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Phantom correction
•
Phantom material MUST be checked for density variation and composition (Ca or
other high Z content variation that can be up to 30%) to minimize type B
uncertainty.
Figure from: Luxton, Med. Phys. 21(5), 631 (1994)
•
High purity plastics (PMMA,
polystyrene) might be preferable since
p
phant
deviation from unity is greater
for LE source dosimetry BUT type B
uncertainty of the correction will be
lower.
phant
p
1
) (
) (
,
,
Q D
QD
p
phant
w
ww
phant
=