Effects of CT-MRI co-localization on stereotactic radiosurgery treatment planning of pituitary neoplasms

Abstract

Objective This study was designed to evaluate the CT-MRI co-localization in Gamma Knife radiosurgery treatment of pituitary neoplasms.Methods There were 31 patients who were diagnosed as pituitary adenomas based on MRI and endocrine disorders without microsurgical history enlisted in the study.All these patients were treated with Leksell Perfexion Gamma Knife System (GKS) and localized with CT-MRI images.Two experienced treatment plan-designers were asked to perform treatment planning based on MRI only (control group) or CT-MRI co-localization images (experiment group).The plans' parameters such as coverage,selectivity and gradient index were compared using paired t-test to evaluate the planning style differences between two plan-designers.The treatment volume (TV),12 Gy volume,average dose of TV and the maximal dose of optical structure (OS) were compared between two groups.Results There was no difference of planning style between two plan-designers.The TVs were 4.3 cm3 in the control group and 3.4 cm3 in the experiment group (P ＜0.0001).The 12 Gy volumes were 8.0 cm3 in the control group and 7.3 cm3 in the experiment group (P =0.042).The multiple factors analysis indicated that the miss definition of osseous structure of optical canal was the only statistical significant factor.Conclusion CT-MRI co-localization was a useful way to define the boundary of pituitary neoplasms.It was more accurate and could minimize the target volume / 12 Gy volume. Key words: Pituitary adenoma; Co-localization ; Stereotactic radiosurgery ; Gamma knife radiosurgery