To study the dosimetric peculiarity of 3D intracavitary brachytherapy in the application of endometrial carcinoma comparing with traditional 2D plans.

39 3D brachytherapy treatment plans of 11 patients with endometrial carcinoma were retrospectively analyzed with re-planning 2D treatment plan, the dose volume histogram (DVH) parameters such as the target dose volume parameters V₁₅₀ and D₉₀, the 2-cc doses to organs such as bladder, small intestine, rectum and sigmoid and the total reference air kerma TRAK were analyzed. The differences between the two groups are compared by paired samples T test.

For target with V<60 cm³, there is no statistically significant difference between 2D and 3D plans, the D₉₀ is (551.17±90.33) cGy and (574.15±117.18) cGy, respectively (P=0.390). As the increase of target volume, the D₉₀ came to be significantly different (P=0.001), high dose region V₁₅₀ for 3D and 2D plans is (51.05±21.61) cm³ and (53.41±11.71) cm^3, respectively (P=0.482). With the target volume larger than 60 cm³, compare to 2D plans, the 3D plan can increase the target coverage as well as OAR dose except for small intestine (P=0.128). In addition, with different plan mode, the BMI did not affect the crisis organ dose such as rectum, small intestine, bladder and sigmoid, the P value is 0.239, 0.198, 0.744 and 0.834, respectively.

For endometrial carcinoma, compared with traditional two-dimensional plans, the 3D brachytherapy treatment plans can significantly improve the target coverage and avoiding overdose of organs, clinical curative effect and side effect still needs further observation.

Endometrial carcinoma/three-dimensional intracavitary brachytherapy; Dose volume histogram; Body mass index