Radiological imaging apparatus

Abstract

A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a γ-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a γ-ray image pickup signal is output). The use of accurate information about γ-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the tomogram accuracy, that is, the PET examination accuracy.

1 - 34 . (canceled)  
   
   
       35 . A positron emission tomography apparatus comprising: 
 a bed on which a subject is to be laid;    an image pickup device that is provided with a plurality of semiconductor radiation detectors for detecting γ rays from said subject, said plurality of semiconductor radiation detectors comprising first semiconductor radiation detectors and second semiconductor radiation detectors, said second semiconductor radiation detectors being provided so as to detect γ rays passed through said first semiconductor radiation detectors, said first and second semiconductor radiation detectors, said first and second semiconductor radiation detectors being arranged around said bed and in a direction away from said bed;    a plurality of γ ray discriminators each connected to each of said first and second semiconductor radiation detectors for generating pulse signals on the basis of γ ray detection signals output from said plurality of semiconductor radiation detectors;    a signal processor connected to said plurality of γ ray discriminators for coincidence processing said pulse signals; and    a tomogram generator for creating tomogram data of said subject on the basis of positional information of said semiconductor detectors representing an arrived position of a pair of coincidence processed γ rays in said direction away from said bed, said positional information being output information of said signal processor.    
   
   
       36 . A positron emission tomography apparatus according to  claim 35 , wherein said first and second semiconductor radiation detectors are mounted on a support member.  
   
   
       37 . A positron emission tomography apparatus according to  claim 35 , wherein said first and second semiconductor radiation detectors are arranged in a straight line.  
   
   
       38 . A positron emission tomography apparatus comprising: 
 a bed on which a subject is to be laid;    an image pickup device that is provided with a plurality of semiconductor radiation detectors for detecting γ rays from said subject, said plurality of semiconductor radiation detectors being arranged around a hole portion formed in said image pickup device into which said bed is inserted, and said plurality of semiconductor radiation detectors being arranged at different positions in a radius direction of said hole portion;    a plurality of γ ray discriminators each connected to each of said semiconductor radiation detectors for generating pulse signals on the basis of γ ray detection signals output from said plurality of semiconductor radiation detectors;    a signal processor connected to said plurality of γ ray discriminators for coincidence processing said pulse signals; and    a tomogram generator for creating tomogram data of said subject on the basis of positional information of said semiconductor radiation detectors representing an arrived position of a pair of coincidence processed γ rays in said direction away from said bed, said positional information being output information of said signal processor.    
   
   
       39 . A positron emission tomography apparatus according to  claim 38 , wherein said semiconductor radiation detectors are mounted on a support member.  
   
   
       40 . A positron emission tomography apparatus according to  claim 38 , wherein said semiconductor radiation detectors are arranged in a straight line.  
   
   
       41 . A positron emission tomography apparatus according to  claim 35 , wherein said image pickup device comprises a γ ray source for moving around said subject and for irradiating γ rays to said subject, and said semiconductor radiation detectors detect first γ rays passed trough said subject after irradiation of γ rays from said γ ray source and second γ rays emitted from said subject due to a radiopharmaceutical administered to said subject.  
   
   
       42 . A positron emission tomography apparatus according to  claim 41 , wherein first output information is output from said signal processor in response to an input of first γ ray detection signals output from said semiconductor radiation detectors, said first γ ray detection signals being generated upon detection of said first γ rays, and second output information is output from said signal processor in response to an input of second γ ray detection signals output from said semiconductor radiation detectors, said second γ ray detection signal being generated upon detection of said second γ rays, and 
 wherein said tomogram generator corrects said second output information on the basis of said first output information and creates tomogram data of said subject using said second output information after correction.    
   
   
       43 . A positron emission tomography apparatus according to  claim 42 , further comprising a radiation detector deterioration check device for obtaining a ratio of measurement values of detection efficiency of said semiconductor radiation detectors arranged in said direction away from said bed on a side surface of a support member and judging deterioration of said semiconductor radiation detectors on the basis of said ratio of said measurement values and a ratio of logical values of detection efficiency of said semiconductor radiation detectors.  
   
   
       44 . a positron emission tomography apparatus comprising: 
 a bed on which a subject is to be laid;    an image pickup device that is provided with a plurality of semiconductor radiation detectors for detecting γ rays from said subject, said plurality of semiconductor radiation detectors being laminated and arranged around said bed in a direction away from said bed;    a plurality of γ ray discriminators each connected to each of said semiconductor radiation detectors laminated for generating pulse signals on the basis of γ ray detection signals output from said plurality of semiconductor radiation detectors;    a signal processor connected to said plurality of γ ray discriminators for coincidence processing said pulse signals; and    a tomogram generator for creating tomogram data of said subject on the basis of positional information of said semiconductor radiation detectors representing an arrived position of a pair of γ rays detected by said semiconductor radiation detectors laminated in said direction away from said bed, said positional information being output information of said signal processor.    
   
   
       45 . A positron emission tomography apparatus comprising: 
 a bed on which a subject is to be laid;    an image pickup device that is provided with a plurality of semiconductor radiation detectors for detecting γ rays from said subject, said plurality of semiconductor radiation detectors being formed in a plurality of layers and arranged around said bed in a direction away from said bed;    a plurality of γ ray discriminators each connected to each of said semiconductor radiation detectors layered for generating pulse signals on the basis of γ ray detection signals output from said plurality of semiconductor radiation detectors;    a signal processor connected to said plurality of γ ray discriminators for coincidence processing said pulse signals; and    a tomogram generator for creating tomogram data of said subject on the basis of positional information of said semiconductor radiation detectors representing an arrived position of a pair of γ rays detected by said semiconductor radiation detectors layered in said direction away from said bed, said positional information being output information of said signal processor.    
   
   
       46 . A method of controlling a positron emission tomography apparatus comprising the steps of: 
 detecting radiations radiated from a subject laid on a bed by a plurality of semiconductor radiation detectors, said plurality of semiconductor radiation detectors being laminated and arranged around said bed in a direction away from said bed;    generating pulse signals by a plurality of γ ray discriminators each connected to each of said semiconductor radiation detectors laminated on the basis of γ ray detection signals output from said plurality of semiconductor radiation detectors;    coincidence processing said pulse signals by a signal processor connected to said plurality of γ ray discriminators; and    creating tomogram data of said subject by a tomogram generator on the basis of positional information of said semiconductor radiation detectors representing an arrived position of a pair of γ rays detected by said semiconductor radiation detectors layered in said direction away from said bed, said positional information being output information of said signal processor.    
   
   
       47 . A method of controlling a positron emission tomography apparatus comprising the steps of: 
 detecting radiations radiated from a subject laid on a bed by a plurality of semiconductor radiation detectors, said plurality of semiconductor radiation detectors being arranged in a plurality of layers around said bed in a direction away from said bed;    generating pulse signals by a plurality of γ ray discriminators each connected to each of said semiconductor radiation detectors layered on the basis of γ ray detection signals output from said plurality of semiconductor radiation detectors;    coincidence processing said pulse signals by a signal processor connected to said plurality of γ ray discriminators; and    creating tomogram data of said subject by a tomogram generator on the basis of positional information of said semiconductor radiation detectors representing an arrived position of a pair of γ rays detected by said semiconductor radiation detectors layered in said direction away from said bed, said positional information being output information of said signal processor.