1. An optical method of mapping three-dimensional properties of objects comprising the steps of:
providing an interferometer with a source emitting a low-coherence white light, a reference arm producing a reference beam, an object arm producing an object beam, and means for combining said reference and object beams to produce a combined interference beam; and
modulating the low-coherence white light in a frequency domain to yield a spectral distribution with simultaneous frequencies adapted to produce fringes with a modulation peak at a non-zero optical path length difference between the reference beam and the object beam along an optical path of the combined interference beam, wherein said non-zero optical path length difference is predetermined by the modulating step.
2. The optical coherence tomography method of claim 1, wherein said spectral distribution is a sinusoidal distribution.
3. The optical coherence tomography method of claim 1, wherein said interferometer is a Fizeau interferometer.
4. The optical coherence tomography method of claim 3, wherein said non-zero optical path length difference between the reference beam and the object beam along the optical path of the combined interference beam is half an optical path length difference between said reference arm and object arm of the interferometer.
5. The optical coherence tomography method of claim 1, wherein said fringes with a modulation peak at a non-zero optical path length difference between the reference and object beams are visible over an optical path length smaller than a distance between a surface feature in said object being measured by the interferometer and an optical interface positioned along an optical path of said object beam.
6. The optical coherence tomography method of claim 1, wherein said low-coherence white light is modulated in the frequency domain by sequentially changing a period of modulation over time so as to produce a succession of predetermined spatial patterns of interference fringes produced by said reference and object beams.
7. The optical coherence tomography method of claim 1, further including the step of modifying said spectral distribution to sequentially produce changes in a phase of interference fringes produced by said reference and object beams.
8. The optical coherence tomography method of claim 1, wherein said low-coherence white light is modulated independently for different pixels of an object surface.
9. An interferometric method for optical coherence tomography, comprising the steps of:
illuminating a tissue with a low-coherence light source;
illuminating a reference surface with the light source so as to cause light received back from the tissue and from the reference surface to be combined into an interference beam and produce interference fringes along an optical path of the interference beam; and
modulating the low-coherence light source in a frequency domain to yield a spectral distribution with simultaneous frequencies adapted to produce said interference fringes with a modulation peak at a selected location along said optical path of the combined interference beam;
wherein said location corresponds to a non-zero optical path length difference between said light reflected from the tissue and from the reference surface, said non-zero optical path length difference being predetermined by said modulating step.
10. The method of claim 9, further comprising determining the position of one or more points of a structure in the tissue based on the modulation required to localize interference fringes produced thereby at selected locations.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. Apparatus for minimally invasive access to the epicardial surface of the human heart, the apparatus comprising:
an elongated flexible body including a proximal end portion and a distal end portion,
at least one lumen extending between a proximal inlet and a distal outlet for carrying out a procedure in association with the epicardial surface of the heart,
the elongated body being of sufficient length for insertion of at least the distal end portion through a transcutaneous access to a location between the pericardium and the epicardial surface of the heart, and
at least a portion of the body adapted for insertion between the pericardium and epicardial surface having a non-circular shape.
2. The apparatus of claim 1 in which a portion of the non-circular shape has a width greater than its thickness.
3. The apparatus of claim 1 in which a portion of the non-circular shape has a convex surface.
4. The apparatus of claim 1 in which a portion of the non-circular shape has a concave surface.
5. The apparatus of claim 2 in which a portion of the non-circular shape has a width in the range of 2 mm to 20 mm and a thickness in the range of 1 mm to 10 mm.
6. The apparatus of claim 1 comprising a plurality of lumen extending between a proximal inlet and a distal end of each such lumen.
7. The apparatus of claim 1 having a length in the range of 10 cm to 40 cm.
8. The apparatus of claim 1 in which the distal end of the body is thinner than a more proximal portion of the body.
9. The apparatus of claim 1 in which the non-circular portion has an upper surface and a lower surface and the distal outlet of the lumen is located in the upper surface.
10. The apparatus of claim 1 in which the non-circular portion has an upper surface and a lower surface, the upper surface being convex in a transverse direction and the lower surface being concave in a transverse direction.