Joseph Harms, PhD

Building a New Detector to Safely Deliver Proton FLASH
 

Joseph Harms, PhD, of the University of Alabama at Birmingham is leading the development of a new detection system to be used with proton FLASH radiation therapy (RT) to measure the radiation dose and how fast the dose is delivered (dose rate). His collaborators on the project are Petr Bruza, PhD, of Dartmouth College and Rongxiao Zhang, PhD, of New York Medical College. FLASH RT is an emerging delivery technology that uses ultra-high dose rates to treat cancer and has been shown to reduce radiation-induced damage in healthy tissues. “FLASH has the potential to change the game for radiation therapy, compressing treatment from a few weeks into a few seconds. The goal of this project is to accurately and repeatably measure the intense radiation fields delivered with FLASH treatment fields so we can safely bring this new technology one step closer to the clinic,” says Dr. Harms.

A key step in safely delivering radiation therapy to patients is verifying that the delivered dose matches the planned dose. Currently, there is no accepted way to verify dose rate from FLASH RT treatment plans, and many of the commonly used radiation detectors do not function at the very high dose rates of FLASH. In the new system developed by Dr. Harms’s team, an ultra-fast camera in the treatment room is focused on a scintillator, a material that emits light when it is exposed to radiation. The measurement of this light is then converted to the radiation dose, allowing for real-time verification of the dose and dose rate.

With support from ROI, Dr. Harms and his collaborators are:

• Assessing the accuracy of the new detection system to measure dose rate of proton FLASH RT in a wide range of scenarios that vary the dose and other factors, including scan speed, delivery time and treatment plan design.
• Testing the system’s ability to identify errors in the delivery of patient treatment plans.
• Developing a protocol for patient-specific quality assurance for proton FLASH RT that will be based on realistic fields for treatment of lung, brain and abdominal tumors.
• Comparing measured treatment plans to calculated treatment plans by confirming the dose and dose rate at the surface and the dose at the depth of the treatment target.

The detection system being developed by Dr. Harms’ team would play a vital role in patient safety by ensuring that FLASH fields can be delivered with confidence that the planned dose rate distribution matches the radiation treatment received by the patient. Novel methods for patient-specific quality assurance like this are necessary to fully realize the promise of FLASH RT to reduce treatment-induced side effects and drastically shorten treatment times.