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3D (CBCT)
•
Limitations
Collision
Field of view
Increased dose to contra lateral breast
•
CBCT not acquired at the isocentre to avoid collision
•
Then once matched the shift includes the offset from isocentre
position
•
Adds time and potential errors
•
Donovan et al. (2012) stipulate limitations on iso position to
account for this
•
Half bowtie filter (Varian OBI) increases FOV in longitudinal
direction