Avertable dose

Especially in the last two situations, the optimization with respect to the averted dose (risk)... 

The projected dose (PD) is the overall exposure to the population, which is projected to occur as a result of the exposure situation if no protective actions are implemented and should first be estimated for each exposure pathway (ICRP 1991b). The dose that would result when the protection strategy is implemented is called the residual dose (RD). The difference dose from each pathway (projected dose minus residual dose) is called the averted dose (AD). This is the dose saved by implementing a given protective action and is the concept for the optimization of the protective measures that will make up the overall protection strategy. 

The intervention levels of averted doses recommended by ICRP are those at which intervention is almost always justified. In the early phase, these doses are 50 mSv for sheltering, 500 mSv equivalent dose to thyroid for administration of stable iodine, 500 mSv (1 week) whole body dose or 5,000 mSv equivalent dose to skin for evacuation (ICRP 1991d). For the late phase countermeasures 1,000 mSv for relocation (5-15 mSv per month for prolonged exposure), and 10 mSv (in 1 year) for restriction to a single foodstuff (1,000-10,000 Bq kg for beta/gamma emitters and 10-100 Bq kg for alpha emitters) are recommended. 

Category 2 (Implementing early protective actions and taking action to protect the public.) This group consists of workers who will incur additional exposure in order to avert doses to the public, such as police, medical personnel, drivers, and crews of vehicles used for evacuation and similar group. Ideally, the aim should be to keep the doses below those permitted in normal conditions. 

If a differential cost-benefit analysis is performed, a monetary value for the averted dose needs to be established, which may or may not be approved by the regulatory body. Different values are used in different States [1-7,1-8]. 

Where a monetary value of averted dose is used in the control of occupational exposure, a baseline value for the monetary value of dose and an increase in this value as the individual dose approaches the dose limit may be applied. This approach is consistent with the aim of avoiding major disparities in the doses that are received by personnel of different types who work in the controlled area. This relationship reflects the aversion to both such disparities and to the risk itself and ensures that the major effort is focused on those workers who may receive the highest doses. 

Special guidance for exposures often in excess of dose limits is required for emergency response operations. In severe disasters, prompt but well considered actions can potentially save lives and avert significant harm to the public. NCRP Report 116 titled Limitations of Exposure to Ionizing Radiation2 provides broad guidance for emergency responders. 

Ibogaine has demonstrated toxic effects, which could potentially limit its usefulness in treating addiction. However, the proper dosage of alternative iboga alkaloids may avert this problem. The median lethal dose of ibogaine is 82 mg/kg in the guinea pig and 327 mg/kg in the rat (Dhahir 1971 Delourme-Houde 1946). Use of ibogaine for addiction treatment has been associated with two deaths overseas. 

Methadone maintenance is precisely what the name implies. Patients who will not or cannot tolerate being totally abstinent of opiates are maintained long-term on methadone replacement therapy. As noted previously, this continues the addiction but in a more controlled manner that averts the serious social and medical consequences of uncontrolled addiction. Daily doses for methadone maintenance range from 20mg/day to over lOOmg/day. 

Reversibility of Noncarcinogenic Systemic Effects. Most case reports of humans intoxicated with carbon tetrachloride indicate that, if death can be averted, clinical signs of renal and hepatic dysfunction diminish within 1-2 weeks, and recovery often appears to be complete. This is primarily because both liver and kidney have excellent regenerative capacity and can repair injured cells or replace dead cells (Dragiani et al. 1986 Norwood et al. 1950). However, high doses or repeated exposure can lead to fibrosis or cirrhosis that may not be reversible. The depressant effects of carbon tetrachloride on the central nervous system do appear to be reversible, although any neural cell death that occurs (Cohen 1957) is presumably permanent. 

The specific antidote flumazenil is probably only justified in patients with severe (for example, parenteral) poisoning and co-existent disease (for example, chronic obstructive airways disease), where it may avert the need for mechanical ventilation. Humazenil 200 pg intravenously over about 15 s, repeated every 60 s up to a total dose of 1 mg can... 

SSRIs sometimes cause an initial jitteriness similar to that noted with initial imipramine therapy for PD. This may be more common with SSRIs than with other currently available non-TCA antidepressant therapies for PD. Just as low initial imipramine doses avert this reaction, initiating SSRI therapies with one fourth to one half the usual starting antidepressant dose followed by gradual increments with low doses can avert this reaction. This syndrome can also be blocked by add-on, low-dose, as-needed BZD therapy (e.g., alprazolam or lorazepam). 

The proper interpretation of the dose limit is that higher doses (and their associated risks) from controlled sources are regarded as unacceptable, meaning intolerable. Thus, the dose limit normally must be met in routine exposures to controlled sources regardless of cost or other circumstances. Application of the ALARA principle to further control of exposures takes into account, for example, the cost of reducing radiation doses in relation to the benefits in health risks averted and other societal concerns. 

Small doses of cyanide are converted to thiocyanate by an enzymatic reaction catalyzed by rhodanase. The rhodanase system can detoxify large amounts of cyanide but may not respond quickly enough to avert serious symptomatology. 

In CEA, incremental costs are compared (in a ratio) to incremental outcomes (as measured in physical or natural units). Physical and natural units can include both intermediate (surrogate) clinical endpoints (for example millimetres of mercury blood pressure reduction, changes in FEVj), or final endpoints (for example deaths averted or life-years gained). In a study that assessed the cost per deaths due to pulmonary embolism averted, Hull and associates reported that subcutaneous administration of low-dose heparin starting two hours before surgery was a cost-effective approach to prophylaxis compared to the four alternative regimens. It should be noted that although this study is somewhat dated, it was... 

Other case reports have sugge.stcd that a high dose of oxime may not avert IMS. Thus, in a case of severe malathion self-poi.soning, 1 g PAM was administered iv approximately 7 hr after poisoning and at 12 hi an infu-.sion of 400 mg/hr PAM was administered iv. The patient developed IMS on hospital day 3 (Sudakin et al., 2000). 

Onset of colds and flu Echinacea should be used at the very early onset of a cold or flu when you feel just the earliest hint of that tingle in the body that signals the approach of symptoms. It is at this point that echinacea is most effective, but it must be taken in large doses and frequently to be effective. When it is taken after the full onset of symptoms, I have found (in over 10 years of clinical experience) that echinacea is not effective, irrespective of its proven ability to increase white blood cell count. Usually, assertive action at this early point in infection will result in averting the full onset of either colds or flu as long as the immune system is relatively healthy. A compromised immune system will, after a while, fail to prevent disease in spite of any stimulation you give it (see contraindications, on the next page). 

Nirenberg A, Mbsende C, Mehta BM, Gisolfi AL, Rosen G. H dose methotrexate with cit-rovorum factor rescue predictive value of serum methotrexate concentrations and ccrrective measures to avert toxicity. Cancer Treat Rep ( 91T) 61,779-83. 

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