KAMURAN İBİŞ, UĞUR AKBAŞ, CANAN KÖKSAL, MUSA ALTUN
Turkish Journal of Oncology - 2018;33(2):65-72
OBJECTIVE In this study, three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated RT (IMRT), and volumetric-modulated arc therapy (VMAT) techniques were compared in patients with glioblastoma multiforme (GBM) receiving RT. Comparisons were made in terms of sparing the organs at risk (OAR), by using European Organisation for Research and Treatment of Cancer-Advisory Committee on Radiation Oncology Practise (EORTC-ACROP) guideline. METHODS RT in 10 patients was replanned. Treatment volume was created according to the EORTC-ACROP, and 60 Gy/30 fraction dose was prescribed for planning target volume (PTV). PTV-less brain volume (BPTV) Dmean, OARs doses; V5Gy and V50Gy of B-PTV volumes; conformality, and homogeneity indices were analyzed. RESULTS B-PTV was spared better in IMRT. The optic chiasm, contralateral optic nerve, ipsilateral/contralateral cochlea were significantly spared in IMRT and VMAT. The best sparing for brainstem, pituitary gland, ipsilateral eye, ipsilateral lacrimal gland was obtained with VMAT. B-PTV volume received at least 5 Gy was similar in three plans, but lower with 50 Gy in IMRT and VMAT (p<0.001). Although homogenous dose distribution was obtained with similar homogeneity index in all three planning techniques, conformity index was the best in VMAT (p<0.001). CONCLUSION VMAT provides improved conformity index and good homogeneity in GBM RT using the EORTCACROP target and dose definition. The best sparing for OAR was obtained with VMAT.
