Dosimetry and plan parameters study of three-dimensional-printed template-based intra-cavitary/interstitial interpolation technology using computed tomography-guided high-dose-rate brachytherapy in locally advanced cervical cancer

Baoxi Liu; Yaqin Wu; Li Sun; Chang Guo; Qi Wang; Zhongde Mu

doi:10.5114/jcb.2023.132695

Dosimetry and plan parameters study of three-dimensional-printed template-based intra-cavitary/interstitial interpolation technology using computed tomography-guided high-dose-rate brachytherapy in locally advanced cervical cancer

J Contemp Brachytherapy. 2023 Oct;15(5):325-333. doi: 10.5114/jcb.2023.132695. Epub 2023 Oct 31.

Authors

Baoxi Liu¹, Yaqin Wu¹, Li Sun¹, Chang Guo¹, Qi Wang¹, Zhongde Mu¹

Affiliation

¹ Jiangsu Cancer Hospital, Jiangsu Institute of Cancer Research, The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.

Abstract

Purpose: To explore differences in dosimetry and planning parameters between intra-cavitary/interstitial interpolation (IC + ISBT) three-dimensional (3D)-printed template-based (3D-printed) and simple intra-cavity (ICBT) radiation techniques using a fixed Rotterdam three-tube applicator (TT) for computed tomography-guided high-dose-rate brachytherapy in locally advanced cervical cancer.

Material and methods: This retrospective study included 100 patients (n = 50 each in 3D-printed and Rotterdam three-tube applicator treatment groups) with FIGO stages IIB-IVB cervical cancer from May 2019 to May 2022. Using high-risk clinical target volume, 377 of 400 plans categorized at intervals of 10 cm³ into 20-30, 30-40, 40-50, 50-60, 60-70, and 70-80 cm³; 23 plans with < 20 and > 80 cm³ volume were excluded. Dosimetry parameters (D₉₀ and D₉₈ of high-risk clinical target volume, and D_2cc of organs at risk, including bladder, rectum, sigmoid, and bowel) and planning parameters (homogeneity index [HI], conformation number [CN], and organ at risk sparing factor) were compared between the two groups separately for six high-risk clinical target volume plan categories.

Results: For the 3D-printing group, target coverage, organs at risk protection, and plan conformity and uniformity were better than those for the Rotterdam three-tube group. Particularly, in high-risk clinical target volume plans between 50-60 cm³, the mean D₉₀ and D₉₈ of high-risk clinical target volume were approximately 0.35 and 0.3 Gy higher, while the average D_2cc of the bladder, rectum, sigmoid, and bowel were approximately 1.3, 0.9, 0.9, and 0.8 Gy significantly lower than those of the Rotterdam three-tube group, respectively (p < 0.05). The above-mentioned planning parameters differed significantly between the groups (p < 0.05).

Conclusions: For the 3D-printing group, IC/ISBT reduced the dose for organs at risk while ensuring target coverage and conformation. This was especially noticeable for plans with high-risk clinical target volume of 50-60 cm³.

Keywords: 3D-printed (3D) template-based applicator; dosimetry and planning parameters; intra-cavitary/interstitial brachytherapy; locally advanced cervical cancer.