Penumbra and umbra Flashcards
What happens if the radiation is found in unwanted areas?
its classed as unprescribed
how does scatter occur?
its when the x-rays and metal make contact with each other, causing a change in direction
how does a collimator aid penumbra?
it stops radiation and deliberately limits the field
what is the penumbra dose transition?
its the region near the borders of the field, at which the dose rate rapidly changes, a function of distance of distance from the central axis
what is transmission penumbra?
variable beam transmission through non divergent collimator angle
what is the point source?
describes the IR source, which can be represented in a point of space, used when estimating exposure.
what is a line source?
describes the source which can be represented by a line a-b in a chosen plane.
