Comparison of three-dimensional conformal radiation therapy and intensity-modulated radiation therapy (IMRT) techniques in radiation therapy treatment planning for glioblastoma multiforme

In this study, 10 patients diagnosed with Glioblastoma Multiforme under went pre-treatment computed tomography (CT). Thetreatment was planned by using both Three-Dimensional Conformal Radiotherapy (3DCRT) and Intensity-Modulated Radiotherapy (IMRT) techniques after the scan. The data were compared. In the 3DCRT method, vertex angle and 3 field methods were used by using wedge with mutual right and left angles. In IMRT, thetreatment was planned using the static method. Critical organ dose limitations were created so as not to exceed 1% of the volume at 60 Gy for the brainstem, optic chiasm and optic nerves, 30 Gy for the eyes 10 Gy for the lenses. A total of 60 Gy of 2 Gy per day was planned for the target volume for each treatment plan. According to data, the mean dose for target volume decreased by 0.27% in the IMRT plans compared to the 3DCRT, while the average dose in creased by 0.61%. In IMRT plans, the maximum dose in healthy brain tissue decreased by 0.09% and the average dose decreased by 1.6%. The IMRT planning greduced the maximum doses in the brainstem, chiasma and right optic nevre by 0.17%, 2.7% and 3.4%, respectively. Although 3DCRT received lower doses than IMRT in the left eye, left lens and left optic nerve, these doses were on an acceptable level because they were low. In the treatment of Glioblastoma Multiforme, the IMRT technique showed beter results in the protection of critical organs.