# US 10,768,103 B2 · Infrared imaging of biological material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,768,103 B2 - Document ID: US10768103B2 - Status: Granted - Kind: B2 - Application number: 15/569,549 - Filed: 2016-04-28 - Published: 2018-10-25 - Granted: 2020-09-08 - Earliest claimed: 2015-04-29 - Assignees: Imperial Innovations Limited - Applicants: Imperial Innovations Lilmited - Inventors: Christopher Clement Phillips; Hemmel Amrania - Web page: https://patentgrep.com/patent/US10768103B2 ## CPC - G01N 21/3563: for analysing solids; Preparation of samples therefor - A61B 5/0075: {by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence)} - G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08) - G01N 21/314: {with comparison of measurements at specific and non-specific wavelengths (dual wavelength spectrometry G01J3/427)} - G01N 21/35: using infrared light (G01N21/39 takes precedence) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract A method of mapping a tissue characteristic in a tissue sample comprises gathering infrared absorption data from the sample at selected wavelengths, and determining, from the infrared absorption data, a first measure of the amount of power or energy absorbed attributable to an amide moiety and a second measure of the amount of power or energy absorbed attributable to a phosphate moiety. A ratio of the first measure and the second measure is used to establish a histological index. The histological index may be used to indicate a malignancy grade of tumour in the tissue. ## Claims ### Claim 1 A method of mapping a tissue characteristic in a tissue sample comprising, for each of a plurality of pixels in a two dimensional array: gathering infrared absorption data from the sample at selected wavelengths; determining, from the infrared absorption data, a first measure of the amount of energy or power absorbed attributable to an amide moiety and a second measure of the amount of energy or power absorbed attributable to a phosphate moiety, and determining a ratio of the first measure and the second measure to establish a histological index, to thereby generate a dataset corresponding to pixel values of a spatial map of the sample wherein the histological index, PA, is derived according to the expression PA=[|M(λ3)−M(λ4)|]/[|M(λ1)−M(λ2)|] or PA=[X M(λ3)−M(λ4)]/[X M(λ1)−M(λ2)], where: M(λn) is a measure of the absorbed energy or power at λn; λ1 is a wavelength corresponding to a peak absorption value attributable to an amide moiety; λ2 is a wavelength corresponding to a baseline absorption value attributable to an amide moiety; λ3 is a wavelength corresponding to a peak absorption value attributable to a phosphate moiety; λ4 is a wavelength corresponding to a baseline absorption value attributable to a phosphate moiety; X is numerical factor ≥1 which is set to a value sufficient to ensure that the measure M for a peak absorption values λ3 and λ1 is always greater than the measure M for the corresponding baseline absorption values λ4 and λ2 for all measurements; and λ1=6.0±0.1 microns; λ2=6.5±0.1 microns; λ3=a number selected from a group consisting of 8.13±0.1 microns and 9.26±0.1 microns; λ4=a number selected from a group consisting of 8.57±0.1 microns and 10.0±0.1 microns. ### Claim 2 (depends on 1) The method of claim 1 in which the value X is set according to the signal-to-noise ratio of the measurement system. ### Claim 3 (depends on 1) The method of claim 1 in which the value of X lies in the range 1.2 to 1.5. ### Claim 4 (depends on 1) The method of claim 1 in which each of the first and second measures is obtained from: sample data S; environment data Es; background data B; and background environment data Eb, the method further comprising compensating the sample data S using Es, B, Eb, where: (i) sample data S is taken with the sample loaded in the machine on the sample stage and the shutter open/removed; (ii) environment data Es is taken with the sample loaded in the machine and the shutter in/closed; (iii) background data B is taken with the sample out of the apparatus and the shutter open/removed; and (iv) background environment data Eb is taken with the sample out and the shutter in/closed. ### Claim 5 (depends on 4) The method of claim 4 wherein each of the first and second measures M is obtained from one or more measurements M according to the expression M=[S−Es]/B−Eb]. ### Claim 6 (depends on 1) The method of claim 1 further including performing a bad pixel replacement procedure comprising: deriving a at least one histogram of a measured absorption value selected from a group consisting of measured absorption values λ1, λ2, λ3, and λ4 in the array; identifying pixels having the lowest frequency of occurrence of the measured absorption values; replacing the absorption value of each of the identified pixels with a substitute value comprising an average value of one or more adjacent pixels to the identified pixel. ### Claim 7 (depends on 6) The method of claim 6 further including performing the bad pixel replacement procedure for each of the wavelengths λ1, λ2, λ3, and λ4. ### Claim 8 (depends on 1) The method of claim 1 further including plotting spatial variations in the histological index in at least two dimensions. ### Claim 9 (depends on 7) The method of claim 7 further including classifying each pixel as indicative of first, second or third tissue type based on the histological index for each pixel. ### Claim 10 (depends on 7) The method of claim 7 further including classifying each pixel as indicative of a non-cancerous tissue candidate type or a cancerous tissue candidate type. ### Claim 11 (depends on 10) The method of claim 10 applied to breast tissue. ### Claim 12 (depends on 1) The method of claim 1 further including using the histological index to derive a cancer grading. ### Claim 13 (depends on 12) The method of claim 12 in which the cancer grading is breast cancer. ### Claim 14 (depends on 1) Apparatus for mapping a tissue characteristic in a tissue sample comprising: a detector configured to obtain infrared absorption data from a tissue sample at selected wavelengths; a processing module configured to process said infrared absorption data; the apparatus being configured to carry out the method of claim 1.