Dose Course 2018_Flipping book

Factor-based dose calculations basic dosimetric quantities

Relative depth dose (RDD, or PDD) at an SSD=SAD setup

SSD

SAD

=

ref

Relative depth dose, RDD

SAD

SAD

) SSD dsD SSD dsD ) , ,( ref

RDD

) , ,( SSD ds

=

ref

ref

, ,( ref

ref

s

s

or

d

ref

Dref

d

Percentage depth dose, PDD

D

d

100 SSD dsD SSD dsD ) ) , ,( ref 

= SSD ds PDD

) , ,(

ref

, ,( ref

ref