Equivalent dose , definition

Notice that the dose has a strict definition of energy per unit mass of the absorber and, in principle, can be measured for a given radiation at a certain energy in a specific material. The equivalent dose is a relative unit in that a radiation weighting factor is applied to a measured quantity. The dose can be measured from ionization in an electronic radiation detector the equivalent dose must take into account the type of radiation causing the ionization. 

It is important to note that in the various studies reviewed in the preparation of this document, dose levels have been presented by those authors in several ways. In order to facilitate comparisons among studies, these levels have generally been converted to an equivalent dose in microcuries (p Ci) and kilo-Becquerels (kBq). The historical definition of one curie is the disintegration rate exhibited by one gram of radium. There are 0.027 pCi per kBq. In this document, comparisons are usually made between total administered amounts of radioactivity, in pCi/kg and kBq/kg, instead of using a daily dosage level. 

Df course, this definition assumes equivalent doses. For slightly different doses, linearity between dose and AUC is a reasonable assumption, and the ratio of dose-normalized AUCs (AUC/dose) can be used in the above definition. Because a good delivery system not only increases exposure to the active agent at the target site, but also decreases the corre-... 

It is necessary to take into account the different sensitivities of various tissues and organs to the induction of deleterious health effects to the whole organism. The effective dose (E) is defined as a summation of the tissue equivalent doses multiplied by the appropriate tissue weighting factor W[. According to this definition. 

From the definition of the equivalent dose, it follows that... 

For approximately 20% to 30% of people with schizophrenia, drug treatment is ineffective. A standard definition of treatment resistance includes patients who have persistent positive symptoms despite treatment with at least two different antipsychotics given at adequate doses (at least 600 chlorpro-mazine equivalents) for an adequate duration (4 to 6 weeks). In addition, patients must have a moderately severe illness as defined by rating instruments, and have a persistence of illness for at least 5 years.40 These patients are often highly symptomatic and require extensive periods of hospital care. 

Maleate/vinyl ether formulations based on a model unsaturated polyester prepared from maleic anhydride and 1,5-pentane diol and triethylene glycol divinyl ether were studied. At molecular weights of less than about 10,000 the cured films were extremely brittle. When the equivalent weight of the unsaturated polyester was increased by replacing some of the maleic anhydride with succinic anhydride, measurable values for film elongation could be obtained but the cure speed was definitely slower. When either diethyl maleate or isobutyl vinyl ether were added as monofunctional diluents the cure dose needed to obtain 200 MEKDR was increased and the flexibility measured by pencil hardness increased as the amount of diluent was increased. A urethane vinyl ether was synthesized and used to replace DVE-3 and films with increased elongation were obtained at equivalent at dosages as low as 1 J/cm2. 

At a given dose D, the distribution /(z ) [or, equivalently,/(z Z))] is determined uniquely by /i(z). This can be understood from the following argument By definition, the probability of exactly v events is given by the Poisson distribution ... 

In experimental animals the effect of ephedrine administered intravenously is similar to that of epinephrine. The arterial pressure — systolic, diastolic, and mean pressure — rises and vagal slowing occurs. Compared with epinephrine, the pressor response to ephedrine occurs somewhat more slowly and lasts about ten times longer. Furthermore, it requires more ephedrine than epinephrine to obtain an equivalent pressor response. How much more depends on the species tested, type and degree of anesthesia, dose level, and individual variability of the test animal. It is, therefore, almost impossible to give a definite figure for the relative potency of ephedrine and epinephrine. It is commonly accepted that it requires about 250 times more ephedrine than epinephrine to achieve equipressor responses. 

Ambiguity- there should be no statements that might require interpretation by the scientific staff during conduct of the study. This applies particularly to those factors where numbers are critical. Examples are dose rates or application levels, sacrifice or harvest intervals, and replication requirements. The protocol, however, must also retain a degree of flexibility in those areas where exact definition is not needed or cannot be determined prospectively. Specifications should not be so detailed that there is no allowance for equivalent substitution. Usually, it is not necessary to specify brand names however, there may be times when experience dictates that a specific brand or manufacturer are required to perform a given function. In those cases, of course, specificity is not only desirable but mandatory. 

Definitive information regarding the acute toxicity of di-N-octylphthalate is not available. An estimated lethal oral dose in humans is between 0.5 and 15gkg, or between 1 oz equivalent to 29.6 mis and 1 qt equivalent to 0.96 liters in a 70 kg adult. Compounds that are structurally similar to di-N-oct-ylphthalate are known to irritate mucous membranes resulting in irritation of the eyes, throat, and upper respiratory tract passages and in gastrointestinal disturbances. There is evidence that some phthalates, such as di-s-octylphthalate, may be reproductive and developmental toxicants. Generally, the acute oral toxicity of alkylphthalates is low and the acute oral toxicity decreases as molecular weight increases. 

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