PHYS-2506EL Lecture 20: MRP_Dec4
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The exposure rate is linearly proportional to the activity of the source, is capital gamma, greek letter. 0: a0 = initial activity = 1 ci, x = a. 2 d (cid:1) d0 = initial distance = 1 m. X = exposure rate (cid:1) unit: r/hr. will be the result, r/min. is commonly used. (cid:1) = gamma ray constant. In r/hr. (cid:1) unique to each isotope (cid:1) a = activity. In m (cid:1) for any activity of any isotope at any distance. X = exposure rate (cid:1) unit: r/hr. will be the result, r/min. is commonly used, = gamma ray constant (cid:1) In r/hr: unique to each isotope, a = activity. In m (cid:1) (cid:1: for any activity of any isotope at any distance, radiation sources for treatment used to be 80 cm from the patient. Now they"re placed 100 cm (1 m) from the patient because people have gotten fatter and many people don"t fit inside.