The sliding slit test for dynamic IMRT: a useful tool for adjustment of MLC related parameters.

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

abstract：:In this work, we investigate longitudinal sampling and aliasing effects in multi-slice helical CT. We demonstrate that longitudinal aliasing can be a significant, complicated, and potentially detrimental effect in multi-slice helical CT reconstructions. Multi-slice helical CT scans are generally undersampled longitudi...

journal_title：Physics in medicine and biology

authors： La Rivière PJ,Pan X

更新日期：2002-08-07 00:00:00

abstract：:The absolute dose rate around beta sources for intravascular brachytherapy was measured with thin thermoluminescent (TL) dosimeters and radiochromic film. The calibration of these dosimeters was performed at the dose maximum in a 6 MeV electron beam of a linear accelerator. Compared to the values given by the manufact...

journal_title：Physics in medicine and biology

authors： Piessens M,Reynaert N

更新日期：2000-08-01 00:00:00

abstract：:Coherent x-rays from synchrotron sources are increasingly used in non-conventional radiological techniques ('phase-contrast' radiology). Our experiments demonstrate that by using white (unmonochromatic) radiation and a time-resolving system, it is possible to image microscopic details of moving blood vessels in differ...

journal_title：Physics in medicine and biology

authors： Hwu Y,Tsai WL,Je JH,Seol SK,Kim B,Groso A,Margaritondo G,Lee KH,Seong JK

更新日期：2004-02-21 00:00:00

abstract：:The least known parameters in a Monte Carlo simulation of a linear accelerator treatment head are often the properties of the initial electron beam directed onto the exit vacuum window. Several initial beams with different spatial fluence distributions, angular divergences and energy spectra have been transported thro...

journal_title：Physics in medicine and biology

authors： Björk P,Knöös T,Nilsson P

更新日期：2002-11-21 00:00:00

abstract：:The accuracy of delivered radiation dose and the reproducibility of employed radiotherapy methods are key factors for preclinical radiobiology applications and research studies. In this work, ionization chamber (IC) measurements and Monte Carlo (MC) simulations were used to accurately determine the dose rate for total...

journal_title：Physics in medicine and biology

authors： Zhong Y,Lai Y,Saha D,Story MD,Jia X,Stojadinovic S

更新日期：2020-09-08 00:00:00

abstract：:The current UK code of practice for high-energy photon therapy dosimetry (Lillicrap et al 1990 Phys. Med. Biol. 35 1355-60) gives instructions for measuring absorbed dose to water under reference conditions for megavoltage photons. The reference conditions and the index used to specify beam quality require that a mach...

journal_title：Physics in medicine and biology

authors： Thomas SJ,Aspradakis MM,Byrne JP,Chalmers G,Duane S,Rogers J,Thomas RA,Tudor GS,Twyman N,IPEM Working Party.

更新日期：2014-03-21 00:00:00

abstract：:Respiratory-correlated 4D-MRI can characterize respiratory-induced motion of tumors and organs-at-risk for radiotherapy treatment planning and is a necessity for image guidance of moving tumors treated on an MRI-linac. Essential for 4D-MRI generation is a robust respiratory surrogate signal. We investigated the feasib...

journal_title：Physics in medicine and biology

authors： Navest RJM,Mandija S,Bruijnen T,Stemkens B,Tijssen RHN,Andreychenko A,Lagendijk JJW,van den Berg CAT

更新日期：2020-01-13 00:00:00

abstract：:Dose reconstruction is a process that re-creates the treatment-time dose deposited in a patient provided there is knowledge of the delivered energy fluence and the patient's anatomy at the time of treatment. A method for reconstructing dose is presented. The process starts with delivery verification, in which the inci...

journal_title：Physics in medicine and biology

authors： Kapatoes JM,Olivera GH,Balog JP,Keller H,Reckwerdt PJ,Mackie TR

更新日期：2001-04-01 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：:Results from dielectric studies on the freshwater fish Cyprinus carpio exposed to a sublethal concentration of sodium alkyl benzene sulphonate were compared with those from untreated control fish; recovery from the test solution was also checked. The influence of the anionic detergent on the intracellular matter of fi...

journal_title：Physics in medicine and biology

authors： Bielinska I,Terlecki J

更新日期：1984-05-01 00:00:00

abstract：:Mean glandular dose (MGD) is the figure of merit to assess breast dose after a mammographic acquisition. The use of normalized MGD obtained from Monte Carlo computations with measured incident air kerma determines the MGD delivered to patients. The Geant4 Application for Tomographic Emission (GATE) toolkit is a modern...

journal_title：Physics in medicine and biology

authors： Myronakis ME,Zvelebil M,Darambara DG

更新日期：2013-04-07 00:00:00

abstract：:We propose and evaluate the performance of an improved preclinical positron emission tomography (PET) scanner design, referred to as Polaroid-PET, consisting of a detector equipped with a layer of horizontal Polaroid to filter scintillation photons with vertical polarization. This makes it possible to improve the spat...

journal_title：Physics in medicine and biology

authors： Sanaat A,Ashrafi-Belgabad A,Zaidi H

更新日期：2020-12-02 00:00:00

abstract：:Fractional flow reserve (FFR) provides an objective physiological evaluation of stenosis severity. A technique that can measure FFR using only angiographic images would be a valuable tool in the cardiac catheterization laboratory. To perform this, the diseased blood flow can be measured with a first pass distribution ...

journal_title：Physics in medicine and biology

authors： Wong JT,Molloi S

更新日期：2008-07-21 00:00:00

abstract：:Dynamic SPECT is a relatively new technique that may potentially benefit many imaging applications. Though similar to dynamic PET, the accuracy and precision of dynamic SPECT parameter estimates are degraded by factors that differ from those encountered in PET. In this work we formulate a methodology for analytically ...

journal_title：Physics in medicine and biology

authors： Kadrmas DJ,DiBella EV,Huesman RH,Gullberg GT

更新日期：1999-08-01 00:00:00

abstract：:EEG recordings made in combined EEG-fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artef...

journal_title：Physics in medicine and biology

authors： Chowdhury ME,Mullinger KJ,Bowtell R

更新日期：2015-06-21 00:00:00

abstract：:In positron emission tomography (PET), there is an increasing interest in studying not only the regional mean tracer concentration, but its variation arising from local differences in physiology, the tissue heterogeneity. However, in reconstructed images this physiological variation is shadowed by a large reconstructi...

journal_title：Physics in medicine and biology

authors： Forma J,Niemi JA,Ruotsalainen U

更新日期：2013-07-21 00:00:00

abstract：:The aim of this study is to determine the impact of longitudinal micro-CT imaging on the growth of B16F1 tumours in C57BL/6 mice. Sixty mice received 2 × 10(5) B16F1 cells subcutaneously in the hind flank and were divided into control (no scan), 'low-dose' (80 kVp, 70 mA, 8 s, 0.07 Gy), 'medium-dose' (80 kVp, 50 mA, 3...

journal_title：Physics in medicine and biology

authors： Foster WK,Ford NL

更新日期：2011-01-21 00:00:00

abstract：:In this work, five 4D image-guidance strategies (two population, an offline adaptive and two online strategies) were evaluated that compensated for both inter- and intra-fraction variability such as changes to the baseline tumour position and respiratory pattern. None of the strategies required active motion compensat...

journal_title：Physics in medicine and biology

authors： Hugo GD,Yan D,Liang J

更新日期：2007-01-07 00:00:00

abstract：:This study aims to build a feasible mathematical model to analyze the mass evolution of NSCLC during standard fractionated radiotherapy. Seventy-three cases of NSCLC who were received radiotherapy with prescription dose of 2 Gy  ×  30 fx were selected retrospectively and divided into adenocarcinoma (ADC) group and squ...

journal_title：Physics in medicine and biology

authors： Chen J,Wang K,Jian J,Zhang W

更新日期：2019-11-26 00:00:00

abstract：:Recently, there has been an increased interest in flattening-filter-free (FFF) linear accelerators. Removal of the filter results in available dose rates up to 24 Gy min(-1) (for nominal energy 10 MV in depth of maximum dose, a source-surface distance of 100 cm and a field size of 10×10 cm2). To guarantee accurate rel...

journal_title：Physics in medicine and biology

authors： Lang S,Hrbacek J,Leong A,Klöck S

更新日期：2012-05-07 00:00:00

abstract：:We are developing a three-dimensional (3D) position-sensitive detector with isotropic spatial resolution, the X'tal cube. Originally, our design consisted of a crystal block for which all six surfaces were covered with arrays of multi-pixel photon counters (MPPCs). In this paper, we examined the feasibility of reducin...

journal_title：Physics in medicine and biology

authors： Hirano Y,Inadama N,Yoshida E,Nishikido F,Murayama H,Watanabe M,Yamaya T

更新日期：2013-03-07 00:00:00

abstract：:We report the first experimental soft-tissue phase-contrast tomography results using a conventional x-ray tube source, with a millimeter-sized focal spot. The setup is based on a Talbot-Lau grating interferometer operated at a mean energy of 28 keV. We present three-dimensional ex vivo images of a chicken heart sample...

journal_title：Physics in medicine and biology

authors： Bech M,Jensen TH,Feidenhans'l R,Bunk O,David C,Pfeiffer F

更新日期：2009-05-07 00:00:00

abstract：:A method of measuring the image quality of medical imaging equipment is considered within the framework of statistical decision theory. In this approach, images are regarded as random vectors and image quality is defined in the context of the image information available for performing a specified detection or discrimi...

journal_title：Physics in medicine and biology

authors： Tapiovaara MJ,Wagner RF

更新日期：1993-01-01 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：:The dose-response of LiF:Mg,Ti (TLD-100) exposed to 15 and 35 kVp (8.0 +/- 0.1 and 8.1 +/- 0.1 keV effective energy respectively) x-rays and 60Co gamma-rays has been measured in the dose interval from (1.2-5.4) x 10(3) Gy for x-rays, and from 0.14 to 850 Gy for gamma-rays. In both cases the total TL signal and glow cu...

journal_title：Physics in medicine and biology

authors： Gamboa-deBuen I,Buenfil AE,Ruiz CG,Rodríguez-Villafuerte M,Flores A,Brandan ME

更新日期：1998-08-01 00:00:00

abstract：:This paper describes the algorithm and examines the performance of an intensity-modulated radiation therapy (IMRT) beam-angle optimization (BAO) system. In this algorithm successive sets of beam angles are selected from a set of predefined directions using a fast simulated annealing (FSA) algorithm. An IMRT beam-profi...

journal_title：Physics in medicine and biology

authors： Djajaputra D,Wu Q,Wu Y,Mohan R

更新日期：2003-10-07 00:00:00

abstract：:Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measure...

journal_title：Physics in medicine and biology

authors： Viator JA,Choi B,Peavy GM,Kimel S,Nelson JS

更新日期：2003-01-21 00:00:00

abstract：:EEG interictal epileptiform discharges in temporal lobe epilepsy are associated with magnetic fields. The maxima of magnetic spikes recorded over the spherical portions of the head appear fairly symmetric, whereas those over the lower temporal region often have irregular shapes. Furthermore, their magnitude is often u...

journal_title：Physics in medicine and biology

authors： Rose DF,Sato S,Smith PD,White J

更新日期：1987-01-01 00:00:00

abstract：:The measured attenuation correction technique is widely used in cardiac positron tomographic studies. However, the success of this technique is limited because of insufficient counting statistics achievable in practical transmission scan times, and of the scattered radiation in transmission measurement which leads to ...

journal_title：Physics in medicine and biology

authors： Yu SK,Nahmias C

更新日期：1996-10-01 00:00:00