Method and device for creating a cephalometric image

Patent metadata

Field	Value
Publication number	US-11723610-B2
Application number	US-202117203222-A
Country	US
Kind code	B2
Filing date	Mar 16, 2021
Priority date	Dec 23, 2015
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

An extra-oral dental imaging system comprises an X-ray source ( 102 ) and an imaging device ( 101 ) suitable for producing multiple frames during at least part of an exposure of an object ( 200 ), the imaging device ( 101 ) being displaced along a scanning direction (X). A method for creating a cephalometric image of a human skull comprises a step of setting said imaging device ( 101 ) with an active area having in an imaging plane a width extending along said scanning direction (X), said width varying along a height direction perpendicular to said scanning direction (X); a step of synchronously displacing the X-ray source ( 102 ) and the imaging device ( 101 ) along said exposure profile; and a step of registering multiple frames produced by the imaging device ( 101 ) during the exposure of said object ( 200 ) to be imaged. Using for creating a cephalometric image by digital tomosynthesis.

First claim

The invention claimed is:

1. A method for creating a cephalometric image of at least part of a human skull using an extra-oral dental imaging system having a conical shape x-ray beam and no cephalometric arm, said system comprising:
an X-ray source for producing a conical shape x-ray beam used to irradiate an object to be imaged;
an imaging device suitable for producing multiple frames during at least part of an exposure of said object;
a manipulator for displacing the imaging device along an exposure profile between multiple frames during said at least part of the exposure of said object, the manipulator permitting the movement of the imaging device along a scanning direction (X),
wherein the method comprises the steps of:
setting said imaging device with an active area having in an imaging plane a width extending along said scanning direction (X), said width varying along a height direction (Y) perpendicular to said scanning direction (X);
synchronously displacing the X-ray source and the imaging device along said exposure profile;
modifying the conical shape of said conical shape x-ray beam during displacement of the X-ray source and the imaging device to vary along a height direction (Y) perpendicular to said scanning direction (X); and
registering said multiple frames produced by the imaging device during the exposure of said object to be imaged.

2. A method according to claim 1 , wherein said active area is symmetric in said imaging plane, with a central axis extending along said height direction (Y) of said active area.

3. A method according to claim 1 , wherein said active area has at least two portions having widths different from each other, said two portions being superposed in said imaging plane along said height direction (Y).

4. A method according to claim 3 , wherein the height of said active area is between 120 mm and 280 mm, the width of a first portion is between 2 mm and 50 mm, and the width of a second portion is between 50 and 140 mm.

5. A method according to claim 1 , wherein said active area has at least three portions with respectively three different widths.

6. A method according to claim 1 , wherein said active area has a central portion, a lower portion, and an upper portion each extending along said height direction (Y) in said imaging plane, the width of the central portion is larger than the width of the lower portion and the width of the lower portion is larger than the width of the upper portion.

7. A method according to claim 1 , further comprising a step of computing said multiple frames produced during at least one part of the exposure:
by a shift-and-add processing, thereby reconstructing at least one slice; or
by a volumetric approach, thereby reconstructing a three-dimensional volume and subsequently extracting at least one slice from this volume;
wherein said at least one slice includes in-focus imaging data belonging respectively to at least one depth of said object to be imaged.

8. A method according to claim 7 , wherein the volumetric approach is selected from a Statistical Algebraic Reconstruction Technique (SART), a Statistical Iterative Reconstruction Technique (SIRT), or a Filtered Back Projection technique.

9. A method according to claim 7 , further comprising a step of using each reconstructed slice for the extraction of cephalometric features.

10. A method according to claim 9 , further comprising a step of automatic cephalometric tracing, wherein said extracted cephalometric features of each slice are put together.

11. A method according to claim 9 , wherein several slices are reconstructed and combined to give a separate linear projection for the left and right sides of said object to be imaged.

12. A method according to claim 7 , wherein several slices are reconstructed and retro projected to a distance superior to 1.50 meters, and preferably superior to 4 meters, on a cone beam or parallel geometry so as to create a synthesized 2D cephalogram of the skull.

13. A method according to claim 1 , comprising the following steps:
synchronously displacing the X-ray source and the imaging device along a first part of said exposure profile, said X-ray source being in an upper position along said height direction (Y);
registering said multiple frames produced by the imaging device during said first part of the exposure profile;
synchronously displacing the X-ray source and the imaging device along a second part of said exposure profile, said X-ray source being in a lower position along said height direction (Y);
registering said multiple frames produced by the imaging device during said second part of the exposure profile; and
combining said multiple frames registered during said first and second parts of the exposure profile.

14. The method according to claim 1 , wherein the step of modifying the conical shape of said conical shape x-ray beam includes modifying the conical shape of said conical shape x-ray beam to conform to the shape of the active area of said imaging device.

15. The method according to claim 1 , wherein the step of synchronously displacing said X-ray source and said imaging device along said exposure profile includes a step of synchronously rotating said X-ray source and said imaging device through an angle while translating said X-ray source and said imaging device.

16. The method according to claim 15 , wherein the angle has an angular measure between zero degrees and thirty degrees.

17. An extra-oral dental imaging system having a conical shape x-ray beam for creating a cephalometric image of at least part of a human skull without using a cephalometric arm, said system comprising:
an X-ray source for producing said conical shape x-ray beam for irradiating an object to be imaged;
an imaging device suitable for producing multiple frames during at least part of an exposure of said object;
a manipulator for displacing the imaging device along an exposure profile between multiple frames during said at least part of the exposure of said object, the manipulator permitting the movement of the imaging device along a scanning direction (X); and
a collimator;
wherein said imaging device has an active area having in an imaging plane a width extending along said scanning direction (X), said width varying along a height direction (Y) perpendicular to said scanning direction (X);
wherein in that said manipulator is configured to synchronously displace the X-ray source and the imaging device along said exposure profile using translation and rotation of the X-ray source and the imaging device; and
wherein said collimator is configured to modify the shape of said conical shape x-ray beam to vary in unison with varying of said width of said imaging plane along the height direction (Y) perpendicular to said scanning direction (X).

18. The system according to claim 17 , wherein said manipulator is configured to rotate the X-ray source and the imaging device in unison through an angle having an angular measure between zero and thirty degrees during displacement of the X-ray source and the imaging device along the exposure profile.

19. A method for creating a cephalometric image of at least part of a human skull using a cone beam computed tomography (CBCT) extraoral imaging system without a cephalometric arm, the method comprising the steps of:
generating, via an X-ray source, an x-ray beam having a conical shape to irradiate an object to be imaged;
producing, via an imaging device, multiple image frames during at least part of an exposure of said object to the x-ray bea

Assignees

• Trophy

Inventors

• Vlachomitrou Anna-Sesilia
• Loustauneau Vincent

Classifications

• G06T12/20

  Inverse problem, i.e. transformations from projection space into object space · CPC title

• A61B6/51 Primary

  for dentistry · CPC title

• A61B6/14 Primary

  Human Necessities · mapped topic

• A61B6/025

  Tomosynthesis · CPC title

• A61B6/027

  characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral · CPC title