Akademik Veri Yönetim Sistemi
INTERNATIONAL CONFERENCE ON RADIATION APPLICATIONS, 06 Eylül 2021
Abstract. Radiotherapy is the one of the major treatment modality for thoracic esophagus cancer patients.
Delivering high radiation dose to the planning target volume (PTV) while protecting the surrounding normal tissues
can be achieved by volumetric modulated arc therapy (VMAT) which is the advanced radiotherapy technique. For
creating VMAT dose distributions, optimization algorithms and dose calculation algorithms in commercial treatment
planning systems (TPS) are used. Especially in cases of tissue heterogeneity, the final calculated dose volume
histogram (DVH) differs from optimal DVH acquired via the optimization procedure. The intermediate dose
calculation (IDC) module, in the Eclipse treatment planning system, is utilized on optimization of the VMAT plan to
solve these differences. The aim of the present study is to investigate the impact of IDC module during the
optimization of VMAT for the thoracic esophagus cancer patients. The VMAT plans were generated on Eclipse TPS
v15.1 using AAA algorithm without IDC module for ten patients with thoracic esophagus cancer patients. Then, the
plans were re-optimized without changing optimization criteria by using same dose calculation algorithm with IDC
module. The prescribed dose to PTV was 50.4 Gy/28 fr. The homogeneity index (HI) and the conformity index (CI) of
PTV, maximum dose of spinal cord, mean dose of heart, the lung volume of receiving 5 and 20 Gy, were compared
between plans created with and without IDC module. The CI of PTV for VMAT plans with and without IDC module
were found to be 0.822±0.030 and 0.729±0.039, respectively (p=0.005). The HI of PTV for VMAT plans with and
without IDC module were found to be 0.073±0.017 and 0.126±0.022, respectively (p=0.005). The maximum dose of
spinal cord (p=0.028) and the mean dose of heart (p=0.047) were found lower in VMAT plans with IDC module.
However, there was no significant difference for the volume of the lung receiving 5 (p=0.236) and 20 Gy (p=0.053).
In conclusion, applying IDC module on VMAT optimization increases the plan quality in thoracic esophagus cancer
patients