Small Field of View Detector Head ("Spect") Attenuation Correction System

Abstract

A detector head having a small field of view, for example one which receives information from less than half a body imaged, is used to form a transmission attenuation map. The same detector head both receives information for the transmission attenuation map and also receives imaging information e.g. from a radioisotope.

1 . A method, comprising:
 obtaining first and second detector heads, each of which receives imaging information a portion of a total area of interest to be imaged for medical purposes; and adjusting an orientation of said first and second detector heads to minimize an unimaged area outside an extent of said first and second detector heads, by increasing an unimaged area between the first and second detector heads.   
   
   
       2 . A method as in  claim 1 , wherein said unimaged area outside the extent includes a position just outside lungs of the body being imaged. 
   
   
       3 . A method as in  claim 2 , wherein said moving the position relationship comprises moving the patient. 
   
   
       4 . A method, comprising:
 aligning first and second small field of view detector heads, such that each of said detector heads receives imaging information from less than half of a portion of a total area of interest to be imaged for medical purposes; and   adjusting an orientation of said first and second detector heads to maximize a sampling of the outer region relative to the inner region to minimally truncate the area.   
   
   
       5 . A method as in  claim 4 , further comprising moving a position relationship between the detector heads and the area to be imaged. 
   
   
       6 . A method as in  claim 4 , wherein said adjusting comprises minimizing a size of an outer unsampled area relative to an inner unsampled area. 
   
   
       7 . A method as in  claim 6  wherein said outer unsampled area includes only an area outside and adjacent lungs of a body. 
   
   
       8 . A medical imaging system, comprising:
 a first small width field of view detector, having an imaging area which spans less than a complete area of a subject being imaged;   a first collimator, associated with said small with field of view detector, and focused on a medical transmission source;   a second small width field of view detector, having a second imaging area that spans different areas in said first area, and also spans less than a complete area of the subject being imaged; and   a second collimator pointed in a different orientation than said first collimator, and pointing towards said medical transmission source.   
   
   
       9 . A system as in  claim 8 , further comprising an orienting part, which changes an orientation of said small field of view detectors. 
   
   
       10 . A system as in  claim 9 , wherein said orienting part changes said small field of view detectors between a first emission position which points at the transmission source, and a second transmission position which points at an emission source within the body being imaged. 
   
   
       11 . A system as in  claim 9 , wherein said first emission position points at a body organ being imaged. 
   
   
       12 . A system as in  claim 11 , wherein said body organ being image is a lung. 
   
   
       13 . A system as in  claim 8 , wherein said small field of view detector heads include scintillators of arrays formed of photodiodes. 
   
   
       14 . A system as in  claim 8 , wherein said small field of view detector heads include wide band gap direct detection semiconductors that are capable of direct gamma ray to photon electron conversions. 
   
   
       15 . A system as in  claim 8  wherein the medical transmission source is a line source. 
   
   
       16 . A system as in  claim 8  wherein the medical transmission source is a line source. 
   
   
       17 . A system as in  claim 8  wherein the medical transmission source is a radiopharmaceutical. 
   
   
       18 . A system as in  claim 8  wherein said imaging is spec imaging. 
   
   
       19 . A method, comprising:
 in a first mode, using two small field of view detectors to sample less than an entire width of a body; and   in a second mode, using said two small field of view detectors to sample a larger area of the body.   
   
   
       20 . A method as in  claim 19 , wherein said first mode focuses said detectors on an organ of interest to the exclusion of other parts of the body. 
   
   
       21 . A method as in  claim 20 , wherein said first mode maximizes a sampling area of an outer region of the body relative to an inner region of the body. 
   
   
       22 . A method as in  claim 21 , wherein said first mode maximizes imaging at an area around the lungs. 
   
   
       23 . A system for detecting emissions from an object within a body comprising:
 a transmission source, which produces an output transmission along a path through the body;   a first detector head, which detects information from the transmission source, said first detector head being sized to detect said transmission information from a maximum portion of 90% or less of said body at any given time, said first detector head oriented to detect information from an area defining its imaging area, and wherein said first detector head is oriented such that said area has a center and said center is spaced from a central portion of said object;   an orienting part which includes a first position that orients said body, said transmission source and said detector head in a plurality of different orientations by rotating one of said body or said transmission source and detector, and such that a center most portion of said imaging area of said first detector head is offset from said axis of rotation, and includes a second position that orients said first detector head to detect emissions from the object, and such that the center most portion of said imaging area of said first detector head is centered on the object while the first orienting part orients said body in a plurality of different orientations by rotating one of said body or said detector around said object; and   a processor, that forms a transmission attenuation correction map from said output transmission, and uses said transmission attenuation map to correct the information received from said emission signal, said first detector head and said processor producing output information indicative of less than all of said body, after said plurality of orientations of said orienting part, where said processor computes said transmission attenuation correction map of said body that is centered at said object.