title: Phantoms for diffuse optical imaging based on totally absorbing objects, part 1: Basic concepts.
abstract: The design of inhomogeneous phantoms for diffuse optical imaging purposes using totally absorbing objects embedded in a diffusive medium is proposed and validated. From time-resolved and continuous-wave Monte Carlo simulations, it is shown that a given or desired perturbation strength caused by a realistic absorbing inhomogeneity of a certain absorption and volume can be approximately mimicked by a small totally absorbing object of a so-called equivalent black volume (equivalence relation). This concept can be useful in two ways. First, it can be exploited to design realistic inhomogeneous phantoms with different perturbation strengths simply using a set of black objects with different volumes. Further, it permits one to grade physiological or pathological changes on a reproducible scale of perturbation strengths given as equivalent black volumes, thus facilitating the performance assessment of clinical instruments. A set of plots and interpolating functions to derive the equivalent black volume corresponding to a given absorption change is provided. The application of the equivalent black volume concept for grading different optical perturbations is demonstrated for some examples.
authors.affiliation: Dipartimento di Fisica e Astronomia dell'Università degli Studi di Firenze, Via G. Sansone 1, 50019 Sesto Fiorentino, Firenze, Italy. fabrizio.martelli@unifi.it
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Martelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Pifferi
authors.forename: Davide
authors.initials: D
authors.lastname: Contini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Spinelli
authors.forename: Alessandro
authors.initials: A
authors.lastname: Torricelli
authors.forename: Heidrun
authors.initials: H
authors.lastname: Wabnitz
authors.forename: Rainer
authors.initials: R
authors.lastname: Macdonald
authors.forename: Angelo
authors.initials: A
authors.lastname: Sassaroli
authors.forename: Giovanni
authors.initials: G
authors.lastname: Zaccanti
mesh_terms: D000042:Absorption; D000465:Algorithms; D003952:Diagnostic Imaging / Q000379:methods*; D004058:Diffusion; D006801:Humans; D008027:Light; D009010:Monte Carlo Method; D061848:Optical Imaging / Q000379:methods*; D055095:Optics and Photonics / Q000379:methods*; D019047:Phantoms, Imaging; D017785:Photons; D012542:Scattering, Radiation; D013997:Time Factors