Experimental optimization of photon-counting dual-energy thoracic imaging

Jeffrey Dhari; Jesse Tanguay

doi:10.1117/12.2652983

7 April 2023 Experimental optimization of photon-counting dual-energy thoracic imaging

Jeffrey Dhari, Jesse Tanguay

Proceedings Volume 12463, Medical Imaging 2023: Physics of Medical Imaging; 1246329 (2023) https://doi.org/10.1117/12.2652983
Event: SPIE Medical Imaging, 2023, San Diego, California, United States

Conference Poster

Abstract

Dual-energy (DE) thoracic imaging with photon counting detectors (PCDs) enables suppressing anatomic noise due to bone structures, potentially improving the detection of lung nodules. Relative to DE approaches based on the kV-switching method, a PCD-based, single-exposure approach may reduce the potential for motion artifacts and suppress electronic noise. In this work, we experimentally optimize the energy thresholds and tube voltages for single-exposure DE thoracic imaging implemented with PCDs. We used a phantom consisting of uniform acrylic slabs totaling 8.6 cm in thickness with a 16 cm air gap between slabs. A lung nodule was simulated by adding 2 mm of acrylic in a small region of interest in the center of the phantom. We imaged the phantom using a PCD with a 750-μm-thick cadmium telluride x-ray convertor, 100×100 μm² detector elements, two user-defined energy thresholds, and analog charge summing for charge sharing correction. We acquire images for tube voltages ranging from 90 kV to 130 kV in 10-kV increments. For each tube voltage, we varied the energy threshold from 32 keV to 90% of the maximum beam energy. The contrast-to-noise ratio (CNR) of the simulated nodule was measured for each combination of tube voltage and energy threshold. Optimal energy thresholds range from 45 keV to 55 keV for tube voltages ranging from 110 kV to 120 kV. When optimized for the energy thresholds, there was relatively little variability in the CNR across tube voltages beyond that due to measurement error. Future work will compare the CNR of PCD-based DE radiography with the conventional kV-switching approach.

Citation Download Citation

Jeffrey Dhari and Jesse Tanguay "Experimental optimization of photon-counting dual-energy thoracic imaging", Proc. SPIE 12463, Medical Imaging 2023: Physics of Medical Imaging, 1246329 (7 April 2023); https://doi.org/10.1117/12.2652983

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