X-ray calibration
View Patent ↗Methods, devices, and kits for determining the magnification of an x-ray image of an object, or a portion of an object are described. An exemplary method comprises the steps of providing an object to be x-rayed, providing a first posterior x-ray marker having a pre-determined dimension, providing anteriorly to the object to be x-rayed, a second x-ray marker having predetermined dimensions, recording an x-ray image of the object, the first posterior x-ray marker, and second x-ray markers, and comparing a dimension of the first posterior x-ray marker recorded on the x-ray image, and a dimension of the second x-ray marker recorded on the image to a pre-determined value for the object x-rayed, to estimate a magnification of the x-ray image of the object.
1. A method of determining the magnification of an x-ray image of an object, or a portion of an object, the method comprising the steps of:
(i) providing an object to be x-rayed;
(ii) providing a first posterior x-ray marker having a pre-determined dimension;
(iii) providing anteriorly to the object to be x-rayed, a second x-ray marker having predetermined dimensions;
(iv) recording an x-ray image of the object, the first posterior x-ray marker, and second x-ray markers; and
(v) comparing a dimension of the first posterior x-ray marker recorded on the x-ray image, and a dimension of the second x-ray marker recorded on the image to a pre-determined value for the object x-rayed, to estimate a magnification of the x-ray image of the object.
2. A method according to claim 1 , wherein the object is selected from a group consisting of a human patient and an animal patient.
3. A method according to claim 1 , wherein the first x-ray marker is provided substantially adjacent to an x-ray detector.
4. A method according to claim 1 , wherein the second x-ray marker is placed on a surface of the object anteriorly to an x-ray source.
5. A method according to claim 2 , wherein a portion of the object is selected from a group consisting of a hip joint, a knee joint, a shoulder joint, an elbow and a portion of a spine.
6. A method according to claim 5 , wherein the portion of the object x-rayed is a human hip joint and the predetermined value is the typical distance between a line passing through the centers of both hip joints to the position of the anterior second x-ray marker on the surface of an abdomen, compared to the distance between the anterior second x-ray marker and the first posterior x-ray marker.
7. A method according to claim 1 , wherein the magnification of the image is determined according to the following equation
M
=
100
[
S
a
X
a
]
+
R
[
S
p
X
p
-
S
a
X
a
]
S a =a dimension of the second x-ray marker,
S p =a dimension of the first posterior x-ray marker,
X a =the dimension of the second x-ray marker recorded on the image,
X p =the dimension of the first posterior x-ray marker recorded on the image,
R=the pre-determined value for the object,
M=magnification of the image.
8. A method according to claim 1 , wherein the first posterior x-ray marker is one more first posterior x-ray markers selected from a group consisting of rods, discs, washers, wires, and balls.
9. A method according to claim 1 , wherein the dimension is selected from the group consisting of a length of a rod, a diameter of a ball, a diameter of washer or a diameter of disc, and the distance between two parallel rods or wires.
10. A method according to claim 1 , wherein the object is placed on a mat adjacent to an x-ray detector, and the mat comprises one or more markers.
11. A method according to claim 1 , wherein the anterior second x-ray marker is one or more anterior second x-ray markers selected from a group consisting of balls, washers and discs.
12. A method according to claim 1 , wherein the estimation of the magnification of an x-ray image is conducted using the following equation:
M
=
100
[
S
a
X
a
]
+
R
[
S
p
X
p
-
S
a
X
a
]
S a =a dimension of the second x-ray marker,
S p =a dimension of the first posterior x-ray marker,
X a =the dimension of the second x-ray marker recorded on the image,
X p =the dimension of the first posterior x-ray marker recorded on the image,
R=the pre-determined value for the object,
M=magnification of the image.
13. A kit for use in a method according to claim 1 , the kit comprising a mat comprising one or more markers, the one or more markers having a pre-determined dimension and capable of being detected by x-ray imaging.
14. A kit according to claim 13 , wherein the one or more markers are selected from a group consisting of discs, washers, rods, and wires.
15. A kit according to claim 13 , additionally comprising a first marker, the first marker is one or more first markers selected from a group consisting of ball-bearings, washers, and discs for placing on an anterior surface of an object to be x-rayed.
16. A kit according to claim 15 , further comprising a plurality of second markers selected from a group consisting of ball-bearings, discs and washers, wherein the plurality of second markers are linked together via one or more strips of flexible material.
17. A system for determining the magnification of an x-ray image of an object comprising a processor and a memory, the memory comprising an image, the image comprising an image of a first x-ray marker, an image of a second x-ray marker and an image of an object or part of an object; the processor configured to:
(i) place a cursor over the image of the first x-ray marker and calculate a dimension of the first x-ray marker;
(ii) place a cursor over the image of the second x-ray marker and calculate a dimension of the second x-ray marker; and
(iii) compare the two dimensions with a pre-determined value for the object, or part of the object, of the image to provide an estimate of the magnification of the image.
18. The system of claim 17 , wherein the system is operable to:
(i) provide an object to be x-rayed;
(ii) provide a first posterior x-ray marker having a pre-determined dimension;
(iii) provide anteriorly to the object to be x-rayed, a second x-ray marker having predetermined dimensions;
(iv) record an x-ray image of the object, the first posterior x-ray marker, and second x-ray markers; and
(v) compare a dimension of the first x-ray marker recorded on the x-ray image, and a dimension of the second x-ray marker recorded on the image to a pre-determined value for the object x-rayed, to estimate a magnification of the x-ray image of the object.
19. The method of claim 17 , wherein the estimate of the magnification of the image is conducted using the following equation:
M
=
100
[
S
a
X
a
]
+
R
[
S
p
X
p
-
S
a
X
a
]
S a =a dimension of the anterior marker,
S p =a dimension of the posterior marker,
X a =the dimension of the anterior marker recorded in the image,
X p =the dimension of the posterior marker recorded on the image,
R=the pre-determined value for the object,
M=Magnification of the image.
20. An x-ray device comprising:
an x-ray source;
an x-ray detector; and
a mat comprising one or more markers, the mat arranged to be placed adjacent to the x-ray detector; and
one or more markers for placing on an anterior surface of an object to be x-rayed;
wherein the one or more markers have a pre-determined dimension and are capable of being detected by x-ray imaging.