X-ray or gamma ray systems or devices – Specific application – Computerized tomography
Patent
1998-04-17
1999-12-07
Porta, David P.
X-ray or gamma ray systems or devices
Specific application
Computerized tomography
378207, 25036304, 25036309, G01T 120
Patent
active
059995882
ABSTRACT:
A method of correcting for deadtime in an attenuation map generated by a nuclear medicine imaging system is provided. The imaging system includes a gamma ray detector that is rotatable about an object to be imaged. A region is defined on the imaging surface of the detector, such as the edge of the field of view of the detector, such that during a transmission scan of the object, the radiation shadow of the object is substantially less likely to fall upon the defined region than upon other regions of the imaging surface. A blank transmission scan is then performed, including recording the radiation intensity level detected in the region as a reference intensity level. A transmission scan of the object is then performed to acquire an attenuation map of the object, including recording a radiation intensity level detected in the first region during the transmission scan. A correction value is then determined as the ratio of the reference intensity level to the intensity level detected in the region during the transmission scan. The attenuation map is then corrected for deadtime based on the correction value.
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Bertelsen Hugo
Coles David
Koster Jacobus
Nellemann Peter
Shao Lingxiong
ADAC Laboratories
Dunn Drew A.
Porta David P.
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