Search tips
Search criteria 


Logo of transbThe Royal Society PublishingPhilosophical Transactions BAboutBrowse By SubjectAlertsFree Trial
Philos Trans R Soc Lond B Biol Sci. 1997 June 29; 352(1354): 717–726.
PMCID: PMC1691961

Image reconstruction in optical tomography.


Optical tomography is a new medical imaging modality that is at the threshold of realization. A large amount of clinical work has shown the very real benefits that such a method could provide. At the same time a considerable effort has been put into theoretical studies of its probable success. At present there exist gaps between these two realms. In this paper we review some general approaches to inverse problems to set the context for optical tomography, defining both the terms forward problem and inverse problem. An essential requirement is to treat the problem in a nonlinear fashion, by using an iterative method. This in turn requires a convenient method of evaluating the forward problem, and its derivatives and variance. Photon transport models are described for obtaining analytical and numerical solutions for the most commonly used ones are reviewed. The inverse problem is approached by classical gradient-based solution methods. In order to develop practical implementations of these methods, we discuss the important topic of photon measurement density functions, which represent the derivative of the forward problem. We show some results that represent the most complex and realistic simulations of optical tomography yet developed. We suggest, in particular, that both time-resolved, and intensity-modulated systems can reconstruct variations in both optical absorption and scattering, but that unmodulated, non-time-resolved systems are prone to severe artefact. We believe that optical tomography reconstruction methods can now be reliably applied to a wide variety of real clinical data. The expected resolution of the method is poor, meaning that it is unlikely that the type of high-resolution images seen in computed tomography or medical resonance imaging can ever be obtained. Nevertheless we strongly expect the functional nature of these images to have a high degree of clinical significance.

Full Text

The Full Text of this article is available as a PDF (788K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Arridge SR, Hebden JC. Optical imaging in medicine: II. Modelling and reconstruction. Phys Med Biol. 1997 May;42(5):841–853. [PubMed]
  • Arridge SR, Cope M, Delpy DT. The theoretical basis for the determination of optical pathlengths in tissue: temporal and frequency analysis. Phys Med Biol. 1992 Jul;37(7):1531–1560. [PubMed]
  • Arridge SR, Hiraoka M, Schweiger M. Statistical basis for the determination of optical pathlength in tissue. Phys Med Biol. 1995 Sep;40(9):1539–1558. [PubMed]
  • Arridge SR, Schweiger M, Hiraoka M, Delpy DT. A finite element approach for modeling photon transport in tissue. Med Phys. 1993 Mar-Apr;20(2 Pt 1):299–309. [PubMed]
  • Boas DA, O'Leary MA, Chance B, Yodh AG. Scattering of diffuse photon density waves by spherical inhomogeneities within turbid media: analytic solution and applications. Proc Natl Acad Sci U S A. 1994 May 24;91(11):4887–4891. [PubMed]
  • Cope M, Delpy DT. System for long-term measurement of cerebral blood and tissue oxygenation on newborn infants by near infra-red transillumination. Med Biol Eng Comput. 1988 May;26(3):289–294. [PubMed]
  • Delpy DT, Cope M, van der Zee P, Arridge S, Wray S, Wyatt J. Estimation of optical pathlength through tissue from direct time of flight measurement. Phys Med Biol. 1988 Dec;33(12):1433–1442. [PubMed]
  • Firbank M, Arridge SR, Schweiger M, Delpy DT. An investigation of light transport through scattering bodies with non-scattering regions. Phys Med Biol. 1996 Apr;41(4):767–783. [PubMed]
  • Hebden JC, Arridge SR, Delpy DT. Optical imaging in medicine: I. Experimental techniques. Phys Med Biol. 1997 May;42(5):825–840. [PubMed]
  • Henderson RP, Webster JG. An impedance camera for spatially specific measurements of the thorax. IEEE Trans Biomed Eng. 1978 May;25(3):250–254. [PubMed]
  • Pogue BW, Patterson MS, Jiang H, Paulsen KD. Initial assessment of a simple system for frequency domain diffuse optical tomography. Phys Med Biol. 1995 Oct;40(10):1709–1729. [PubMed]
  • Schweiger M, Arridge SR, Hiraoka M, Delpy DT. The finite element method for the propagation of light in scattering media: boundary and source conditions. Med Phys. 1995 Nov;22(11 Pt 1):1779–1792. [PubMed]
  • Singer JR, Grünbaum FA, Kohn P, Zubelli JP. Image reconstruction of the interior of bodies that diffuse radiation. Science. 1990 May 25;248(4958):990–993. [PubMed]

Articles from Philosophical Transactions of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society