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TAMPA, Fla. — Nearly half of all cancer patients receive radiation therapy during their treatment. The ideal course should deliver the optimum dose directly to the cancer cells while simultaneously limiting exposure to the surrounding normal cells to avoid unwanted toxicities. Several approaches have been developed over the decades that use image guidance to improve the efficacy of radiation therapy. More recently a new technology based on photoacoustic principles has been developed for radiotherapy guidance called ionizing radiation acoustic imaging (iRAI).

In a new study published in Nature Biotechnology, Moffitt Cancer Center researchers share their further development of the iRAI technology in collaboration with investigators from the University of Michigan to show the first visualization ever of radiation therapy distribution inside a living being in real time. This includes preclinical animal models and patients being treated for liver cancer.

There are several inherent challenges that radiation oncologists face when delivering radiation therapy to a tumor, including the movement of both the target tissue and surrounding normal tissues, and anatomical deformations. Several approaches or devices have been developed to overcome these challenges; however, these alternative approaches have limitations, such as a lack of real-time information, measuring the dose applied at a single point on the external surface of the tumor rather than the entire tissue volume, and dependency on dose rate or energy.

Researchers in Moffitt’s Machine Learning and Radiation Oncology departments wanted to further develop radiation therapy imaging technology to avoid these limitations. Specifically, the team wanted to develop a system capable of monitoring the dose of radiation therapy administered in real time and throughout the entire volume of the target tissue within the person being imaged. They chose to further develop iRAI, which is a noninvasive imaging technology that constructs images of radiation doses based on acoustic waves induced by radiation through soft tissue. This technology has the potential to map and monitor radiation doses at deep anatomical organs and structures in real time, and unlike other approaches, iRAI is directly proportional to the radiation dose absorbed by the targeted tissue.

The Moffitt team developed a clinical ready iRAI system to be used in real time that measures the dose in the entire volume of the target tissue with high sensitivity and high spatial resolution. They first tested their approach on a model, followed by a rabbit model in collaboration with the veterinary team at the University of South Florida. The researchers then successfully tested and confirmed their approach on a person being treated with radiation therapy for liver cancer.

“This breakthrough represents the first visualization of radiation inside a living being,” said Issam El Naqa, Ph.D., chair of the Machine Learning Department at Moffitt.

He hopes these developments in iRAI will lead to further improvements for personalized radiation therapy effectiveness in the clinic.

“These studies demonstrate the potential of iRAI to monitor and quantify the 3D radiation dose deposition during treatment, potentially improving radiotherapy treatment efficacy using real-time adaptive treatment,” said El Naqa.

This study was supported by grants received from the National Cancer Institute (R37CA222215 and P30CA046592) and the Michigan Institute for Clinical and Health Research (UL1TR002240).

About Moffitt Cancer Center
Moffitt is dedicated to one lifesaving mission: to contribute to the prevention and cure of cancer. The Tampa-based facility is one of only 53 National Cancer Institute-designated Comprehensive Cancer Centers, a distinction that recognizes Moffitt’s scientific excellence, multidisciplinary research, and robust training and education. Moffitt’s expert nursing staff is recognized by the American Nurses Credentialing Center with Magnet® status, its highest distinction. With more than 7,800 team members, Moffitt has an economic impact in the state of $2.4 billion. For more information, call 1-888-MOFFITT (1-888-663-3488), visit, and follow the momentum on Facebook, Twitter, Instagram and YouTube.