Effect of respiratory movement on the dose distribution in the TOMO therapy target area / 中国辐射卫生

ABSTRACT

Objective To explore the effect of respiratory movement on the dose distribution in the TOMO therapy target area. Methods The motion phantom was used to simulate human respiratory movement. The SNC patient analysis software was used to compare the films of the study group with those of the control group, and the effect of respiratory movement on the dose distribution in the TOMO target area was evaluated by the “pass rate” index. Results Visual observation showed that the distribution of film gray in the head-foot direction (i.e., direction of movement) was significantly different with or without respiratory movement. Film analysis showed that the maximum deviation between the width of the target wrapping curve and the treatment plan value was about 2.4 mm at no respiratory movement and about 27.2 mm at respiratory movement; the penumbra width of the target area was 31 mm (head direction) and 28.5 mm (foot direction) at no respiratory movement and 39.7 mm (head direction) and 37 mm (foot direction) at respiratory movement; the “pass rate” of target dose distribution was only 12.3%. Conclusion Respiratory movement has a great impact on the dose distribution in the TOMO target area in the direction of movement. When making clinical treatment plan, the impact of respiratory movement on the dose distribution in the TOMO target area can not be ignored.