A method is provided for forming a three-dimensional article through successive fusion of parts of a powder bed. The method includes the steps of: applying a first powder layer on a work table; directing an electron beam from an electron beam source over the work table, the directing of the electron beam causing the first powder layer to fuse in first selected locations according to a pre-determined model, so as to form a first part of a cross section of the three dimensional article, and intensity modulating X-rays from the powder layer or from a clean work table with a patterned aperture modulator and a patterned aperture resolver, wherein a verification of at least one of a size, position, scan speed, or shape of the electron beam is achieved by comparing detected intensity modulated X-ray signals with saved reference values.

A method of reconstructing the position of a source using a gamma camera. The gamma camera combines two imaging modalities: a coded mask imaging modality and a Compton imaging modality. The method comprises the selection of at least one isotope, the reconstruction being carried out according to a Bayesian probabilistic approach, taking into account each selected isotope.

Improved imaging devices and methods. A portable SPECT imaging device may co-register with imaging modalities such as ultrasound. Gamma camera panels including gamma camera sensors may be connected to a mechanical arm. A coded aperture mask may be placed in front of a gamma-ray photon sensor and used to construct a high-resolution three-dimensional map of radioisotope distributions inside a patient, which can be generated by scanning the patient from a reduced range of directions around the patient and with radiation sensors placed in close proximity to this patient. Increased imaging sensitivity and resolution is provided. The SPECT imaging device can be used to guide medical interventions, such as biopsies and ablation therapies, and can also be used to guide surgeries.

For emission tomography, a greater number of emissions are detected. To detect a greater number of emissions and provide better resolution than provided by a parallel hole collimator, the collimator is replaced by an attenuation object with exterior and interior edges. Rather than enforcing directionality, larger holes with different shapes may be used to allow a greater number of emissions to be detected. By moving the attenuation object, the differences in the shadows on the sensor may be used as a time-encoded aperture to reconstruct the source of emissions with greater resolution and sensitivity than where a fixed parallel hole collimator is used.

Systems and methods for a non-invasive determination of the characteristics of a light source include placing a non-redundant aperture mask in a path of light emanating from the light source, capturing an image of the interference pattern caused by the light passing through the non-redundant aperture mask, generating visibilities of the light distribution from the image, and determining the characteristics of the light source based on the visibilities of the light distribution, including a process of self-calibration in which the phase-solutions provide a sub-nanometer precision wavefront sensor, and through the use of closure amplitudes without requiring the process of self-calibration.

Measurement system and method are presented for determining spatial distribution of chemical elements in a sample. The system comprises a measurement unit and a control system. The measurement unit is adapted to produce primary radiation having spectral characteristic adapted to excite a number M of chemical elements in the sample to induce secondary radiation responses, and generate spectral measured data indicative of intensity of detected responses. The primary radiation interacting with the sample includes a sequence of two or more encoded radiation patterns of the primary radiation, each having its predetermined spatial intensity pattern. The measured spectral data includes a sequence of data pieces, each being modulated by the respective one of the two or more predetermined spatial intensity patterns of the encoded primary radiation and characterized by sparsity in spectral domain with respect to each spectral component of the secondary radiation response.

Improved imaging devices and methods. A portable SPECT imaging device may co-register with imaging modalities such as ultrasound. Gamma camera panels including gamma camera sensors may be connected to a mechanical arm. A coded aperture mask may be placed in front of a gamma-ray photon sensor and used to construct a high-resolution three-dimensional map of radioisotope distributions inside a patient, which can be generated by scanning the patient from a reduced range of directions around the patient and with radiation sensors placed in close proximity to this patient. Increased imaging sensitivity and resolution is provided. The SPECT imaging device can be used to guide medical interventions, such as biopsies and ablation therapies, and can also be used to guide surgeries.

A tuning method for a collimator of a CT machine, which, in each cycle of X-ray scan operation and stop, may include determining whether an X-ray is generated from the anode plate; calculating the Z-direction heating displacement of the slot plate during the current scan based on a detected X-ray, driving the slot plate to move by the heating displacement in the Z-direction, calculating the total Z-direction heating displacement of the slot plate at the end of the current scan, calculating the cooling displacement of the slot plate during the current stop based on the stop time of the X-ray, and driving the slot plate to move.