نتایج جستجو برای: dose estimates

تعداد نتایج: 485027  

Journal: :Regulatory toxicology and pharmacology : RTP 2000
S H Kang R L Kodell J J Chen

Much research on food safety has been conducted since the National Food Safety Initiative of 1997. Risk assessment plays an important role in food safety practices and programs, and various dose-response models for estimating microbial risks have been investigated. Several dose-response models can provide reasonably good fits to the data in the experimental dose range, but yield risk estimates ...

Journal: :Toxicological sciences : an official journal of the Society of Toxicology 2011
W M Oshiro E M Kenyon C J Gordon B Bishop Q T Krantz J Ford P J Bushnell

Recent research on the acute effects of volatile organic compounds suggests that extrapolation from short (∼1 h) to long durations (up to 4 h) may be improved by using estimates of brain toluene concentration (Br[Tol]) instead of cumulative inhaled dose (C × t) as a metric of dose. This study compared predictions of these two dose metrics on the acute behavioral effects of inhaled toluene in ra...

Journal: :Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine 2003
Thomas M Cross Richard C Smart Julian E M Thomson

OBJECTIVE To understand the estimation of both the effective dose and the risk estimate associated with diagnostic ionizing radiation in sports medicine and to appreciate strategies by which this radiation exposure may be minimized. DESIGN Observational study. SETTING Sports medicine practice. PATIENTS A theoretical patient, athlete X (male, aged 20-29 years, 80 kg), was used to illustrat...

Journal: :iranian journal of medical physics 0
mohsen mirhabibi department of physics, payame noor university , tehran, iran

introduction radon is a colorless and tasteless gas which exists in most soils. it is a substance that poses a potential risk for lung cancer in case a person is exposed to high levels over long periods of time. the environmental protection agency (epa) estimates that 90% of lung cancers per year are caused by radon. the aim of this paper is to estimate the absorbed doses of 222rn by mcnpx simu...

Journal: :Health physics 2007
Hiroko Ohuchi Toshimitsu Satoh Yoichi Eguchi Yuji Kaga Takeshi Arai Shin-ichi Suzuki Akira Yamadera

A method using europium-doped BaFBr imaging plates (IPs) has been developed to estimate and map values of entrance skin doses during interventional radiology (IR). IPs offer many advantages for measuring the entrance skin dose because they have a wide dynamic range (up to 100 Gy), provide high spatial resolution as a detector of two-dimensional images, and can be used repeatedly. The entrance s...

Journal: :journal of biomedical physics and engineering 0
s zargan department of medical physics, babol university of medical sciences, babol, iran p ghafarian chronic respiratory diseases research center, national research institute of tuberculosis and lung diseases (nritld), shسازمان اصلی تایید شده: دانشگاه علوم پزشکی بابل (babol university of medical sciences)سازمان های دیگر: pet/ct and cyclotron center, masih daneshvari hospital, shahid beheshti university of medical sciences, tehran,

background: pet/ct imaging using [18f]-fdg is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. essential consideration must be taken for radiation staff due to high gamma radiation in pet/ct and cyclotron center. the aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in pet/ct an...

Journal: :iranian journal of radiation research 0
m.n. anjum mcgill university health centre l5-112, 1650-cedar avenue, montreal general hospital, canada h3g 1a4 w. parker mcgill university health centre l5-112, 1650-cedar avenue, montreal general hospital, canada h3g 1a4 i. aldahlawi mcgill university health centre l5-112, 1650-cedar avenue, montreal general hospital, canada h3g 1a4 r. ruo mcgill university health centre l5-112, 1650-cedar avenue, montreal general hospital, canada h3g 1a4 m. afzal department of physics, the islamia university of bahawalpur, pakistan

background: we have validated the monitor unit calculations from a commercially available treatment planning system (tps) for three intensity modulated radiotherapy (imrt) planning techniques for tangential breast irradiation by using ionization chamber measurements. materials and methods: treatment plans were generated for forty-two breast patients by a forward planned field in field technique...

Journal: :Journal of the American College of Radiology : JACR 2014
J Anthony Seibert John M Boone Sandra L Wootton-Gorges Ramit Lamba

PURPOSE The volume CT dose index (CTDIvol) and the dose-length product, commonly reported for examinations performed on clinical CT scanners, should not be used as surrogates for patient dose. This is because significant under or overestimates of these actual values can occur when there is a mismatch between the actual body size of the patient and the 16 cm or 32 cm diameter CTDIvol phantoms. T...

Journal: :Health physics 1998
D M Hamby A A Simpkins

The models used in the NRC approach to assess chronic atmospheric releases of radioactivity generate deterministic dose estimates by using standard assumptions about exposure conditions and environmental transport mechanisms. This approach has been used at the Savannah River Site since 1983. Total dose to off-site maximally exposed individuals at the SRS from atmospheric releases has been on th...

2011
Lutz Dümbgen Kaspar Rufibach

Maximum likelihood estimation of a log-concave density has attracted considerable attention over the last few years. Several algorithms have been proposed to estimate such a density. Two of those algorithms, an iterative convex minorant and an active set algorithm, are implemented in the R package logcondens. While these algorithms are discussed elsewhere, we describe in this paper the use of t...

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