Near-infrared optical imaging of tissue phantoms with measurement in the change of optical path lengths.
Using 2-D Monte Carlo simulations, we have demonstrated that values of delta < L > at varying delta t, T1 and T2 can contain significant information concerning the presence and location of a light absorbing volume in scattering media such as tissue. Specifically, we have illustrated that relationships exist between ZPW measured in x,y reflectance geometries and the absorber x,y,z position. These relationships are predictable yet can be expected to furthermore vary with (i) absorber z-dimensions, (ii) the optical properties of the surrounding media, and (iii) the source/detector separation, rho. In addition, while we have reported absorber positions located within 1 cm of tissue thickness for rho = 2 cm, One can expect interrogation of absorbers located at greater tissue thicknesses with greater rho 4. Most importantly, it is noteworthy that there exists greater opportunity to monitor specific population of photons in time-domain PMI than in frequency-domain PMI. Therefore, time-domain localization may be more sensitive than in the frequency-domain. From comparison to PMI, Figure 8 illustrates the values of delta I* computed from equation (1) versus absorber position for the same values T1 and T2 as in Figure 3. Upon inspection of Figures 3 and 8, one can see that it is easier to infer the relationship between the PSV and the absorber position from delta < L > than from delta I*. As a consequence, the measurement of delta < L > may enable creation of an inverse localization algorithm for photon migration imaging.(ABSTRACT TRUNCATED AT 250 WORDS)
Sevick
E M
EM
Department of Chemical Engineering, Vanderbilt University, Nashville, TN 37235.
Burch
C L
CL
Chance
B
B
D001698:Biomedical Engineering; D055592:Biophysical Phenomena; D001703:Biophysics; D006454:Hemoglobins / Q000032:analysis; D007091:Image Processing, Computer-Assisted; D008961:Models, Structural; D008962:Models, Theoretical; D009010:Monte Carlo Method; D055095:Optics and Photonics; D010100:Oxygen / Q000032:analysis*; D010108:Oxyhemoglobins / Q000032:analysis; D017785:Photons; D012542:Scattering, Radiation; D013055:Spectrophotometry, Infrared / Q000379:methods*
D006454:Hemoglobins; D010108:Oxyhemoglobins; C100003:deoxyhemoglobin; D010100:Oxygen