A note on computing the derivative at a constant direction.

abstract：:In response to the recognized fragility of reactor-produced (99)Mo supply, direct production of (99m)Tc via (100)Mo(p,2n)(99m)Tc reaction using medical cyclotrons has been investigated. However, due to the existence of other Molybdenum (Mo) isotopes in the target, in parallel with (99m)Tc, other technetium (Tc) radioa...

journal_title：Physics in medicine and biology

authors： Hou X,Tanguay J,Buckley K,Schaffer P,Bénard F,Ruth TJ,Celler A

更新日期：2016-01-21 00:00:00

abstract：:Conventional molecular assessment of tissue through histology, if adapted to fresh thicker samples, has the potential to enhance cancer detection in surgical margins and monitoring of 3D cell culture molecular environments. However, in thicker samples, substantial background staining is common despite repeated rinsing...

journal_title：Physics in medicine and biology

authors： Xu X,Wang Y,Xiang J,Liu JTC,Tichauer KM

更新日期：2017-06-21 00:00:00

abstract：:Numerous studies have reported the measurements of the dielectric properties of the skin. Clarifying the manner in which the human body interacts with electromagnetic waves is essential for medical research and development, as well as for the safety assessment of electromagnetic wave exposure. The skin comprises sever...

journal_title：Physics in medicine and biology

authors： Sasaki K,Wake K,Watanabe S

更新日期：2014-08-21 00:00:00

abstract：:In recent years there has been a large amount of research into the potential use of radiation sensitive gels for three-dimensional verification of clinical radiotherapy doses. In this paper we report the use of a MAGIC gel dosimeter (Fong et al 2001 Phys. Med. Biol. 46 3105) for the verification of a specific patient'...

journal_title：Physics in medicine and biology

authors： Trapp JV,Partridge M,Hansen VN,Childs P,Bedford J,Warrington AP,Leach MO,Webb S

更新日期：2004-05-07 00:00:00

abstract：:This paper presents a computerized method for the selection of an irregular region of interest (ROI) in broadband ultrasound attenuation (BUA) images. A region growing algorithm searches an initial region in the posterior part of the calcaneus until the pixel with the lowest attenuation value is found; this is the sta...

journal_title：Physics in medicine and biology

authors： Damilakis J,Stratakis J,Perisinakis K,Gourtsoyiannis N

更新日期：2002-01-21 00:00:00

abstract：:Sensing and enumeration of specific types of circulating cells in small animals is an important problem in many areas of biomedical research. Microscopy-based fluorescence in vivo flow cytometry methods have been developed previously, but these are typically limited to sampling of very small blood volumes, so that ver...

journal_title：Physics in medicine and biology

authors： Zettergren E,Swamy T,Runnels J,Lin CP,Niedre M

更新日期：2012-07-21 00:00:00

abstract：:A silicon semiconductor photodiode was used to measure the TL-signal of TLD-300 (CaF2:Tm) detectors irradiated with 60Co gamma rays and 226Ra alpha particles. The applied dose values varied from 0.12 to 14.3 Gy for gamma rays and from about 50 to 300 Gy for alpha particles. Because of the infrared sensitivity of the p...

journal_title：Physics in medicine and biology

authors： Meissner P,Jacob M,Rassow J

更新日期：1988-12-01 00:00:00

abstract：:An algorithm is described for three-dimensional whole-body (3DWB) image reconstruction in positron emission tomography. For whole-body applications, improvements to the popular fixed-axial-acceptance-angle technique are achieved by combining axially adjacent projection data available with a long-axis data set. Time-co...

journal_title：Physics in medicine and biology

authors： Cutler PD,Xu M

更新日期：1996-08-01 00:00:00

abstract：:A recently described, computer aided method of attenuation analysis has been applied to free-air chamber measurements of the attenuation by up to 30mm A1 of the exposure rate of a narrow beam of X-radiation excited at a thick W target in a Be window tube by constant potentials of 60, 80, 100, 120 and 140 kV. It has ...

journal_title：Physics in medicine and biology

authors： Soole BW

更新日期：1977-03-01 00:00:00

abstract：:The radiofrequency dielectric behaviour of packed human erythrocytes has been investigated in normal haemoglobins F and AA and also abnormal haemoglobins homozygous SS and heterozygous AS. Dielectric measurements were made in tightly packed blood cells at an average room temperature of 26.5 +/- 0.5 degrees C in the fr...

journal_title：Physics in medicine and biology

authors： Laogun AA,Ajayi NO,Okafor LO,Osamo NO

更新日期：1983-04-01 00:00:00

abstract：:An iterative Bayesian reconstruction algorithm for limited view angle tomography, or ectomography, based on the three-dimensional total variation (TV) norm has been developed. The TV norm has been described in the literature as a method for reducing noise in two-dimensional images while preserving edges, without intro...

journal_title：Physics in medicine and biology

authors： Persson M,Bone D,Elmqvist H

更新日期：2001-03-01 00:00:00

abstract：:In charged particle therapy with pencil beam scanning (PBS), localization of the dose in the Bragg peak makes dose distributions sensitive to lateral tissue heterogeneities. The sensitivity of a PBS plan to lateral tissue heterogeneities can be reduced by selecting appropriate beam angles. The purpose of this study is...

journal_title：Physics in medicine and biology

authors： Toramatsu C,Inaniwa T

更新日期：2016-12-21 00:00:00

abstract：:Noise equivalent count rate (NECR) and image noise are two different but related metrics that have been used to predict and assess image quality, respectively. The aim of this study is to investigate, using patient studies, the relationships between injected dose (ID), body mass index (BMI) and scanner type on NECR an...

journal_title：Physics in medicine and biology

authors： Chang T,Chang G,Kohlmyer S,Clark JW,Rohren E,Mawlawi OR

更新日期：2011-08-21 00:00:00

abstract：:Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B. The purpose of this study is to system...

journal_title：Physics in medicine and biology

authors： Pojtinger S,Dohm OS,Kapsch RP,Thorwarth D

更新日期：2018-06-07 00:00:00

abstract：:Positron emission tomography is one of the most mature techniques for monitoring the particles range in hadron therapy, aiming to reduce treatment uncertainties and therefore the extent of safety margins in the treatment plan. In-beam PET monitoring has been already performed using inter-spill and post-irradiation dat...

journal_title：Physics in medicine and biology

authors： Kostara E,Sportelli G,Belcari N,Camarlinghi N,Cerello P,Del Guerra A,Ferrero V,Fiorina E,Giraudo G,Morrocchi M,Pennazio F,Pullia M,Rivetti A,Rolo MD,Rosso V,Wheadon R,Bisogni MG

更新日期：2019-01-21 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：:Radiation dose calculation using models of the human anatomy has been a subject of great interest to radiation protection, medical imaging, and radiotherapy. However, early pioneers of this field did not foresee the exponential growth of research activity as observed today. This review article walks the reader through...

journal_title：Physics in medicine and biology

authors： Xu XG

更新日期：2014-09-21 00:00:00

abstract：:This paper extends the kernel method that was proposed previously for dynamic PET reconstruction, to incorporate anatomical side information into the PET reconstruction model. In contrast to existing methods that incorporate anatomical information using a penalized likelihood framework, the proposed method incorporate...

journal_title：Physics in medicine and biology

authors： Hutchcroft W,Wang G,Chen KT,Catana C,Qi J

更新日期：2016-09-21 00:00:00

abstract：:In x-ray based imaging of the breast, contrast between fibroglandular (Fg) tissue and adipose (Ad) tissue is a source of anatomic noise. The goal of this work was to validate by simulation and experiment a mathematical framework for modelling the Fg component of anatomic noise in digital mammograpy (DM) and dual-energ...

journal_title：Physics in medicine and biology

authors： Tanguay J,Lalonde R,Bjarnason TA,Yang CJ

更新日期：2019-10-23 00:00:00

abstract：:A novel approach to read out radiochromic film was introduced recently by the manufacturer of GafChromic film. In this study, the performance of this triple-channel film dosimetry method was compared against the conventional single-red-channel film dosimetry procedure, with and without inclusion of a pre-irradiation (...

journal_title：Physics in medicine and biology

authors： van Hoof SJ,Granton PV,Landry G,Podesta M,Verhaegen F

更新日期：2012-07-07 00:00:00

abstract：:The use of calibrated tissue-equivalent (TE) ionisation chambers is commonly considered to be the most practical method for total absorbed dose determinations in mixed neutron-photon fields for biomedical applications. The total absorbed dose can be derived from the charge produced within the cavity of an ionisation c...

journal_title：Physics in medicine and biology

authors： Zoetelief J,Broerse JJ

更新日期：1983-05-01 00:00:00

abstract：:It is difficult to test near-infrared spectrophotometry instruments in vivo. Therefore we constructed a liquid phantom which mimics the neonatal head. It consists of a spherical 3.5 mm thick layer of silicone rubber simulating skin and bone and a 0.5 mm thick clear layer of polypropylene imitating cerebrospinal fluid....

journal_title：Physics in medicine and biology

authors： Wolf M,Keel M,Dietz V,von Siebenthal K,Bucher HU,Baenziger O

更新日期：1999-07-01 00:00:00

abstract：:Uncertainties in determining clinically used relative biological effectiveness (RBE) values for ion beam therapy carry the risk of absolute and relative misestimations of RBE-weighted doses for clinical scenarios. This study assesses the consequences of hypothetical misestimations of input parameters to the RBE modell...

journal_title：Physics in medicine and biology

authors： Böhlen TT,Brons S,Dosanjh M,Ferrari A,Fossati P,Haberer T,Patera V,Mairani A

更新日期：2012-12-07 00:00:00

abstract：:A post-processing noise suppression technique for biomedical MRI images is presented. The described procedure recovers both sharp edges and smooth surfaces from a given noisy MRI image; it does not blur the edges and does not introduce spikes or other artefacts. The fine details of the image are also preserved. The pr...

journal_title：Physics in medicine and biology

authors： Placidi G,Alecci M,Sotgiu A

更新日期：2003-07-07 00:00:00

abstract：:At present, there exists few openly available methods for evaluation of simultaneous segmentation and registration algorithms. These methods allow for a combination of both techniques to track the tumor in complex settings such as adaptive radiotherapy. We have produced a quality assurance platform for evaluating this...

journal_title：Physics in medicine and biology

authors： Markel D,Levesque I,Larkin J,Léger P,El Naqa I

更新日期：2016-10-07 00:00:00

abstract：:Average penetration depths and detour factors of 1-50 MeV electrons in water and plastic materials have been computed by means of analytical calculation, within the continuous-slowing-down approximation and including multiple scattering, and using the Monte Carlo codes ITS and PENELOPE. Results are compared to detour ...

journal_title：Physics in medicine and biology

authors： Fernández-Varea JM,Andreo P,Tabata T

更新日期：1996-07-01 00:00:00

abstract：:The infrasonic part of the spectrum of the carotid artery wall vibration in the neck was obtained. Differences between the spectral content and vibrational amplitude in normal and occluded carotids were found. The application of this technique in clinical practice could be useful in the detection of the carotid insuff...

journal_title：Physics in medicine and biology

authors： Anastassiades AJ,Petounis AD

更新日期：1976-01-01 00:00:00

abstract：:The lipid disordering effect of aspirin on the liposomal membrane of dipalmitoyl phosphatidyl choline has recently been studied using the fluorescence polarization method. From the anisotropy-temperature curve, we have calculated here the associated change in van't Hoff enthalpy. Since the fluorescence technique requi...

journal_title：Physics in medicine and biology

authors： De S,Ghosh AK,Basu R,Nandy P

更新日期：1996-03-01 00:00:00

abstract：:Magnetoencephalography (MEG) source analysis has largely relied on spherical conductor models of the head to simplify forward calculations of the brain's magnetic field. Multiple- (or overlapping, local) sphere models, where an optimal sphere is selected for each sensor, are considered an improvement over single-spher...

journal_title：Physics in medicine and biology

authors： Lalancette M,Quraan M,Cheyne D

更新日期：2011-09-07 00:00:00

abstract：:This work aims to investigate the dosimetric impact of dental implants on volumetric modulated arc therapy (VMAT) for head-and-neck patients and to evaluate the effectiveness of using the material's electron-density ratio for the correction. An in-house Monte Carlo (MC) code was utilized for the dose calculation to ac...

journal_title：Physics in medicine and biology

authors： Lin MH,Li J,Price RA Jr,Wang L,Lee CC,Ma CM

更新日期：2013-02-21 00:00:00