New research suggests that specialized systems, sometimes, could defend cancer in patients with particles to deliver a full course of flash radiation therapy in mere microseconds.
By accepting an emerging technology known as Flash Radiotherapy, doctors could now abolish tumors just in a few milliseconds and at a fraction of the cost of common radiation therapy at least in theory. As of yet, the lightning-fast procedure has not faced legal clinical trials in human patients, although one man experienced the experimental treatment, researchers reported in October 2019 in the journal Radiotherapy and Oncology.
Now, a new rat study, published Jan. 9 in the International Journal of Radiation Oncology, Biology and Physics, has more explained the promise of this cancer therapy. Co-author Dr. Keith Cengel who is an associate professor of radiation oncology at the Hospital of the University of Pennsylvania said, “It has the identical tumor-control rate as conventional radiation but significantly less effect on normal tissue.”
In other words, the flash technique appears to eliminate tumor cells while forgiving healthy tissues. The method works by attacking the tumor site with a steady stream of particles, normally, light particles, called photons, or negatively energized electrons. Now, Cengel and his colleagues have started added particle into the mix the positively charged proton.
Time is everything
The name “flash” completely refers to the ultrafast rate at which the technique delivers radiation to target tissues. Flash beats cells with the equivalent total amount of radiation as current therapies do, but rather than determining the dose over recurring weeks in minutes-long sessions, the complete treatment lasts just tenths of a second, Vozenin said. Vozenin also stated, “That would be even more helpful if we can go to hundredths of a second.”
The speed advances all the difference. In conventional radiation therapy, a subject may experience dozens of treatment sessions, throughout which time healthy tissues may become damaged long before the tumor cells die. But when the same dose of radiation is delivered at a speedier rate, as with a flash, healthy tissues outlast unharmed. Specifically why that happens remains a mystery.
“That’s the million-dollar question, we are working hard to try to understand that,” Vozenin said. Analysis suggests that the temporary discharge of radiation may create a dip in levels of oxygen in the healthy tissues, which typically contain far more oxygen than cancerous cells. Tumors resist traditional radiation therapy thanks in part to their lack of oxygen, so the temporary effect inspired by flash might support healthy cells upon the damage, as well as reduce the generation of harm-free radicals, according to a report in the journal Clinical Oncology, published in 2019.
Put to the test
The team practiced an existing proton accelerator, known as a cyclotron, to run the tests, but made several adjustments. The trick was to ramp up the rate at which the protons could be discharged from the machine while also improving procedures to monitor where the protons landed and in what amount. With this infrastructure in place, the team could better control the current of protons flowing from the cyclotron, “variety of like a faucet that you can turn on complete blast or drip,” Cengel said.
