Linac-based SBRT

Overview

Linac-based SBRT uses a conventional medical linear accelerator (linac) with IMRT/VMAT planning, cone-beam CT image guidance (IGRT), and custom immobilisation to deliver stereotactic body radiation therapy to extracranial tumours. It is the most widely available SBRT platform and is used for pancreatic cancer when CyberKnife or proton beam systems are not available. Motion management is typically achieved with 4D-CT simulation, respiratory gating, or abdominal compression.

Used by

• Linac-based IMRT-SBRT used for locally advanced pancreatic cancer in multiple prospective trials; a Stanford Phase II (n=20) with explicit duodenal constraints (≤5% duodenum ≥22.5 Gy) achieved 94% 1-year local control; the multi-institutional Herman et al. Phase II (n=49, 33 Gy / 5 fx) demonstrated 79% 1-year local control with only 2% acute and 6% late grade 3+ GI toxicity — the current reference standard. PMID:27826200

Notes

• Preferred delivery platform for the pancreatic SBRT reference regimen (33 Gy / 5 fractions, gemcitabine-concurrent, Herman et al.).
• PTV margins of 2–5 mm required to maintain duodenal dose constraints; larger margins (5 mm transverse / 1 cm craniocaudal) associated with higher toxicity and lower local control in the Danish series.
• Requires 4D-CT simulation and cone-beam CT IGRT for motion management (see related methods: four-dimensional-ct-simulation, cone-beam-ct-igrt).

Sources

This page was processed by entity-page-writer on 2026-05-15.