Multispectral single-scan lung imaging system: initial feasibility

Abstract

This paper describes a system for multi-spectral single-scan lung imaging. The proposed approach relies on a low noise detector sampled at a high rate. The proposed method overcomes limitations of CCD time-and-delay integration slot-scanning systems. The system design and preliminary specifications are described. The results of initial spectral and system simulations in support of system feasibility per the outlined specifications are described. Initial investigations support the potential of the proposed approach to alleviate four shortcomings of the current digital flat-panel approach to chest radiography: (i) by enabling dynamic multi-spectral imaging in a single scan, the approach reduces the time delay between exposures, thus reducing sensitivity to motion; (ii) the approach enables dynamic technique feedback and technique adaptation, eliminating the need for a pre-exposures and reducing the likelihood of poor x-ray techniques in local image areas; (iii) by enabling direct measurement of the scatter field, the proposed method allows further scatter correction resulting in image quality improvements; (iv) finally, full-frame sampling of a digital detector allows imaging of the beam penumbra, thereby reclaiming the detection quantum efficiency loss due to over-collimation in current TDI slotscanning approach; the resulting DQE potentially exceeds that of flat-panel detectors by a factor up to two.

New CT system architectures for high temporal resolution with applications to improved geometric dose efficiency and cardiac imaging

“…For instance, with respect to spectral multiplexing, tungsten target spectra at (60 kVp, 2-mm Al filtration) and at (120 kVp, 2-mm Al, 3-mm Cu) present a spectral overlap of just a few percent. 5 However, the total flux of the 120 kVp spectrum is significantly reduced by the copper filtration; also scatter and fluorescence effects in the detector material do contribute a "cross talk" (spectrum tailing) from the high-energy band to the low energy band(s). Similarly, time multiplexing leads to an instantaneous power increase requirement proportional to the respective exposure times for the sources to be multiplexed.…”