Characteristics of preplan‐based three‐dimensional individual template‐guided brachytherapy compared to freehand implantation

Abstract

Image‐guided adaptive intracavitary/interstitial brachytherapy (IC/IS IGABT) has exhibited superior dosimetry advantage and local control for locally advanced cervical cancer (LACC). Our group designed a type of cylindrical three‐dimensional (3D) printed vaginal template combining an intracavitary applicator with straight and oblique interstitial needles according to the preplan on computed tomography images. This work aimed to research the consistency of the preplan with the treatment plan at every fraction to verify the practical guiding significance of the preplan. We also investigated the difference between 3D‐printed template‐guided implantation compared with freehand implantation for LACC. Twenty‐six patients were treated with 3D‐printed individual templates (3D template group), and 20 patients were treated by using freehand insertion (freehand group). Patients in the 3D template group would take a preplan one week before treatment to design and print the individual template, while the freehand group did not. All patients accepted volumetric rotational intensity‐modulated radiotherapy at a dose of 49.4 Gy in 26 fractions and subsequent brachytherapy at a dose of 26 Gy in four fractions. All analyses were performed by utilizing SPSS 26. The insertion depth was decreased in fractions 1 and 4 compared with the preplan. None of the dose volume histogram parameters of fractions 1–3, nor the D2cc of bladder and bowel at fraction 4 were barely changed compared with the preplan. The D90 and D98 of the high‐risk clinical target volume in the 3D template group were statistically higher than those in the freehand group (p < 0.01). The D2cc of the rectum, bladder, bowel, and sigmoid in the 3D template group were all lower than those in the freehand group (p < 0.01). The preplan in this research is consistent with treatment plans, which is important to ensure the feasibility of applying a 3D‐printed template in brachytherapy. The 3D‐printed individual guidance template was an effective method in brachytherapy for locally advanced cervical cancer.

Clinical implementation of three-dimensional standardized template-guided brachytherapy for patients with locally advanced cervical cancer

“…The D 90 of HR-CTV and IR-CTV in the ST group were increased to 3.58% (p = 0.031) and 10.22% (p = 0.002) compared with the FH group, while D 2cc of the bladder and sigmoid were lower than those in the FH group (p < 0.05). These dosimetric results of 3D standardized template were similar to previous reports, in which individualized templates were mainly used [6][7][8][16][17][18][19][20]. Furthermore, the mean value of CI in this study was significantly improved by 23.21% in the ST group compared with the FH group (p < 0.001).…”

“…Recently, several studies [ 7 , 16 , 17 ] have reported the use of 3D-printed templates for IC/ISBT, proposing patient-specific applicators, novel applicator designs, and optimized source trajectories. These prior published experiences tend to focus on using an individualized template for each patient with the lack of widespread clinical use of IC/ISBT technology.…”

The Montreal split ring applicator: Towards highly adaptive gynecological brachytherapy using 3D-printed biocompatible patient-specific interstitial caps

“…Lindegaard et al used a Vienna-style 3D-printed intra-vaginal template (without a ring channel) to combine a tandem with both straight and oblique needles [30]. Several authors reported using 3D-printing to produce intra-vaginal cylindrical templates for curved IS needles with or without the use of a central channel to accommodate a metallic fixation rod or an intra-uterine tandem [31][32][33][34][35][36]. Logar et al modified a T&R IC applicator with a 3D-printed add-on, resulting in a Vienna-style IC/IS applicator with straight and oblique IS needles [37].…”