Dosimetric comparison between two brachytherapy applicators in cervical cancer treatment / 中华放射肿瘤学杂志

ABSTRACT

Objective To compare the dosimetric parameters between the use of Tandem and Ring (TR;Nucletron#090.617) or Tandem and Ovoid (TO;Nucletron#189.730) applicators during three-dimensional (3D) high-dose rate (HDR) brachytherapy (BT) for cervical cancer.Methods The records of 40 cervical cancer (ⅡB-ⅣA) patients treated with 3D-image-guided HDR-BT were reviewed.Of these 40 patients, 20 were treated with the TO applicator, and 20 with the TR applicator.The D100% and V150% of the clinical target volume (CTV) and the D2 cc of organs at risk (OAR)(the rectum, bladder, and small intestine) during 3D-HDR-BT using TO and TR were compared using the independent sample t-test.ResultsOverall metricsCTV volume66.04±13.86 cm3(TR) vs.65.67±15.08 cm3(TO)(P=0.052);CTV D1003.71±0.34 Gy (TR) vs.3.37±0.49 Gy (TO)(P=0.016);CTV V150%0.54±0.02(TR) vs.0.56±0.04(TO)(P=0.034);rectum D2 cc3.38±0.30 Gy (TR) vs.2.95±0.80 Gy (TO)P=0.037);bladder D2 cc4.33±0.39 Gy (TR) vs.2.93±1.27 Gy (TO)(P=0.00);and small ntestine D2 cc3.04±1.02 Gy (TR) vs.3.41±0.57 Gy (TO)(P=0.171).Conclusions TR has better CTV coverage than TO during 3D HDR brachytherapy for cervical cancer.In addition, D2 cc of the rectum and bladder were both igher with TR than with TO, though there is no significant dosimetric difference in the small intestine between the two applicators.Therefore, tumor location, extent of invasion, and vaginal conditions should be considered when selecting the suitable pplicator for the treatment of cervical cancer.