DEV Community: willan-med

ZAP-X Stereotactic Radiosurgery: The Initial Experience Involving 200 Patients

willan-med — Wed, 18 Mar 2026 02:25:24 +0000

Abstract
The ZAP-X (ZAP Surgical Systems, Inc., San Carlos, CA) is the newest dedicated cranial stereotactic radiosurgery (SRS) platform. A prospective study was conducted between October 2023 and January 2025 involving 200 patients with 374 intracranial targets treated using ZAP-X. The study aimed to assess the feasibility of the ZAP-X workflow, as well as its safety, clinical and dosimetric performance, and patient satisfaction. The study cohort included various central nervous system pathologies, including 106 brain metastases (BM), 42 meningiomas (MA), 18 trigeminal neuralgias (TN), 11 acoustic neuromas (AN), nine recurrent glioblastomas (RGBM), seven pituitary adenomas (PA), three spinal tumors (ST), three arteriovenous malformations (AVM), and one cavernous hemangioma of the pons (HM).

The average number of patients treated per month was 13 ± 2, and the average number of treatments per month was 35 ± 9. The maximum number of patients treated in a day was five. The average gamma passing rate was 98.5 ± 1.7% (91.2 - 100%) at a 10% low-dose threshold, 2% dose difference, and 1 mm distance-to-agreement. The average conformity index (CI), Paddick conformity index (PCI), gradient index (GI), homogeneity Index (HI), and gradient measure across all patients were 1.3 ± 0.3, 0.77 ± 0.11, 3.3 ± 0.8, 1.5 ± 0.3, and 0.38 ± 0.16 cm, respectively. The largest tumor volume treated was 29.29 cm3, and the highest number of targets treated in a single course was 10. Average treatment time was 50 ± 20 minutes, with setup time being the most significant predictor (adjusted r² = 0.972). The Efficast head and shoulder mask significantly improved patient comfort and reduced alignment errors compared to head-only masks. Patient satisfaction was high across all measured domains, with average scores ranging from 4.7 to 5.0 on a 5-point scale. The most common treatment side effects were fatigue and headache.

This initial experience represents the largest single institution series to date and supports the ZAP-X as a promising alternative to conventional SRS platforms such as Gamma Knife (GK) and CyberKnife (CK). Continued research and multi-institutional studies are warranted to further validate these findings and assess long-term outcomes.

Keywords: gyroscopic, radiosurgery, srs, stereotactic radiosurgery, zap-x

A Study of Feasibility for Reusing Thermoplastic Masks – Toward a Green Environment

willan-med — Tue, 17 Mar 2026 09:38:50 +0000

PMCID: PMC12893356 PMID: 41684495
Abstract
Aim:
This study evaluated the feasibility of reusing thermoplastic masks in radiation oncology to reduce environmental waste and financial costs.

Materials and Methods:
The study conducted from July 2024 to December 2024 involved 70 thermoplastic masks across three types: 3-clamp brain masks, 5-clamp head-and-neck masks, and 4-clamp chest/abdomen/pelvis masks. Measurements of fresh masks were compared to those after molding and re-flattening post-treatment. Dimensions were recorded in superior–inferior (SI) and lateral directions at specific anatomical levels.

Results:
The 3-clamp brain thermoplastic cast expanded 46% ± 7% in SI directions postmolding. Width increased by 63% ± 16% (chin) and 75% ± 10% (forehead). Re-flattened casts showed 25% ± 4% SI reduction and 19% ± 8% (chin) and 26% ± 5% (forehead) contraction in width. The 5-clamp head-and-neck thermoplastic cast expanded 16% ± 3% SI postmolding, with width expansion of 54% ± 15% (chest), 62% ± 10% (forehead), and 66% ± 5% (chin). Re-flattened casts showed 6% ± 3% SI expansion and 26% ± 5.5%, 40% ± 16%, and 37% ± 17% width enlargement at chest, chin, and forehead levels, respectively. The 4-clamp chest/abdomen/pelvis thermoplastic casts expanded 3% ± 5% (SI) in 26 casts and contracted by 7.5% ± 2.5% in 2 casts postmolding.

Conclusion:
Thermoplastic masks demonstrated acceptable dimensional changes while reusing, with consistent structural integrity and minimal compromise in functionality. Single reuse could significantly reduce costs and waste, particularly in resource-limited settings, making this practice a viable option for sustainable health care.

Keywords: Biomedical waste, cancer patients, reusage, thermoplastic

For the full content, please visit: https://pmc.ncbi.nlm.nih.gov/articles/PMC12893356/

The investigation of opening modes of head and neck thermoplastic mask for radiotherapy based on finite element analysis

willan-med — Tue, 17 Mar 2026 09:30:18 +0000

PMCID: PMC12038929 PMID: 40301880
Abstract
Radiotherapy is a crucial treatment modality for head and neck tumors. Precise patient positioning is vital for ensuring the reproducibility and accuracy of the treatment. Clinically, thermoplastic head and neck masks are used for positioning, and patients often require openings in these masks. However, the relationship between opening locations and the fixation effectiveness of the masks has not been thoroughly studied. This study reconstructs a patient’s imaging data to create finite element models with 10 different opening patterns. By assigning various thicknesses and material properties to the fixation masks, we analyzed the displacement distribution of different opening models under diverse loading conditions. The results indicate that the opening location significantly impacts fixation effectiveness under different loading conditions. In particular, the opening in the forehead area has the most significant impact on the fixation effect of the mask near the region of interest (ROI). Therefore, in clinical practice, the design of openings in the forehead area should be carefully considered. This study provides valuable insights into the fixation effectiveness of thermoplastic masks and serves as a reference for future personalized positioning treatments.

Keywords: Radiotherapy, Head and neck tumors, Head and neck thermoplastic mask, Fixation effectiveness, Finite element analysis

For the full content, please visit: https://pmc.ncbi.nlm.nih.gov/articles/PMC12038929/