1. Validating performance of optical imaging system for diagnosis of
metastatic breast cancer
Morgan Fogarty, Lagnojita Sinha, Dr. Ken Tichauer
BME, Health
• Assess the spatial resolution of the ADEPT system. Our aim is to achieve
a resolution of approximately 100 microns, for optimal sensitivity.
• I was specifically tasked with creating physical phantoms that would mimic
the optical properties of human tissue. Resolution patterns were implanted
at various depths in these phantoms, to further asses the effect of depth
on ADEPT resolution.
Phantom Design
• The phantoms in this study were four layer, polyester resin phantoms with
titanium dioxide used as the scattering agent.
• Each layer of the phantom is 1mm in height.
• To reach the desired scattering coefficient, 6 mg of TiO2 was added per mL of
resin. TiO2 was combined with 10 μL of ethanol before adding it to the resin.
• 5 drops of catalyst was added to the first layer and the amount of drops
decreased by one with each additional layer.
Calculating the Optical Properties
• Calculated the values for the reduced scattering coefficient (μs’) and the
absorption coefficient (μa).
• Utilized MATLAB to calculate the optical properties through convolving the
instrument response function and the temporal pulse spread function using
Green’s function. [2]
Phantom Images
Phantom images below display the improvement of the system’s spatial
resolution.
Optical Properties
The reduced scattering coefficient is equal to 1.1715 mm-1 and the absorption
coefficient equals 0.0282 mm-1.
• Adjust the amount of TiO2 to better reflect the reduced scattering
coefficient and absorption coefficient in lymph nodes.
• Improve the model for determining optical properties though collecting
more data to correct for experimental errors.
• The value for the absorption coefficient was expected to be low since no
absorbers were added to the phantom.
• When using 6 mg/mL of TiO2 in the phantoms, the scattering coefficient is
expected to be approximately 10 mm-1 [3]
• Since μs’ = μs(1-g) the expected reduced scattering coefficient is
approximately 1.0 mm-1 based on the average tissue anisotropy factor of
0.9.
• Based on these approximations, the value of 1.1715 mm-1 is slightly
higher but still a reasonable reduced scattering coefficient.
INTRODUCTIONINTRODUCTION
OBJECTIVE OF PURE RESEARCHOBJECTIVE OF PURE RESEARCH
REFERENCESREFERENCES
METHODSMETHODS
FUTURE WORKFUTURE WORK
RESULTSRESULTS
CONCLUSIONCONCLUSION
[1] Howlader N, Noone AM, Krapcho M, et al., eds. SEER Cancer Statistics Review, 1975-2010. Bethesda, MD: National
Cancer Institute; 2013. http://seer.cancer.gov/csr/1975_2010/, based on November 2012 SEER data submission.
[2] Tichauer, K. M., Miguels, M., Leblond, F., Elliott, J. T., Diop, M., St. Lawrence, K., and Lee, T. Depth resolution and
multiexponential lifetime analyses of reflectance-based time-domain fluorescence data. Applied Optics, 50(21), 3962-
3972. 2011.
[3] Bykov, A.V., Popov, A.P., Priezzhev, A.V., and Myllyla, R. Multilayer tissue phantoms with embedded capillary system
for OCT and DOCT imaging. SPIE Proceedings. 8091, 2011.
• After breast cancer metastasizes, the 5 year survival rate drops to 24%. [1]
• The most common method for determining metastasis is lymph node biopsy.
• However, this method only
samples < 1% of a lymph
node and studies suggest
that up to 40% of patients
who undergo biopsy have
undetected metastatic
cancer.
• The agent dependent
early photon tomography
system (ADEPT Cancer
Imager) is being
developed to rapidly scan
lymph nodes in 3D and
detect microscopic levels
of cancer spread.
• This many orders-of-magnitude improvement in lymph node sensitivity will
allow patients with more aggressive disease to be identified earlier, when
more aggressive therapies are known to be more effective, leading to better
patient outcomes in terms of prolonged survival and improved quality of life.