A joint team of Dartmouth and Dartmouth-Hitchcock researchers from the departments of engineering, radiation oncology, and surgery have developed a method of delivering radiation therapy that reduces damage to healthy tissue while maintaining its efficacy against tumors.

To achieve this, the team converted a standard linear accelerator (LINAC) to a FLASH ultra-high-dose rate radiation therapy beam. The work, entitled “Electron FLASH Delivery at Treatment Room Isocenter for Efficient Reversible Conversion of a Clinical LINAC,” is newly published online in International Journal of Radiation Oncology, Biology & Physics.

The exceptionally high dose rate is 3,000 times higher than normal therapy treatment. Instead of treatment over 20 seconds, an entire treatment is completed in 6 milliseconds, giving the therapy its nickname, “FLASH.”

“These high dose rates have been shown to protect normal tissues from excess damage while still having the same treatment effect on tumor tissues, and may be critically important for limiting radiation damage in patients receiving radiation therapy,” says Brian Pogue, the MacLean Professor of Engineering at Dartmouth, Co-Director of the Norris Cotton Cancer Center (NCCC) Translational Engineering in Cancer Research Program, and co-author of the project.

While the team awaits news of potential funding from the National Institutes of Health (NIH), early pilot funding from NCCC and Dartmouth's Thayer School of Engineering allowed for prototyping of the converted LINAC. Pre-clinical testing of the beam began in August and has already provided key data on its potential for different tumor plans.

“This is the first such beam in New England and on the east coast, and we believe it is the first reversible FLASH beam on a clinically used LINAC where the beam can be used in the conventional geometry with patients on the treatment couch,” says Pogue.

The FLASH beam is currently being used in preclinical studies and the research group has expanded to involve physicians in clinical radiation oncology and dermatology, designing what they hope will be the first human safety trial with FLASH radiotherapy at Dartmouth-Hitchcock, treating patients’ advanced skin lesions that cannot be removed surgically.

In addition to Pogue, the project was led by Rongxiao Zhang, Adjunct Assistant Professor of Engineering; Petr Bruza, Assistant Professor of Engineering; and David Gladstone and P. Jack Hoopes, both Adjunct Professors of Engineering. Work was also done by Dartmouth engineering PhD candidates and first authors Ronny Rahman and Ramish Ashraf, and Dartmouth-Hitchcock engineers Lawrence Thompson and Chad Dexter.