# Ultrasound-Based Therapies in Primary Central Nervous System Tumors

## TL;DR

Ultrasound-based therapies like focused ultrasound and sonodynamic therapy may help treat brain tumors by improving drug delivery and targeting cancer cells.

## Contribution

The paper reviews how ultrasound-based therapies can enhance drug delivery and tumor cell destruction in CNS tumors.

## Key findings

- Focused ultrasound can temporarily open the blood–brain barrier to improve drug delivery.
- Sonodynamic therapy generates reactive oxygen species to selectively kill tumor cells.
- Combining ultrasound therapies with chemotherapy or immunotherapy may improve treatment outcomes.

## Abstract

Primary central nervous system tumors are difficult to treat due to their complex biology and the protective blood–brain barrier, which limits drug delivery. Ultrasound-based therapies are emerging as promising non-invasive strategies to overcome these challenges. Focused ultrasound can temporarily open the blood–brain barrier and enhance drug delivery, while sonodynamic therapy can selectively kill tumor cells through the generation of reactive oxygen species. These approaches may improve the effectiveness of existing treatments such as chemotherapy and immunotherapy. Although early results are encouraging, further research is needed to optimize treatment protocols and confirm long-term safety and efficacy.

Primary central nervous system (CNS) tumors remain a major challenge in neuro-oncology due to their cellular heterogeneity, infiltrative growth, and the protective blood–brain barrier (BBB), which limits the effectiveness of systemic therapies. Despite aggressive multimodal treatments, patient survival remains poor, highlighting the urgent need for new therapeutic strategies. Ultrasound-based therapies, including focused ultrasound (FUS) and sonodynamic therapy (SDT), have emerged as promising approaches. FUS can transiently open the BBB and induce localized mechanical and thermal effects, enhancing drug delivery, while SDT activates tumor-specific sensitizers to generate reactive oxygen species that trigger cancer cell death. Preclinical and early clinical studies suggest that combining these modalities with chemotherapy, immunotherapy, or radiotherapy may improve treatment outcomes. Emerging tools such as AI-guided monitoring, theranostic platforms, and ultrasound-responsive nanoparticles could further enable personalized interventions. However, challenges remain, including protocol variability, tumor heterogeneity, and limited long-term safety data. Careful optimization and clinical validation are needed before these strategies can be widely adopted in the management of CNS tumors.