A Novel Stereotactic Device for Spinal Irradiation in Rats Designed for a Linear Accelerator

Abstract

Objective: Our purpose was to report the design and positioning accuracy testing of a stereotactic device designed for a linear accelerator to perform spinal radiosurgery in rats. Methods: To define the spatial and repositioning accuracy of the device, we measured the 3-dimensional (3D) translation of a paraspinal fiducial mark implanted by microsurgery in 5 Wistar rats during a sequence of setups and treatment simulations, thus obtaining final 3D translation vectors and maximum displacements. Results: For spatial accuracy, the differential coordinate translations were 0.8 ± 0.3, 0.6 ± 0.2 and 0.5 ± 0.1 mm in the x-, y- and z-directions, respectively. The median magnitude of the 3D vector was 1.3 mm (σ = 0.2 mm), with a maximum error of 2.2 mm. The differential coordinate translation for the repositioning accuracy showed values of 1.4 ± 0.3, 1.3 ± 0.3 and 0.8 ± 0.1 mm for the x-, y- and z-coordinates, resulting in a 3D displacement vector of 2.2 mm (σ = 0.2 mm) and a maximum displacement error of 3.6 mm. Conclusions: Using a linear accelerator, our novel stereotactic device provides accurate immobilization and repositioning of paraspinal structures under experimental conditions in rats.