Thickness evaluation method of cell sheet

Patent metadata

Field	Value
Publication number	US-2022090909-A1
Application number	US-202117469119-A
Country	US
Kind code	A1
Filing date	Sep 8, 2021
Priority date	Sep 23, 2020
Publication date	Mar 24, 2022
Grant date	—

Abstract

A thickness evaluation method of the cell sheet according to the invention includes tomographically imaging a cell sheet by optical coherence tomography and obtaining a thickness distribution of the cell sheet based on a result of the tomography imaging. A tomographic image corresponding to one cross section of the cell sheet is obtained by tomography imaging while scanning the light in a main scanning direction. The tomography imaging is performed in every time while moving an incident position of the light at a predetermined feed pitch in a sub-scanning direction, thereby a plurality of the tomographic images corresponding to a plurality of cross-sections are obtained. One-dimensional thickness distributions of the cell sheet in the corresponding cross-sections are obtained based on each of the plurality of tomographic images, and a two-dimensional thickness distribution of the cell sheet is obtained by interpolating the one-dimensional thickness distributions.

First claim

What is claimed is:

1 . A thickness evaluation method of a cell sheet, comprising:
tomographically imaging the cell sheet by optical coherence tomography by causing light to be incident on the cell sheet in a direction intersecting a principal surface of the cell sheet; and obtaining a thickness distribution of the cell sheet based on a result of the tomography imaging, wherein a tomographic image corresponding to one cross section of the cell sheet is obtained by the tomography imaging while scanning the light in a main scanning direction, the tomography imaging is performed in every time while moving an incident position of the light in a sub-scanning direction intersecting the main scanning direction at a predetermined feed pitch, thereby a plurality of the tomographic images corresponding to cross-sections at positions different from each other in the sub-scanning direction are obtained, the feed pitch being larger than a size corresponding to one pixel in the tomographic image, one-dimensional thickness distributions of the cell sheet in the corresponding cross-sections are obtained based on each of the plurality of tomographic images, and a two-dimensional thickness distribution of the cell sheet is obtained by interpolating the one-dimensional thickness distributions.

2 . The thickness evaluation method of the cell sheet according to claim 1 , further comprising:
capturing a plurality of partial tomographic images corresponding to parts of the cell sheet by moving the light incident position in the sub-scanning direction at an interval smaller than the feed pitch, obtaining the one-dimensional thickness distributions of the cell sheet in cross-sections corresponding to the partial tomographic images and setting the feed pitch based on the obtained one-dimensional thickness distributions.

3 . The thickness evaluation method of the cell sheet according to claim 2 , wherein
a part of the partial tomographic images are thinned at a certain rate in the sub-scanning direction, the one-dimensional thickness distributions of the cell sheet in the partial tomographic images remained after thinning are interpolated in the sub-scanning direction, and the feed pitch is set based on errors between the thicknesses obtained by interpolation and actually measured thicknesses in the thinned partial tomographic images.

4 . The thickness evaluation method of the cell sheet according to claim 3 , wherein
an approximation curve representing a change of the error is obtained using the thinning rate as a variable and a thinning interval when a derivative value of the approximation curve becomes minimum is set as the feed pitch.

5 . The thickness evaluation method of the cell sheet according to claim 3 , wherein
a change of the error when the thinning rate is used as a variable is approximated by two regression lines corresponding to a side where the thinning interval is large and a side where the thinning interval is small and the thinning interval corresponding to an intersection of these lines is set as the feed pitch.

6 . The thickness evaluation method of the cell sheet according to claim 2 , wherein
for determining the feed pitch, the main scanning direction and the sub-scanning direction are switched and the partial tomographic images are imaged before and after that switch.

7 . The thickness evaluation method of the cell sheet according to claim 1 , wherein
tomographic images are imaged with the main scanning direction and the sub-scanning direction switched and one-dimensional thickness distributions obtained for the respective tomographic images are two-dimensional interpolated to obtain the two-dimensional thickness distribution.

8 . The thickness evaluation method of the cell sheet according to claim 2 , wherein
tomographic images are imaged with the main scanning direction and the sub-scanning direction switched and one-dimensional thickness distributions obtained for the respective tomographic images are two-dimensional interpolated to obtain the two-dimensional thickness distribution.

Assignees

• Screen Holdings Co Ltd

Inventors

• HASEBE Ryo

Classifications

• G01B9/02085

  Combining two or more images of different regions · CPC title

• G01B9/02091 Primary

  Tomographic interferometers, e.g. based on optical coherence · CPC title

• G01B2290/65

  Spatial scanning object beam · CPC title

• G01N33/4833

  of solid biological material, e.g. tissue samples, cell cultures (tissue in vivo A61B5/00; cell suspensions G01N33/48735) · CPC title

• G01B9/02012

  using temporal intensity variation · CPC title