MEDRADSC 2X03 Chapter Notes - Chapter 30: Intellectual Disability, Lead, Inverse-Square Law
11 Sep 2017
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This refers to the x-ray beam prior to any interaction with the patient, grid, table or image intensifier. The beam that interacts with the detector is termed the exit beam and. And, consequently, will be harder and more penetrating than the primary beam. the beam will have been heavily filtered. Leakage radiation: this is leakage from the x-ray tube housing. However, this is limited to a maximum of 1 mgy/hr at 1 metre from the focus and, in practice, is usually much less. Scattered radiation: this is a direct result of the compton effect in the patient and contributes the most to staff radiation dose. The amount (fluence) of scatter depends on: field size, volume of patient, quality of primary beam, an increase in scatter can be caused by: Increase kv : no. photons proportional to square of applied potential. Increase ma : no. photons directly proportional to tube current.
