Apparatus for fully automated X-ray tomography system performance validation according to standards for metrology and image quality testing
An apparatus for calibrating or validating performance of a computed tomography (CT) scanner including a first element having a first diameter, a second element having a base structure and a first set of test objects that can be coupled to the base structure and separated from one another by a first set of distances. The apparatus also includes a third element having a second diameter and a first length, a fourth element having a first face and a second face parallel to one another with a first depth defined there between. The fourth element can include: a first cavity depressed a second depth into the first face, a fifth element including a plurality of wire pairs and disposed within the first cavity, a second cavity depressed into the first face such that a third depth is defined between a back wall of the second cavity and the second face, a sixth element including a first plurality of holes and a first thickness, the sixth element disposed within the second cavity, and a seventh element including a second plurality of holes and a second thickness, the seventh element disposed on the first face. A center of the first element, the second element, the third element, and the fourth element, respectively, are be aligned along a first axis.
1 . An apparatus for validating performance of a computed tomography (CT) system comprising:
a first spherical element having a first diameter;
a base structure comprising a plurality of test objects coupled to the base structure and separated from one another by a first set of distances;
a cylindrical element having a second diameter and a first length; and
a prismatic element coupled to the base structure by the cylindrical element and having a first face and a second face parallel to one another and separated by a first thickness, wherein the apparatus is configured to be scanned by the CT system to determine a plurality of calibration metrics of the CT system based on the first spherical element, the base structure, the cylindrical element, and the prismatic element.
2 . The apparatus of claim 1 , further comprising a positioning element configured to rotate the apparatus about a first axis during scanning by the CT system.
3 . The apparatus of claim 2 , wherein the positioning element is further configured to move the apparatus in a three-dimensional space between a CT scanner and a detector of the CT system.
4 . The apparatus of claim 3 , wherein a center of the first spherical element, the base structure, the cylindrical element, and the prismatic element, respectively, are aligned along a first axis, and wherein the first spherical element is removably coupled to the base structure.
5 . The apparatus of claim 1 , wherein the plurality of test objects include a plurality of second spherical elements having varying sizes.
6 . The apparatus of claim 5 , wherein the base structure is a ceramic plate and the plurality of test objects are made from ruby or ceramic.
7 . The apparatus of claim 1 , further comprising a resolution element, wherein plurality of calibration metrics include a resolution of the CT system determined based on the resolution element.
8 . The apparatus of claim 7 , wherein the resolution element includes a plurality of wire pairs ranging in diameter from a smallest wire diameter to a largest wire diameter, and wherein a first wire of each pair is separated from a second wire of the pair by a distance equivalent to the diameter of each wire in the pair.
9 . The apparatus of claim 8 , wherein the resolution element is depressed a first depth into the first face of the prismatic element.
10 . The apparatus of claim 1 , wherein the plurality of calibration metrics include probing error metrics determined based on the first spherical element, a sphere distance error (SDE) determined based on the base structure, a Modulation Transfer Function (MTF) and a Contrast Discrimination Function (CDF) determined based on the cylindrical element, and a signal-to-noise ratio (SNR) determined based on the prismatic element.
11 . The apparatus of claim 1 , further comprising one or more image quality indicators (IQIs) provided on the first face of the prismatic element, wherein plurality of calibration metrics include a contrast-to-noise ratio (CNR) and a contrast sensitivity (CS) of the CT system determined based on the one or more IQIs.
12 . The apparatus of claim 11 , wherein the one or more IQIs include a first IQI having a second thickness that is a first predefined percentage of the first thickness of the prismatic element, a first hole having a diameter substantially equal to the second thickness, a second hole having a diameter substantially equal to twice the second thickness, and a third hole having a diameter substantially equal to four times the second thickness.
13 . The apparatus of claim 12 , wherein the one or more IQIs further comprise a second IQI having a third thickness that is a second predefined percentage of the first thickness of the prismatic element, a fourth hole having a diameter substantially equal to the third thickness, a fifth hole having a diameter substantially equal twice the third thickness, and a sixth hole having a diameter substantially equal four times the third thickness.
14 . The apparatus of claim 13 , wherein the first IQI is depressed a first into the first face of the prismatic element such that the first IQI is closer to the second face than the second IQI is to the second face.
15 . The apparatus of claim 1 , wherein the first spherical element, the base structure, the cylindrical element, and the prismatic element are removably coupled to one another to allow for replacement of any of the first spherical element, the base structure, the cylindrical element, and the prismatic element.
16 . An apparatus comprising:
a first spherical element having a first diameter;
a base structure comprising a plurality of test objects coupled to the base structure and separated from one another by a first set of distances;
a cylindrical element having a second diameter and a first length; and
a prismatic element coupled to the base structure by the cylindrical element and having a first face and a second face parallel to one another and separated by a first thickness, wherein the apparatus is configured to be scanned by a CT system to determine a plurality of calibration metrics of the CT system including at least two of a probing error metric, a sphere distance error (SDE), a Modulation Transfer Function (MTF), a Contrast Discrimination Function (CDF), a signal-to-noise ratio (SNR), a resolution metric, a contrast-to-noise ratio (CNR), and a contrast sensitivity (CS) metric.
17 . The apparatus of claim 16 , further comprising:
a resolution element provided on the first face of the prismatic element, wherein the resolution element includes a plurality of wire pairs ranging in diameter from a smallest wire diameter to a largest wire diameter;
at least one image quality indicator (IQI) provided on the first face of the prismatic element, wherein the at least one IQI has a second thickness that is a first predefined percentage of the first thickness of the prismatic element, a first hole having a diameter substantially equal to the second thickness, a second hole having a diameter substantially equal to twice the second thickness, and a third hole having a diameter substantially equal to four times the second thickness.
18 . The apparatus of claim 17 , further comprising a positioning element configured to rotate the apparatus about a first axis during scanning by the CT system configured to move the apparatus in a three-dimensional space between a CT scanner and a detector of the CT system, wherein a center of the first spherical element, the base structure, the cylindrical element, and the prismatic element, respectively, are aligned along the first axis.
19 . The apparatus of claim 17 , wherein dimensions of the first spherical element, the base structure, the cylindrical element, the prismatic element, the resolution element and the at least one IQI are designed based on predetermined calibration and validation standards for the CT system.
20 . The apparatus of claim 17 , wherein the first spherical element, the base structure, the cylindrical element, the prismatic element, the resolution element, and the at least one IQI are removably coupled to the apparatus to allow for replacement of any of the first spherical element, the base structure, the cylindrical element, the prismatic element, the resolution element, and the at least one IQI.