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Dose per MU formalisms:
factor-based dose calculations
(
)
(
)
)(
; ,
; ,
ref
ref
ref
d
s
factor
M
SSD d cD
M
d SSD dsD
ref
=
+
dosimetric quantities to account for all differences
from
the reference irradiation geometry in terms of:
• distance from source (
~
inverse square law)
• field size and depth (
~
scatter dose in medium)
• modulation (
~
beam intensity)
• attenuators in the beam path
• position off axis
• heterogeneities