Digital Detector

Abstract

An extra-oral dental imaging apparatus for obtaining an image from a patient has a radiation source and a digital imaging sensor that provides, for each of a number of image pixels, at least a first digital value according to a count of received photons that exceed at least a first energy threshold. A mount supports the radiation source and the digital imaging sensor on opposite sides of the patient's head. There can be a computer in signal communication with the digital imaging sensor for acquiring one or more two-dimensional images.

What is claimed is: 
     
         1 . An extra-oral dental imaging apparatus for obtaining an image from a patient, the apparatus comprising:
 a radiation source;   a digital imaging sensor that provides, for each of a plurality of image pixels, at least a first digital value according to a count of received photons that satisfy at least a first energy threshold;   a mount that supports the radiation source and the digital imaging sensor on opposite sides of the patient's head; and   a computer in signal communication with the digital imaging sensor for acquiring one or more two-dimensional images.   
     
     
         2 . The apparatus of  claim 1  wherein the mount is coupled to a rotational actuator that is energizable to revolve the imaging sensor and source in a scan pattern about the patient's head, wherein a volume image of at least a part of the patient's head is reconstructed based on the plurality of image pixels. 
     
     
         3 . The apparatus of  claim 2  further comprising one or more vertical actuators energizable for changing the relative vertical position of the imaging sensor and the radiation source to the patient's head and wherein the computer combines two or more images in the series to form a helical computed tomography volume image. 
     
     
         4 . The imaging apparatus of  claim 3  wherein the one or more vertical actuators translate the mount for changing the relative vertical position of the imaging sensor and the radiation source to the patient's head during imaging. 
     
     
         5 . The imaging apparatus of  claim 3  wherein the one or more vertical actuators translate the patient for changing the relative vertical position of the imaging sensor and the radiation source to the patient's head during imaging. 
     
     
         6 . The imaging apparatus of  claim 3  wherein the one or more vertical actuators change the relative vertical position of the imaging sensor and the radiation source to the patient's head at a variable rate. 
     
     
         7 . The apparatus of  claim 1  wherein the sensor is a two-dimensional sensor, and wherein the sensor and radiation source follow a trajectory in plane about a patient's head. 
     
     
         8 . The imaging apparatus of  claim 1  further comprising an alignment apparatus to provide alignment of the patient's head for obtaining the one or more images or at least one height sensor in communication with the computer. 
     
     
         9 . The imaging apparatus of  claim 1  wherein the mount is coupled to a rotational actuator that is energizable to revolve the imaging sensor and source in a scan pattern about the patient's head, wherein a two-dimensional image of at least a part of the patient's head is reconstructed based on the plurality of image pixels. 
     
     
         10 . The imaging apparatus of  claim 9  wherein the two-dimensional image is a panoramic image of a portion of the patient or the two-dimensional image is generated using tomosynthesis imaging techniques. 
     
     
         11 . The imaging apparatus of  claim 1  wherein the at least the first energy threshold is selectable, and wherein the sensor is a direct imaging sensor. 
     
     
         12 . The imaging apparatus of  claim 1  wherein the imaging sensor further provides, for each of the plurality of image pixels, a second digital value obtained from a count of photons of ionizing radiation energy that exceed a second threshold. 
     
     
         13 . The imaging apparatus of  claim 12  wherein the imaging sensor further provides an upper threshold, wherein the at least the first digital value is according to the count of received photons that both exceed the first energy threshold and are less than the upper threshold, and wherein the at least a second digital value is according to the count of received photons that both exceed the second energy threshold and are less than the upper threshold. 
     
     
         14 . An imaging apparatus for obtaining a volume image of at least a portion of a patient's head, the apparatus comprising:
 a rotatable mount comprising a radiation source and a digital imaging sensor and coupled to a rotational actuator that is energizable to revolve the imaging sensor and source about the patient's head;   one or more vertical actuators energizable for changing the relative vertical position of the imaging sensor and the radiation source to the patient's head; and   a computer in signal communication with the rotational and vertical actuators for performing a helical scan pattern of the imaging sensor and the radiation source about the patient's head and further in signal communication with the digital imaging sensor for acquiring a plurality of two-dimensional images at successive positions along the helical scan pattern;   wherein the imaging sensor provides, for each of a plurality of image pixels, a digital value according to the ionizing radiation energy received.   
     
     
         15 . The imaging apparatus of  claim 14  wherein the pitch of the helical scan pattern is adjustable. 
     
     
         16 . The imaging apparatus of  claim 14  wherein the imaging sensor provides, for each of a plurality of image pixels, a first digital value obtained from a count of photons of ionizing radiation energy that exceed a first threshold and a second digital value obtained from a count of photons of ionizing radiation energy that exceed a second threshold. 
     
     
         17 . A method for obtaining volume image data of at least a portion of a patient's head, the method comprising:
 obtaining a set of values that relate to one or more of an exposure energy level and a helical scanning pattern;   registering an initial height setting for scan components;   scanning a radiation source and a digital detector in a helical orbit about the patient's head according to the obtained set of values and registered initial height setting;   acquiring a plurality of digital images at intervals in the helical scan according to the helical scanning pattern; and   generating and displaying a volume image formed from the plurality of acquired digital images.   
     
     
         18 . The method of  claim 17  wherein obtaining the set of values comprises obtaining values entered by an operator relating to two or more exposure energy levels, wherein registering the initial setting is performed in response to an operator, and wherein scanning in the helical orbit allows a variable height between successive images and a variable pitch angle of revolution relative to the patient's head, according to a selected tissue type.