Abstract
Introduction: The objective is to demonstrate dosimetrically preserving scalp in whole-brain irradiation in the treatment of brain metastases and making dosimetry at 20 points determined on the rando phantom while comparing between Linac and Tomotherapy devices.
Materials and Methods: 10 randomized patients, who had previously undergone radiotherapy for whole-brain metastasis cancer, were determined prospectively. In Helical Tomotherapy (HT) and Linac devices, Intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) were planned to be 30 Gray(Gy) 10 Fractions for the whole brain region.
Results: The average target volume (PTV), Homogeneity Index (HI), conformity index (CI), and integral dose (ID) for IMRT and VMAT were 0.075, 0.77, 0.94, 0.97 and 29.67, 23.57, respectively. Mean median doses for scalp IMRT and VMAT were 19.71Gy and 18.01 Gy (p<0.005). Lenses and body doses were significant for IMRT and VMAT. The mean median plan doses for Rando phantom scalp were 19.43Gy and 19.55Gy in IMRT and VMAT, respectively. The mean median film doses for Rando phantom scalp were 17.03Gy and 20.64Gy in IMRT and VMAT, respectively (p<0.005).
Conclusion: By using both VMAT and Helical Tomotherapy techniques, it is possible to dry the lens and scalp without low PTV doses in whole-brain irradiation.

Key words: Brain metastasis, Scalp, Intensity-Modulated Radiotherapy, Volumetric Modulated Arc Therapy, Helical Tomotherapy