871 / 1224
Phantom correction
•
Plastics fabricated for water equivalence in
MV beams used as phantom material (solid
water 457-Gamex, white water RW3-PTW,
plastic water CIRS)
•
Williamson (1991) first noted the need for a
p
phant
correction
Table from: Luxton, Med. Phys. 21(5), 631 (1994)
) (
,
) ( ,
Q phant
wD
QwwD
phant
p
=