Abstract:
Background: The aim of this study was to compare the treatment plans of
three techniques namely three-dimensional conformal radiotherapy (3DCRT),
Electronic tissue compensator (ECOMP) based planning and Volumetric
Modulated Arc Therapy (VMAT). Material and Methods: The planning
goal was set to cover 95% of the planning target volume with 95%
prescription dose for the dose plan of 40 Gy in 16 fractions. Treatment
techniques with improved dose homogeneity, optimum skin dose, lung dose
(V20Gy) and contralateral breast dose were used as the criteria to select the
optimized treatment plan. The treatment planning time and the number of
monitor units (MU) required to execute the plan were also taken into
consideration. Result: PTV coverage (V95%) for the patient of ca-right breast
and the ca-left breast was superior in VMAT plans. Ipsilateral lung (V5Gy %)
showed significant dose reduction in ECOMP plans compared to 3DCRT and
VMAT plans. Similarly, for the heart and contralateral lung, the mean doses
were least in ECOMP plans. Dose homogeneity Index (HI) and Dose
conformity Index (CI) was better in ECOMP plans compared to 3DCRT, but
VMAT plans were superior to both the other techniques. The skin surface
dose was less in VMAT plan. Conclusion: VMAT has high CI as well as HI but at
the cost of higher OAR doses (lung and heart) and large treatment planning
time. For a busy center, ECOMP can be a good choice of treatment technique
which can optimize the OAR doses and treatment planning time but for dose
homogeneity and conformity, VMAT is superior to others.
