Process and device for deploying an anti-scattering grid
A process for deploying an anti-scattering grid in a mammograph is provided. The mammograph comprises a radiation source configured to emit radiation for taking mammographic images of a patient, a radiation detector comprising a network of sensors arranged periodically with a first pitch, and an anti-scattering grid arranged between the source and the detector, the anti-scattering grid comprising absorption laminates of radiations arranged parallel to each other and distributed periodically with a second pitch. The process comprises: displacing the anti-scattering grid relative to the detector or displacing the detector relative to the anti-scattering grid during emission of radiation; and adapting the second pitch to the first pitch, wherein displacement is perpendicular to the direction of the laminates of the anti-scattering grid, the laminates being arranged parallel to a side of the anti-scattering grid positioned against the patient.
1. A process for deploying an anti-scattering grid in a mammograph comprising a radiation source configured to emit radiation for taking mammographic images of a patient, a radiation detector comprising a network of sensors arranged periodically with a first pitch, and an anti-scattering grid arranged between the source and the detector, the anti-scattering grid comprising radiation adsorbing laminates arranged parallel to each other and distributed periodically with a second pitch, the process comprising:
displacing the anti-scattering grid or the detector during radiation emission,
adjusting the second pitch in relation to a setting of the first pitch and;
wherein displacement is rotational, during radiation emission, around an axis perpendicular to a plane of the anti-scattering grid, or perpendicular to a plane of the detector, wherein the axis defines a center of rotation located outside the anti-scattering grid.
2. The process as claimed in claim 1 , wherein displacement has minimal amplitude of the second pitch.
3. The process as claimed in claim 1 , wherein displacing comprises shifting the anti-scattering grid or the detector in at least two points with speeds different to each other.
4. The process as claimed in claim 1 , wherein the anti-scattering grid or the detector is displaced at constant speed.
5. The process as claimed in claim 4 , wherein the amplitude of displacement of the anti-scattering grid, or of the detector, is equal to k times the second pitch, wherein k is an integer or a semi-integer.
6. The process as claimed in claim 5 , wherein k is between about one and about twenty.
7. The process as claimed in claim 1 , wherein displacement is oscillatory.
8. The process as claimed in claim 7 , wherein displacement is periodical.
9. The process of claim 1 , further comprising moving the source relative to the detector to acquire three-dimensional mammographic images.
10. The process as claimed in claim 1 , wherein an amplitude of the rotation around the axis is a function of a distance between the anti-scattering grid or the detector and the center of rotation.
11. A mammograph comprising:
a radiation source configured to emit radiation for taking mammographic images of a patient;
a radiation detector comprising a network of sensors arranged periodically with a first pitch;
an anti-scattering grid arranged between the source and the detector, the anti-scattering grid comprising radiation adsorbing laminates arranged parallel to each other and distributed periodically with a second pitch; and
an actuator configured to displace the detector or the scattering grid relative to each other during emission of radiation;
an axis perpendicular to a plane of the anti-scattering grid or a plane of the detector;
a center of rotation defined by the axis located outside the anti-scattering grid;
wherein displacement is rotational, during radiation emission, around the axis perpendicular to the plane of the anti-scattering grid or perpendicular to the plane of the detector, and wherein the second pitch is adjusted in relation to a setting of the first pitch during displacement.
12. The mammograph as claimed in claim 11 , wherein the actuator is configured to displace the anti-scattering grid or the detector at constant speed.
13. The mammograph as claimed in claim 11 , wherein the actuator comprises a piezoelectric motor.
14. The mammograph as claimed in claim 11 , wherein the actuator comprises a motor connected to a reducer and a cam.
15. The mammograph as claimed in claim 11 , wherein the actuator is arranged on a side of the anti-scattering grid opposite the side of the grid positioned against the patient.
16. The mammograph as claimed in claim 11 , wherein the second pitch is a multiple of the first pitch.
17. The mammograph as claimed in claim 11 , wherein the second pitch is a multiple of the Nyquist frequency of the detector.
18. The mammograph as claimed in claim 11 , further comprising a control and processing unit configured to control the source and the detector and configured to control acquisition and processing of images.
19. The mammograph as claimed in claim 11 , wherein an amplitude of the rotation around the axis is a function of a distance between the anti-scattering grid or the detector and the center of rotation.