Describe in your own words the following terms and give at least two examples for each: a) radiation, b) radioactive,
c) ionizing radiation.
Compare and contrast deterministic and stochastic effects of ionizing radiation. What is the role of how the radiation
dose is delivered in time impact these effects?
SOLUTION This solution is FREE courtesy of BrainMass!
Radiation is most loosely defined as the transmission of energy through some form of medium or space. So for example, radio waves, a form of energy, can pass through completely empty space from point A to B. Note that electromagnetic radiation (e.g. radio, visible light, UV) does not require a medium. Another form of radiation is that of particle radiation, as would be the case when unstable atoms decay and release particles into space or the medium that surrounds them. For example, alpha radiation is the decay of a source particle such that it releases an alpha particle (2 neutrons + 2 protons).
Something is radioactive when a material source actively releases radiation. Put differently, it is actively giving off radiation. For example, an unstable atom with lots of energy might undergo radioactive decay and release an alpha particle (as described above). This unstable atom (such as Americium-241) is said to be radioactive. Note that particle radiation isn't the only way for something to be radioactive. Potassium-40, for example, is also an unstable atom that decays, but instead of releasing particles, it releases pure energy in the form of gamma rays. Both these examples are radioactive elements.
Ionizing radiation refers specifically to radiation that has enough energy to free electrons from atoms, ionizing these atoms by doing so. Either photons or high velocity particles are able to have enough energy that, when in close contact with electrons of a target atom, will cause that electron to escape from its source atom. In the case of photons, the electron can absorb all or part of the energy and escape. In the case of particle radiation, the particle knocks the electron off its orbit causing it to escape (transfers energy in the process). X-rays, for example, is a form of radiation that has enough energy to do so. Gamma rays are another example.
Stochastic effects from ionizing radiation refer to effects caused by radiation-induced mutation of genetic material, causing downstream effects. They may not be detectable right away, and cannot be predicted. Importantly, any dose - small or large - can cause equal amounts of stochastic effects. For example, imagine a single photon of gamma rays. This photon may have just as much of a chance to cause DNA damage in a subject as 10 photons of gamma rays, there's simply no way we can tell. In general, stochastic effects when it comes to ionizing radiation largely refers to radiation-induced cancer or loss of / mutation of germinal cells such that offspring are negatively affected.
Deterministic effects on the other hand, follow a dose-curve: the more ionizing radiation is given, the more likely these effects would arise, and in greater quantity. These effects are predictable based on dosage of radiation received. For example, radiation burns are known to only occur if a certain amount of radiation is received within a certain amount of time.
Therefore, any amount of ionizing radiation delivered over any amount of time can cause similarly destructive stochastic effects, whereas the more radiation is delivered over a longer period of time, the more deterministic effects will be incurred.
Hope that helps!© BrainMass Inc. brainmass.com October 3, 2022, 1:51 am ad1c9bdddf>