Study of the feasibility and precision in dose calculation with the method of bulk density assignment / 中华放射肿瘤学杂志

ABSTRACT

Objective To study investigate the dose accuracy that can be achieved with the method of bulk density assignment.Methods Sixteen cases of nasopharyngeal cancer patients and nineteen cases of esophageal cancer patients who accept radiotherapy in our department were selected.The planning CT images with bulk density assignment to different classes of tissues were applied to calculate the dose distributions,and then the resulting dose volume histograms (DVH) of the tumor and organs of risk were compared with the original treatment plan.The paired t-test was taken for dose comparison between two plans.Results The DVH comparison based on the planning CT and the bulk density assignment CT showed good agreements.With nasopharyngeal cancer patients,differences between the two plans about target and normal tissue were less than 1％.With esophageal cancer patients,the dose differences were less than 2％.Conclusion Preliminary results confirm that the bulk density assignment method can be applied to calculate the dose distributions.