Oxygen imaging for non‐invasive metastasis detection

Joshua Punnoose, Henry Nachman, Shai Ashkenazi

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Sentinel lymph node (SLN) biopsy is an integral part of treatment planning for a variety of cancers as it evaluates whether a tumor has metastasized, an event that significantly reduces survival probability. However, this invasive procedure is associated with patient morbidity, and misses small metastatic deposits, resulting in the removal of additional nodes for tumors with high meta-static probability despite a negative SLN biopsy. To prevent this over‐treatment and its associated morbidities for patients that were truly negative, we propose a tissue oxygen imaging method called Photoacoustic Lifetime Imaging (PALI) as an alternative or supplementary tool for SLN biopsy. As the hyper‐metabolic state of cancer cells significantly depresses tissue oxygenation compared to normal tissue even for small metastatic deposits, we hypothesize that PALI can sensitively and specifically detect metastases. Before this hypothesis is tested, however, PALI’s maximum imaging depth must be evaluated to determine the cancer types for which it is best suited. To evaluate imaging depth, we developed and simulated a phantom composed of tubing in a tissue‐mimicking, optically scattering liquid. Our simulation and experimental results both show that PALI’s maximum imaging depth is 16 mm. As most lymph nodes are deeper than 16 mm, ways to improve imaging depth, such as directly delivering light to the node using penetrating optical fibers, must be explored.

Original languageEnglish (US)
Article number237
Issue number1
StatePublished - Jan 1 2022

Bibliographical note

Funding Information:
Funding: This research was funded by National Institute of Health, grant number CA183749‐02.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.


  • Head and neck cancer
  • Imaging
  • Oxygen imaging
  • Photoacoustic
  • Sentinel lymph node biopsy


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