RESUMO
Objective: To evaluate the potential dose influence to organs at risk (OARs) and targets of adaptive radiotherapy (ART) for non-small cell lung cancer (NSCLC). Methods:Twice positional CT images of 12 patients with locally advanced NSCLC were captured during radio-(n=3) or radio-chemotherapy (n=9) for ART simulation. The twice positional scanningplan was fused using MIM software. The variation of irradiation doses for the lung, heart, and spinal cord was evaluated, and the prescription doses for the targets were escalated. Results:Adaptive radiation enabled dose reduction by an average of 3.53%for lung V20 and by 2.55%for V30. The mean dose for the lung decreased by 2.11 Gy. The dose was reduced by an average of 4.17%for heart V30 and by 3.37%for V40. Meanwhile, the maximum dose for the spinal cord was reduced by 3.52 Gy on average. Lung sparing with ART enabled an iso-mean lung dose escalation of the Planning gross tumor target volume dose, which improved by an average of 1.25 Gy. Conclusion:The adap-tation of radiotherapy for continuous tumor shrinkage during the treatment course for NSCLC reduces doses to OARs, enables signifi-cant dose escalation, and has the potential to increase local control.
