In a newly established collaboration between the OSF Healthcare Cancer Institute (OSF) in Peoria, IL and the Cancer Center at Illinois (CCIL), five project proposals were selected to receive funding through the Breakthrough and Advanced Treatment of (BEAT) Cancer Initiative. This program facilitates collaboration between researchers at Illinois and clinical physicians at OSF, aiming to improve various aspects of cancer diagnostics, treatment, and prevention.
One of the five recipients of this generous grant from OSF is CCIL member Angela Di Fulvio, who is working in collaboration with OSF clinicians on the enhancement of FLASH proton therapy. According to Di Fulvio, this form of cancer treatment aims to “deliver radiation much more precisely and effectively on the tumor, compared to standard X-ray external radiation therapy.” This therapeutic approach can reduce side effects compared to X-rays, thanks to the unique energy deposition pattern of protons.
“This is already a very promising strategy that is especially important when the tumor is close to other organs that are sensitive to radiation,” says Di Fulvio. “In traditional X-ray radiotherapy, while the beam was mostly focused on the cancer, it would also largely irradiate the surrounding tissues. This is not the case with protons, or heavy charged particles like carbon ions, because they have an energy deposition peak called the Bragg peak at the end of their path. This can be focused to accurately cover the volume of the tumor while sparing surrounding healthy tissues.”
A newly established partnership between the OSF Healthcare Cancer Institute in Peoria, IL and the Cancer Center at Illinois, called Breakthrough and Advanced Treatment of (BEAT) Cancer Initiative, facilitates collaboration to improve cancer diagnostics, treatment, and prevention. Shown here at OSF is the new FLASH proton therapy system.
The Bragg peak described by Di Fulvio is a sharp increase in radiation dose, characteristically followed by a rapid decrease. This is a key feature of protons, allowing for precise targeting of tumors while minimizing damage to healthy tissue. With this higher conformality of proton beams to an exact volume, it is paramount to deliver proton beam therapy precisely to the tumor–otherwise the Bragg peak could miss the tumor while irradiating surrounding organs. Because of the proton beam’s power, if a cancerous tumor is missed by even a millimeter, a significant risk of irradiating healthy, sensitive tissues arises. With such a small margin of error, much uncertainty arises, as organs can shift slightly in their internal positions between the times of treatment and initial imaging. Therefore, the BEAT Cancer team is working to develop methods to track the Bragg peak accurately.
The Bragg peak described by Di Fulvio is a sharp increase in radiation dose, characteristically followed by a rapid decrease. This is a key feature of protons, allowing for precise targeting of tumors while minimizing damage to healthy tissue. With this higher conformality of proton beams to an exact volume, it is paramount to deliver proton beam therapy precisely to the tumor–otherwise the Bragg peak could miss the tumor while irradiating surrounding organs. Because of the proton beam’s power, if a cancerous tumor is missed by even a millimeter, a significant risk of irradiating healthy, sensitive tissues arises. With such a small margin of error, much uncertainty arises, as organs can shift slightly in their internal positions between the times of treatment and initial imaging. Therefore, the BEAT Cancer team is working to develop methods to track the Bragg peak accurately.
“Uncertainty associated with the proton range, at the moment, is simply dealt with by increasing the cushion between the tumor and surrounding tissue,” reports Di Fulvio. “But this has the drawback of reducing the dose that we’re giving to the tumor.”
A graph comparing the dosages needed by X-rays and proton beams to reach the depth of the tumor. Proton beams, as displayed, spike at the end of their path near the location of the tumor, eliminating the extra radiation on healthy tissue present in X-ray radiation.
Therefore, Di Fulvio and her research team are working to develop ways to monitor precisely where a proton’s energy is delivered in real time, including methods that rely on prompt gamma rays and neutrons produced by beam-tissue interactions and ultrasound contrast agents (UCA) that vaporize upon interaction with protons. The figure below shows an example of UCA interaction with neutrons.
This system is set for its first round of tests in the coming weeks, with a final iteration aimed for Spring 2025. Future work with this project involves moving these methods to clinical testing, and identifying how this project can be implemented, at OSF and surrounding clinical cancer centers, for patient care and treatment.
“It’s an incredibly huge opportunity,” says Di Fulvio, on working with OSF and the CCIL. “The ability to engage with such a vibrant and active clinical center and research center that targets the treatment of cancer is invaluable to expand our work in the medical field.”
Ultrasound images of phantoms with UCAs suspended in poly(acrylamide) hydrogel and irradiated with neutrons.
Editor’s notes:
Angela Di Fulvio is an Associate Professor of Nuclear, Plasma, and Radiological Engineering, and the Director of the Arms Control & Domestic and International Security (ACDIS) program. She can be reached at difulvio@illinois.edu.
The paper “Potential of BPA functionalized poly(vinylalcohol)-shelled perfluorobutane nanodroplets towards enhanced boron neutron capture therapy and in-situ dosimetry” is available online: doi.org/10.1016/j.apmt.2023.102052
The article “Proton Beam Therapy Versus Photon-Beam Therapy: The Debate Continues” is available online: https://www.ilcn.org/proton-beam-therapy-versus-photon-beam-therapy-the-debate-continues/
This story was written by Chloe Zant, CCIL Communications Intern.