Search results
Results from the WOW.Com Content Network
For other radiation types, the RBE is not a well-defined physical quantity, since it varies somewhat with the type of tissue and with the precise place of absorption within the cell. Thus, for example, the RBE for alpha radiation is 2–3 when measured on bacteria, 4–6 for simple eukaryotic cells, and 6–8 for
The deterministic effects that can lead to acute radiation syndrome only occur in the case of high doses (> ~10 rad or > 0.1 Gy) and high dose rates (> ~10 rad/h or > 0.1 Gy/h). A model of deterministic risk would require different weighting factors (not yet established) than are used in the calculation of equivalent and effective dose.
Equivalent dose (symbol H) is a dose quantity representing the stochastic health effects of low levels of ionizing radiation on the human body which represents the probability of radiation-induced cancer and genetic damage.
The most widely accepted model posits that the incidence of cancers due to ionizing radiation increases linearly with effective radiation dose at a rate of 5.5% per sievert. [3] If this linear model is correct, then natural background radiation is the most hazardous source of radiation to general public health, followed by medical imaging as a ...
The roentgen or röntgen (/ ˈ r ɛ n t ɡ ə n,-dʒ ə n, ˈ r ʌ n t-/; [2] symbol R) is a legacy unit of measurement for the exposure of X-rays and gamma rays, and is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air (statcoulomb per kilogram).
For an exposure of 1 roentgen by gamma rays with an energy of 1 MeV, the dose in air will be 0.877 rad, the dose in water will be 0.975 rad, the dose in silicon will be 0.877 rad, and the dose in averaged human tissue will be 1 rad. [10] "rad" stands for radiation absorbed dose. [4]
Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. The National Academies Press. doi:10.17226/11340. ISBN 978-0-309-09156-5. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2; Radiation Hormesis Overview by T. D. Luckey, who wrote a book on the subject (Luckey, T. D. (1991 ...
[2] [3] The most common definitions are: [4] The monitor chamber reads 100 MU when an absorbed dose of 1 gray (100 rads) is delivered to a point at the depth of maximum dose in a water-equivalent phantom whose surface is at the isocenter of the machine (i.e. usually at 100 cm from the source) with a field size at the surface of 10 cm × 10 cm.