Abstract:
:By analyzing the radiobiological model, and the equations derived from the model, it is shown that the main results of the article 'The influence of dose heterogeneity on tumor control probability in fractionated radiation therapy' by Wiklund et al (2011 Phys. Med. Biol. 56 7585-600) are valid only under the condition that the dose to any cell is statistically independent of the dose to any other cell in the same fraction. This condition is in practice not fulfilled for radiotherapy. Hence the main results and most of the discussion are not applicable to fractionated radiation therapy.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Grusell Edoi
10.1088/0031-9155/58/18/6585subject
Has Abstractpub_date
2013-09-21 00:00:00pages
6585-9issue
18eissn
0031-9155issn
1361-6560journal_volume
58pub_type
评论,信件abstract::A novel transmission detector (IBA Dosimetry, Germany) developed as an IMRT quality assurance tool, intended for in vivo patient dose measurements, is studied here. The goal of this investigation is to use Monte Carlo techniques to characterize treatment beam parameters in the presence of the detector and to compare t...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/4/020
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/36/8/001
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abstract::Using Monte Carlo simulation of 99Tcm single-photon-emission computed tomography (SPECT), we investigate the effects of tissue-background activity, tumour location, patient size, uncertainty of energy windows, and definition of tumour region on the accuracy of quantification. The dual-energy-window method of correctio...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/40/1/015
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abstract::In this work we present a new 3D numerical model for heat transfer in the human eye, which takes into account the aqueous humour flow in the anterior chamber. We show that consideration of this phenomenon in the calculations alters the temperature distribution on the corneal and lens surfaces, without, however, notice...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/55/19/003
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/52/14/019
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abstract::We investigated the physical characteristics of two complementary metal oxide semiconductor (CMOS) mammography detectors. The detectors featured 14-bit image acquisition, 50 microm detector element (del) size and an active area of 5 cm x 5 cm. One detector was a passive-pixel sensor (PPS) with signal amplification per...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/6/022
更新日期:2009-03-21 00:00:00
abstract::In this paper, we investigate an off-line strategy to incorporate inter-fraction organ motion in IMRT treatment planning. It was suggested that inverse planning could be based on a probability distribution of patient geometries instead of a single snap shot. However, this concept is connected to two intrinsic problems...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/17/013
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/6/2582
更新日期:2016-03-21 00:00:00
abstract::Light propagation in a turbid medium is considered using the linear transport equation. The existence of a diffusion length is proved for the Henyey-Greenstein scattering kernel for all absorption ratios. Numerical methods are given that allow accurate computation of the diffusion coefficient quite easily. ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/48/23/012
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abstract::In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diamet...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aaa4fb
更新日期:2018-02-12 00:00:00
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/6/1685
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/52/2/004
更新日期:2007-01-21 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
pub_type: 杂志文章
doi:10.1088/0031-9155/56/11/002
更新日期:2011-06-07 00:00:00
abstract::The radiation used in hadrontherapy treatments interacts with the patient body producing secondary particles, either neutral or charged, that can be used for dose and Bragg peak monitoring and to provide a fast feedback on the treatment plans. Recent results obtained from the authors on simplified setups (mono-energet...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/7/1857
更新日期:2014-04-07 00:00:00
abstract::In order to measure in vivo resistivity of tissues in the thorax, the possibility of combining anatomical data extracted from high-resolution images with multiple-electrode impedance measurements, a priori knowledge of the range of tissue resistivities, and a priori data on the instrumentation noise is assessed in thi...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/39/1/001
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abstract::Dynamic modulation can be affected by inaccuracies when the required acceleration is larger than the highest allowed by the mechanical characteristics of the whole apparatus. In this study, inertia effects have been investigated with regard to the single absorber 1D modulation, analysing primarily how the acceleration...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/11/401
更新日期:1999-11-01 00:00:00
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/21/7583
更新日期:2013-11-07 00:00:00
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa6b45
更新日期:2017-06-21 00:00:00
abstract::The values of the replacement correction factors (P(repl), or in the IAEA's notation p(dis)p(cav)) used for cylindrical chambers in high-energy photon beams represent one of the most significant differences between the AAPM and the IAEA dosimetry protocols. In a previous study (Wang L L W and Rogers D W O 2008 Med. Ph...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/6/014
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/abaa26
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/34/1/008
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journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/3/1309
更新日期:2016-02-07 00:00:00
abstract::The dielectric properties of glycerol, propylene glycol, ethylene glycol and dimethyl sulphoxide have been measured in various aqueous concentrations generally sufficient to allow supercooling rather than freezing. The temperature range investigated is from -80 degrees C to +20 degrees C and the frequency range is 100...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/10/014
更新日期:1996-10-01 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
pub_type: 杂志文章
doi:10.1088/0031-9155/26/1/011
更新日期:1981-01-01 00:00:00
abstract::The free space method using a pair of lens antennas was modified for the complex permittivity measurement of biological samples from 20 to 110 GHz. Two methodologies were used to obtain the complex permittivities by the free space method, which were based on the reflection and transmission coefficients. The measuremen...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/5/1625
更新日期:2013-03-07 00:00:00
abstract::Monte Carlo methods have been applied to the study of the performance of antiscatter grids in radiography. Photon histories for imaging with a 20 cm thick water phantom irradiated with an 80 kV x-ray spectrum were generated by Monte Carlo simulation. The scattering and absorption of the photons transmitted from the ph...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/27/6/002
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abstract::We have developed deformable and durable optical tissue phantoms with a simple and well-defined microstructure including a novel combination of scatterers and a matrix material. These were developed for speckle and elastography investigations in optical coherence tomography, but should prove useful in many other field...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/13/N01
更新日期:2008-07-07 00:00:00
abstract::This study presents a new approach to accurately account for the medium-dependent effect in model-based dose calculations for kilovoltage (kV) x-rays. This approach is based on the hypothesis that the correction factors needed to convert dose from model-based dose calculations to absorbed dose-to-medium depend on both...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/13/011
更新日期:2011-07-07 00:00:00
abstract::A significant timer error has been found on a linear accelerator used for intraoperative radiation therapy. Since typical treatment doses range up to 20 Gy, calibrations that do not account for this effect can incur a large dosimetry error. The effect is dose rate dependent, but energy independent. For a dose rate of ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/43/10/031
更新日期:1998-10-01 00:00:00
abstract::Computational phantoms are commonly used in internal radiation dosimetry to assess the amount and distribution pattern of energy deposited in various parts of the human body from different internal radiation sources. Radiation dose assessments are commonly performed on predetermined reference computational phantoms wh...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa75b4
更新日期:2017-07-13 00:00:00