Dosimetric impacts of Utrecht applicator on three-dimensional brachytherapy for advanced cervical carcinoma

Objective To investigate the effect of Utrecht applicator on dosimetrics of targets and OARs in brachytherapy for advanced cervical cancer. Methods Data of patients with locally advanced cervical cancer who received brachytherapy with Utrecht Source Applicator from 2017 to 2018 in the Department of Radiotherapy, Cangzhou Hospital of Integrated Traditional Chinese and Western Medicine, Hebei province, were collected. The original plan was intracavitary /interstitial brachytherapy (IC/IS-BT). With the original contour and prescription dose unchanged, the implantation was removed and new intracavitary brachytherapy (IC) plan was designed. The dosimetric parameters of IC/IS plan and IC plan were compared and analyzed, and the effect of IS implantation on dose was evaluated. Results The D90 of HR-CTV was (88.68±1.84) Gy in IC/IS group and (85.54±0.54) Gy in IC group, with significant difference(t=6.200, P 0.05). Conclusions For the brachytherapy of locally advanced cervical cancer, the use of Utrecht Source Applicator can satisfy the prescription dose coverage. Adding IS insertion needle can improve the optimization space of the plan. Without exceeding the dose limit of OAR, the radiation dose to HR-CTV can be significantly increased, and the uniformity of dose distribution can be improved as well. Key words: Cervical cancer; Brachytherapy; Utrecht applicator; Dosimetry