Advanced Mode of Spatially Fractionated Radiotherapy: Lattice-Based Radiotherapy

Abstract

Lattice radiation therapy (LRT) is a three-dimensional advanced model of spatially fractionated radiation therapy that precisely regulates the peak-to-valley dose ratio by distributing high-dose vertices (1–2 cm) and low-dose valleys (3–5 cm apart) through a three-dimensional matrix (PVDR≥3:1), maximizing dose heterogeneity to destroy tumors and protect normal tissues. Its core technology relies on multiple leaf collimators or proton beams to generate high-dose peck zones with regular geometric arrangements, combined with reverse optimization algorithms and real-time image guidance (such as CBCT and MRgRT), to ensure dose conformity and safety. LRT has therapeutic advantages through multidimensional biological effects, including bystander effects on the activation of apoptosis in unirradiated areas, immune microenvironment remodelling (increased infiltration of CD8+ T cells), and vascular normalization, which enhances chemoradiotherapy sensitivity, thereby resulting in a high local control rate (symptom relief rate of 82.9%-98.7%) and low toxicity (acute grade 3 toxicity<5%) for giant tumors (>5 cm) and metastases (such as bone and liver metastases). Clinical protocols are divided into curative options (a single dose of 15–20 Gy combined with conventional fractionation) and palliative options (a single dose of 10–45 Gy), combined with immune checkpoint inhibitors or antiangiogenic drugs, which can significantly prolong survival (such as PFS reaching 8.5 months). The technological innovation progress has focused on AI dynamic optimization, the Bragg peak advantage of proton LRT, and real-time tracking of multimodal images. In the future, it is necessary to promote phase III multicenter validation, dose standardization, and biomarker research to expand its application boundaries in personalized precision radiotherapy.