Rectal and bladder dose prediction in volumetric modulated arc therapy for cervical cancer based on dose-volume histogram

Abstract

To predict rectal and bladder radiation doses during volumetric modulated arc therapy (VMAT) for cervical cancer, a relevant model was established to guide clinical practice. Forty-four cases of cervical cancer treated using VMAT radiotherapy were retrospectively analyzed. The positional relationships of the anatomical spaces between the cervical cancer target volume and the organs at risk (bladder and rectum) were evaluated. Volume and spatial location characteristics of the target volume for the bladder and rectum were inserted as input data in a dose-volume histogram and Python toolkit for statistical analysis. The output data were the bladder and rectal V40 and D33. A mathematical model was developed to predict the bladder and rectal doses. When the actual and predicted values were compared, they were quite similar for both the bladder and rectal doses. The relative error ranges of rectal V40 and D33 were between 1.40% and 6.89%, and between 2.12% and 6.81%, respectively. Likewise, the relative error ranges of bladder V40 and D33 were between 2.47% and 6.67%, and between 0.38% and 4.28%, respectively. There were no significant differences between the actual and predicted values (p>0.05). This model can effectively predict the bladder and rectal doses needed during intensity-modulated radiotherapy for cervical cancer and could serve as a guide for radiotherapy clinical practice.

Keywords

• cervical cancer
• volumetric modulated arc therapy (vmat)
• bladder dose
• rectum dose
• model dose prediction