title: Localizing fluorophore (centroid) inside a scattering medium by depth perturbation.
abstract: Fluorescence molecular tomography (FMT) imaging can be used to determine the location, size, and biodistribution of fluorophore biomarkers inside tissues. Yet when using FMT in the reflectance geometry it is challenging to accurately localize fluorophores. A depth perturbation method is proposed to determine the centroid of fluorophore inside a tissue-like medium. Through superposition of a known thin optical phantom onto the medium surface, the fluorophore depth is deliberately perturbed and signal localization is improved in a stable way. We hypothesize that the fluorophore centroid can be better localized through use of this fluorescent intensity variation resulting from the depth perturbation. This hypothesis was tested in tissue-like phantoms. The results show that a small-size fluorophore inclusion (1.2 mm(3)volume, depth up to 4.8 mm) can be localized by the method with an error of 0.2 to 0.3 mm. The method is also proven to be capable of handling multiple fluorescent inclusion conditions with the assistance of other strategies. Additionally, our further studies showed that the method's performance in the presence of background fluorophores indicated that the small inclusion could be located at a 1.8 (3.8) mm depth with accurate localization only when its concentration was not <10 (100) times the background level.
authors.affiliation: The University of Tokyo, Graduate School of Engineering, Department of Precision Engineering, 7-3-1 Hongo Bunkyoku, Tokyo 1138656, Japan.
authors.forename: Tuo
authors.initials: T
authors.lastname: Zhou
authors.affiliation: The University of Tokyo, Graduate School of Engineering, Department of Precision Engineering, 7-3-1 Hongo Bunkyoku, Tokyo 1138656, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Ando
authors.affiliation: The University of Tokyo, Graduate School of Engineering, Department of Precision Engineering, 7-3-1 Hongo Bunkyoku, Tokyo 1138656, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
authors.affiliation: Tsinghua University, School of Medicine, Department of Biomedical Engineering, 1 Qinghuayuan Haidian District, Beijing 100084, China.
authors.forename: Hongen
authors.initials: H
authors.lastname: Liao
authors.affiliation: The University of Tokyo, Graduate School of Engineering, Department of Precision Engineering, 7-3-1 Hongo Bunkyoku, Tokyo 1138656, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kobayashi
authors.affiliation: The University of Tokyo, Graduate School of Engineering, Department of Precision Engineering, 7-3-1 Hongo Bunkyoku, Tokyo 1138656, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sakuma
mesh_terms: D004058:Diffusion; D005456:Fluorescent Dyes / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D019047:Phantoms, Imaging; D017785:Photons; D015203:Reproducibility of Results; D014054:Tomography / Q000295:instrumentation / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes