摘要:
An apparatus and a method of processing a collection of uncorrected radiographs are described with the apparatus comprising an X-ray scatter compensator and a controller. The compensator is configured for iteratively generating a refined value of a normalized estimated X-ray scatter signal corresponding to an uncorrected radiograph of said collection of uncorrected radiographs. The controller is configured to be coupled to the compensator and further configured to subtract said refined value of said normalized estimated X-ray scatter signal from a corresponding normalized total X-ray signal of a respective one of said uncorrected radiographs so as to form a corresponding corrected radiograph.
摘要:
The present invention, in one form, is a system for reducing contribution of scatter signal to an image of an object constructed from projection data acquired during a computed tomography scan. The system includes an x-ray source which emits an x-ray beam toward a detector array. A collimator plate is movable with respect to the detector array. The system is configured to move the collimator between a first position and a second position. In the first and second positions, the collimator does not cover the detector array, i.e., the collimator does not collimate the x-ray beam impacting the detector array. When moving between the first and second positions, the collimator at least partially covers the detector array, i.e., the collimator at least partially collimates the x-ray beam impacting the detector array. A first signal intensity at the detector array is obtained when the collimator is in the first position and a second signal intensity at the detector array is obtained when the collimator is moved between the first and second position. The determined signal intensities are then utilized to determine the scatter signal of the x-ray beam and to generate substantially uncorrupted projection data.
摘要:
A flexible imager, for imaging a subject illuminated by incident radiation, includes a flexible substrate, a photosensor array disposed on the flexible substrate, and a scintillator. The scintillator is disposed so as to receive and absorb the incident radiation, is configured to convert the incident radiation to optical photons, and is optically coupled to the photosensor array. The photosensor array is configured to receive the optical photons and to generate an electrical signal corresponding to the optical photons. A digital imaging method for imaging subject includes conforming flexible digital imager to subject, the subject being positioned between flexible digital imager and a radiation source. The method further includes activating radiation source to expose the subject to radiation and collecting an image with the flexible digital imager.
摘要:
Focal spot position determination systems having a high sensitivity to focal spot movement for use in connection with multi-slice computed tomography imaging systems are described. In one embodiment, the determination system is configured for application in a two slice system. Signals from adjacent detector cells in separate rows are compared to determine focal spot position. More particularly, the signal intensity A of the signal output by a first detector cell and the signal intensity B of the signal output by the second detector cell are related to the position of the focal spot. That is, the z position of the centerline of the fan beam can be determined by relating the signal intensities A and B according to the ratio [(A−B)/(A+B)]. Such ratio is representative of the beam location and can be used to control adjustment of the imaging system pre-patient collimator to maintain the beam in the desired position.
摘要:
A multi-slice or volumetric CT system has a 2D array of detector elements arranged in columns along the slice direction and rows along the in-slice direction. Channels in a digital acquisition system connect to the respective columns and a switch assembly is operated during a scan to sequentially enable detector elements in each column either one or two at a time. By enabling two elements at a time, the SNR of the acquired data is increased and the expected resolution loss in the slice direction is compensated for by detector wobbling.
摘要:
An attenuator and detector cell arrangement for generating a signal ratio representative of focal spot position is described. The ratio is highly sensitive to focal spot position and facilitates generating, or reconstructing, a high quality image from the projection data. Further, and importantly, even if one detector cell is fully flooded, the signal intensity from such cell will vary depending upon the alignment between the focal spot and attenuator slot. Therefore, the focal spot movement detector is effective for detecting fan beam movement even if the detector cell is fully flooded. In one embodiment, the x-ray beam attenuator is configured to be positioned over the detecting surface of z-position detection cells. Slots or openings extend through the attenuator so that at least a portion of each detector cell is in free communication with an x-ray beam from the x-ray source. The slots are positioned and oriented so that one detector cell signal has its highest x-ray response at one extreme position along the focal spot trajectory and the other detector cell has its highest x-ray response at the other extreme position along the focal spot trajectory.