Patent ID: 7109489

Claim:
A method of obtaining and reconstructing an image of a portion of a body, administered by radiopharmaceutical substance radiating gamma rays, by using SPECT (single photon emission computerized tomography), for determination of functional information thereon, comprising the steps of: (a) acquiring photons emitted from said portion of the body, by means of a detector capable of converting the photons into electric signals, the detector having at least one crystal and a collimator having a plurality of elongated bores; (b) processing said electric signals by a position logic circuitry and thereby deriving therefrom data indicative of positions on said photon detector crystal, where the photons have impinged the detector; and (c) reconstructing an image of a spatial distribution of the pharmaceutical substance within the portion of the body by processing said data in conjunction with weight values, derived from functions of either solid angles or solid angles and distances between different discrete elements of the portion of the body and corresponding discrete elements of the projection of the portion of the body on the detector, as viewed through the collimator; wherein said reconstructing an image by processing said data comprises the steps of: (i) dividing an area of the detector facing the body into M bins; (ii) dividing the portion of the body into N voxels; (iii) providing a set of values D i (wherein i=1, . . . , M) reflective of the number of photons acquired by each bin; (iv) constructing a matrix P having matrix elements P ij of weight values of the voxels of the portion of the body (wherein i=1, . . . , M and j=1, . . . , N), the matrix P setting a relation between each bin of the detector and each voxel of the portion of the body; (v) modeling a relation between said set of values D i and a set of voxel values V j of said image and deriving said set of voxel values V j of said image, whereby said spatial distribution of the pharmaceutical substance indicating the functional information on said portion of the body is obtained.