MRI-Conditional Eccentric-Tube Injection Needle: Design, Fabrication, and Animal Trial

Effective radiation therapy aims to maximize the radiation dose delivered to the tumor, while minimizing damage to the surrounding healthy tissues, which can be a challenging task when the tissue–tumor space is small. To eliminate the damage to healthy tissue, it is now possible to inject biocompatible hydrogels between cancerous targets and surrounding tissues to create a spacer pocket. Conventional methods have limitations in poor target visualization and device tracking. In this article, we leverage our MR-tracking technique to develop a novel injection needle for hydrogel spacer deployment. Herein, we present the working principle and fabrication method, followed by benchtop validation in an agar phantom, and magnetic resonance imaging (MRI)-guided validation in tissue-mimic prostate phantom and sexually mature female swine. Animal trials indicated that the spacer pockets in the rectovaginal septum can be accurately visualized on T2-weighted MRI. The experimental results showed that the vaginal–rectal spacing was successfully increased by 12
$ \pm {\bm{\ }}$
2 mm anterior–posterior.