Disclosed herein are devices and methods for modifying a conventional imager to have functional features similar to that of a lock-in camera. Optical mask devices are configured to be coupled to conventional imager sensors and the configuration of the mask devices can be adjusted to acquire image data in rapid succession. One variation of an optical mask device comprises a substrate comprising a pattern of light-blocking and light-transmitting regions and an attachment structure for coupling the optical mask device to the imager. The substrate is configured to adjust the position of the light-blocking regions and light-transmitting regions relative to the light-sensing region of the imager based on a set of one or more predetermined substrate configurations. In some variations, the mask device and/or the imager sensor may be mechanically moved relative to each other based on the set of one or more predetermined substrate configurations.

A method for evaluating image quality is provided. The method may include: obtaining an image, the image including a plurality of elements, each element of the plurality of elements being a pixel or voxel, each element having a gray level; determining, based on a maximum gray level of the plurality of elements, one or more thresholds for segmenting the image; determining one or more sub-images of a region of interest by segmenting, based on the one or more thresholds, the image; and determining, based on the one or more sub-images of the region of interest, a quality index for the image.

Techniques are provided for reconstructing cardiac frequency phenomena from a sequence of angiographic images, i.e., two-dimensional projection images acquired at faster than cardiac rate (greater than two-fold), and analyzed to provide a spatiotemporal reconstruction of moving vascular pulse waves according to that projection. In aspects, a cardiac frequency bandpass filter and/or a Eulerian magnification may be applied to the angiographic data to output the spatiotemporal reconstruction of cardiac frequency angiographic phenomena.

A method of scanning parameter optimization, which method may be useful with image-guided radiation therapy (IGRT), allows for controlling exposure of a beam from an x-ray source and/or controlling the detection mechanism for an x-ray detector of imaging radiation of a radiation-delivery device based on one or more parameters of a region of interest of a patient. The one or more parameters of the region of interest may include a dimension, outer contour, density, location relative to an outlet of the beam, location relative to isocenter, location to the whole patient body, etc. Exposure of the patient to the beam may be varied via modulation of one or more scanning parameters for controlling an aspect of the beam and/or the detector to provide for targeted and or reduced radiation exposure of the patient or portion of the patient, and/or for improved quality of guiding images. The modulation may be varied depending on a view angle of the region of interest from a portion of the radiation-delivery device.

Various methods and systems are provided for stationary CT imaging. In one embodiment, an imaging system comprises a stationary distributed x-ray source unit comprising a plurality of emitters positioned to emit x-ray beams through the imaging volume, one or more detector arrays extending around at least a portion of an imaging volume, each detector array comprising a plurality of detector elements, each detector element configured to receive x-ray beams from more than one emitter, and an anti-scatter device configured to be positioned between one or more emitters of the plurality of emitters and an object in the imaging volume.

A method for reconstructing an image may include obtaining scan data relating to a subject. The method may also include determining a first field of view (FOV) and determining a second FOV. The method may further include reconstructing a first image based on a first portion of the scan data corresponding to the first field of view, and reconstructing a second image based on a second portion of the scan data corresponding to the second field of view. The method may also include generating a third image based on the first image and the second image.

An x-ray imaging apparatus and associated methods are provided to receive measured projection data from a wide aperture scan of a wide axial region and a narrow aperture scan of a narrow axial region within the wide axial region and determine an estimated scatter in the wide axial region using an optimized scatter estimation technique. The optimized scatter estimation technique is based on the difference between the measured scatter in the narrow axial region and the estimated scatter in the narrow axial region. Kernel-based scatter estimation/correction techniques can be fitted to minimize the scatter difference in the narrow axial region and thereafter applying the fitted (optimized) kernel-based scatter estimation/correction to the wide axial region. Optimizations can occur in the projection data domain or the reconstruction domain. Iterative processes are also utilized.

A method of imaging includes obtaining a plurality of dynamic sinograms, each dynamic sinogram representing detection events of gamma rays at a plurality of detector elements, summing the plurality of dynamic sinograms to generate an activity map based on a radioactivity level of the gamma rays; reconstructing, using the plurality of dynamic sinograms, a plurality of dynamic images, each of the plurality of dynamic images corresponding to one of the each of the plurality of dynamic sinograms, and generating, using the plurality of dynamic sinograms and the activity map, at least one parametric image.

A medical imaging apparatus includes an X-ray source configured to irradiate X-rays to an object; an X-ray detector configured to detect the X-rays radiated from the X-ray source to obtain projection data; and an image processor configured to reconstruct the projection data based on a motion parameter representing movement of at least one of the object, the X-ray source, and the X-ray detector, and to generate a medical image by applying a weighting process to the reconstructed projection data.

Multimodal imaging apparatus and methods include a rotatable gantry system with multiple sources of radiation comprising different energy levels (for example, kV and MV). Fast slip-ring technology and helical scans allow data from multiple sources of radiation to be combined or utilized to generate improved images and workflows, including for IGRT. Features include increasing the precision of spatial registrations between respective image sets to allow more precise radiation treatment delivery, reducing image artifacts (e.g., scatter, metal and beam hardening, image blur, motion, etc.), and utilization of dual energy imaging (e.g., for material separation and quantitative imaging, patient setup, online adaptive IGRT, etc.).