Photoacoustic imaging of rat kidney tissue oxygenation using NIR-II wavelengths

Significance: Conventionally, spectral photoacoustic imaging (sPAI) to assess tissue oxygenation (sO2) uses optical wavelengths in the first near infrared window (NIR-I). This limits the maximum photoacoustic imaging depth (~1 cm) due to the high spectral coloring of biological tissues and has been a major barrier to the clinical translation of the technique.

Aim: Here, we demonstrate the second near infrared (NIR-II) tissue optical window (950-1400 nm) for the assessment of blood and tissue sO2.

Approach: The NIR-II PA spectra of oxygenated and deoxygenated hemoglobin were first characterized using a phantom. Optimal wavelengths to minimize spectral coloring were identified. The resulting NIR-II PA imaging methods were then validated in vivo by measuring kidney sO2 in adult female rats.

Results: sPAI of whole blood, in a phantom, and of blood in kidneys in vivo, produced PA spectra proportional to wavelength-dependent optical absorption. Using the NIR-II wavelengths for spectral..., , , # Photoacoustic imaging of rat kidney tissue oxygenation using NIR-II wavelengths

[https://doi.org/10.5061/dryad.wpzgmsbxn](https://doi.org/10.5061/dryad.wpzgmsbxn)

## Description of the data and file structure

The data presented in the paper titled \"Photoacoustic Imaging of Rat Kidney Tissue Oxygenation using NIR-II Wavelengths\" 

The data in the repository has the following two files:

1. \"PA_Blood_NIR2_data.xlsx\" - Tabulated data of the phantom and in vivo experiments used for Figures 3 and 4, respectively, from the main manuscript.   
2. \"PA_Blood_NIR2_DataSets.zip\" - A zip file containing all the raw photoacoustic and ultrasound images acquired as part of the results demonstrated in figures 3 & 4 of the main manuscript. 

### Files and variables

#### File #1: PA\_Blood\_NIR2\_data.xlsx

**Description:** Tabulated (Excel) data of the phantom and in vivo experiments with replicates

1. Sheet 1 - Photoacoustic spectra of oxygenated and deoxygenated hemoglobin recorded from the Pha...,