Two-Dimensional Breast Tomosynthesis with a Stationary Array of Thermionic Cathodes for Higher Resolution Images and Fast Acquisition
J Boone1*, A Sisniega2, J Siewerdsen3, P Schwoebel4, (1) UC Davis Medical Center, Sacramento, CA, (2) Johns Hopkins University, Balitmore, MD, (3) Johns Hopkins University, Department of Biomedical Engineering, Baltimore, MD, (4) SRI International, Albuquerque, NM
Presentations
SU-F-TRACK 3-5 (Sunday, 7/25/2021) 4:30 PM - 5:30 PM [Eastern Time (GMT-4)]
Purpose: To develop a two-dimensional (2D) stationary thermionic x-ray source array for breast tomosynthesis, in order to dramatically improve image quality and reduce acquisition time.
Methods: A Multiple X-ray source Array (MXA) was developed with 11 focal spots distributed along a ~28 cm long rotating anode shaft which supports eleven ~10 cm diameter anode disks. Individual thermionic (hot) grid-pulsed cathode assemblies supply pulsed electron beams which strike the end of each disk. All x-ray sources are within the same vacuum enclosure and are individually addressable using TTL control electronics. Coupled with a flat panel detector, this 11-source array of x-ray sources was used to collect tomosynthesis data using an orange as a test object. By adding a second row of cathodes on the other side of the anode disks, two rows of 11 x-ray focal spots will produce a 2D array (2 x 11) of sources for breast tomosynthesis. A breast CT data set was used to simulate 22 projection images with the 2D source distribution, and a model-based iterative reconstruction algorithm with spatially invariant regularization was used to reconstruct tomosynthesis images.
Results: The 11-source x-ray tube demonstrated rapid acquisition, robust performance at 35 kV, and small focal spots (~0.3 mm each). Computer simulation of the proposed 2D array tomosynthesis system with 22 source positions shows a marked improvement for in-plane sharpness and thinner slices. Acquisition time using a 20 FPS detector would be 1.1 sec.
Conclusion: All clinical breast tomosynthesis systems use a one-dimensional arc with acquisition times ranging from 3.7 to 25 s. Due to constraints on acquisition time, moving sources are not practical for 2D geometry tomosynthesis. The proposed stationary hot-cathode source array provides rapid acquisition (1.1 s for 22 sources) for low motion artifact tomosynthesis images with much better slice separation and in-plane object delineation.
Funding Support, Disclosures, and Conflict of Interest: JMB is a stockowner and board member in Izotropic Corp, has funding from Canon Medical Systems, is on the board of ICRU, receives a stipend from AAPM as Editor-in-Chief of Medical Physics, and receives book royalties from Wolters Kluwer. JMB and JHS have patent-pending with royalties from The Phantom Lab.
Handouts
Keywords
Taxonomy
IM- Breast X-Ray Imaging: Digital Breast Tomosynthesis (DBT)
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