keyword
https://read.qxmd.com/read/37429311/gpu-accelerated-calculation-of-proton-microdosimetric-spectra-as-a-function-of-target-size-proton-energy-and-bounding-volume-size
#1
JOURNAL ARTICLE
Joseph M DeCunha, Mark Newpower, Radhe Mohan
Shortcomings of dose-averaged linear energy transfer (LET_D), the quantity which is most commonly used to quantify proton relative biological effectiveness (RBE), have long been recognized. Microdosimetric spectra may overcome the limitations of LET_D but are extremely computationally demanding to calculate. A systematic library of lineal energy spectra for monoenergetic protons could enable rapid determination of microdosimetric spectra in a clinical environment. The objective of this work was to calculate and validate such a library of lineal energy spectra...
July 10, 2023: Physics in Medicine and Biology
https://read.qxmd.com/read/36097336/the-mayo-clinic-florida-microdosimetric-kinetic-model-of-clonogenic-survival-formalism-and-first-benchmark-against-in-vitro-and-in-silico-data
#2
JOURNAL ARTICLE
Alessio Parisi, Chris J Beltran, Keith M Furutani
Objective . To develop a new model (Mayo Clinic Florida microdosimetric kinetic model, MCF MKM) capable of accurately describing the in vitro clonogenic survival at low and high linear energy transfer (LET) using single-event microdosimetric spectra in a single target. Methodology . The MCF MKM is based on the 'post-processing average' implementation of the non-Poisson microdosimetric kinetic model and includes a novel expression to compute the particle-specific quadratic-dependence of the cell survival with respect to dose ( β of the linear-quadratic model)...
September 12, 2022: Physics in Medicine and Biology
https://read.qxmd.com/read/35851050/microdosimetry-performance-of-the-first-multi-arrays-of-3d-cylindrical-microdetectors
#3
JOURNAL ARTICLE
Diana Bachiller-Perea, Mingming Zhang, Celeste Fleta, David Quirion, Daniela Bassignana, Faustino Gómez, Consuelo Guardiola
The present work reports on the microdosimetry measurements performed with the two first multi-arrays of microdosimeters with the highest radiation sensitive surface covered so far. The sensors are based on new silicon-based radiation detectors with a novel 3D cylindrical architecture. Each system consists of arrays of independent microdetectors covering 2 mm[Formula: see text]2 mm and 0.4 mm[Formula: see text]12 cm radiation sensitive areas, the sensor distributions are arranged in layouts of 11[Formula: see text]11 microdetectors and 3[Formula: see text]3 multi-arrays, respectively...
July 18, 2022: Scientific Reports
https://read.qxmd.com/read/34467447/human-motion-capture-for-movement-limitation-analysis-using-an-rgb-d-camera-in-spondyloarthritis-a-validation-study
#4
JOURNAL ARTICLE
Manuel Trinidad-Fernández, Antonio Cuesta-Vargas, Peter Vaes, David Beckwée, Francisco-Ángel Moreno, Javier González-Jiménez, Antonio Fernández-Nebro, Sara Manrique-Arija, Inmaculada Ureña-Garnica, Manuel González-Sánchez
A human motion capture system using an RGB-D camera could be a good option to understand the trunk limitations in spondyloarthritis. The aim of this study is to validate a human motion capture system using an RGB-D camera to analyse trunk movement limitations in spondyloarthritis patients. Cross-sectional study was performed where spondyloarthritis patients were diagnosed with a rheumatologist. The RGB-D camera analysed the kinematics of each participant during seven functional tasks based on rheumatologic assessment...
September 1, 2021: Medical & Biological Engineering & Computing
https://read.qxmd.com/read/33853055/microdosimetry-in-low-energy-proton-beam-at-therapeutic-equivalent-fluence-rate-with-silicon-3d-cylindrical-microdetectors
#5
JOURNAL ARTICLE
Consuelo Guardiola, Diana Bachiller-Perea, Juan Prieto-Pena, M C Jimenez-Ramos, Javier Garcia-Lopez, Cédric Esnault, Celeste Fleta, David Quirion, Faustino Gomez
In this work we show the first microdosimetry measurements on a low energy proton beam with therapeutic-equivalent fluence rates by using the second generation of 3D-cylindrical microdetectors. The sensors belong to an improved version of a novel silicon-based 3D-microdetector design with electrodes etched inside silicon, which were manufactured at the National Microelectronics Centre (IMB-CNM, CSIC) in Spain. A new microtechnology has been employed using quasi-toroid electrodes of 25 μm diameter and a depth of 20 μm within the silicon bulk, resulting in a well-defined cylindrical radiation sensitive volume...
April 14, 2021: Physics in Medicine and Biology
https://read.qxmd.com/read/33280836/-trunk-kinematics-during-walking-in-stroke-patients-a-systematic-review
#6
REVIEW
M F Calvo, O D Valencia, J P González, F Palma, W Mella, M Cárcamo
The trunk and pelvis are affected after stroke, predisposing individuals to falls and dependency. The aim of this review was to describe the lineal and angular kinematics of the trunk and pelvis in patients with post-stroke sequels during walking. We included studies published up to June 1918 using a 2-3 D motion capture system during walking. We searched the Cochrane, Medline, PEDRo, Lilacs, Scielo, EBSCO, ClinicalKey and Elsevier databases. Twelve articles were selected. Linear kinematics showed greater lateral displacement and acceleration in all axes...
December 4, 2020: Rehabilitación
https://read.qxmd.com/read/33212618/generation-and-structural-characterization-of-debye-random-media
#7
JOURNAL ARTICLE
Zheng Ma, Salvatore Torquato
In their seminal paper on scattering by an inhomogeneous solid, Debye and coworkers proposed a simple exponentially decaying function for the two-point correlation function of an idealized class of two-phase random media. Such Debye random media, which have been shown to be realizable, are singularly distinct from all other models of two-phase media in that they are entirely defined by their one- and two-point correlation functions. To our knowledge, there has been no determination of other microstructural descriptors of Debye random media...
October 2020: Physical Review. E
https://read.qxmd.com/read/32467079/-safety-in-radiationtherapy-results-after-9-years-implementation-of-incidents-reporting-system
#8
JOURNAL ARTICLE
M Beltran Vilagrasa, A Varó Curbelo, X Fa Asensio, D García Relancio, J Giralt López de Sagredo
INTRODUCTION: Radiation therapy (RT) is a complex process that employs high-dose radiation for therapeutic purposes. Incident reporting and analysis, in addition to being a legal requirement in RT, provides information that helps to improve patient safety. This paper describes our experiences over a 9 year period in which a local incident reporting and learning system (SNAI) specific to RT was employed. MATERIALS AND METHODS: The center has 4 lineal accelerators that treat a total of 1900 patients annually...
May 2020: Journal of Healthcare Quality Research
https://read.qxmd.com/read/32279312/experimental-investigation-of-the-characteristics-of-radioactive-beams-for-heavy-ion-therapy
#9
JOURNAL ARTICLE
Andrew Chacon, Benjamin James, Linh Tran, Susanna Guatelli, Lachlan Chartier, Dale Prokopvich, Daniel R Franklin, Akram Mohammadi, Fumihiko Nishikido, Yuma Iwao, Go Akamatsu, Sodai Takyu, Hideaki Tashima, Taiga Yamaya, Katia Parodi, Anatoly Rosenfeld, Mitra Safavi-Naeini
PURPOSE: This work has two related objectives. The first is to estimate the relative biological effectiveness of two radioactive heavy ion beams based on experimental measurements, and compare these to the relative biological effectiveness of corresponding stable isotopes to determine whether or not they are therapeutically equivalent. The second aim is to quantitatively compare the quality of images acquired post-irradiation using an in-beam whole-body positron emission tomography scanner for range verification quality assurance...
April 11, 2020: Medical Physics
https://read.qxmd.com/read/31785458/water-runoff-harvesting-systems-for-restoration-of-degraded-rangelands-a-review-of-challenges-and-opportunities
#10
REVIEW
I Stavi, S M Siad, A P Kyriazopoulos, R Halbac-Cotoara-Zamfir
Mismanagement of rangelands worldwide has accelerated processes of overland flow and soil erosion, resulting in extensive land degradation. Wherever self-restoration processes of degraded rangelands are hindered or negated, active recovery efforts, coupled with livestock pressure management, might be needed. The objective of this review paper is to provide land managers and environmental planners with applied and practical knowledge on advantages and disadvantages of the main methodologies and practices for runoff harvesting in rangelands...
November 27, 2019: Journal of Environmental Management
https://read.qxmd.com/read/31528981/possible-association-between-dysnatremias-and-mortality-during-hospitalization-in-patients-undergoing-acute-hemodialysis-analysis-from-a-peruvian-retrospective-cohort
#11
COMPARATIVE STUDY
Edward Mezones-Holguin, Roberto Niño-Garcia, Percy Herrera-Añazco, Álvaro Taype-Rondan, Josmel Pacheco-Mendoza, Adrian V Hernandez
OBJECTIVE: To evaluate the association between dysnatremias or dyschloremias and mortality during hospitalization in patients with acute kidney injury (AKI) or chronic kidney disease (CKD) undergoing acute hemodialysis. METHODS: We carried out a retrospective cohort study on adult patients undergoing acute hemodialysis with AKI or CKD diagnosis at a public hospital in Lima, Peru. Dysnatremias were categorized as hyponatremia (Na < 135mmol/L) or hypernatremia (Na > 145mmol/L), and dyschloremias were defined as hypochloremia (Cl < 98 mmol/L) or hyperchloremia (Cl > 109mmol/L)...
2019: Jornal Brasileiro de Nefrologia: ʹorgão Oficial de Sociedades Brasileira e Latino-Americana de Nefrologia
https://read.qxmd.com/read/30462672/effect-of-dose-delivery-time-for-flattened-and-flattening-filter-free-photon-beams-based-on-microdosimetric-kinetic-model
#12
JOURNAL ARTICLE
Hisashi Nakano, Daisuke Kawahara, Kaoru Ono, Yukio Akagi, Yutaka Hirokawa
The effect of dose-delivery time with flattening filter (FF) and flattening filter-free (FFF) photon beams based on microdosimetric kinetic model (MKM) was investigated in this study. Monte Carlo simulation with the particle and heavy ion transport code system (PHITS) was performed to calculate the dose-mean lineal energy yD (keV/μm) of FF and FFF 6 MV photon beams using the IAEA phase-space files of Varian TrueBeam linear accelerator. Human non-small cell lung cancer NCI-H460 cells were used to determine the MKM parameters under the condition that dose-delivery times with continuous irradiation were 1, 5, 10, 30, and 60 min, and the adsorbed dose was 2, 4, and 8 Gy in this study...
2018: PloS One
https://read.qxmd.com/read/29572856/the-relative-biological-effectiveness-for-carbon-nitrogen-and-oxygen-ion-beams-using-passive-and-scanning-techniques-evaluated-with-fully-3d-silicon-microdosimeters
#13
JOURNAL ARTICLE
Linh T Tran, David Bolst, Susanna Guatelli, Alex Pogossov, Marco Petasecca, Michael L F Lerch, Lachlan Chartier, Dale A Prokopovich, Mark I Reinhard, Marco Povoli, Angela Kok, Vladimir L Perevertaylo, Naruhiro Matsufuji, Tatsuaki Kanai, Michael Jackson, Anatoly B Rosenfeld
BACKGROUND: The aim of this study was to measure the microdosimetric distributions of a carbon pencil beam scanning (PBS) and passive scattering system as well as to evaluate the relative biological effectiveness (RBE) of different ions, namely 12 C, 14 N, and 16 O, using a silicon-on-insulator (SOI) microdosimeter with well-defined 3D-sensitive volumes (SV). Geant4 simulations were performed with the same experimental setup and results were compared to the experimental results for benchmarking...
May 2018: Medical Physics
https://read.qxmd.com/read/28582241/studying-upper-limb-kinematics-using-inertial-sensors-embedded-in-mobile-phones
#14
JOURNAL ARTICLE
Cristina Roldan-Jimenez, Antonio Cuesta-Vargas, Paul Bennett
BACKGROUND: In recent years, there has been a great interest in analyzing upper-limb kinematics. Inertial measurement with mobile phones is a convenient and portable analysis method for studying humerus kinematics in terms of angular mobility and linear acceleration. OBJECTIVE: The aim of this analysis was to study upper-limb kinematics via mobile phones through six physical properties that correspond to angular mobility and acceleration in the three axes of space...
May 20, 2015: JMIR Rehabilitation and Assistive Technologies
https://read.qxmd.com/read/25953788/nanodosimetry-and-rbe-values-in-radiotherapy
#15
JOURNAL ARTICLE
Lennart Lindborg, Martha Hultqvist, Å Carlsson Tedgren, Hooshang Nikjoo
In a recent paper, the authors reported that the dose mean lineal energy, [Formula: see text] in a volume of about 10-15 nm is approximately proportional to the α-parameter in the linear-quadratic relation used in fractionated radiotherapy in both low- and high-LET beams. This was concluded after analyses of reported radiation weighting factors, WisoE (clinical RBE values), and [Formula: see text] values in a large range of volumes. Usually, microdosimetry measurements in the nanometer range are difficult; therefore, model calculations become necessary...
September 2015: Radiation Protection Dosimetry
https://read.qxmd.com/read/22570919/dosimetric-response-of-a-rem-500-in-low-energy-neutron-fields-typical-of-nuclear-power-plants
#16
JOURNAL ARTICLE
Aslam, W Matysiak, J Atanackovic, A J Waker
This study investigates the response of a REM-500 to assess neutron quality factor and dose equivalent in low energy neutron fields, which are commonly encountered in the workplace environment of nuclear power stations. The McMaster University 3 MV Van de Graaff accelerator facility was used to measure the response of the instrument in monoenergetic neutron fields in the energy range 51 to 727 keV by bombarding a thin LiF target with 1.93-2.50 MeV protons. The energy distribution of the neutron fields produced in the facility was measured by a (3)He filled gas ionization chamber...
June 2012: Health Physics
https://read.qxmd.com/read/21928645/microdosimetric-study-on-influence-of-low-energy-photons-on-relative-biological-effectiveness-under-therapeutic-conditions-using-6-mv-linac
#17
COMPARATIVE STUDY
Hiroyuki Okamoto, Toshiyuki Kohno, Tatsuaki Kanai, Yuki Kase, Yoshitaka Matsumoto, Yoshiya Furusawa, Yukio Fujita, Hidetoshi Saitoh, Jun Itami
PURPOSE: Microdosimetry has been developed for the evaluation of radiation quality, and single-event dose-mean lineal energy y(D) is well-used to represent the radiation quality. In this study, the changes of the relative biological effectiveness (RBE) values under the therapeutic conditions using a 6 MV linac were investigated with a microdosimetric method. METHODS: The y(D) values under the various irradiation conditions for x-rays from a 6 MV linac were measured with a tissue-equivalent proportional counter (TEPC) at an extremely low dose rate of a few tens of microGy/min by decreasing the gun grid voltage of the linac...
August 2011: Medical Physics
https://read.qxmd.com/read/21245064/spectra-of-linear-energy-transfer-and-other-dosimetry-characteristics-as-measured-in-c290-mev-n-mono-and-sobp-ion-beams-at-himac-bio-nirs-japan-with-different-detectors
#18
COMPARATIVE STUDY
F Spurný, K Pachnerová Brabcová, O Ploc, I Ambrožová, Z Mrázová
Active mobile dosimetry unit (Liulin), passive plastic nuclear track detectors (PNTD) and thermoluminescent detectors (TLD) were exposed in a C290 MeV/n beam at HIMAC-BIO (NIRS, Japan). Two different types of beam configuration were used--monoenergetic beam (MONO) and spread-out Bragg peak (SOBP); the detectors were placed at several depths from the entrance up to the depths behind the Bragg peak. Relative response of TLDs in beams has been studied as a function of the depth, and it was re-proved that it can depend on the linear energy transfer (LET)...
February 2011: Radiation Protection Dosimetry
https://read.qxmd.com/read/20938444/meal-size-can-be-decreased-in-obese-subjects-through-pharmacological-acceleration-of-gastric-emptying-the-oberyth-trial
#19
RANDOMIZED CONTROLLED TRIAL
S Torra, L Ilzarbe, J R Malagelada, M Negre, A Mestre-Fusco, S Aguadé-Bruix, E Florensa, P Suñé, B Gras, J J Hernandez, R Casamitjana, M Andreu Garcia, F Bory Ros, S Delgado-Aros
BACKGROUND: Entry of nutrients into the small intestine activates neuro-hormonal signals that regulate food intake through induction of satiation. OBJECTIVE: To evaluate whether caloric intake can be decreased by pharmacologically accelerating gastric emptying (GE) of nutrients into the small intestine. METHODS: Subjects were tested in 2 days, at baseline (day1) and after randomly receiving, in a double-blind manner, a 1 h infusion of erythromycin (3 mg Kg(-1), to accelerate GE) or placebo (day 2)...
June 2011: International Journal of Obesity
https://read.qxmd.com/read/20879566/measurement-of-absorbed-dose-quality-factor-and-dose-equivalent-in-water-phantom-outside-of-the-irradiation-field-in-passive-carbon-ion-and-proton-radiotherapies
#20
JOURNAL ARTICLE
Shunsuke Yonai, Yuki Kase, Naruhiro Matsufuji, Tatsuaki Kanai, Teiji Nishio, Masao Namba, Wataru Yamashita
PURPOSE: Successful results in carbon-ion and proton radiotherapies can extend patients' lives and thus present a treatment option for younger patients; however, the undesired exposure to normal tissues outside the treatment volume is a concern. Organ-specific information on the absorbed dose and the biological effectiveness in the patient is essential for assessing the risk, but experimental dose assessment has seldom been done. In this study, absorbed doses, quality factors, and dose equivalents in water phantom outside of the irradiation field were determined based on lineal energy distributions measured with a commercial tissue equivalent proportional counter (TEPC) at passive carbon-ion and proton radiotherapy facilities...
August 2010: Medical Physics
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