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Recommendation for reporting
•
PTV median absorbed dose
: D
50%
Ø
D
50%
can also
be reported for the CTV
•
HOWEVER
:
Ø
In the specific case of
peripheral lung lesions
, where the dose
distribution is strongly affected by tissue density variations, a dose to
a target, which does
not include uninvolved
lung parenchyma
D
50%
(GTV/CTV), SHOULD BE SYSTEMATICALLY REPORTED
.
§
The median dose, D
50%
, is likely to be a good measure for a typical dose
in a relatively homogeneously irradiated tumor.
§
The original rationale for reporting the dose at the ICRU reference point
and reporting of D
50%
are very similar.
§
If it were possible to obtain the “true” DVH for the CTV, where motion
and setup uncertainties were accounted for in detail, it would typically be
contained within the DVHs of the CTV and PTV
§
Wherever the CTV lies within the PTV envelope, the CTV median dose
is almost constant.
SBRT 2017 - D. Verellen