Computerized method for X-ray imaging with varying X-ray dose.

Abstract

This invention provides a computer-aided method for generating a two-dimensional final image of at least a subregion of the maxillofacial region of a patient using X-ray cone-beam CT. [Solution] The acquisition step includes changing the amount of X-ray dose used to acquire each X-ray projection image such that, for X-ray projection images acquired when the projection direction is within a first predetermined angular range (a) centered on a first direction parallel to the normal direction of the 2D final image to be generated, the total amount of X-ray dose increases above a predetermined level, and for X-ray projection images acquired when the projection direction is within a second predetermined angular range (b) centered on a second direction perpendicular to the normal direction of the 2D final image to be generated, the total amount of X-ray dose decreases below a predetermined level; and generating a 2D final image as a virtual projection having parallel X-ray beam geometry of a subregion of the maxillofacial region of the patient.

Claims

1. A computer-aided method for generating a two-dimensional (2D) final image (16) of at least a subregion of the maxillofacial region of a patient (P) using X-ray cone-beam CT, A step of defining the position and alignment of the 2D final image to be generated for the sub-region of the maxillofacial region of the patient's teeth, wherein the 2D final image is essentially identical to the X-ray projection image of the sub-region having parallel beam geometry. A step of acquiring a plurality of X-ray projection images by rotating an X-ray source (3) and an X-ray detector (4) around the head of the patient, wherein the X-ray source and the X-ray detector are configured for acquiring X-ray cone-beam CT images. During the acquisition step, the amount of X-ray dose used to acquire each of the X-ray projection images is For the X-ray projection image obtained when the projection direction is within a first predetermined angular range (a) centered on a first direction parallel to the normal direction of the 2D final image to be generated, the total amount of X-ray dose increases beyond a predetermined level, For the X-ray projection image obtained when the projection direction is within a second predetermined angular range (b) centered on a second direction perpendicular to the normal direction of the 2D final image to be generated, the total amount of X-ray dose is reduced to below the predetermined level. The steps to change it in this way, The steps include generating the 2D final image as a virtual projection having parallel X-ray beam geometry of the sub-region of the maxillofacial region of the patient by using the acquired X-ray projection image, and A computer implementation method, including

2. During the acquisition step, The aforementioned X-ray projection image is read out from the X-ray detector with a higher resolution compared to a predetermined resolution when the X-ray dose increases relatively, and The aforementioned X-ray projection image is read out from the X-ray detector with a lower resolution compared to the predetermined resolution when the X-ray dose decreases relatively. The computer implementation method according to claim 1, characterized by the above.

3. The computer-aided method according to claim 1, characterized in that, in the generation step, a volume image is reconstructed using the plurality of X-ray projection images, and then the 2D final image is generated by virtually projecting a sub-region of the volume image with a parallel X-ray beam geometry.

4. The computer implementation method according to claim 1, characterized in that the 2D final image is a CEFF image.

5. The computer-aided method according to claim 1, characterized in that, in the step of changing, the rotation speed and / or emission of the X-ray source are changed in order to adaptively change the amount of the X-ray dose.

6. A computer program comprising computer-readable code that, when executed by a computer-assisted X-ray cone-beam imaging system (1), causes the system to perform the method according to claim 1.

7. Extraoral X-ray cone-beam imaging system (1), An X-ray source (3) and an X-ray detector (4) are rotatably positioned around the patient's head, Control means for controlling the X-ray source and the X-ray detector Equipped with, An extraoral X-ray cone-beam imaging system (1) wherein the control means is configured to perform the method according to any one of claims 1 to 5.

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