CT guided DOT for Breast cancer imaging

Institution: University of California, Merced
Investigator(s): Changqing  Li , Ph.D -
Award Cycle: 2014 (Cycle 20) Grant #: 20IB-0125 Award: $187,500
Award Type: IDEA
Research Priorities
Detection, Prognosis and Treatment>Imaging, Biomarkers, and Molecular Pathology: improving detection and diagnosis



Initial Award Abstract (2014)

Chemotherapy is used widely for breast cancer treatment to improve the survival, especially of young women under 50. Chemotherapy given before surgery, called neoadjuvant chemotherapy, enables patients to undergo breast conservation therapy without risking a higher recurrence associated with simply removing larger tumors. Monitoring neoadjuvant chemotherapy provides evidence of responsiveness to the chosen chemotherapeutic drugs. If evidence of responsive is not observed, the monitoring process makes it possible to change the therapeutic drugs early in the treatment process. Hence patients will receive individualized therapy, be spared from unnecessary toxicity, and be treated with more effective drugs early.

Tumor responsive to chemotherapy results in changes in blood concentrations that can be monitored by optical tomography. Optical tomography imaging has been used to monitor response to neoadjuvant chemotherapy previously. However, the low quality of the optical tomography limits its applications. X-ray CT can provide the location and size of breast lesions, especially for the patients undergoing neoadjuvant chemotherapy. Optical tomography systems can be combined with x-ray CT systems at a very low extra cost. CT will guide the optical tomography imaging to improve its image quality.

The question(s) or central hypotheses of the research:
Hypothesis 1: CT guidance will improve the spatial resolution and quantitative accuracy of the optical tomography imaging.
Hypothesis 2: CT guided optical tomography can monitor the breast cancer response to neoadjuvant chemotherapy at an early time.

The general methodology: We will use laser beams in the optical tomography imaging. The laser beams will be projected at different locations on the breast surface. Laser photons will be absorbed and scattered inside the breast. Most photons will be absorbed. Some photons will escape to the breast surface and detected by a charge-coupled device (CCD) camera as measurements for the optical tomography imaging. Laser beam will be scattered and blurred by breast tissues. Thus optical tomography imaging usually has a low spatial resolution. CT will improve the spatial resolution of optical tomography imaging by adding tumor location information in the optical imaging algorithms. There are two operational, dedicated breast CT imaging systems in Professor John M. Boone’s lab at UC Davis Medical Center. We will mount our optical imaging system inside one of the CT imaging systems. CT imaging will be performed first for about 17 seconds. Then the optical tomography will be performed for about 10 minutes. Optical imaging algorithm with CT guidance will be developed. Interference between the two systems will be evaluated and is expected to be negligible. At last, we will scan three patients and monitor their breast cancer’s responses to the neoadjuvant chemotherapy.

Innovative elements of the project: Compared with the current monitoring methods such as magnetic resonance imaging (MRI) and optical tomography, the CT guided optical tomography imaging has innovation elements listed below:
1. It will be the first CT guided optical tomography system for breast cancer imaging in the world.
2.The CT system is ready. It is straightforward for us to combine the optical imaging system with the CT imaging system.
3. he cost to combine the optical tomography imaging system in the CT system is low. The cost to monitor the chemotherapy is low.
4. The interference between two imaging systems is negligible.
5. The total imaging system cost is low compared with MRI system, much more affordable to patients.
6. The CT has very low radiation dose (equal or less than two-view mammography). The optical imaging has no radiation dose.
7. The CT guided optical tomography system could be used for breast cancer detection (while it is not part of this proposal).




Progress Report 1 (2015)

Optical imaging has been emerged for two decades as a functional imaging method to detect breast cancer by sensing the increased hemoglobin concentrations in the breast tumors. However, the applications of optical imaging have been limited by its low spatial resolution due to optical photon scattering in the deep breast tissues. The structural guidance provided by the computed tomography (CT) imaging will overcome the effects from optical scattering to improve the spatial resolution of optical imaging. Here, we report our research progress of the CT guided optical imaging for breast cancer detection.

In the past year, we have built a prototype system of optical imaging. We validated the system performance by numerical simulation and experimental studies. We have also worked closely with Professor John Boone’s lab in UC Davis to prepare the integration of our optical imaging system with the breast CT imaging system located in UC Davis. In this report, section 1 describes the prototype imaging system built in our lab at UC Merced, the experimental results, and our preparation of combining the optical imaging system into the breast CT system. Section 2 describes the algorithms briefly. The last section describes our future plan in the coming year.

The experimental results indicate that the CCD camera based optical imaging system can obtain the targets successfully with the CT guidance and with measurements at 6 projections. This also means that noise level of the CCD camera is acceptable for the CT guided optical imaging. Finally, the successful extraction of phantom targets validates our algorithms.




Progress Report 2 (2015)

Diffuse optical tomography (DOT) has been emerged for two decades as a functional and noninvasive imaging modality to image the absorption chromophore concentration in deep tissues such as breast cancers. However, the applications of DOT have been limited by its low spatial resolution caused by strong optical scattering. The structural guidance provided by computed tomography (CT) will enhance the DOT imaging substantially. Here, we report a CT guided DOT imaging system for breast cancer detection.

In the past year, we have built a diffuse optical tomography prototype imaging system in our lab and tested our algorithm and the computed tomography (CT) guided DOT concept with the numerical simulations and phantom experiments performed with the prototype DOT imaging system. We have also worked closely with Professor John Boone’s lab to prepare the integration of our DOT imaging system with the breast CT imaging system. In this report, section 1 describes the prototype DOT imaging system built in my lab at UC Merced, the phantom experiments and results, and our preparation of combining the DOT system into the breast CT system. Section 2 describes the reconstruction algorithms briefly. The last section describes the future plan in the coming year.

The phantom experimental results indicate that the EMCCD camera based DOT imaging system can reconstruct the targets successfully with the CT guidance and with measurements at 6 projections. This also means that noise level of the EMCCD camera is acceptable for the CT guided DOT imaging. Finally, the successful reconstruction of phantom targets validates our reconstruction algorithms.

In past 5 months, we made progress in two aspects: finish the imaging system design and develop the calibration algorithm for better DOT image quality. We have purchased all components of optical imaging. In the requested extension period, we will assembly the imaging scanner and perform clinical imaging for breast cancer patients. It is worth noting that we will build a CT guided both DOT and PET imaging scanner, instead of the planned CT guided DOT imaging scanner