US 6,272,207 B1 · Method and apparatus for obtaining high-resolution digital X-ray and gamma ray images

Abstract

An apparatus and method for obtaining a high-resolution digital image of an object or objects irradiated with radiation having a wavelength in the x-ray or gamma ray spectrum generated by a radiation source, or of an object or objects emitting radiation within the x-ray or gamma ray spectrum. The apparatus comprises a detector matrix and a radiation mask. The detector matrix comprises a plurality of detector pixels, each comprising a detection surface having a respective surface area which generates a signal in response to an energy stimulus. The radiation mask has an opaque portion, and a plurality of apertures. The aperture size and position relative to the detector array determines the image resolution not the size of the detector pixels. The mask is positioned between the detector matrix and the radiation source, such that the opaque portion prevents portions of the radiation from passing through the mask, and each of the apertures permits a portion of the radiation which has passed through or has been emitted from a respective portion of the object to propagate onto an area of the detection surface, less than the surface area, of a respective one of the detector pixels. The signal from a large detector pixel or from a group of small detector pixels represent an image of the respective portion of the object. The detector matrix and radiation mask are moved in synchronism in relation to the object to enable the areas of the detection surfaces of the detector pixels to receive portions of the radiation propagating through or emitted from other portions of the object, and to output signals representative of those other portions. These steps of moving the detector pixels and mask and irradiating the object are repeated until digital images of all portions of the object have been obtained. Alternatively, the x-ray source can be moved to image all portions of the object. The images are then arranged into an image representative of the entire object.

Claims84

Dependent claims

An apparatus for obtaining a digital image of an object or objects being irradiated with radiation having a wavelength in the x-ray or gamma ray spectrum generated by a radiation source, comprising:

a detector matrix, comprising a plurality of detector pixels, arranged such that the centers of each adjacent detector pixels are spaced at a first pixel pitch distance from each other in a direction along the width of said detector matrix, and at a second pixel pitch distance from each other in a direction along the length of said detector matrix, with each detector pixel comprising a detection surface having a respective surface area and being adapted to generate a signal in response to an energy stimulus applied thereto;
and
at least one radiation mask having an opaque portion and a plurality of apertures therein, arranged such that the centers of each adjacent apertures are spaced at a first aperture pitch distance from each other in a direction along the width of said radiation mask, and at a second aperture pitch distance from each other in a direction along the length of said radiation mask, said first and second aperture pitch distances being smaller than said first and second pixel pitch distances, respectively, said radiation mask being positioned between the radiation source and the object or objects, such that said opaque portion substantially prevents portions of said radiation from passing therethrough, and each of said apertures permits a portion of said radiation that has passed through to strike at least a portion of said detection surface of a respective one of said detector pixels, so that said detector pixels each output a respective signal representative of an image of said respective portion of said object.

A method for using a detector matrix comprising a plurality of detector pixels to obtain a digital image of an object or objects the detector pixels being arranged such that the centers of each adjacent detector pixels are spaced at a first pixel pitch distance from each other in a direction along the width of said detector matrix, and at a second pixel pitch distance from each other in a direction along the length of said detector matrix, the method comprising the steps of:

emitting from a radiation source radiation having a wavelength in the x-ray or gamma ray spectrum generated in a direction toward said object or objects;
and
positioning at least one radiation mask having an opaque portion and a plurality of apertures therein between said radiation source and said object or objects, said radiation mask being configured such that the centers of each adjacent apertures are spaced at a first aperture pitch distance from each other in a direction along the width of said radiation mask, and at a second aperture pitch distance from each other in a direction along the length of said radiation mask, said first and second aperture pitch distances being smaller than said first and second pixel pitch distances, said opaque portion substantially preventing first portions of said radiation from passing therethrough, and each of said apertures permitting a respective second portion of said radiation that has passed through to strike at least a portion of said detection surface of a respective one of said detector pixels, so that said detector pixels each output a respective signal representative of an image of said respective portion of said object.

An apparatus for obtaining a digital image of an object or objects being irradiated with radiation having a wavelength in the x-ray or gamma ray spectrum generated by a radiation source, or of an object or objects emitting radiation within the x-ray or gamma ray spectrum, comprising:

a detector matrix, comprising a plurality of detector pixels, each detector pixel comprising a detection surface having a respective surface area and being adapted to generate a signal in response to an energy stimulus applied thereto;
and
at least one radiation mask having an opaque portion and a plurality of apertures therein, said radiation mask being positioned between the detector matrix and the object or objects, such that said opaque portion substantially prevents portions of said radiation from passing therethrough, and each of said apertures permits a portion of said radiation that has passed through or has been emitted from a respective portion of said object to pass therethrough and strike a portion of said detection surface of a respective one of said detector pixels, said portion being less than the entire said detection surface of said respective one said detector pixel, so that said detector pixels each output a respective signal representative of an image of said respective portion of said object having a resolution based on a size of a respective one of said apertures.

A method for using a detector matrix comprising a plurality of detector pixels to obtain a digital image of an object or objects being irradiated with radiation having a wavelength in the x-ray or gamma ray spectrum generated by a radiation source, or of an object or objects emitting radiation within the x-ray or gamma ray spectrum, the method comprising the steps of:

preventing first portions of said radiation which have passed through said object or have been emitted from said object from propagating onto any of said detector pixels;
and
permitting second portions of said radiation which have passed through or have been emitted from respective portions of said object to each propagate onto at least a portion of a detection surface of at least a respective one of said detector pixels, so that said detector pixels each output a respective signal representative of an image of said respective portion of said object;
wherein:
said detector pixels are arranged in said detector matrix in a plurality of detector rows, each comprising a first number of said detector pixels, and a plurality of detector columns, each comprising a second number of said detector pixels, said detector pixels in each of said detector rows being separated by a first pixel pitch distance, and said detector pixels in each of said detector columns being separated by a second pixel pitch distance;
and
a radiation mask is disposed between said radiation source and said object, or between said object and said detector matrix, and includes apertures that are arranged in a plurality of aperture rows, each comprising a first number of apertures, and a plurality of aperture columns, each comprising a second number of said apertures;
and
wherein said method further comprises at least one of the following steps:
after performing said preventing and permitting steps, performing a first step of moving said detector matrix and said radiation mask in synchronism in relation to said object by a first distance equal to a fraction of said first pixel pitch distance in a first direction substantially parallel to said detector rows, and repeating said preventing and permitting steps to enable said areas of said detection surfaces of said detector pixels to receive portions of said radiation propagating through or emitted from other portions of said object and to output signals representative of said other portions;
and
after performing said preventing and permitting steps, performing a second step of moving said detector matrix and said radiation mask in synchronism in relation to said object by a second distance equal to a fraction of said second pixel pitch distance in a second direction substantially parallel to said detector rows, and repeating said preventing and permitting steps to enable said areas of said detection surfaces of said detector pixels to receive portions of said radiation propagating through or emitted from other portions of said object and to output signals representative of said other portions.

9 more elements

Dependencies are inferred from the claim text.

Method and apparatus for obtaining high-resolution digital X-ray and gamma ray images

Life of this patent

Method and apparatus for obtaining high-resolution digital X-ray and gamma ray images

Life of this patent

Abstract

Claims84