Dosimetry analysis on IMRT, VMAT, and HT technique in hippocampal sparing whole-brain radiotherapy

Background: External radiation is frequently used to reduce brain metastases symptoms. Whole-brain palliative radiation technique is the standard treatment for cancer patient with brain metastases. The technique, however, caused deterioration of cognitive function due to post-radiation hippocampal inflammation. Hippocampal Sparing Whole Brain Radiotherapy (HS-WBRT) was used to lessen the side effect, however, the standard delivery technique has not been established. This study aimed to compare the dosimetric parameter between IMRT, VMAT, and HT technique on HS-WBRT. Methods: This explorative experimental study used brain metastases patient CT-plan data. Conformity Index, Homogeneity Index, Treatment Time, D98%, D2%, D50%, and Hippocampal D100% and DMax were assessed. Results: It was found that Homogeneity Index, Treatment Time, D98%, D2%, D50%, and Hippocampal D100%, were statistically different among three techniques, with HT giving the best results. There were no significant differences between IMRT and VMAT in other parameters, making both techniques feasible for sparing hippocampus with acceptable parameters. Conclusion: Further research is needed with larger samples to assess the best method among HS-WRBT technique to increase treatment efficacy.