Dedicated breast CT is an emerging technology with less than 10 clinical prototypes worldwide. It can eliminate breast tissue superposition and provides 3D images at near-isotropic spatial resolution. Earlier generations of breast CT used detectors that were suboptimal in terms of inactive region near the chest wall (chest-wall dead space), limited resolution and frame rate, and higher electronic (system) noise. Newer detectors such as the one proposed in this research reduces electronic noise by a factor of 20-30, increases the spatial resolution by a factor of at least 2, and has chest-wall dead space similar to mammography that would enable excellent posterior coverage. However, these detectors are smaller in size and it is a challenge to cover large breasts. Hence, in this research we propose to design, develop and integrate the high-resolution, low-noise detector in a laterally-shifted imaging geometry that would cover the largest breast. The three major concerns regarding breast CT are, chest-wall and axillary coverage, ability to visualize microcalcification clusters, and the ability to provide diagnostic quality images at radiation dose equivalent to screening mammography. We hypothesize that the proposed technological approach will address all of these concerns. Chest-wall coverage will be improved with the proposed detector due to its chest-wall dead space of 3 mm compared to 34.2 mm used in previous clinical studies. With the proposed detector, the combination of smaller pixel size (0.15 mm compared to 0.388 mm detector pixel size in previous generations) and lower electronic noise (~200 electrons compared to ~6,000 electrons in previous generations) will allow low-dose high-resolution imaging. Additionally, it allows for completing the scan in less than 4 seconds compared to at least 10 seconds in previous generations, reducing the possibility of patient motion. The study will also integrate a beam shaping filter that further reduces the radiation dose and will incorporate scatter-reduction and residual scatter-correction methods that will improve the quantitative accuracy. This would allow for more reliable use of the Hounsfield scale (CT numbers) that can allow for better discrimination between benign and malignant findings. The research is broadly organized in three phases. In the first phase, all aspect of the design will be verified and validated on a bench-top platform to determine the best choice of parameters. In the second phase, these results will be used to design, modify and integrate the approach to a clinical prototype breast CT system. In the third phase, we will conduct a clinical feasibility stuy that will recruit BIRADS 4 or 5 subjects with microcalcifications to determine if the implemented technological advancements translate to improved visualization of microcalcifications and better discrimination between benign and malignant calcification-based lesions. Thus, the proposed research will provide an innovative design concept for unprecedented improvements that will enable imaging without physical compression of the breast and at radiation dose approximately similar to screening mammography.

Public Health Relevance

Mammography has been a valuable tool for detecting and diagnosing breast cancer. However, it requires vigorous breast compression and often it is difficult to see the tumor in women with dense breasts. Dedicated breast CT is an emerging technology that does not require breast compression and provides full 3D images of the breast. In this technology-focused research study we will design, develop, integrate and clinically evaluate the next generation of breast CT that can be performed at approximately similar radiation dose as screening mammography. Women who have suspicious microcalcifications based findings that require biopsy will participate in the study.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA199044-03
Application #
9478140
Study Section
Biomedical Imaging Technology Study Section (BMIT)
Program Officer
Zhang, Yantian
Project Start
2017-05-01
Project End
2021-04-30
Budget Start
2018-05-01
Budget End
2019-04-30
Support Year
3
Fiscal Year
2018
Total Cost
Indirect Cost
Name
University of Arizona
Department
Radiation-Diagnostic/Oncology
Type
Schools of Medicine
DUNS #
806345617
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Vedantham, Srinivasan; Karellas, Andrew (2018) Emerging Breast Imaging Technologies on the Horizon. Semin Ultrasound CT MR 39:114-121
O'Connell, Avice M; Karellas, Andrew; Vedantham, Srinivasan et al. (2018) Newer Technologies in Breast Cancer Imaging: Dedicated Cone-Beam Breast Computed Tomography. Semin Ultrasound CT MR 39:106-113
Shi, Linxi; Vedantham, Srinivasan; Karellas, Andrew et al. (2018) The role of off-focus radiation in scatter correction for dedicated cone beam breast CT. Med Phys 45:191-201
Vijayaraghavan, Gopal R; Vedantham, Srinivasan; Kataoka, Milliam et al. (2017) The Relevance of Ultrasound Imaging of Suspicious Axillary Lymph Nodes and Fine-needle Aspiration Biopsy in the Post-ACOSOG Z11 Era in Early Breast Cancer. Acad Radiol 24:308-315
Shrestha, Suman; Vedantham, Srinivasan; Karellas, Andrew (2017) Towards standardization of x-ray beam filters in digital mammography and digital breast tomosynthesis: Monte Carlo simulations and analytical modelling. Phys Med Biol 62:1969-1993