Related Experiment Video
Updated: Jan 13, 2026
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
Published on: June 7, 2015
Tumor geometry adjusted lattice structures for animal spatially fractionated SBRT
Sergejs Unterkirhers1, Jürgen Besserer1, Carla Rohrer Bley2
1Clinic for Radiation Oncology & Medical Oncology, Small Animal Department, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland; Department of Physics, University of Zurich, Zurich, Switzerland; Radiotherapy Hirslanden, Rain 32, Aarau, Switzerland.
Purpose:
Spatially fractionated lattice radiotherapy (LRT) intensifies dose inside bulky tumors by embedding multiple high‑dose "vertices", but fixed‑template lattices cannot fully cover irregular volumes. We introduce an automated planning method that combines principal‑component analysis (PCA) for lattice orientation with adaptive vertex sizing to conform the lattice to each tumor's geometry. The technique is demonstrated in a companion‑animal stereotactic body radiotherapy (SBRT) case.
Methods:
A scripted module within a commercial treatment‑planning system computed the gross tumor volume's principal axes, aligned a three‑dimensional grid to those axes, and iteratively placed spherical high‑dose vertices (nominal radius 5 mm) at alternate grid nodes. Vertex diameters were automatically reduced (floor 70 % of nominal) near the tumor edge to maintain a 5 mm internal margin and a 20 mm (center‑to‑center) peak‑to‑peak spacing. The script generated matching low‑dose "void" structures, and produced a simultaneous‑integrated‑boost plan (66.7 Gy to vertices, 20 Gy to the periphery in five fractions).
Results:
In a 643 cm3 canine sarcoma (PTV = 1011 cm3) the algorithm created 12.8 cm3 of boost vertices (≈ 2 % of GTV) in < 5 min without manual intervention. The plan delivered 71.5 Gy mean (76.4 Gy max) to vertices and 22.2 Gy mean to voids, satisfied all organ‑at‑risk constraints, and preserved steep dose fall‑off.
Conclusion:
Geometry‑aligned, adaptively sized lattices can be generated rapidly and safely for complex tumors, extending lattice SBRT to veterinary patients and providing a framework for future human applications.
