[Comparison of classic simulation and virtual simulation in breast irradiation: prospective study on 14 patients].
OBJECTIVE
To compare conventional 2D simulation and virtual simulation on 14 patients with breast cancer.


METHODS
Patients were simulated for treatment using standard procedure. They subsequently underwent CT scan in the treatment position. The CTV was defined as breast tissue. The PTV was obtained by adding a 3D margin of 1 cm around CTV. Organs at risk (lungs and heart) were outlined. Ballistics and dose distribution obtained with the two planning methods were compared.


RESULTS
With conventional simulation, 95% of CTV received 95% of the dose prescribed. Virtual simulation significantly improved dosimetric coverage of PTV without increasing irradiation volume of lung and heart. In 2D simulation, using three slices allowed optimisation by adjusting wedge angle. The five-slice plan was a much better predictor of the maximum dose regions when compared to the three-slice plan. Using entire CT data didn't give any benefit.


CONCLUSIONS
Variations in CTV delineation and PTV definition limit interest of virtual simulation. In classic simulation, a 5 CT slice-plan can be used to optimise dose distribution.
Bauduceau
O
O
Service d'oncologie-radiothérapie, HIA du Val-de-Grâce, 74, boulevard du Port-Royal, 75005 Paris, France. rthoncovdg@yahoo.fr
Pons
P
P
Campana
F
F
Bollet
M
M
Romero
L
L
Fayolle
M
M
D001943:Breast Neoplasms / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008875:Middle Aged; D011878:Radiotherapy / Q000379:methods*; D016896:Treatment Outcome; D014584:User-Computer Interface