Dosimetric Study and Neurocognitive Function of Hippocampal-Sparing Whole-Brain Radiotherapy

Objective: To investigate the feasibility of hippocampal-sparing whole-brain radiotherapy and reduction in neurocognitive function impairment after radiotherapy. Methods: Forty-three patients with brain metastases were selected. Whole-brain radiotherapy was performed in 22 patients, with 3-dimensional conformal radiotherapy in parallel opposed fields. Twenty-one patients had significant difference. Planning parameter values and neurocognitive function scores in 2 groups were statistically analyzed. Results: Homogeneity index in the 3-dimensional conformal radiotherapy group and tomotherapy group was 0.12 + 0.02 and 0.36 + 0.03, respectively, with a significant difference (P < .05). The homogeneity of target doses was better in the tomotherapy group than in the 3-dimensional conformal radiotherapy group. There was a statistical significance in Dmean and Dmax between the 2 groups (P < .05). The dose in hippocampal was less in the tomotherapy group than in the other group. Dmean and Dmax of the left hippocampus declined to 20.14% and 35.39% of prescription dose, respectively, and Dmean and Dmax of the right hippocampus declined to 19.92% and 35.14% of prescription dose, respectively. Neurocognitive function score between the 2 groups before treatment and 1 month after treatment had no significant difference (P > .05), while there was a significant difference in 3 and 6 months after treatment (P < .05). Neurocognitive function score was higher in the tomotherapy group than in the other group. No level III or above adverse reactions were observed. Conclusions: Hippocampal-sparing whole-brain radiotherapy in brain metastases treatment is feasible. Homogeneity index value is higher in the tomotherapy group than in the 3-dimensional conformal radiotherapy group. All V95% in the 2 groups meet the requirements. Hippocampal sparing could avoid neurocognitive function impairment to some extent.