IMRT

è Effectiveness of Tracking relies on a stable relationship between the marker and tumor l Changes in tumor geometry (long-course RT) l Migration between CT and radiation delivery (bronchofiberscopy)

è Ideal location Visicoil:

in the center of the lesion

l

l not in the same axial-CT image plane (e.g. 45 degree angle)

è Time interval between marker placement and CT for ‘scarring in’

è Lung and liver: percutaneous insertion under CT- fluoroscopic guidance

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