University of Oklahoma spots pancreatic cancer with multispectral optoacoustics

01 Feb 2024

A $3 million grant will fund a study combining imaging technique with new contrast agent.

Sounding out blood vessels: arteries and veins

A research study at the University of Oklahoma (OU) will investigate how optoacoustic techniques can play a part in detection of pancreatic cancer.

Backed by $3 million from the National Cancer Institute, the study is said to be the first of its specific kind in the world.

"Pancreatic cancer is one of the hardest cancers to cure because it is difficult to detect cancer cells at the microscopic level," said Ajay Jain from OU College of Medicine.

"Because there are usually no early symptoms it is typically not diagnosed until after it has spread, and outcomes are very poor, about a 9-percent overall chance of survival. Surgery and chemotherapy offer the patients the best chance, but for surgery to work, we have to remove all the cancer, and that is difficult to do."

The study will combine multispectral optoacoustic tomography (MSOT) and a newly formulated contrast agent, with the goal of assessing if the combination can detect pancreatic cancer cells down to 200 microns in size.

Optoacoustic, or photoacoustic, imaging has been an attractive technique in cancer diagnosis ever since the method began its clinical translation after the pioneering work of Lihong Wang, now at Caltech.

Early clinical trials showed that it was a potentially versatile technique in cancer detection, able to distinguish malignant from healthy tissues in breast cancer potentially even without a contrast agent, and detecting cervical cancer with high accuracy, thanks to its ability to map hemoglobin in blood vessels.

Developments since then have seen the same principles applied to a range of bioimaging scenarios, with photoacoustic microscopy (PAM) breaking speed and resolution barriers in brain imaging.

Real-time identification of cancer cells

The new study builds on research at Oklahoma's Stephenson Cancer Center into clinical translation of its multispectral optoacoustic approach, in which multiwavelength illumination of tissue allows for the mapping of multiple chromophores.

In 2020 OU reviewed the progress of MSOT translation towards clinical use for the imaging of breast, prostate, bowel and skin cancers and concluded that, alongside developments in the infrared sources and ultrasound detectors employed, the nature of the optoacoustic dyes added to the tissues as exogenous contrast agents for imaging was a key challenge.

OU's Lacey McNally has now devised a contrast agent intended to be unique to pancreatic cancer cells. When this agent is delivered intravenously it can differentiate pancreatic cancer cells from other cells because the environment of pancreatic cancer is acidic. When the contrast agent encounters that acidity, its dye essentially "turns on" and becomes optoacoustically active.

"This is a hybrid approach that accomplishes what a CT scan cannot," McNally said. "Pancreatic cancer often creates tentacles that spread out beyond the primary tumor. Currently, there is no way for the surgeon to know where they are. But if the surgery team can use this MSOT approach in the operating room, it can tell them in real time where the cancer has metastasized so they can remove it."

Clinical trials underway at OU are applying MSOT to the study of breast cancer, and the $3 million grant will allow McNally and team to pursue several other clinical studies as well.

"This type of research collaboration between a translational scientist and a surgeon is extremely unusual," commented McNally. "The scientific and medical communities have made great strides in treating some types of cancer, but pancreatic cancer patients have the poorest survival. The outcome of this research could fundamentally change people’s lives."