in contour-based deformable registration error analysis. Four images were acquired of the same phantom that has experienced varying levels of deformation. The deformations were simulated with deformable image regi...

journal_title：Physics in medicine and biology

authors： Bender ET,Tomé WA

更新日期：2009-09-21 00:00:00

abstract：:The use of thermographic techniques has increased as infrared detector technology has evolved and improved. For laser-tissue interactions, thermal cameras have been used to monitor the thermal response of tissue to pulsed and continuous wave irradiation. It is important to note that the temperature indicated by the th...

journal_title：Physics in medicine and biology

authors： Choi B,Pearce JA,Welch AJ

更新日期：2000-02-01 00:00:00

abstract：:Thermal therapy is an experimental treatment to destroy solid tumours by heating them to temperatures ranging from 55 degrees C to 90 degrees C, inducing thermal coagulation and necrosis of the tumour. We are investigating the feasibility of interstitial microwave thermal therapy as a salvage treatment for prostate ca...

journal_title：Physics in medicine and biology

authors： McCann C,Kumaradas JC,Gertner MR,Davidson SR,Dolan AM,Sherar MD

更新日期：2003-04-21 00:00:00

abstract：:The objective of this study was to be able to distinguish between healthy skin tissue and malignant ones, furthermore determining a unique pattern of roughness for each skin lesion by microtopographic analysis of the skin surface of Mexican patients during the period from April to October 2002. The standard technique ...

journal_title：Physics in medicine and biology

authors： del Carmen López Pacheco M,da Cunha Martins-Costa MF,Zapata AJ,Cherit JD,Gallegos ER

更新日期：2005-12-07 00:00:00

abstract：:Many of the inadequacies of the system presently used for surveying environments containing penetrating radiation stem from the impossibility of defining a radiation parameter which is additive, measurable and closely related to peak dose equivalent in the body. Many of the present conceptual difficulties would be eli...

journal_title：Physics in medicine and biology

authors： Harvey JR

更新日期：1975-11-01 00:00:00

abstract：:Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to do...

journal_title：Physics in medicine and biology

authors： Huber S,Mooslechner M,Mitterlechner B,Weichenberger H,Serpa M,Sedlmayer F,Deutschmann H

更新日期：2013-09-21 00:00:00

abstract：:Digital phantoms continue to play a significant role in modeling and characterizing medical imaging. The currently available XCAT phantom incorporates both the flexibility of mathematical phantoms and the realistic nature of voxelized phantoms. This phantom generates images based on a regular breathing pattern and can...

journal_title：Physics in medicine and biology

authors： Mishra P,St James S,Segars WP,Berbeco RI,Lewis JH

更新日期：2012-06-07 00:00:00

abstract：:A bright flash of light is emitted by the plasma formed at the focus of an ophthalmic Nd: YAG laser. The purpose of this investigation is to determine whether the plasma flash constitutes a hazard to the operator. The intensity of the flash at the slit lamp eyepiece was measured and the experimentally derived value wa...

journal_title：Physics in medicine and biology

authors： Moseley H,Allan D

更新日期：1987-09-01 00:00:00

abstract：:The established theory for the collection efficiency of an ionisation chamber irradiated by a series of uniform short pulses is extended to the more complex case of irradiation in a pulsed and electromagnetically swept electron beam. The radial variation of exposure rate is assumed to be Gaussian with scale constant e...

journal_title：Physics in medicine and biology

authors： Boag JW

更新日期：1982-02-01 00:00:00

abstract：:The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic prot...

journal_title：Physics in medicine and biology

authors： Gomà C,Lorentini S,Meer D,Safai S

更新日期：2014-09-07 00:00:00

abstract：:Gas target systems have been used for decades on cyclotrons to produce radionuclides for medical imaging. However, the activity recovered from such targets is often lower than its theoretically predicted value. Past research has suggested that nuclide interactions with the walls of the target body may play a key role ...

journal_title：Physics in medicine and biology

authors： Zacchia NA,Buckley KR,Martinez GM,Ruth TJ,Martinez DM,Hoehr C

更新日期：2018-09-28 00:00:00