Application of diffusion tensor imaging in tracking visual pathway fiber bundles in postoperative intensity-modulated radiotherapy for cerebral gliomas / 中华放射肿瘤学杂志

ABSTRACT

Objective To analyze the feasibility of incorporation of tracking visual pathway fiber bundles by diffusion tensor imaging ( DTI) in computed tomography ( CT) simulation to develop a protective radiotherapy regimen for cerebral gliomas.Methods A total of 31 patients with cerebral gliomas who were admitted to our hospital from 2013 to 2015 and planed to receive postoperative radiotherapy were enrolled as subjects.All patients underwent CT simulation, conventional or contrast-enhanced magnetic resonance imaging, and DTI.The obtained DTI images of visual pathway fiber bundles were fused with 3DT1 anatomical scans and then imported into the treatment planning system.A protective treatment plan ( setting the entire visual pathway fiber bundles as organs at risk (OARs)) and a conventional treatment plan were made for intensity-modulated radiotherapy ( IMRT) .Comparison of treatment outcomes was made by paired t test.Results There were no significant differences in the conformity index and heterogeneity index of the planning target volume between the two treatment plans ( P=0.875,0.597), both of which had sufficient radiation doses to the target volume and conventional OARs protected.For the patients undergoing the protective treatment plan, the Dmax and Dmean values were reduced to 9.01%and 9.05%, respectively, in the ipsilateral optic tract and to 17.96%and 15.52%, respectively, in the contralateral optic tract;the Dmax and Dmean values were reduced to 5.37%and 5.48%(P=0.000), respectively, in the ipsilateral optic radiation tract and to 12.89%and 11.21%( P=0.000) , respectively, in the contralateral optic radiation tract.Conclusions The protective treatment plan based on CT simulation combined with the display of visual pathway fiber bundles by DTI can reduce the radiation dose to the entire visual pathway fiber bundles, which keeps the risk of visual dysfunction after radiotherapy as low as possible.