Method and system of x-ray data calibration

Abstract

A process of data calibration and correction is disclosed that utilizes feedback from a temperature sensor of an x-ray detector to isolate or otherwise select an appropriate calibration or correction map that is specific to the temperature of the x-ray detector during data acquisition. The method is also designed to take into account changes in power transients of an x-ray detector between the acquisition of imaging data and the acquisition of offset data. The method is particularly applicable in optimally selecting and applying gain correction, conversion factor, bad pixel, and offset calibrations.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]The present invention is a continuation and claims priority of U.S. patent application Ser. No. 10 / 905,935 filed Jan. 27, 2005.BACKGROUND OF THE INVENTION[0002]The present invention relates generally to diagnostic imaging and, more particularly, to a method and system of calibrating an x-ray detector to reduce artifacts in an image reconstructed from x-ray attenuation imaging data acquired by the x-ray detector.[0003]X-ray imaging is a non-invasive technique to capture images of medical patients for clinical diagnosis as well as inspect the contents of sealed containers, such as luggage, packages, and other parcels. Increasingly, x-ray systems are being used to non-invasively search and / or screen airplane, boat, and train passengers as well as entrants to court buildings, government offices, sporting events, concerts, and other venues of heightened security interest. To capture these images, an x-ray source irradiates a scan subject with a...

AI Technical Summary

Benefits of technology

"The present invention is about a method of calibrating an x-ray detector by using feedback from temperature sensors on the detector. This method takes into account changes in power transients and can select the appropriate calibration or correction map for the temperature of the detector during data acquisition. The method can be used to calibrate the radiographic data output by the detector and reduce artifacts in the image reconstructed from the data. The invention also includes a system and method for identifying and ignoring corrupted detector elements during image reconstruction. Overall, the invention improves the accuracy and reliability of x-ray imaging."

Problems solved by technology

The chiller, however, adds to the size, weight, and complexity of the detector.

Since natural convection is a passive means of regulating temperature, it can be difficult to timely maintain detector temperature during heavy detector usage periods.

If the intervals between data acquisitions are short, the x-ray detector may not sufficiently cool between data acquisitions to maintain a desired thermal equilibrium.

As a result of the acquisition of data when the detector is outside the desired temperature range, image quality is affected.

Moreover, the calibration and corrective measures generally ignore the specific temperature of x-ray detector even when the temperature is within the desired range.

By failing to take into account the specific temperature of the x-ray detector or that the temperature is outside a predefined temperature range, the calibration and corrective measures may inadequately or improperly applied.

Also affecting the accuracy and precision of x-ray data calibration that is particularly applicable for offset correction is the time interval between the acquisition of x-ray imaging data and the acquisition of offset imaging data.

As a result of the time differences between the acquisition of imaging data and offset data, power transients may introduce artifacts that are not removed in the subtraction process.

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