Purpose: Curative
radiation therapy is an established treatment option for non-surgical patients
with early-stage endometrial carcinoma. Dosimetric analyses were performed
using a single tandem, double tandem, Heyman capsules, and an inflatable
intrauterine balloon to assess the dose homogeneity and conformality in the
definitive treatment of inoperable endometrial cancer. Methods and Materials:
Patients’ informed-consent was obtained. Dosimetric analyses were performed
using four different after-loading applicators to assess the dose homogeneity
and conformality of isodose to the three-dimensional (3-D) shape of the target
volume (uterus) based on CT data in four patients (n = 4). The single tandem
and double tandems were standard Fletcher-type (Nucletron Corporation,
Columbia, MD). Heyman capsules were the disposable after-loading type
(Radiation Products Design, Inc., Albertville, MN). The inflatable balloon with
a central bi-lumen catheter was the Mammo Site Radiation Therapy System
(Proxima Therapeutics, Alpharetta, GA) that is currently used for local breast
brachytherapy. Treatment planning and dosimetric analyses for all four
techniques were done with HDR PLATO Brachytherapy (v14.2.3) Software (Nucletron
Corporation). Results: The average dose gradient within the target (uterine
wall) is highest with the tandem methods, followed by Heyman capsules. The
intrauterine balloon method showed the least dose gradient across the uterine
wall. The corresponding average homogeneity indices were 3.81, 3.83, 2.97, 2.50
for single tandem, double tandem, Heyman capsules, and intrauterine balloon
respectively. Conclusions: The intra-uterine inflatable balloon appears to have
the best overall dosimetric advantages for the treatment of the uterine wall.
Furthermore, the potential ease of use, shorter time of applicator placement,
and better patient comfort warrant further investigation and subsequent
clinical implementation.