Clinical thermometer

Abstract

The disclosure relates to a clinical thermometer for non-invasive measurement of sub-cutaneous temperature of tissue of a human or animal subject. Probe light is collected from a collection region spatially offset from an entry region on a visible surface of the subject, following scattering within the tissue, and a temperature of the tissue is determined from Raman spectral features in the collected light.

1 . A clinical thermometer for determining a temperature in tissue beneath a visible surface of a human or animal subject, comprising:
 a light source arranged to form a beam of probe light directed to an entry region on the visible surface;   collection optics arranged to receive said probe light from a collection region on the surface following scattering within the tissue, the collection region being spaced from the entry region;   a spectral analyser arranged to detect corresponding Stokes and anti-Stokes Raman scattering spectral features in the probe light received through the collection optics; and   a processor arranged to determine a temperature in the tissue from differences between the Stokes and anti-Stokes Raman spectral features.   
     
     
         2 . The clinical thermometer of  claim 1  wherein at least a part of the tissue of which the temperature is measured lies between the entry and collection regions. 
     
     
         3 . A method of measuring temperature in a subsurface volume of a sample, comprising:
 directing probe light to an entry region on the sample surface;   collecting said probe light from a collection region on the sample surface, following scattering within the subsurface volume of the sample, the collection region being spatially offset from the entry region;   detecting one or more Raman spectral features in the collected probe light; and   determining a temperature of the subsurface volume from the one or more Raman spectral features.   
     
     
         4 . The method of  claim 3  wherein the method is a method of non-invasive measurement of a sub-cutaneous temperature of a tissue of a human or animal subject. 
     
     
         5 . The method of  claim 3  wherein determining a temperature of the subsurface volume from the one or more Raman spectral features comprises determining the temperature using differences between one or more Stokes features and the corresponding anti-Stokes features in the detected Raman spectral features. 
     
     
         6 . The method of  claim 3  wherein determining the temperature using differences between one or more Stokes features and the corresponding anti-Stokes features comprises using ratios of said Stokes and anti-Stokes features. 
     
     
         7 . The method of  claim 3  wherein the entry and collection regions are disposed on opposite sides of the sample. 
     
     
         8 . The method of  claim 3  comprising separately detecting said one or more Raman spectral features in the collected probe light for each of a plurality of different spatial offsets between said entry and collection regions. 
     
     
         9 . The method of  claim 8  wherein determining a temperature of a subsurface volume from the one or more Raman spectral features comprises associating the Raman features from each of said plurality of different spatial offsets with a different depth or distribution of depth within the sample, 
     
     
         10 . The method of  claim 9  further comprising combining said Raman features from said different spatial offsets to determine a separate temperature for each of one or more depths or distributions of depth within the sample. 
     
     
         11 . The method of  claim 3  further comprising setting said entry and collection regions to be coincident or overlapping, and detecting one or more Raman spectral features in the collected probe light when said entry and collection regions are coincident or overlapping. 
     
     
         12 . The method of  claim 11  wherein determining a temperature of a subsurface volume from the Raman spectral features comprises compensating said Raman spectral features detected when the entry and collection regions are spatially offset using the Raman spectral features detected when the entry and collection regions are coincident or overlapping. 
     
     
         13 . The method of  claim 11  further comprising determining a temperature of the sample surface from the one or more Raman spectral features detected when the entry and collection regions are coincident or overlapping. 
     
     
         14 . The method of  claim 3  wherein the entry region comprises one or more segments which are located around a centrally disposed collection region. 
     
     
         15 . The method of  claim 14  wherein the entry region comprises an annulus disposed around the collection region. 
     
     
         16 . The method of  claim 3  wherein the entry and collection regions are spatially offset by an offset in the range from 1 mm to 50 mm, and more preferably in the range from 3 mm to 20 mm. 
     
     
         17 . The method of  claim 3  wherein the sample is a diffusely scattering sample. 
     
     
         18 . The method of  claim 3  wherein the subsurface volume for which temperature is determined is diffusely scattering. 
     
     
         19 . The method of  claim 17  wherein the diffusely scattering sample or volume has a transport length of less than 3 mm. 
     
     
         20 . The method of  claim 3  wherein the subsurface volume comprises tissue of a human or animal subject, and the determined temperature is a subsurface temperature of the tissue. 
     
     
         21 . The method of  claim 20  wherein the sample surface is a surface of skin of the human or animal subject. 
     
     
         22 . The method of  claim 3  wherein the sample comprises a fluid within a containing wall, the entry and collection regions are provided on said containing wall, and the subsurface volume comprises a volume of the fluid. 
     
     
         23 . The method of  claim 3  comprising providing one or more Surface Enhanced Raman Spectroscopy (SERS) substrates in the subsurface volume of the sample such that the detected one or more Raman spectral features in the collected probe light from which temperature is detected comprise one or more SERS spectral features. 
     
     
         24 . The method of  claim 23  wherein the SERS spectral features are SERS spectral features of one or more particular chemical components adjacent to the one or more SERS substrates. 
     
     
         25 . The method of  claim 23  wherein the one or more SERS substrates comprise one or more of: nanoparticles, nanospheres, and one or more substrates comprising SERS active surface features. 
     
     
         26 . The method of  claim 23  wherein the subsurface volume of the sample comprises human or animal tissue, the method further comprising heating the subsurface volume of the sample using plasmonic heating with the one or more SERS substrates or with one or more other substrates. 
     
     
         27 . The method of  claim 3  wherein the subsurface volume of the sample comprises human or animal tissue, the method further comprising heating the subsurface volume of the sample. 
     
     
         28 . The method of  claim 27  further comprising controlling the step of heating the subsurface volume of the sample in response to the determined temperature of the subsurface volume. 
     
     
         29 . The method of  claim 28  wherein controlling the step of heating comprises controlling the step of heating so as to maintain the temperature of the subsurface volume of the sample within a predetermined range. 
     
     
         30 . An apparatus for measuring temperature within a subsurface volume of a sample having a surface, comprising:
 a light source for generating probe light;   delivery optics arranged to direct the probe light to an entry region on the surface;   collection optics arranged to collect said probe light from a collection region on the surface, following scattering within the subsurface volume of the sample, the collection region being spatially offset from the entry region;   a spectral analyser arranged to detect Raman spectral features in the collected probe light; and   a processor arranged to determine a temperature of the subsurface volume from the Raman spectral features.   
     
     
         31 . The apparatus of  claim 30  wherein the processor is arranged to determine a temperature of the subsurface volume from the Raman spectral features using differences between one or more Stokes features and corresponding anti-Stokes features in the detected Raman spectral features. 
     
     
         32 . The apparatus of  claim 30  arranged such that the entry and collection regions are spatially offset by an offset by a distance in the range from 1 mm to 50 mm, and more preferably in the range from 3 mm to 20 mm. 
     
     
         33 . The apparatus of  claim 30  wherein the apparatus is a non-invasive clinical thermometer. and wherein the subsurface volume comprises tissue of a human or animal subject, and the determined temperature is a subsurface temperature of the tissue. 
     
     
         34 . The apparatus of  claim 30  further comprising a fluid within a containing wall, the apparatus being arranged such the entry and collection regions are provided on said containing wall, and the subsurface volume comprises a volume of the fluid, the apparatus being arranged to determine a temperature of the fluid. 
     
     
         35 . The apparatus of  claim 30  wherein the processor is arranged to determine a temperature of a particular chemical component present in the subsurface volume, by detecting Raman features characteristic of the particular chemical component, and by determining the temperature of the particular chemical component from the detected Raman features characteristic of the particular chemical component. 
     
     
         36 . The apparatus of  claim 35  further arranged such that the detected Raman spectral features comprise one or more Surface Enhanced Raman Spectroscopy (SERS) spectral features of one or more particular chemical components adjacent to one or more SERS substrates in the subsurface volume. 
     
     
         37 . The apparatus of  claim 36  further comprising said one or more Surface Enhanced Raman Spectroscopy (SERS) substrates located in the subsurface volume of the sample. 
     
     
         38 . The apparatus of  claim 36  where in the one or more SERS substrates comprise one or more of: nanoparticles, nanospheres, one or more substrates comprising SERS active surface features. 
     
     
         39 . The apparatus of  claim 36  wherein the processor is arranged to determine a temperature of the subsurface volume by determining a temperature of the one or more particular chemical components from the one or more SERS spectral features. 
     
     
         40 . The apparatus of  claim 36  further comprising a heating driver arranged to heat the subsurface volume of the sample by plasmonic heating using the one or more SERS substrates. 
     
     
         41 . The apparatus of  claim 30  further comprising a heating driver arranged to heat the subsurface volume of the sample. 
     
     
         42 . The apparatus of  claim 41  arranged to control the heating driver to heat the subsurface volume of the sample dependent upon the determined temperature of the subsurface volume. 
     
     
         43 . The apparatus of  claim 42  arranged to control the heating driver so as to maintain the temperature of the subsurface volume of the sample within a predetermined range. 
     
     
         44 . The apparatus of  claim 30 , arranged to carry out plasmonic photo thermal therapy on a human or animal subject.