Split energy level radiation detection

A digital radiography system comprising:

• (a) an x-ray source for directing x-rays along a path;
• (b) a split energy radiation detector spaced from the source to receive x-rays from said source, said detector comprising:
• (i) a first element comprising a first material of a kind which is preferentially responsive to radiation of a first energy range and being located in said path;
• (ii) a first sensor for sensing radiation response of said first element;
• (iii) a second element at least partially positioned to receive source radiation passing through said first element, said second element comprising a second material of a kind which is preferentially responsive to radiation of a second energy level extending higher than said first range;
• (iv) a second sensor for sensing radiation response of said second element;
• and
• (c) interpretive circuitry coupled to said sensors for at least partially digitizing information from said sensors and producing from said digitized information a representation of at least a portion of internal body structure of a subject when interposed in said path.

An imaging method comprising the steps of:

• (a) directing x-rays through a subject to be imaged, said x-rays including both higher and lower energy radiation;
• (b) separately detecting higher and lower energy x-radiation emergent from the subject by passing said radiation successively through scintillators comprising respectively different kinds of materials each preferentially responsive to radiation of a different one of said lower and higher energy ranges, including sensing responses of said scintillators;
• (c) at least partially digitizing information derived in said detecting step;
• (d) processing said digitized information;
• and
• (e) utilizing said processed digital information to produce a representation of internal structure of the subject.

An energy discriminating radiation detecting method utilizing first and second detector elements, a first of said elements being preferentially responsive to radiation of a first energy range, a second of said elements being preferentially responsive to energy of a second range extending higher than said first energy range, said method comprising the steps of;

• (a) directing radiation extending over both said first and second energy ranges through a subject;
• (b) positioning said first element to receive incident radiation emergent from the subject for response thereto;
• (c) positioning said second element to receive radiation from the source passing through said first element, and
• (d) filtering radiation transmitted through said first element prior to the arrival of said energy incident upon said second element.

A radiographic system comprising:

• (a) an x-ray source;
• (b) a radiation detector positioned to receive x-rays from the source;
• (c) a phototimer comprising:
• (i) an energy discriminating detector located to receive x-rays from the source and to produce signals indicating x-ray energy received in each of two energy ranges, and
• (ii) circuitry coupled between the discriminating detector and the source for controlling the source as a function of the x-rays detected in said two energy ranges.

A radiation imaging system comprising:

• (a) a source of penetrative radiation;
• (b) a dual energy detector assembly comprising two side-by-side columns of individual detector elements, one column being staggered with respect to the other by a distance equal to less than the dimension of a single detector element taken along the direction of its column, and additional detector elements positioned behind said columns, relative to said source;
• (c) mounting structure for maintaining said source and said detector assembly sufficiently spaced to provide a subject examining space and for maintaining said detector aligned continuously in said penetrative radiation when produced by said source;
• (d) power means for actuating said source to direct penetrative radation through the subject examination space and incident onto the detector assembly;
• (e) means coupled to said detector elements for producing an image of a portion of a subject, when located in the subject space, from radiation emergent from said subject.

A method for detecting area distribution of differing energy levels of penetrative radation, said method comprising:

• (a) detecting preferentially lower energy radiation by passing it through a first detector element including a scintillator and a plurality of segments;
• (b) detecting higher energy radiation by transmitting radiation emergent from said first detector incident onto a second detector element including a scintillator and a plurality of segments;
• (c) filtering penetrative radiation emergent from said first detector before said second detecting step, and
• (d) producing information in said first and second detecting steps spatially locating radiation over an area with respect to at least one of said detector elements.

A radiation imaging system comprising:

• (a) a source for propagating penetrative radiation along a path from a focal spot;
• (b) a detector assembly spaced from said source and interposed in said path, said detector assembly comprising:
• (i) a front array of individual detector elements, each front array element including a penetrative radiation sensitive receiving face having a discrete geometry, said front array element faces being located at substantially a distance F.sub.1 from said focal spot;
• (ii) a rear array of individual detector elements, each said rear array element including a penetrative radiation sensitive receiving face having a discrete geometry, wherein each element of said rear array is substantially aligned behind a corresponding element of said front array, with respect to said focal spot, and in which each rear array element has a receiving face which has a larger area then the receiving face of its corresponding aligned front array element, said rear array receiving faces being located at substantially a distance F.sub.2 from said focal spot, and
• (c) circuitry coupled to said detector arrays for producing a representation of radiation when incident on said detector elements.