An innovative imaging technique for dynamic optical nanothermometry
Measuring temperature in 2D, without contact, with an ultrafast single-
shot camera

Date:
November 9, 2021
Source:
Institut national de la recherche scientifique - INRS
Summary:
A new imaging technique can measure temperature in 2D, without
contact, and in just a snap.



FULL STORY ==========================================================================
A new imaging technique, developed by the teams of Professors Jinyang
Liang and Fiorenzo Vetrone at the Institut national de la recherche scientifique (INRS), can measure temperature in 2D, without contact,
and in just a snap. The results of their research were published in
the journal Nature Communications. This accurate real-time temperature detection could one day improve photothermal therapy and help in the
early diagnosis of skin cancers.


==========================================================================
This technology, known as single-shot photoluminescence lifetime imaging thermometry (SPLIT), is based on the luminescence of nanoparticles
doped with rare earth ions. "They are considered as nanothermometers
because their luminescent properties change with the temperature of
the environment. They are also biocompatible," says Professor Vetrone,
a pioneer in this field of study.

Instead of imaging the luminescence point by point, which is time
consuming, SPLIT uses a novel ultrahigh-speed camera to track how
quickly the luminescence decays of these nanoparticles in every spatial
point. "Our camera is different from a common one, where each click gives
one image: our camera works by capturing all the images of a dynamic
event into one snapshot. Then we reconstruct them, one by one," says
Xianglei Liu, a PhD student at INRS and the lead author of this article.

The temperature can then be sensed by checking how fast the emitted light
fades out. Since it is in real time, SPLIT can follow the phenomenon as
it happens.

For the first time, it enables the luminescence thermometry using the nanoparticle's lifetime with a moving sample. "Compared to existing
thermometry techniques, SPLIT is faster and has higher resolution. This
allows a more accurate temperature sensing with both an advanced and
economical solution," adds Professor Liang, an expert in ultra-fast
imaging.

Health applications Professors Liang and Vetrone believe that SPLIT
technology could, among other things, increase the ability to detect and
treat skin cancers. At present, the capacity to detect melanomas, and
more specifically micro-melanomas, is still limited. Existing diagnostic approaches are restricted by their invasiveness, resolution and accuracy,
which leads to a large number of unnecessary biopsies.

Optical thermometry could thus be used to detect cancer cells, whose
rapid metabolism leads to a higher temperature than that of normal tissue, making them more visible with SPLIT.

To detect melanoma, clinics can use a thermal camera, but the resolution
is low. "SPLIT marks an important step in the technical development. With
high resolution, the technology could be used to precisely locate the
cancerous mole," says Professor Liang.

Beyond detection, this technology could also be used to monitor the
light dose during certain types of treatment. For example, photothermal
therapy attacks cancer cells through the heat generated by exposure
to near-infrared light. "We want to eradicate the cancer, but not the surrounding tissue, so if the temperature is too high, the treatment
could be decreased or stopped for a while. If it's too low, we can
increase the light to get the right dose," says Vetrone.

In 2020, the Canadian Cancer Society estimated that 8,000 Canadians had
been diagnosed with this form of cancer alone.

========================================================================== Story Source: Materials provided by Institut_national_de_la_recherche_scientifique_-_INRS.

Original written by Audrey-Maude Ve'zina. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Xianglei Liu, Artiom Skripka, Yingming Lai, Cheng Jiang, Jingdan
Liu,
Fiorenzo Vetrone, Jinyang Liang. Fast wide-field upconversion
luminescence lifetime thermometry enabled by single-shot compressed
ultrahigh-speed imaging. Nature Communications, 2021; 12 (1) DOI:
10.1038/s41467-021-26701-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211109085056.htm

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