322 / 1674
Comparison of effective target volume between MammoSite
and 3D CRT
Shaitelman et al, IJROBP, 2012
CTV-1.5
CTV-1.0
CTV effective
~MammoSite Treated
Effective CTV was on average
38%
±
4% smaller than CTV-1.5
and 7%
±
10% larger than CTV-1.0
The effective CTV was on average
16%
±
10% smaller than the
MammoSite CTV, suggesting that
tissue is stretched during therapy
Direction-specific margins from the
cavity to the effective CTV was
median 1.0 cm (range 0.5-1.5cm)
Conclusion: The 1 cm margin used to define the MammoSite CTV treated a
smaller volume surrounding the lumpectomy cavity than previously thought and
less than that targeted by 3D CRT APBI