Comparative Dosimetric Analysis of Tandem-Ovoid and Tandem-Ring Brachytherapy Applicators in Cervical Cancer

Abstract

Brachytherapy plays a vital role in the treatment of locally advanced cervical cancer by delivering high radiation doses directly to the tumor while minimizing exposure to surrounding healthy tissues. This retrospective study compared the dosimetric performance of tandem–ovoid (T&O) and tandem–ring (T&R) intracavitary brachytherapy applicators in 60 cervical cancer patients treated at CMH Cancer Center, Dhaka. Patients were divided into two groups according to applicator type, with 30 patients in each arm. Dosimetric parameters including HR-CTV 90% coverage, rectal dose, and bladder dose were analyzed. The average HR-CTV 90% coverage was 106.91% for the tandem–ovoid applicator and 100.43% for the tandem–ring applicator. The average rectal dose was lower in the tandem–ring applicator (4.93 Gy) compared to the tandem–ovoid applicator (5.57 Gy). However, the bladder dose was slightly higher in the tandem–ring applicator (5.31 Gy) than in the tandem–ovoid applicator (5.20 Gy). The findings indicate that both applicators provide clinically acceptable dose distribution, although tandem–ovoid demonstrated comparatively better target coverage while tandem–ring showed improved rectal dose sparing. Applicator selection should therefore be individualized according to treatment priorities and patient anatomy.