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About 10,000 papers for “reference dose”

reference dose

2008

Citation: 'reference dose' in the IUPAC Compendium of Chemical Terminology, 3rd ed.; International Union of Pure and Applied Chemistry; 2006. Online version 3.0.1, 2019. 10.1351/goldbook.RT06912 • License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International for individual terms. Requests for commercial usage of the compendium should be directed to IUPAC.

Cited by 0

developmental reference dose

2025

Citation: 'developmental reference dose' in the IUPAC Compendium of Chemical Terminology, 5th ed.; International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.14583 • License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International for individual terms. Requests for commercial usage of the compendium should be directed to IUPAC.

Cited by 0Open access

Reference Dose (RfD)

Monica Nordberg, John H. Duffus, Douglas M. Templeton · IUPAC Standards Online · 2016

This glossary contains definitions of 365 terms frequently used in the multidisciplinary field of toxicokinetics. The glossary is compiled primarily for chemists who find themselves currently working in toxicology and requiring a knowledge of the expressions used in toxicokinetics, especially in relation to hazard and risk assessment. Some medical terms are included, where relevant, because of their frequent occurrence in the toxicological literature and because chemists would not normally be expected to be familiar with them. There are three annexes, one containing a list of abbreviations and acronyms used in toxicokinetics, one containing a list of abbreviations and acronyms of names of international bodies and legislation that are relevant to toxicology and chemical safety, and one giving sources for further reading.

Cited by 0Open access

Inhalation Reference Dose (RfDi)

Annie M. Jarabek, Margaret G. Ménache, J. H. Overton et al. · Health Physics · 1989

Accurate extrapolation of animal toxicity data for human health risk assessment requires determination of the effective dose to the target tissue and the sensitivity of the target tissue to that dose. The methodology for deriving reference doses [the U.S. Environmental Protection Agency's (EPA) benchmark values for gauging systemic toxicity] for oral exposures has not included dosimetry modeling. Dosimetry data facilitate evaluation of concentration-response data with respect to the dose-response relationships used in quantitative risk assessment. Extension of this methodology to derivation of inhalation reference doses (RfDi) should account for the dynamics of the respiratory system as the portal of entry. Predictive physiologically based modeling of the inhalation of reactive gases has recently been demonstrated (Overton and Miller 1988). Models that describe the deposition of hygroscopic particles and account for chemical factors that affect clearance mechanisms and gas uptake are under development. This paper presents a method for calculating a dosimetric adjustment factor based on the values for the initial deposited dose of insoluble particles in an animal species and in humans. The ratio of these two values serves as a scaling factor that can be applied in the R f D methodology to account for the dosimetric differences in the inhaled deposited dose. This application for insoluble particles illustrates the feasibility of interspecies dosimetry calculations for extrapolating the toxicological results of inhaled agents to human exposure conditions for more accurate risk estimation.

Cited by 30

REFERENCE DOSE (chRD) FOR PARAQUAT.”

Proposed School Sites · 2010

(OEHHA), in consultation with the appropriate entities within the California Environmental Protection Agency, to identify those chemical contaminants commonly found at school sites and determined by OEHHA to be of greatest concern based on child-specific physiological sensitivities. HSC 901(g) also requires OEHHA to annually evaluate and publish, as appropriate, numerical health guidance values (HGVs) or chRDs for those chemical contaminants. The draft chRD for paraquat being considered at this time is 7 x 10-5 mg/kg-day. In developing the chRD, OEHHA selected two young-animal studies and two adult-animal studies. Collectively these studies paint a cohesive picture that paraquat is a neurotoxicant and impacts brain functions. The chRD is based on the lowest observed adverse effect level (LOAEL) of 0.07 mg/kg-day from one of the studies. This public comment period follows the requirements set forth in Health and Safety Code Section 57003 for receiving public input. The initial draft was released on December 4, 2009, with a review and comment period ending on January 22, 2010. This period was extended to February 22, 2010. A public workshop was held on

Cited by 0

Dose distribution of a reference plan.

Crystian Wilian Chagas Saraiva (8283009), Simone Coutinho Cardoso (8283012), Daniela Piai Groppo (8283015) et al. · Figshare · 2020

<p>The target volume is spherical (Yellow Line = Prescription Isodose) with a diameter of 8 mm: (a) Axial plane, (b) Coronal plane and e (c) Sagittal plane.</p>

Cited by 0Open access

Fast in vivo volume dose reconstruction via Reference Dose Perturbation

Weiguo Lu, Mingli Chen, Mo Xiao-Hu et al. · Journal of Physics Conference Series · 2014

Purpose: Accurate on-line reconstruction of in-vivo volume dose that accounts for both machine and patient discrepancy is not clinically available. We present a simple reference-dose-perturbation algorithm that reconstructs in-vivo volume dose fast and accurately. Methods: We modelled the volume dose as a function of the fluence map and density image. Machine (output variation, jaw/leaf position errors, etc.) and patient (setup error, weight loss, etc.) discrepancies between the plan and delivery were modelled as perturbation of the fluence map and density image, respectively. Delivered dose is modelled as perturbation of the reference dose due to change of the fluence map and density image. We used both simulated and clinical data to validate the algorithm. The planned dose was used as the reference. The reconstruction was perturbed from the reference and accounted for output-variations and the registered daily image. The reconstruction was compared with the ground truth via isodose lines and the Gamma Index. Results: For various plans and geometries, the volume doses were reconstructed in few seconds. The reconstruction generally matched well with the ground truth. For the 3%/3mm criteria, the Gamma pass rates were 98% for simulations and 95% for clinical data. The differences mainly appeared on the surface of the phantom/patient. Conclusions: A novel reference-dose-perturbation dose reconstruction model is presented. The model accounts for machine and patient discrepancy from planning. The algorithm is simple, fast, yet accurate, which makes online in-vivo 3D dose reconstruction clinically feasible.

Cited by 1Open access

Low-dose CT image denoising without high-dose reference images

Nimu Yuan, Jian Zhou, Jinyi Qi · 2019

Reducing radiation dose of computed tomography (CT) and thereby decreasing the potential risk to patients are desirable in CT imaging. Deep neural network has been proposed to reduce noise in low-dose CT images. However, the conventional way to train a neural network requires using high-dose CT images as the reference. Recently, a noise-tonoise (N2N) training method was proposed, which showed that a neural network could be trained with only noisy images. In this work, we applied the N2N training to low-dose CT denoising. Our results show that the N2N training works in both count and image domains without using any high-dose reference images.

Cited by 12

Reference Dose and Reference Concentration Rounding in IRIS: Risk Assessment Ramifications

T. Lawrence · Journal of Toxicology and Risk Assessment · 2020

Commonly, reference doses and reference concentrations, toxicity factors supporting non-cancer assessments for the chemical exposures of humans, are rounded values. While the U.S. EPA's Integrated Risk Information System rather evidently employs this rounding practice so as to arrive at toxicity values that are uniform and simple in appearance, the particulars of the rounding approach are only loosely discussed.

Cited by 0Open access

[A new toxicological concept-acute reference dose].

Zhiwei Liu, Bingheng Chen · PubMed · 2003

Acute reference dose (ARfD) is a new concept in toxicology and risk assessment, and mainly used for assessing health effect from short-time exposure to environmental chemicals. The ARfD of a chemical was defined as "an estimate of a substance in food or drinking water, expressed on a body weight basis, that can be ingested over a short period of time, usually during one meal or one day, without appreciable health risk to the consumer on the basis of all the known facts at the time of the evaluation. It is usually expressed in milligrams per kilogram of body weight." ARfD is different from ADI and reference dose. In this review the principles and methods in establishing ARfD were explained.

Cited by 3

Reference Dose Rates for Fluoroscopy Guided Interventions

Jacob Geleijns, J.J. Broerse, Willy A. Hummel et al. · Radiation Protection Dosimetry · 1998

The wide diversity of fluoroscopy guided interventions which have become available in recent years has improved patient care. They are being performed in increasing numbers, particularly at departments of cardiology and radiology. Some procedures are very complex and require extended fluoroscopy times, i.e. longer than 30 min, and radiation exposure of patient and medical staff is in some cases rather high. The occurrence of radiation-induced skin injuries on patients has shown that radiation protection for fluoroscopy guided interventions should not only be focused on stochastic effects, i.e. tumour induction and hereditary risks, but also on potential deterministic effects. Reference dose levels are introduced by the Council of the European Communities as an instrument to achieve optimisation of radiation protection in radiology. Reference levels in conventional diagnostic radiology are usually expressed as entrance skin dose or dose-area product. It is not possible to define a standard procedure for complex interventions due to the large inter-patient variations with regard to the complexity of specific interventional procedures. Consequently, it is not realistic to establish a reference skin dose or dose-area product for complex fluoroscopy guided interventions. As an alternative, reference values for fluoroscopy guided interventions can be expressed as the entrance dose rates on a homogeneous phantom and on the image intensifier. A protocol has been developed and applied during a nationwide survey of fluoroscopic dose rate during catheter ablations. From this survey reference entrance dose rates of respectively 30 mGy.min-1 on a polymethylmethacrylate (PMMA) phantom with a thickness of 21 cm, and of 0.8 µGy.s-1 on the image intensifier have been derived.

Cited by 10

Zorro: multi‐reference dose‐fractionated image registration

Robert R. McLeod, Benedikt Haas, Henning Stahlberg · European Microscopy Congress 2016: Proceedings · 2016

The technique of single‐particle analysis (SPA) in cryo‐TEM has recently been revolutionized by the simultaneous introduction of direct electron detectors (DEDs) and maximum likelihood, reference‐free reconstruction tools such as Relion [S. Scheres] and Bayesian refinement tools such as Frealign [N. Grigorieff]. CMOS DEDs have much better DQE than scintillator‐coupled CCDs and fast read‐out permits collection of dose‐fractionated image stacks which can be effectively drift‐corrected. SPA is essentially an ensemble‐average in‐line holography technique. Particles (i.e. proteins) are embedded in a vitreous ice matrix, such that they have random projections. Many micrographs are recorded at various defocus values (typically 1.0 – 2.5 µm). With sufficient particle projections recorded (typically 50k‐500k), it is possible to estimate orientations of the particles by maximum likelihood iterative refinement and reconstruct the 3‐D volume via back‐projection using the central projection theorem. Proteins are highly radiation sensitive (critical dose ~20 e − /Å 2 = 0.03 C/cm 2 ) therefore useful per‐frame dose is in the range 0.5 – 2 e − /Å 2 . Ice films are viscous and thought to be semi‐insulating under electron illumination. High, charged‐driven drift rates are observed (x10 compared to hard specimens on carbon). Radiation damage and non‐rigid particle motion results in rapid decay of correlation information amongst frames. In addition, DED's gain reference change quickly due to radiation damage, such that correlated noise is often greater than the correlated signal. We will present Zorro, a new drift registration package, to be open‐sourced ( github.com /C‐CINA/zorro) in the near‐future after publication. Zorro takes a similar multiple reference approach as Motioncorr [Y. Cheng], in that it overcomes noise by cross‐correlating each frame to ~10 frames of similar dose, resulting in an over‐determined set of image shifts. In Zorro the error amongst image shifts is optimized by a global‐minimizer, the Basin hopping algorithm. The individual correlations are logistic‐weighted in the minimizer, based on the statistical significance of the correlation peak compared to the background noise. To deconvolve the impact of correlated noise shared between frames, a masked intensity‐normalized cross‐correlation (MNXC) is used. The MNXC algorithm also deconvolves non‐uniform ice thickness and illumination. A test specimen of urease particles are shown in Fig. 1 with (top) single frames with dose 0.3 e − /Å 2 and (bottom) the aligned sum of 60 frames. The set of correlations can be represented by an upper triangular matrix (Fig. 2), where the diagonal represents the frame number and the horizontal the adjacent cross‐correlation maxima. The correlations rapidly drop to the noise level after the adjacency exceeds frames due to non‐rigid particle motion and radiation damage. Registration success at low‐resolution may be assessed by independently registering the even‐ and odd‐numbered frames, and calculating the cross‐correlation between the independent halves. The normalized, rotationally averaged correlation, known as the Fourier Ring Correlation (FRC), is shown in Fig.3 for a small (145 kDa) protein. FRC oscillations are due to defocus. Zorro is a general‐purpose algorithm without technique‐specific heuristics. Here we show it applied to dose‐fractionated HAADF‐STEM. Shown in Fig. 4, a (top) rapid‐scan rate with 100 ns dwell can be combined with dose‐fractionation to (bottom) dampen scan errors in the sum.

Cited by 0

Low Dose Rate Qualified Precision Shunt Reference Total Ionizing Dose Radiation Report

Lmwg. Rlqv · 2010

The LM4050WG2.5RLQV (SMD # 5962R0923561VZA) is tested and qualified at low dose rate to a total ionizing dose (TID) level of 100 krad(Si) per MIL-STD-883 Test Method 1019, section 3.13.3.b. According to this test method an overtest factor of 1.5 is used. To be low dose rate qualified for 100 krad(Si), the parts must pass testing at 10 mrad(Si)/s to a total dose of 150 krad(Si). National Semiconductor tests and qualifies each wafer. Testing is done with units biased and unbiased during irradiation at 10 mrad(Si)/s. For applications requiring TID less than 100 krad(Si) National has established post irradiation reference voltage drift test limits for 30 krad(Si) and 50 krad(Si), also based on a 1.5 overtest factor. The limits are expressed in terms of percentage drift from the pre irradiation reading and are shown in Table I. TABLE I Post Irradiation Reference Voltage Drift Limits (%)

Cited by 0

The Reference-Dose Place Conditioning Procedure Yields a Graded Dose-Effect Function

Rick A. Bevins · International Journal of Comparative Psychology · 2005

A major criticism of the place conditioning procedure for studying conditioned drug reward is that it is relatively insensitive to large quantitative shifts in drug dose (i.e., dose effects are all or none). Experiment 1 demonstrated this lack of sensitivity using a wide range of intravenous (IV) cocaine doses (0.1, 0.3, 0.45, 0.6, 0.9, or 1.2 mg/kg). Rats had cocaine repeatedly paired with one distinct end compartment of a 3 compartment apparatus; vehicle was administered in the other end compartment. In a subsequent drug-free choice test, the 0.45 to 1.2 mg/kg doses of cocaine conditioned a place preference. The magnitude of the effect did not differ. Experiment 2 used a modified version of this standard place conditioning method. In this alternative method termed reference-dose procedure, a fixed dose of cocaine (reference dose) was repeatedly paired with one end compartment (i.e., 0.45 mg/kg); the comparison dose of cocaine was administered in the other end compartment (vehicle, 0.6, or 1.2 mg/kg). Preference for the comparison-dose compartment increased with dose—a graded doseeffect curve. In contrast to the standard procedure, the reference-dose procedure revealed that the conditioned rewarding effect of 1.2 mg/kg of cocaine was greater than that of 0.45 mg/kg. This increase in sensitivity to conditioned reward with the reference-dose procedure will likely increase the utility of the place conditioning method as a preclinical model, as well as a procedure for studying processes mediating associatively-motivated choice behavior.

Cited by 27Open access