The dose of ionizing radiation

The dose of ionizing radiation - radiation energy, which is to be or has been transferred to the substance, calculated per 1 g of the mass of the substance.
Physical dose of ionizing radiation - energy x-rays or gamma radiation, absorbed in 1 cm3 air and evaluated for manufactured in the air ionization. More modern term exposure dose - has approximately the same meaning. The unit of this dose is x-ray, p (see the so-3, PL. "Units"). Universal is the notion of absorbed dose is the amount of energy absorbed in irradiated object, calculated per 1 g of the mass of matter. Per unit of absorbed dose adopted glad (see the so-3, PL. "Units").
The value of the absorbed dose depends on several factors: type of radiation, its energies, properties of irradiated object, etc. Absorbed dose x-ray and gamma radiation, as a rule, is not equal exposure and different for different fabrics. For example, if the exposure dose of 1 R x-ray radiation with the energy of 180 to 250 kV (see X-raysor gamma radiation From-60 (see Cobalt, radioactive) absorbed dose in bone equal 0,84 happy, muscle - 0,93 happy in adipose tissue - 0,97 happy. An obsolete term tissue dose is close in meaning to the concept of the absorbed dose. Sometimes tissue dose is called the absorbed dose, which is created in the tissues trapped in their radioactive isotopes (see Isotopes, radioactive).
In the radiology practice often, especially before, enjoyed the exposure dose. To judge about the absorbed dose in different points of the irradiated object, use the set of values that define by measuring doses in special models (phantoms), made of the so-called Dane-like materials (see Phantoms dosimetry). Placing the dosimeters in different points of the phantom, determine the distribution of doses of ionizing radiation - dose field (see Isodose), which is judged on the distribution of absorbed energy radiation. The dose of ionizing radiation that is emitted in the depth of the irradiated object, called a deep dose. It consists of the dose produced direct beam, more or less weak, depending on the depth, and the doses of scattered radiation. The latter depends on the energy of the radiation, the size of the object and the irradiated part of it, distance from the radiation source to the surface of the object, etc.
Surface dose dose created on the surface of the irradiated object. Due to inverse scattering radiation surface dose may be 20-25% higher exposure dose, measured at the same point in the absence of an object. Focal dose - dose subject to irradiation focus (e.g., tumors).
In the case of multiple (fractionated) exposure in radiotherapy distinguish a single dose, i.e. the dose in a single session, and a full dose over the entire course of treatment is cumulative dose. The same terms are to apply in relation to any other cases of repeated exposure to ionizing radiation.
When assessing the biological effect of radiation can have a value of integral dose. In the case of uniform irradiation of the whole body integral dose is found by multiplying the exposure dose on body weight. With uneven exposure are averaged value of dose - medium-tissue dose.
There is the term of the indicator the dose. However, it should be deemed unsuccessful, as it characterizes not the dose of ionizing radiation, and the activity labeled any of a radioactive drug is injected into the body for radioisotope diagnostics (see).
The dose of ionizing radiation, calculated per unit of time is called the dose. Per unit of dose received x-rays or happy for 1 sec. (p/s, rad/sec) and the values derived from it (for example, rad/min, happy/hour, Mr/s, etc). In the case of continuous chronic exposure dose rate, R/day or happy/day called daily dose.

  • Biological dose of ionizing radiation