Dual-layer detector system and method for spectral imaging and contrast enhanced digital breast tomosynthesis

An apparatus comprising:

• a separation filter for spectrally separating radiation from an X-ray radiation source into first energy level band and second energy level band for incident radiation upon an imaging object;
• a first substrate;
• a x-ray photon counting front detector formed on the first substrate, the x-ray photon counting detector comprising an array of detector pixels, each detector pixel comprising a sensor for detecting interactions of individual x-ray photons of the incident radiation transmitted through the imaging object during a fixed period of time;
• each detector pixel of the array having an associated count circuit operable to generate a first electrical signal representing a respective count of the number of detected interactions of individual x-ray photons of the first energy level band and a second electrical signal representing a respective count of the number of detected interactions of individual x-ray photons of the second energy level band, wherein the first electrical signals and second electrical signals from the detector pixels of the array provide respective low energy and high energy spectral images of the imaging object;
• and
• a back detector formed on a second substrate and located below said first substrate, said back detector comprising:
• a scintillating screen for converting incident radiation containing x-ray photons of said second energy level band transmitted through the imaging object and through said front detector into light photons;
• and
• a photosensor array disposed between said scintillating screen and the second substrate for said back detector, said photosensor array operable to capture the light photons from the scintillating screen and convert the captured light photons into further electrical signals, said further electrical signals operable for combination with said second electrical signals from said detector pixel array to obtain images of said imaging object.

An apparatus comprising:

• a separation filter for spectrally separating radiation from an X-ray radiation source into a first energy level band and second energy level band for incident radiation upon an imaging object, the second energy level band being of a greater energy than the first energy level band;
• a glass substrate;
• a front integrating detector formed on the glass substrate, the front integrating detector comprising first pixel sensors for directly converting first energy level band x-ray photons of the incident radiation transmitted through the imaging into first image signals configurable to form a low energy image of the imaging object;
• and
• a back integrating detector located below the glass substrate, the back integrating detector comprising second pixel sensors for indirectly converting second energy level band x-ray photons of the incident radiation transmitted through the imaging object and through the front integrating detector and the substrate and into second image signals configurable to form a high energy image of the imaging object.

An x-ray imaging system comprising:

• an x-ray radiation source;
• a first low energy band filter configured for registration in front of said x-ray radiation source for permitting transmission of a first low energy level band x-ray radiation for incidence upon an imaging object at a first time instance;
• a second high energy band filter configured for subsequent registration in front of said x-ray radiation source for permitting transmission of a second high energy level band x-ray radiation for incidence upon said imaging object at a second time instance;
• and
• a dual layer x-ray radiation detector comprising:
• a glass substrate;
• a front energy integrating detector formed on said glass substrate, said front energy integrating detector comprising first pixel sensors for directly converting photons of the first low energy level band of an incident x-ray radiation transmitted through an imaging object into first image signals during said first time instance and directly converting photons of the second higher energy level band of incident x-ray radiation transmitted through the imaging object into second image signals during said second time instance;
• and
• a back energy integrating detector formed below said glass substrate, said back energy integrating detector comprising second pixel sensors for indirectly converting photons of the first low energy level band of the incident x-ray radiation transmitted through said imaging object and through said front energy integrating detector and said glass substrate into further first image signals during said first time instance, and indirectly converting photons of the second higher energy level band of incident x-ray radiation transmitted through the imaging object and through said front energy integrating detector and said glass substrate into further second image signals during said second time instance;
• wherein said first image signals from the front detector are combinable with said further first image signals from the back detector to form a low energy image of said imaging object, and
• said second image signals from the front detector are combinable with said further second image signals from the back detector to form a high energy image of said imaging object.

A method for x-ray imaging comprising:

• providing a dual layer x-ray radiation detector below an object to be imaged with incident x-ray radiation, said dual layer x-ray radiation detector comprising:
• a glass substrate;
• a front energy integrating detector formed on said glass substrate comprising first pixel sensors;
• and
• a back energy integrating detector formed below said glass substrate comprising second pixel sensors;
• registering a first low energy band filter in front of an x-ray radiation source for permitting transmission of a first low energy level band x-ray radiation for incidence upon said imaging object at a first time instance;
• registering a second high energy band filter in front of said x-ray radiation source for permitting transmission of a second high energy level band x-ray radiation for incidence upon said imaging object at a second time instance, and dual layer x-ray radiation detector receiving said first low energy level band x-ray radiation at said first time instance and second high energy level band x-ray radiation at said second time instance through said imaging object;
• directly converting, using said first pixel sensors of said front energy integrating detector, photons of the first low energy level band of an incident x-ray radiation transmitted through the imaging object into first image signals during said first time instance and directly converting photons of the second higher energy level band of incident x-ray radiation transmitted through the imaging object into second image signals during said second time instance;
• indirectly converting, using said second pixel sensors of said back energy integrating detector, photons of the first low energy level band of the incident x-ray radiation transmitted through said imaging object and through said front energy integrating detector and said glass substrate into further first image signals during said first time instance, and indirectly converting photons of the second higher energy level band of incident x-ray radiation transmitted through the imaging object and through said front energy integrating detector and said glass substrate into further second image signals during said second time instance;
• forming, from said first image signals and further first image signals, a low energy image of said imaging object,
• forming, from said second image signals and further second image signals, a high energy image of said imaging object.