A cobalt-60 source with activity 2.60×10-4 Ci is embedded in a tumor that has mass 0.20 kg. The source emits gamma photons with average energy 1.25 MeV. Half the photons are absorbed in the tumor, and half escape. i. What energy is delivered to the tumor per second? ii. What absorbed dose, in rad, is delivered per second? iii. What equivalent dose, in rem, is delivered per second if the RBE for these gamma rays is 0.70? iv. What exposure time is required for an equivalent dose of 200 rem?
Radioactive decay
The emission of energy to produce ionizing radiation is known as radioactive decay. Alpha, beta particles, and gamma rays are examples of ionizing radiation that could be released. Radioactive decay happens in radionuclides, which are imbalanced atoms. This periodic table's elements come in a variety of shapes and sizes. Several of these kinds are stable like nitrogen-14, hydrogen-2, and potassium-40, whereas others are not like uranium-238. In nature, one of the most stable phases of an element is usually the most prevalent. Every element, meanwhile, has an unstable state. Unstable variants are radioactive and release ionizing radiation. Certain elements, including uranium, have no stable forms and are constantly radioactive. Radionuclides are elements that release ionizing radiation.
Artificial Radioactivity
The radioactivity can be simply referred to as particle emission from nuclei due to the nuclear instability. There are different types of radiation such as alpha, beta and gamma radiation. Along with these there are different types of decay as well.
A cobalt-60 source with activity 2.60×10-4 Ci is embedded in a tumor that has mass 0.20 kg. The source emits gamma photons with average energy 1.25 MeV. Half the photons are absorbed in the tumor, and half escape.
i. What energy is delivered to the tumor per second?
ii. What absorbed dose, in rad, is delivered per second?
iii. What equivalent dose, in rem, is delivered per second if the RBE for these gamma rays is 0.70?
iv. What exposure time is required for an equivalent dose of 200 rem?
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