914-915 / 2239
Direct beam source
- open beam fluence distribution
The joint effect of
–
angular variations of the direct beam source radiance
–
flattening filter absorption/modulation
commonly expressed as an open beam fluence matrix
19
Can be acquired through a variaty of means:
–
diagonal water phantom dose profile
–
”in air” scanning
–
”star” dose measurements and subsequent
deconvolution/fluence fitting