Picker International, Inc.

Stephen D Miller

Piotr J Maniawski

Daniel Gagnon

Hugh T Morgan

William G Hawkins

Gary G Jarkewicz

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.

Gamma camera system having multi-resolution detectors

Radiation indicative of an object being imaged is detected and a data set indicative of the detected radiation is generated. Negative cells within the data set are located and ordered for processing. A negative cell is selected for processing. A mask region is defined in relation to the selected cell, and positive cells within the mask region are identified. A correction factor is determined, the value of the positive cells is adjusted accordingly. The value of the selected cell is also adjusted so that the count value of the data set remains constant. If the value of the selected cell is still negative, new correction factors are determined and the values of the positive cells and the selected cell are again adjusted. The process is repeated until all of the negative cells within the data set have been processed. An image indicative of the object is then generated.

Negativity bias reduction

A method of scatter correction for use with gamma cameras includes the steps of detecting and producing a first count value indicative of gamma radiation falling within a first energy range generally associated with a radionuclide photopeak. Gamma radiation falling within second and third energy ranges is also detected and a corresponding count produced. The second and third ranges are above and below the photopeak, respectively. The location of the second and third energy ranges is determined based on the energy resolution of the gamma camera such that a predetermined percentage of the radiation falling within the second and third ranges results from primary radiation. The second and third energy ranges may be located such that they are non-contiguous with the first energy range. Based on the count of radiation falling within the second and third ranges, the scatter radiation falling within the first energy range can be estimated, and the first count value corrected. The method is suitable for use with radionuclides having multiple closely spaced photopeaks as well as with multiple widely spaced photopeaks.

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Chagrin Falls, OH, United States of America

Stephen D Miller