Picker International, Inc.

Koninklijke Philips Corporation N.V.

William G Hawkins

Daniel Gagnon

Stephen D Miller

A nuclear camera () includes a plurality of detector heads () which have collimators () for fixing the trajectory along which radiation is receivable. A rotating gantry () rotates the detector heads around the subject collecting less than 360&#xb0; of data, e.g., 204&#xb0; of data. A zero-filling processor () generates zero-filled projection views such that the actually collected projection views and the zero-filled projection views span 360&#xb0;. A smoothing processor () smooths an interface between the zero-filled and actually collected projection views. The zero-filled and smoothed views are Fourier transformed () into frequency space, filtered with a stationary deconvolution function (), and Fourier transformed () back into real space. The resolution recovered projection data sets in real space are reconstructed by a reconstruction processor () into a three-dimensional image representation for storage in an image memory ().

Limited-angle frequency-distance resolution recovery in nuclear medicine imaging

A method of ML-EM image reconstruction is provided for use in connection with a diagnostic imaging apparatus ( ) that generates projection data. The method includes collecting projection data, including measured emission projection data and measured transmission projection data. Optionally, the measured transmission projection data is truncated. An initial emission map and attenuation map are assumed. The emission map and the attenuation map are iteratively updated. With each iteration, the emission map is recalculated by taking a previous emission map and adjusting it based upon: (i) the measured emission projection data; (ii) a reprojection of the previous emission map which is carried out with a multi-dimensional projection model; and, (iii) a reprojection of the attenuation map. As well, with each iteration, the attenuation map is recalculated by taking a previous attenuation map and adjusting it based upon: (i) the measured emission projection data; (ii) a reprojection of the previous emission map which is carried out with the multi-dimensional projection model; and (iii) measured transmission projection data.

Source-assisted attenuation correction for emission computed tomography

A method of ML-EM image reconstruction is provided for use in connection with a diagnostic imaging apparatus (,) that generates projection data. The method includes collecting projection data, including measured emission projection data. An initial emission map and attenuation map are assumed. The emission map and the attenuation map are iteratively updated. With each iteration, the emission map is recalculated by taking a previous emission map and adjusting it based upon: (i) the measured emission projection data; (ii) a reprojection of the previous emission map which is carried out with a multi-dimensional projection model; and, (iii) a reprojection of the attenuation map. As well, with each iteration, the attenuation map is recalculated by taking a previous attenuation map and adjusting it based upon: (i) the measured emission projection data; and, (ii) a reprojection of the previous emission map which is carried out with the multi-dimensional projection model. In a preferred embodiment, with source-assisted reconstruction, the recalculation of the attenuation map is additionally based upon: (iii) measured transmission projection data; and, (iv) a reference or blank data set of measured transmission projection data taken without the subject present in the imaging apparatus (,).

A gamma camera system includes a rotatable gantry supporting multiple detector heads each capable of receiving radiation from a region of interest of a subject disposed in an examination region. Each of the detector heads include a collimator which substantially defines the resolution and sensitivity of the respective detector head. At least two of the detector heads include collimators providing different resolution. Preferably, one of the collimators provides a detector head with substantially high resolution and another provides a detector head with substantially high sensitivity. An operator selectively combines image data detected by each of the multiple detector heads. If desired, the operator combine the image data from the multiple detector heads in a variety of manners to obtain images of various resolution and sensitivity from a single imaging procedure. The operator may also selectively weight the contribution that the image data from each of the detector heads has in the overall image. As yet another option, the operator may choose to combine only a high energy portion of the image data so as to minimize the amount of scatter events which are included in a final image.

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Shaker Heights, OH, United States of America

William G Hawkins