# dose

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## dose

1. Med a specific quantity of a therapeutic drug or agent taken at any one time or at specified intervals
2. Physics the total energy of ionizing radiation absorbed by unit mass of material, esp of living tissue; usually measured in grays (SI unit) or rads
3. a small amount of syrup added to wine, esp sparkling wine, when the sediment is removed and the bottle is corked

## Dose

the energy of ionizing radiation absorbed by a unit of mass of irradiated matter (the absorbed dose Da). The absorbed energy is expended in the heating and the chemical and physical transformation of matter. The magnitude of the dose depends on the type of radiation (for example, X-ray or neutron flux), the energy of its particles, the density of their flux, and the composition of the irradiated matter. All other things being equal, the longer the time of irradiation, the greater the dose. Thus, doses accumulate with time. The dose per unit time is called the dose rate.

In addition to the absorbed dose there are the concepts of the exposure dose and the dose equivalent. The exposure dose, a measure of the ionization of air under the action of Xand y-radiation, is measured by the number of charges formed. Coulombs per kg is the unit of exposure dose in the system. An exposure dose of 1 coulomb per kg means that the total charge of all ions of the same sign formed in one kilogram of air is equal to one coulomb. The roentgen is a subsidiary that is widely used for exposure dose; 1 roentgen = 2.57976 x 10-4 coulombs per kg, which corresponds to the formation of 2.08 x 109 pairs of ions in 1 cu cm of air (at 0°C and 760 mm mercury). In order to create that number of ions it is necessary to expend energy equal to 0.114 ergs per cu cm, or 88 ergs per g. Thus, 88 ergs per g is the energy equivalent of the roentgen. The absorbed dose of X-radiation or y radiation in any substance can be calculated from the magnitude of the exposure dose. In order to do this it is necessary to know the composition of the substance and the photon energy.

Thus, the radiation danger to which a human being is subjected under any form of radiation corresponds to the same magnitude of dose equivalent. Natural sources of ionizing radiation (cosmic rays, the natural radioactivity of soil, water, air, and the human body) produce an average equivalent dose rate of 125 millirems per year. A dose equivalent of 400-500 rems received in a short time during irradiation of the whole body may, without special treatment, lead to death. However, the same dose equivalent received evenly during the course of one’s life leads to no perceptible changes. A dose equivalent of 5 rems per year is considered the maximum permissible exposure (MPE) in occupational irradiation.

The minimum dose of γ-radiation that will suppress the reproductive capacity of certain cells after a single irradiation is 5 rems. Inceptive changes in the blood are observed with prolonged daily doses of 0.02-0.05 rems, tumor formation, with 0.11 rems. The long-term consequences of irradiation are judged according to the increase in the frequency of mutation in the offspring. The dosage that will double the frequency of spontaneous mutation in man probably does not exceed 100 rems per generation. With local irradiation—that is, for the purpose of treating malignant tumors—high doses (6,000-10,000 rems in three or four weeks) of X-radiation or γ-radiation are used (carefully shielding the rest of the body).

Radiobiology distinguishes the following doses that lead sooner or later to death in animals: a dose that causes the death of 50 percent of the animals in 30 days (a lethal dose— LD30/50) with single-exposure unilateral X-radiation or γ-radiation is 300 rems for guinea pigs and 1,000 rems for rabbits; the minimum absolute lethal dose (MALD) with general γ-radiation is approximately 600 rems for man. With increases in dosage, the survival time is reduced to 2.8-3.5 days; further increases in dosage do not change that period. Only doses higher than 10,000-20,000 rems shorten the survival time to one day, and with subsequent irradiation, to a few hours. With a dose of 15,000-25,000 rems, cases of “death under the ray” are noted. Particular forms of radiation injury correspond to each dosage range. A number of invertebrate animals, plants, and microorganisms have considerably lower sensitivity.

Dosimeters are used in measuring radiation doses in order to predict radiation effects.

### REFERENCES

GOST 8848-63: Edinitsy radioaktivnosti i ioniziruiushchikh izluchenii. Moscow, 1964.
GOST 12631-67. Koeffitsient kachestva ioniziruiushchikh izluchenii. Moscow, 1967.
Ivanov, V. I. Kurs dozimetrii, 2nd ed. Moscow, 1970.
Golubev, B. P. Dozimetriia i zashchita ot ioniziruiushchikh izluchenii, 2nd ed. Moscow, 1971.

V. I. IVANOV and N. G. DARENSKAIA

## dose

[dōs]
(medicine)
The measure, expressed in number of roentgens, of a property of x-rays at a particular place; used in radiology.
(nucleonics)
References in periodicals archive ?
coli O78 strain, it is clear that the geometric mean of ELISA in inactivated vaccine was increased from 17205 at 1st week after vaccination to 32434 at 3rd week and to57930 at 2nd week then decreased to 22253 at 3rd week after booster dose,, while the titer after challenge decreased to 10760 at 1st week and increased to 36199 in 2nd week (Figure 7).
A single dose of adjuvant containing vaccine can induce protective antibody level for up to one year duration while a booster dose of the non-adjuvant vaccine is needed for such response.
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The latest figures on the impact of the pneumococcal jab were being revealed today in a report at the National Assembly where Assembly Members, doctors, and families affected by disease gathered to highlight the importance of the vaccine and the follow-up booster doses.
"Wales is achieving high levels of pneumococcal vaccination and the launch of this report provides another opportunity to raise awareness of the diseases and to emphasise the need for continued uptake of the vaccine, particularly the booster dose in all communities in Wales."
A booster dose is given after one year of age and at least 6 months after the third dose of vaccine.
The young persons in the present study developed high titres of antitoxin antibody after only one dose of tetanus toxoid substantiating the claim that, provided a primary course of tetanus vaccine had been given even up to 30 years previously, a single booster dose is sufficient to restore protective levels of antibody [19].
Before starting school, children four to six years old should receive a booster dose of Tdap-IPV vaccine to protect them against tetanus, diphtheria, pertussis and polio.
Those who took only one dose of vaccine will be given a second booster dose, he said.
The first cohort became available for the 12-month booster dose in May 2016.
In April 2013, the World Health Organization Strategic Advisory Group of Experts on Immunization concluded that a single primary dose of yellow fever vaccine is sufficient to confer sustained immunity and lifelong protection against yellow fever disease, and that a booster dose is not needed (9).
Vaccine-induced immunity is short-lived, so the first booster dose of vaccine is recommended within 6-9 months after primary vaccination; thereafter, annual booster doses are recommended for 5 years after the last confirmed case in the area (4).

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