AbstractObjective To compare the dosimetric effects of micro-multileaf collimator (MLC)(2 mm leaf width) and conventional MLC (10 mm leaf width) on inverse intensity-modulated radiotherapy (IMRT) in intracranial stereotactic radiosurgery (SRS). Methods In view of the fact that the micro-MLC has a small open field, 30 patients with intracranial tumor with a<10 cm diameter were enrolled in this study. Their inverse dynamic IMRT plans were established using conventional MLC (conventional group) and micro-MLC (micro group) with the same other conditions. The radiation doses to the target volume and the organs at risk (OAR) were compared between the two groups with t test. Results Compared with the conventional group, the micro group had a significantly better dose distribution in the target volume (P=0.019). However, there were no significant differences in D98, D95, D50, and D3 between the two groups (P=0.774,0.650,0.170,0.080). The micro group had a 58.7% lower mean homogeneity index and a 20.1% higher mean conformity index than the conventional group (P=0.000). The micro group had significantly lower radiation doses to OAR than the conventional group (P=0.044). The mean Dmean and Dmax of the brain stem in the micro group were 10.0% and 8.2%, respectively, lower than those in the conventional group (P=0.768,0.753). The mean Dmean and Dmax of the right eye and left eye in the micro group were 16.5%, 19.3%, 21.4%, and 13.4%, respectively, lower than those in the conventional group (P=0.572,0.775 and 0.734,0.630). The mean Dmax of the left lens, right lens, left optic nerve, right optic nerve, and optic chiasm in the micro group were 50.4%, 24.1%, 38.5%, 27.8%, and 5.7%, respectively, lower than those in the conventional group (P=0.172,0.467,0.521,0.740,0.899). The PRV100, PRV50, and PRV25 of the normal tissue in the micro group were no more than those in the conventional group (P=0.839,0.832,0.972). Conclusions In inverse IMRT in intracranial SRS, micro-MLC is better than conventional MLC because it can improve CI of the target volume and reduce the radiation doses to OAR.
Corresponding Authors:
Long Zhixiong,Email longzhixiong@hotmail.com
Cite this article:
Wan Huan,Tao Dan,Yang Zengjing et al. Dosimetric effects of multileaf collimator leaf width on inverse intensity-modulated radiotherapy in intracranial stereotactic radiosurgery[J]. Chinese Journal of Radiation Oncology, 2018, 27(1): 40-43.
Wan Huan,Tao Dan,Yang Zengjing et al. Dosimetric effects of multileaf collimator leaf width on inverse intensity-modulated radiotherapy in intracranial stereotactic radiosurgery[J]. Chinese Journal of Radiation Oncology, 2018, 27(1): 40-43.
2018, Vol. 27 
