Systems and methods for characterizing spatial distortion in 3d imaging systems

A method for characterizing spatial distortion of a medical imaging system, the method comprising:

• estimating a contour and dimensions of a desired target volume;
• determining a desired coordinate system;
• determining a volumetric arrangement and uniform spacing of a plurality of control points in a three-dimensional space, wherein the desired arrangement and spacing is matched to the contour, dimensions, and coordinate system such that the control points are interspersed within and throughout the entire target volume;
• providing a substantially rigid three-dimensional phantom that is matched to the determined volumetric arrangement and uniform spacing of the plurality of control points in the three-dimensional space and that is also configured to rigidly fix the control points in an interspersed manner throughout its substantially rigid structure;
• fixing the phantom with respect to a stereotactic frame such that the plurality of control points defines a corresponding plurality of first known spatial locations;
• imaging the phantom;
• determining second measured spatial locations based on the imaging;
• comparing at least a selected volumetric subset of the first known spatial locations with corresponding second measured spatial locations;
• and
• calculating indicia of any indicated volumetric spatial distortion between the first known spatial locations and the corresponding second measured spatial locations.

A system for characterizing spatial errors in a medical imaging system, the system comprising:

• a substantially rigid three-dimensional phantom having a plurality of control points, wherein the control points are interspersed uniformly within and throughout a three-dimensional volume and are substantially rigidly fixed with respect to each other;
• a fixture rigidly connectable to the phantom and connectable to a stereotactic frame of a medical imaging system such that the control points can be positioned to occupy first known spatial locations within an imaging space of the imaging system;
• and
• an analysis module in communication with the imaging system so as to obtain data indicative of second measured spatial locations of at least a volumetric subset of the plurality of control points as determined by the imaging system and wherein the analysis module compares the first known spatial locations with the corresponding second measured spatial locations and calculates an indicia of any determined variation between the first known spatial locations and the corresponding second measured spatial locations for at least the volumetric subset of the plurality of control points.

An apparatus for characterizing volumetric spatial distortion of a medical imaging system, the apparatus comprising:

• a substantially rigid volumetric phantom comprising:
• a three-dimensional volume;
• an outer perimeter generally enclosing the three-dimensional volume;
• a plurality of control points that are interspersed uniformly within the outer perimeter and throughout the three-dimensional volume and that are substantially rigidly fixed with respect to each other and with respect to the outer perimeter;
• a fixture configured to rigidly fix the phantom to a spatial reference point such that the control points occupy known spatial locations within an imaging space of the imaging system;
• and
• an analysis module configured to:
• communicate with the imaging system to obtain measured spatial locations of at least a volumetric subset of the plurality of control points as determined by the imaging system;
• compare the known spatial locations with the corresponding measured spatial locations as determined by the imaging system;
• and
• calculate any determined variation between the known spatial locations and the corresponding measured spatial locations for at least the volumetric subset of the plurality of control points.