# ZAP-X Stereotactic Radiosurgery for Arteriovenous Malformations: Initial Experience of Three Patients

## TL;DR

This paper reports on the initial use of a new radiosurgery system, ZAP-X, to treat brain arteriovenous malformations in three patients, showing promising safety and precision.

## Contribution

The study presents the first clinical experience using the ZAP-X system for AVM treatment, highlighting its technical advantages and early outcomes.

## Key findings

- Three patients treated with ZAP-X SRS showed no significant acute side effects and stable or reduced AVM volume on follow-up imaging.
- Plan quality metrics met established standards, with conformity indexes between 1.176 and 1.257.
- The ZAP-X system enabled precise dose delivery for complex AVMs without radiation-induced complications.

## Abstract

Arteriovenous malformations (AVMs) are complex cerebrovascular anomalies that carry a significant risk of hemorrhage, particularly in younger patients. Stereotactic radiosurgery (SRS) is a non-invasive treatment option, often employed for AVMs that are deep-seated or surgically inaccessible. The ZAP-X system (ZAP Surgical Systems, Inc., San Carlos, CA), a novel gyroscopic, self-shielded SRS platform, offers advanced beam geometry and real-time imaging, potentially enhancing treatment accuracy while minimizing radiation exposure to surrounding tissues.

This case series presents three patients with AVMs treated with ZAP-X SRS between March 2024 and September 2024 at a single institution. Target volume ranged from 4.84 to 11.56 cm3. Prescription dose ranged from 27 to 37.5 Gy in three or five fractions. Dosimetric parameters, treatment quality metrics, and early clinical and radiographic outcomes were assessed. All three patients tolerated treatment without significant acute side effects. Early follow-up imaging (4-12 months) demonstrated either reduction or stability in AVM volume, with resolution of presenting symptoms in two patients. Plan quality metrics met established standards, with conformity and gradient indexes ranging from 1.176 to 1.257 and 2.68 to 3.139, respectively. No radiation-induced complications were observed.

This initial clinical experience supports the feasibility, safety, and precision of ZAP-X SRS for treating brain AVMs. The system’s technical advancements, including multiangle gyroscopic beam delivery and real-time imaging, enabled precise dose delivery even in complex or high-grade lesions. These findings highlight the potential of ZAP-X as a frontline or adjunctive therapy for AVMs. Further prospective studies are needed to assess long-term obliteration rates and functional outcomes.