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Summary
•
Soft tissue structures cannot be visualized in radiographs ,
therefore, doses to surrogates are used to represent target
and OARs.
•
Standard loading pattern and Point A
plan is a good start for
complicated plans and hence recommended by ICRU 89
•
Point A dose is
NOT
a surrogate for tumor dose. For
small
tumors
, 2D planning delivers high dose to the tumor while
exceeding the dose to the OARs, For
large tumors
, 2D
Planning under-dose the tumor
•
ICRU Rectal point over estimates and bladder point over
estimates as compared to D2cc