A fast, spectrally-selective steady-state free precession (SSFP) imaging method is presented. Combining k-space data from SSFP sequences with certain phase schedules of radiofrequency excitation pulses permits manipulation of the spectral selectivity of the image. For example, lipid and water can be rapidly resolved. The contrast of each image depends on both T 1 and T 2 , and the relative contribution of the two relaxation mechanisms to image contrast can be controlled by adjusting the flip angle. Several applications of the technique are presented, including fast musculoskeletal imaging, brain imaging, and angiography. The technique is referred to herein as linear combination steady-state free precession (LCSSFP) and fluctuating equilibrium magnetic resonance (FEMR).

https://onlinelibrary.wiley.com/doi/pdf/10.1002/%28SICI%291522-2594%28200001%2943%3A1%3C82%3A%3AAID-MRM10%3E3.0.CO%3B2-9

Linear combination steady-state free precession MRI

A large imaging panel useful for direct radiography is prepared from two or four discrete modules, or tiles, containing arrays of solid state pixels. In preparing the large panels, a protective layer (22) is applied over the array of solid state pixels on each module to protect the modules during subsequent processing steps. One or two edges of each protected module is trimmed and polished to form a polished edge which is within a specified distance from the solid state pixels of the array. The polished edges typically are surface treated (e.g., by etching) to enhance wetting and adherence of applied adhesive material. Protected modules are then assembled on a flat surface to form a two-dimensional mosaic of the modules in a way that each polished edge of each module is placed adjacent to the polished edge of a neighboring module to form a gap and a precise separation between the pixels of neighboring modules which is the same as the separation between adjacent pixels of one of the modules.

Fabrication of large area x-ray image capturing element

A detector having a plurality of densely packed x-ray detectors arranged into an array. Each detector preferably includes a scintillator element which is optically coupled to a photodetector element, preferably with a fiber optic link. Each photodetector element is preferably optically separate from adjacent photodetector elements. The detector array preferably includes integral an alignment structure to align the scintillator elements with the photodetector elements. The scintillator array elements are preferably formed from materials which possess a fast response and a minimum afterglow time.

X-ray detector

An Ag film as a light-reflecting film is formed on one surface of an a-C substrate of a scintillator panel. The entire surface of the Ag film is covered with an SiN film for protecting the Ag film. A scintillator having a columnar structure, which converts an incident radiation into visible light, is formed on the surface of the SiN film. The scintillator is covered with a polyparaxylylene film together with the substrate.

Scintillator panel and radiation image sensor

An x-ray imaging system according to the present invention comprising a stepped scanning-beam x-ray source and a multi-detector array. The output of the multi-detector array is input to an image reconstruction engine which combines the outputs of the multiple detectors over selected steps of the x-ray beam to generate an x-ray image of the object. A collimating element, preferably in the form of a perforated grid containing an array of apertures, interposed between the x-ray source and an object to be x-rayed. A maneuverable positioner incorporating an x-ray sensitive marker allowing the determination of the precise position coordinates of the maneuverable positioner.

Scanning-beam x-ray imaging system

A radiation imager includes a photodetector array having topographically patterned surface features, which include support islands disposed over the active portion of one or more photodetectors in the photodetector array. A structured scintillator array having individual columnar scintillator elements is disposed in fixed relation to the photodetector array so that the individual scintillator elements are disposed on scintillator support islands. A barrier layer is disposed between the support islands and the photodetector array to minimize chemical interactions between the material forming the support island and the underlying photodetector array during the fabrication process. After the support islands have been patterned, the scintillator elements are grown by selectively depositing scintillator material on the support islands.

High sensitivity, high resolution, solid state x-ray imaging device with barrier layer

A radiation imager includes a photosensor array having a plurality of individually addressable pixels, each pixel having a photosensor island and an associated thin film transistor (TFT) disposed to selectively electrically couple the photosensor island to a predetermined address line. In each pixel a single common passivation layer is disposed over the TFT and the photosensor island such that the passivation layer is adjacent to both the outer surfaces of the TFT and portions of the photosensor island. In a method of fabricating a photosensor array as described above, after depositon of a source-drain metal layer, the layer is left unpatterned until after the photosensor island has been formed. In the formation of the photosensor island the source-drain metal layer serves as an etch stop to protect the TFT. Following formation of the photosensor island, the source-drain metal layer is patterned to form source and drain electrodes and fabrication of the TFT is completed. The single common passivation layer is then deposited over both the TFT and the photosensor island.

Method of fabricating radiation imager with single passivation dielectric for transistor and diode

A radiation imager includes a photosensor barrier layer disposed between an amorphous silicon photosensor array and the scintillator. The barrier layer includes two strata, the first stratum being silicon oxide disposed over the upper conductive layer of the photosensor array and the second stratum is silicon nitride that is disposed over the first stratum. The photosensor barrier layer has a shape that substantially conforms to the the shape of the underlying upper conductive layer and has a maximum thickness of about 3 microns. The silicon oxide and silicon nitride are deposited in a vapor deposition process at less than about 250° C. using tetraethoxysilane (TEOS) as the silicon source gas.

Method of fabricating solid state radiation imager with high integrity barrier layer

A radiation detector assembly, in some aspects, includes a detector substrate and a detector matrix array disposed on the detector substrate. A scintillator material is disposed on the detector matrix array and a moisture resistant layer is disposed on the scintillator material. The moisture resistant layer includes a plurality of sub-layers. The assembly also includes a protective cover disposed over the detector substrate and the moisture resistant layer, and an adhesive material disposed between the detector substrate and the cover. The adhesive material in some configurations is disposed so that it is not in contact with the moisture resistant layer.

Direct scintillator coating for radiation detector assembly longevity

A solid state imager is provided that comprises an imaging array of gated photodiodes. The imager comprises a plurality of photosensor pixels arranged in a pixel array, and each of the photosensor pixels includes a photodiode having a sidewall, the sidewall having a gate dielectric layer disposed thereon, and a field plate disposed around the photodiode body. The field plate comprises amorphous silicon disposed on the gate dielectric layer and extends substantially completely around the sidewall of said photodiode. The field plate is electrically coupled to the common electrode of the imaging array so that the field plate creates an electric field around the photodiode body in correspondence with the potential of said common electrode. A method of fabricating the gated photodiode array is also provided.

Ching-Yeu Wei

Papers

High sensitivity, high resolution, solid state x-ray imaging device with barrier layer

Method of fabricating radiation imager with single passivation dielectric for transistor and diode

Method of fabricating solid state radiation imager with high integrity barrier layer

Direct scintillator coating for radiation detector assembly longevity

Solid state imager having gated photodiodes and method for making same