Brachytherapy-based multimodality cancer treatment: a concept and design perspective on devices to address the challenges of localized radiation therapy.

PURPOSE: To present a family of novel brachytherapy-based device concepts that address the geometric, dosimetric, and integrative limitations of current localized radiation therapy, aiming to improve local tumor control while reducing collateral exposure. This is a concept and design paper, not a clinical or dosimetric validation study.

METHODS

Multiple device designs were developed over more than a decade, focused on two prototypical clinical settings: intraluminal applicators for the esophagus and intracavitary applicators for the post-resection glioblastoma cavity. Designs include hollow rectangular ribbon (HRR) catheters that encase fluid, gel, or wire isotope sources; modified stents with anti-slippage geometry, dynamic flares, and reservoirs; and a multifunctional cavity device combining brachytherapy with continuous hyperthermia and pressure-modulated diffusional drug, immunotherapy, and nanoparticle delivery. Bench prototypes were constructed and evaluated.

RESULTS

Bench observations demonstrated manipulation of a thermal gradient by modulating the warm source, and an approximately 15-fold increase in dislodgement force for a representative anti-slippage geometry. The designs are further intended to flatten the near-surface dose gradient by expanding the effective source distribution and to integrate drainage, infusion, and pressure modulation in a single device; these dosimetric and integrative benefits are design expectations not yet experimentally tested.

CONCLUSION

These concepts may improve local control where recurrence concentrates near the resection or stented surface, as in post-resection glioblastoma and obstructive luminal malignancies. The integration of continuous hyperthermia, local diffusion of chemotherapeutic, immunotherapeutic, and protective agents, and pressure-modulated nanoparticle delivery is particularly attractive. The concepts are intended to stimulate further bench, computational, animal, and clinical investigation.