PROCEEDINGS ARTICLE | March 22, 2016
Proc. SPIE. 9783, Medical Imaging 2016: Physics of Medical Imaging
KEYWORDS: X-ray computed tomography, Tumors, Imaging systems, X-rays, Lung, Radiotherapy, Image quality, Digital imaging, Lung cancer, Digital x-ray imaging
Two simulated sets of digital tomosynthesis images of the lungs, each acquired at a 90 degree angle from the other,
with 19 projection images used for each set and SART iterative reconstructed, gives dual tomosynthesis slice image
quality approaching that of spiral CT, and with a data acquisition time that is 3% of that of cone beam CT. This fast
kV acquisition, should allow near real time tracking of lung tumors in patients receiving SBRT, based on a novel
TumoTrakTM multi-source X-ray tube design. Until this TumoTrakTM prototype is completed over the next year, its
projected performance was simulated from the DRR images created from a spiral CT data set from a lung cancer
patient. The resulting dual digital tomosynthesis reconstructed images of the lung tumor were exceptional and
approached that of the gold standard Feldkamp CT reconstruction of breath hold, diagnostic, spiral, multirow, CT
data. The relative dose at 46 mAs was less than 10% of what it would have been if the digital tomosynthesis had been
done at the 472 mAs of the CT data set. This is for a 0.77 fps imaging rate sufficient to resolve respiratory motion in
many free breathing patients during SBRT. Such image guidance could decrease the magnitudes of targeting error
margins by as much as 20 mm or more in the craniocaudal direction for lower lobe lesions while markedly reducing
dose to normal lung, heart and other critical structures. These initial results suggest a wide range of topics for future
work.
