Automatic exposure control setup

Abstract

A method for exposure control setup for a volume radiographic imaging apparatus obtains a reconstructed image volume of a subject acquired from the imaging apparatus using a set of x-ray technique settings. An image slice from the reconstructed image volume displays in at least a first rendering having a first corresponding noise factor and a second rendering having a second corresponding noise factor, different from the first noise factor. An operator instruction selects one of the at least first and second renderings and stores the corresponding noise factor for the set of x-ray technique settings. An automatic exposure control of the imaging apparatus is configured according to the stored noise factor.

What is claimed is: 
     
         1 . A method for exposure control setup for a volume radiographic imaging apparatus, the method comprising:
 displaying a first rendering of an image slice of a reconstructed image volume of a subject, the first rendering having a first corresponding noise factor;   displaying a second rendering of the image slice of the reconstructed image volume, the second rendering having a second corresponding noise factor different from the first noise factor; and   in response to an operator selection of the displayed first or second rendering, determining an automatic exposure control for the volume radiographic imaging apparatus according to the corresponding noise factor of the operator-selected rendering.   
     
     
         2 . The method of  claim 1  further comprising configuring the volume radiographic imaging apparatus with the determined automatic exposure control. 
     
     
         3 . The method of  claim 1  wherein the volume radiographic imaging apparatus is a cone-beam computed tomography (CBCT) apparatus, and the method further comprises:
 generating the reconstructed image volume of the subject using 2-D projection images acquired by the CBCT apparatus. 
 
     
     
         4 . The method of  claim 1  wherein displaying the first and second renderings of the image slice comprises simultaneously displaying, on a display, the first and second renderings. 
     
     
         5 . The method of  claim 1  further comprising, prior to displaying, rendering the first rendering at a reference predetermined noise factor. 
     
     
         6 . The method of  claim 1  further comprising:
 configuring the volume radiographic imaging apparatus with the determined automatic exposure control; and 
 storing or displaying data relating to at least one of: patient size, patient dose, and X-ray technique. 
 
     
     
         7 . The method of  claim 1  further comprising displaying an alternate rendering of the first or second image slice in response to an operator entry using an on-screen ruler or slide control. 
     
     
         8 . The method of  claim 7  wherein the on-screen ruler or slide control further displays patient dose data related to the noise factor. 
     
     
         9 . The method of  claim 8  further comprising storing the patient dose data with the stored noise factor. 
     
     
         10 . A method for exposure control setup for a volume radiographic imaging apparatus, the method comprising:
 a) providing, on a display, an operator interface that allows selection of an image slice from a reconstructed image volume;   b) displaying the selected image slice from the reconstructed image volume in at least a first rendering having a first corresponding noise factor;   c) rendering the selected image slice to the display with a second variable noise factor selected by the operator, wherein the noise factor relates to patient exposure corresponding to the rendered image slice; and   d) configuring the imaging apparatus to provide automatic exposure control according to the selected noise factor.   
     
     
         11 . The method of  claim 10  further comprising accepting an operator instruction for reducing a default exposure setting for the volume radiographic imaging apparatus. 
     
     
         12 . The method of  claim 10  wherein the reconstructed volume contains an added disease feature. 
     
     
         13 . The method of  claim 10  wherein the noise factor can be customized by anatomy, examination type and practitioner. 
     
     
         14 . The method of  claim 10  further comprising storing a plurality of reference images from a single subject rendered at a plurality of different noise factors. 
     
     
         15 . The method of  claim 14 , wherein a lowest noise factor in the plurality of reference images corresponds to a highest exposure X-ray technique that the volume radiographic imaging apparatus can generate and a highest noise factor in the plurality of reference images corresponds to a lowest exposure X-ray technique that the volume radiographic imaging apparatus can generate. 
     
     
         16 . The method of  claim 14 , wherein a lowest noise factor in the plurality of reference images corresponds to an upper dose limit for the anatomy or size or examination type selected and a highest noise factor in the plurality of reference images corresponds to a lowest dose that provides acceptable diagnostic results for the anatomy or size or examination type selected. 
     
     
         17 . The method of  claim 10  further comprising displaying an alternate rendering of the selected image slice in response to an operator entry using an on-screen ruler or slide control. 
     
     
         18 . The method of  claim 10  wherein first displayed image slice is rendered at a reference predetermined noise factor. 
     
     
         19 . A system for volume radiographic imaging, comprising:
 a) an x-ray source and a detector configured to acquire a set of projection images of a subject using a set of x-ray technique settings;   b) a display; and   b) a control logic processor in signal communication with the x-ray source, detector and display, configured to:
 (i) reconstruct an image volume of the subject from the acquired set of projection images; 
 (ii) accept operator instructions for displaying one or more slices of the reconstructed image volume; 
 (iii) render the one or more displayed slices to the display according to a variable noise factor selected by the operator; 
 (iv) accept an operator instruction and store an exposure setting corresponding to a selected rendering; and 
 (v) apply the stored exposure setting for patient imaging. 
   
     
     
         20 . A method for exposure control setup for a volume radiographic imaging apparatus, the method comprising:
 a) obtaining a reconstructed image volume of a subject acquired from the imaging apparatus using a set of x-ray technique settings;   b) displaying an image slice from the reconstructed image volume in at least a first rendering having a first corresponding noise factor and a second rendering having a second corresponding noise factor, different from the first noise factor;   c) accepting an operator instruction that selects one of the at least first and second renderings and storing the corresponding noise factor for the set of x-ray technique settings; and   d) configuring an automatic exposure control of the imaging apparatus according to the stored noise factor.