PMT-based pattern matching calibration for gamma camera using non-uniform pinhole aperture grid mask

A method for spatial calibration of a gamma camera including a scintillation crystal and an array of photodetectors optically coupled to the scintillation crystal, comprising the steps of:

• a) mounting a mask having a plurality of pinhole apertures arrayed in a non-rectangular distribution adjacent to said scintillation crystal;
• b) scanning a point source of radiation over the entirety of said plurality of pinhole apertures;
• c) collecting individual point source response data from each of said plurality of pinhole apertures;
• d) modeling said point source response data as a Gaussian function;
• e) generating at least one model patch from the collection of Gaussian model data;
• f) pattern matching said simulated uniform flood image with an actual input image obtained using said mask to obtain a set of transformation factors;
• and
• g) transforming said simulated uniform flood image using said transformation factors, to obtain a transformed uniform flood image that is used to correct input image data for spatial distortions.

A method for spatial calibration of a gamma camera, comprising the steps of:

• pattern matching an input image of a uniform flood radiation field imaged through a pinhole aperture mask, with a Gaussian model estimation of said uniform flood field, to obtain a set of transformation factors;
• transforming said Gaussian model using said obtained set of transformation factors to obtain a transformed Gaussian model;
• and
• using said transformed Gaussian model for spatial calibration of said gamma camera.