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

Area of Science:

• Medical physics
• Biomedical engineering
• Radiology

Background:

• Radiation therapy requires precise targeting to spare healthy tissues, especially in small tumor-tissue spaces.
• Injectable hydrogel spacers can create separation but face challenges in visualization and accurate placement.
• Existing methods lack sufficient target visualization and device tracking for effective hydrogel deployment.

Purpose of the Study:

• To develop and validate a novel MRI-tracking injection needle for precise hydrogel spacer deployment.
• To overcome limitations in target visualization and device tracking associated with conventional methods.
• To enhance the safety and efficacy of radiation therapy by improving tissue sparing.

Main Methods:

• Development of a novel injection needle integrated with an MR-tracking technique.
• Fabrication of the specialized injection needle.
• Benchtop validation using an agar phantom.
• MRI-guided validation in a prostate phantom and in swine models.
• Utilizing T2-weighted MRI for visualization of spacer pockets.

Main Results:

• The novel needle enabled accurate visualization of hydrogel spacer pockets on T2-weighted MRI.
• Successful creation of spacer pockets in the rectovaginal septum of swine.
• Demonstrated an average increase of 12 ± 2 mm in anterior-posterior vaginal-rectal spacing.
• Validated the feasibility and accuracy of the MR-tracking technique in a relevant anatomical location.

Conclusions:

• The MR-tracking injection needle is a viable tool for precise hydrogel spacer deployment.
• This technique significantly improves visualization and accuracy in creating tissue separation for radiation therapy.
• The findings support the potential of this method to enhance radiation therapy outcomes by improving safety and efficacy.