After obtaining the patients ' informed consent , biopsies were performed before treatment and at doses of 4 , 10 , and 20 Gy of radiotherapy , and the specimens were preserved in liquid nitrogen for further examination .
after obtaining the patients ' informed consent , biopsies were performed before treatment and at doses of 4 , 10 , and 20 gy of radiotherapy , and the specimens were preserved in liquid nitrogen for further examination .
O O O B-multi_cell O O O O O O O O O O O O O O O O O O O O O B-other_name O O O O O O O B-atom I-atom O O O O