By a News Reporter-Staff News Editor at Cancer Weekly -- GENERAL ELECTRIC COMPANY (Schenectady, NY) has been issued patent number 9770215, according to news reporting originating out of Alexandria, Virginia, by NewsRx editors (see also GENERAL ELECTRIC COMPANY).
The patent's inventors are Souchay, Henri (Versailles, FR); Cisaruk, Mathias (Paris, FR).
This patent was filed on December 19, 2011 and was published online on September 26, 2017.
From the background information supplied by the inventors, news correspondents obtained the following quote: "Field of the Invention
"The present disclosure is generally related to the field of medical imaging, and more particularly the field of radiography. Embodiments of the present invention relate to the field of the deploying anti-scattering grids used to improve radiographic frames by filtering the photons scattered by the organ under study, and keeping only the photons emitted by the source. Embodiments of the present invention can be utilised within the scope of mammography, and more particularly within the scope of mammary tomosynthesis, which takes a series of frames at different angles to produce a 3D image of the object being studied.
"Description of the Prior Art
"Anti-scattering grids are used widely in radiography devices to eliminate effects due to parasite scattering of some photons, taking place in the organ studied in said devices. These grids filter photons scattered by the organ being studied and mainly keep only photons actually originating from the radiation source of the radiography device, thus improving the contrast on the images obtained.
"In reference to FIG. 1, a conventional use of an anti-scattering grid 2 is illustrated. This grid 2 is placed between an organ of a patient P to be studied and who is irradiated by a radiation source 1, and a radiation detector 3 comprising a network of sensors 31 (illustrated in FIG. 3) distributed periodically with a period p.sub.d (later called the pitch of the detector).
"The assembly made up of the grid and the detector is positioned according to a plane perpendicular to the plane P.sub.T of the torso of the patient. By way of non-limiting example, illustrated in FIG. 1, the patient P can be standing and the grid and the detector are then on a horizontal plane, the walls of the grid and of the detector in contact with the patient being tangential to the plane P.sub.T,
"The grid 2 is generally constituted by alternating radio-opaque and radio-transparent laminates 21, the laminates 21 being parallel and distributed periodically, with a pitch p.sub.g between two radio-opaque laminates so that the scattered photons are absorbed by the radio-opaque laminates and the photons coming directly from the source 1 are transmitted to the detector 3 of the radiography device.
"One drawback of using such a grid is that an image of the grid appears on the detector. Also, alternating laminates can cause interference figures, or moire effect, on the detector and deteriorate the quality and legibility of the frame obtained.
"For deleting the image of the grid, a solution known in mammography and schematically illustrated in FIGS. 1 and 2a is used, consisting of animating the grid 2 by vibration movement perpendicular to the direction according to which the laminates 21 extend, that is, parallel to the side of the grid against which the patient can be positioned.
"In terms of mammary tomosynthesis, acquiring a 3D image of the object means acquiring a series of images of the object according to different relative angular positions between the source and the detector. For this to occur, the radiation source 1 is pivoted about an axis Y-Y, illustrated in FIG. 2b, perpendicular to the plane of the torso of the patient P, since pivoting of the source according to an axis parallel to the plane of the torso P.sub.T of the patient P would create risk of irradiating the latter.
"This configuration necessarily causes the grid to pivot by 90.degree. in its plane so that the trajectory of the source 1 remains near the focal line of the grid 2.
"For reasons associated with bulk, as illustrated in FIG. 3, it then becomes difficult to execute displacement of the grid 2 perpendicularly to the direction of the laminates.
"In effect, in reference to FIG. 3, the detector 3 and the anti-scattering grid 2 are located under a cap 4 likewise supporting the breast of the patient throughout examination. Legislation imposes that the distance between the costal grid of the patient and the closest sensors 31 of the detector 3 be less than 5 mm.
"This interval must also comprise the thickness of the cap 4 and the edge of the grid 2 which is not constituted by laminates. Given these elements, the space remaining for the grid 2 to move is less than 2 mm.
"Since the movement required to erase the image of the grid is of the order of 10 mm, it cannot occur according to an axis perpendicular to the plane of the torso P.sub.T of the patient.
"There is therefore a need for a novel technique for making an image with a grid having laminates parallel to the chest of the patient P, while at the same time avoiding the image of the grid and the moire effects on the detector.
"Solutions adopted in mammary tomosynthesis in the prior art to eliminate the image of the grid on the detector propose adapting the pitch of the grid p.sub.g to the pitch of the detector p.sub.d, so that the pitch of the grid p.sub.g is for example equal to a multiple of the pitch p.sub.d of the detector.
"Another solution presented in document FR 2,939,019 consists of adapting the pitch of the grid to the Nyquist frequency of the detector then digitally filtering the image of the grid on the detector.
"But, none of these solutions gives a completely satisfactory result. In particular, even if the grid is no longer visible on the frame, a moire effect remains, linked to interferences between the laminates of the grid and the network of sensors of the detector."
Supplementing the background information on this patent, NewsRx reporters also obtained the inventors' summary information for this patent: "Embodiments of the present invention provide a process and device for deploying an anti-scattering grid, applicable to mammography and to mammary tomosynthesis, which eliminates both the image of the grid on the detector and the residual moire effects.
"According to one embodiment of the present invention, 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.
"According to another embodiment of the present invention, a mammograph is provided. The mammograph comprises a radiation source configured to emit radiation for taking mammographic images of a patient. The mammograph further comprises 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 mammograph comprises at least one actuator configured to displace the anti-scattering grid relative to the detector or displace the detector relative to the anti-scattering grid during emission of radiation, 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, and wherein the second pitch is adapted to the first pitch during displacement."
For the URL and additional information on this patent, see: Souchay, Henri; Cisaruk, Mathias. Process and Device for Deploying an Anti-Scattering Grid. U.S. Patent Number 9770215, filed December 19, 2011, and published online on September 26, 2017. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=9770215.PN.&OS=PN/9770215RS=PN/9770215
Keywords for this news article include: Oncology, Mammography, Women's Health, Risk and Prevention, Breast Cancer Screening, GENERAL ELECTRIC COMPANY, Diagnostics and Screening.
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