Application of equivalent uniform dose optimization in intracavitary/interstitial brachytherapy for cervical cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective:To investigate the application of equivalent uniform dose (EUD) in the combination of intracavitary and interstitial brachytherapy (combined-BT) for cervical cancer.Methods:Twenty cervical cancer patients treated with combined-BT in Tianjin Medical University Cancer Institute and Hospital were recruited in this study. For each patient, treatment plans were optimized based on EUD and hybrid EUD (h-EUD). The results were statistically compared with predefined plans generated by Oncentra Brachy v4.3 using hybrid inverse planning optimization (HIPO). Furthermore, virtual uniform interstitial experiments were applied to evaluate the advantage of EUD.Results:All three plans showed consistent conformity index. Compared with the HIPO plans, the average D 2cm 3 of bladder, rectum and intestine in the EUD plans were decreased by 0.22 Gy, 0.23 Gy and 0.28 Gy, and those in the h-EUD plans were declined by 0.16 Gy, 0.22 Gy and 0.24 Gy, respectively. The average EUD of bladder, rectum and intestine in the EUD plans were decreased by 0.14 Gy, 0.20 Gy and 0.15 Gy, and those in the h-EUD plans were declined by 0.20 Gy, 0.13 Gy and 0.16 Gy, respectively (all P<0.05). The virtual interstitial experiment showed EUD could significantly improve the dose sparing for organs at risk (OARs). Conclusion:The application of EUD can significantly improve the dose sparing for normal tissues without compromising dose homogeneity and conformity during combined-BT for cervical cancer.