The impact of image-guided radiation therapy on treatment of cervical cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the effect of radical image-guided radiotherapy (IGRT) on the target dose in cervical cancer and investigate the appropriate application mode.Methods:Twenty patients with cervical cancer treated with helical tomotherapy (HT) in Seventh Medical Center of PLA General Hospital from 2012 to 2016 were selected. A megavoltage CT (MVCT) scan was performed before each treatment. The obtained MVCT images were used for dose parameter in the adaptive module of HT to obtain the actual dose (Plan 1) and the non-image-guided dose parameter was simulated (Plan 2). Each single dose distribution and the corresponding fused CT images were transferred to the software Mimvista 6.5 to obtain the total radiation dose parameter by dose superposition.Results:The motion of CTV, uterus and GTV in Plan 2 was significantly larger than that of Plan 1(all P<0.05), and the largest changes were seen in the ventrodorsal and uterine direction. The V 45Gy, V 50Gy, D 98% and D mean of CTV and uterus and V 50Gy of GTV in Plan 2 were significantly decreased compared with those in Plan 1(all P<0.05). The left-right motion of Plan 1 was negatively correlated with D 2% and D 98% of CTV and uterus (both P<0.05). The head-foot motion was negatively associated with V 45Gy and V 50Gy of GTV (both P<0.05). The ventrodorsal motion was negatively correlated with D 98% of uterus ( P<0.05). The left-right motion of Plan 2 was negatively correlated with D 2% of CTV and V 50Gy of uterus (both P<0.05). The head-foot motion was negatively associated with D 98% of CTV, and D 98%, D mean, V 45Gy and V 50Gy of uterus (all P<0.05). The ventrodorsal motion was negatively correlated with D 98% of CTV, D 98%, D mean, V 45Gy and V 50Gy of uterus, and D mean and V 45Gy of GTV (all P<0.05). Conclusions:In intensity-modulated radiotherapy for cervical cancer, the uterine body displacement is large and the low CTV area is mainly located in the uterine body. IGRT can significantly reduce the dosimetric deviation induced by organ movement.