Exact analytic reconstruction in x-ray fluorescence CT and approximated versions.

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：: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：:This paper evaluates results of a survey of electrostimulation models of myelinated nerve. Participants were asked to determine thresholds of excitation for 18 cases involving different characteristics of the neuron, the stimulation waveform, and the electrode arrangement. Responses were received from 7 investigators ...

journal_title：Physics in medicine and biology

authors： Reilly JP

更新日期：2016-06-21 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

abstract：:The reference levels for testing compliance of human exposure with radio-frequency (RF) safety limits have been derived from very simplified models of the human. In order to validate these findings for anatomical models, we investigated the absorption characteristics for various anatomies ranging from 6 year old child...

journal_title：Physics in medicine and biology

authors： Kühn S,Jennings W,Christ A,Kuster N

更新日期：2009-02-21 00:00:00

abstract：:This work modified the commonly used Monte Carlo tool package GATE by developing a new 'multiPatchPET' system so that GATE users can easily simulate PET systems with irregular geometries. The motivation was to design a brain PET scanner with high sensitivity. It is known that compact PET scanners with a large solid co...

journal_title：Physics in medicine and biology

authors： Chen G,Weng F,Hong X,Tao W,Zhao Z,Peng Q,Huang Q

更新日期：2018-09-06 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：:Quantification of nuclear medicine image data is a prerequisite for personalized absorbed dose calculations and quantitative biodistribution studies. The spatial response of a detector is a governing factor affecting the accuracy of image quantification, and the aim of this work was to model this impact. To simulate s...

journal_title：Physics in medicine and biology

authors： Holstensson M,Partridge M,Buckley SE,Flux GD

更新日期：2010-03-21 00:00:00

abstract：:This study investigated the integration of the Calypso real-time tracking system, based on implanted ferromagnetic transponders and a detector array, into the current process for image-guided radiation treatment (IGRT) of prostate cancer at our institution. The current IGRT process includes magnetic resonance imaging ...

journal_title：Physics in medicine and biology

authors： Zhu X,Bourland JD,Yuan Y,Zhuang T,O'Daniel J,Thongphiew D,Wu QJ,Das SK,Yoo S,Yin FF

更新日期：2009-09-07 00:00:00

abstract：:Simultaneous rest perfusion/fatty-acid metabolism studies have the potential to replace sequential rest/stress perfusion studies for the assessment of cardiac function. Simultaneous acquisition has the benefits of increased signal and lack of need for patient stress, but is complicated by cross-talk between the two ra...

journal_title：Physics in medicine and biology

authors： Trott CM,Ouyang J,El Fakhri G

更新日期：2010-11-21 00:00:00

abstract：:In this work we present the first delivery of intensity modulated arc therapy on the Elekta Unity 1.5 T MR-linac. The machine's current IMRT based control system was modified suitably to enable dynamic delivery of radiation, for the purpose of exploring MRI-guided radiation therapy adaptation modes in a research setti...

journal_title：Physics in medicine and biology

authors： Kontaxis C,Woodhead PL,Bol GH,Lagendijk JJW,Raaymakers BW

更新日期：2020-12-23 00:00:00

abstract：:Measurement of total body nitrogen is assuming increasing importance in the nutritional evaluation of seriously ill patients. Nitrogen has been previously measured either by counting (i) the annihilation radiation from 13N immediately after neutron irradiation with 14 MeV neutrons or (ii) the 'prompt' gamma rays from ...

journal_title：Physics in medicine and biology

authors： Spinks TJ,Goode AW,Ranicar AS,Steere E

更新日期：1984-04-01 00:00:00

abstract：:Non-invasively reconstructing the cardiac transmembrane potentials (TMPs) from body surface potentials can act as a regression problem. The support vector regression (SVR) method is often used to solve the regression problem, however the computational complexity of the SVR training algorithm is usually intensive. In t...

journal_title：Physics in medicine and biology

authors： Jiang M,Zhang H,Zhu L,Cao L,Wang Y,Xia L,Gong Y

更新日期：2015-04-21 00:00:00

abstract：:The propagation of errors in quantitative biplane cineroentgenography was investigated to see which variables were the most critical. The analysis was carried out both for the propagation of root-mean-square errors and for errors as derived by a Taylor expansion of the reconstruction equations. The reconstruction is m...

journal_title：Physics in medicine and biology

authors： Smith WM,Starmer CF

更新日期：1978-07-01 00:00:00

abstract：:Modern digital radiographic 'flat panel' detectors can exhibit a progressive form of image degradation arising from non-functioning pixels. The effect of these 'dead pixels' on the quantitive image quality measures of modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE)...

journal_title：Physics in medicine and biology

authors： Padgett R,Kotre CJ

更新日期：2004-03-21 00:00:00

abstract：:Tumor motion is a particular concern for a complex treatment modality such as helical tomotherapy, where couch position, gantry rotation and MLC leaf opening all change with time. In the present study, we have investigated the impact of tumor motion for helical tomotherapy, which could result in three distinct motion-...

journal_title：Physics in medicine and biology

authors： Kim B,Chen J,Kron T,Battista J

更新日期：2009-10-07 00:00:00

abstract：:The variety of treatment options for cancer patients has increased significantly in recent years. Not only do we combine radiation with surgery and chemotherapy, new therapeutic approaches such as immunotherapy and targeted therapies are starting to play a bigger role. Physics has made significant contributions to rad...

journal_title：Physics in medicine and biology

authors： Grassberger C,Paganetti H

更新日期：2016-11-07 00:00:00

abstract：:Both inhomogeneity in the main magnetic field and non-linearity in the gradient fields introduce errors in NMR images reconstructed from projections. It is found that the image artefacts caused by these two sources are separable. The inhomogeneous main field blurs the image while the nonlinear gradients distort the im...

journal_title：Physics in medicine and biology

authors： Lai CM

更新日期：1983-08-01 00:00:00

abstract：:Carotid atherosclerosis measurements for eight subjects at baseline and 14 +/- 2 days later were examined using 1.5 T and 3.0 T magnetic resonance imaging (MRI). A single observer blinded to field strength, subject and timepoint manually segmented carotid artery wall and lumen boundaries in randomized images in five m...

journal_title：Physics in medicine and biology

authors： Vidal A,Bureau Y,Wade T,Spence JD,Rutt BK,Fenster A,Parraga G

更新日期：2008-12-07 00:00:00

abstract：:Respiratory-correlated cone-beam CT (CBCT) not only inhibits rapid scanning due to the slow speed of the LINAC head gantry rotation, but its implementation for routine patient imaging is impractical because of the high radiation dose delivered during the process. Digital tomosynthesis (DTS) is a potentially faster tec...

journal_title：Physics in medicine and biology

authors： Choi S,Lee S,Kang YN,Hsieh SS,Kim HJ

更新日期：2019-05-02 00:00:00

abstract：:This study presents a combined small animal holding fixture system, termed a 'bridge capsule', which provides for small animal re-fixation with positional reproducibility. This system comprises separate holding fixtures for the head and lower body and a connecting part to a gas anesthesia system. A mouse is fixed in p...

journal_title：Physics in medicine and biology

authors： Kokuryo D,Kimura Y,Obata T,Yamaya T,Kawamura K,Zhang MR,Kanno I,Aoki I

更新日期：2010-07-21 00:00:00

abstract：:The purpose of this study is to explain the unplanned longitudinal dose modulations that appear in helical tomotherapy (HT) dose distributions in the presence of irregular patient breathing. This explanation is developed by the use of longitudinal (1D) simulations of mock and surrogate data and tested with a fully 4D ...

journal_title：Physics in medicine and biology

authors： Kissick MW,Flynn RT,Westerly DC,Hoban PW,Mo X,Soisson ET,McCall KC,Mackie TR,Jeraj R

更新日期：2008-09-21 00:00:00

abstract：:A mathematical model has been constructed to simulate the response of cells in vitro to fractionated doses of radiation. The model is capable of describing most of the radiobiological functions that are commonly studied. Input data are measurable cell properties. The details of the model and methods of acquiring the i...

journal_title：Physics in medicine and biology

authors： Niederer J,Cunningham JR

更新日期：1976-09-01 00:00:00

abstract：:Multi-atlas segmentation (MAS) has been widely used to automate the delineation of organs at risk (OARs) for radiotherapy. Label fusion is a crucial step in MAS to cope with the segmentation variabilities among multiple atlases. However, most existing label fusion methods do not consider the potential dosimetric impac...

journal_title：Physics in medicine and biology

authors： Chang J,Tian Z,Lu W,Gu X,Chen M,Jiang SB

更新日期：2017-05-07 00:00:00

abstract：:Many applications of electroporation, especially those utilizing electrofusion and in-vivo electroporation, involve cell environments that include close cell-to-cell proximity and a wide range of target cell size. It is important to understand how this kind of environment may alter optimum electroporation electrical p...

journal_title：Physics in medicine and biology

authors： Gaynor PT,Bodger PS

更新日期：2006-06-21 00:00:00

abstract：:The treatment planning process for patients with head and neck (H&N) cancer is regarded as one of the most complicated due to large target volume, multiple prescription dose levels, and many radiation-sensitive critical structures near the target. Treatment planning for this site requires a high level of human experti...

journal_title：Physics in medicine and biology

authors： Nguyen D,Jia X,Sher D,Lin MH,Iqbal Z,Liu H,Jiang S

更新日期：2019-03-18 00:00:00

abstract：:Intra-fractional motion is a concern during prostate radiation therapy, as it may cause deviations between planned and delivered radiation doses. Because accurate motion information during treatment delivery is critical to address dose deviation, we developed the projection marker matching method (PM3), a novel method...

journal_title：Physics in medicine and biology

authors： Chi Y,Rezaeian NH,Shen C,Zhou Y,Lu W,Yang M,Hannan R,Jia X

更新日期：2017-07-07 00:00:00

abstract：:Incorrect prediction of skin dose in external beam radiotherapy (EBR) can have normal tissue complication such as acute skin desquamation and skin necrosis. The absorbed dose of skin should be evaluated within basal layer, placed between the epidermis and dermis layers. However, current treatment planning systems (TPS...

journal_title：Physics in medicine and biology

authors： Cheon BW,Yoo DH,Shin WG,Choi HJ,Park HJ,Kim JI,Min CH

更新日期：2019-08-14 00:00:00

abstract：:A method for quantifying the tissue sodium concentration (TSC) in the rat brain from ²³Na-MR images was developed. TSC is known to change in a variety of common human diseases and holds considerable potential to contribute to their study; however, its accurate measurement in small laboratory animals has been hindered ...

journal_title：Physics in medicine and biology

authors： Wetterling F,Tabbert M,Junge S,Gallagher L,Macrae IM,Fagan AJ

更新日期：2010-12-21 00:00:00

abstract：:Radiation therapy is an image-guided process whose success critically depends on the imaging modality used for treatment planning and the level of integration of the available imaging information. In this work, we establish a dose optimization framework for incorporating metabolic information from functional imaging m...

journal_title：Physics in medicine and biology

authors： Xing L,Cotrutz C,Hunjan S,Boyer AL,Adalsteinsson E,Spielman D

更新日期：2002-10-21 00:00:00