Clinical application of BOLD-FMRI in guiding protection of the motor cortex during postoperative radiotherapy for brain astrocytoma

Objective: To investigate the clinical value of blood oxygen level-dependent functional magnetic resonance imaging (BOLD-FMRI) in guiding the dose reduction and functional protection of the motor cortex during postoperative radiotherapy for brain astrocytoma. Methods: This study included 27 brain astrocytoma patients with tumors near the motor cortex, who underwent routine MRI and BOLD-FMRI before postoperative radiotherapy. The location and scope of the motor cortex, which were acquired based on BOLD-FMRI results, were marked on positioning CT images, so that the motor cortex would be dealt with as organs at risk. The dose to the motor cortex was reduced as much as possible while ensuring the therapeutic dose to the target area. Finally, the radiotherapy plan that would reduce the mean received dose of the motor cortex was formulated and compared with the routine plan that could not reduce the received dose. Results: With the protective radiotherapy plan, the mean received dose of the motor cortex decreased 0.76%-59.20% (mean 30.78%) on the affected side and 23.33%-68.30% (mean 48.07%) on the unaffected side; the coefficients of variation were 71.41% on the affected side and 36.71% on the unaffected side. Conclusions: BOLD-FMRI can help to reduce the received dose of the motor cortex while ensuring the therapeutic dose to the target area when formulating the postoperative radiotherapy plan for brain astrocytoma, thus protecting the motor function and improving patients; quality of life. (authors)