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Researchers at Lawrence Livermore National Laboratory have shown for the first time the potential for linear-induction-accelerators to deliver effective, targeted doses of "FLASH" radiation to cancer patients. The technique kills cancer cells with minimal damage to healthy cells. The approach is outlined in a paper.
For decades, cancer treatment has often meant weeks of low-dose radiation in hopes of delivering enough to malignant cells without too much damage to the patient's healthy cells. Efforts to deliver a rapid, high, targeted dose of therapy radiation at the required depth have required large, complex machines the size of gymnasiums and have so far proven impractical for clinical use. The authors of the Scientific Reports paper note that LIAs that are powerful enough to deliver the necessary dose rate to cancer cells can be built only 3 meters long.
LIAs have been used in nuclear and stockpile experiments at the Laboratory since the 1960s. The RF and microwave accelerators were not powerful enough. Large versions of the accelerators are used to deliver flashes of radiation, some in a sequence to produce a simulation of a nuclear implosion. Stephen Sampayan, the lead author of the book, said that the potential use of the weapons program in cancer therapy has been underpinned by two of the uses. LIAs have been used for decades, but they were not previously considered for use in clinical applications as the industry is unfamiliar with them.
"You're combining technologies that were developed for weapons, either diagnostics or weapon design itself, and spinning off something that could potentially be a major breakthrough in cancer treatment," he said.
The status of LIA technology, the physics and the research team's efforts to stabilizing the electron beam are outlined in the paper. The minimum dose rate of 40 gy s1 has been shown to be effective, with maximum effect at 100 gy s1 to ensure healthy-tissues. Sampayan said that the instantaneous dose rate is important because it is out of the reach of conventional accelerators. A higher instantaneous dose rate is more effective than a lower one in keeping the patient's time under radiation as low as possible.
To create a dose high enough to kill cancer cells but short enough to avoid damaging healthy cells, the LIA was developed by the team. The researchers can focus a steerable beam by controlling the magnets. It is possible that LIA FLASH-RT can be used to fight cancer in other areas, such as the brain or in blood.
George Caporaso, Yu-Jiuan Chen, Steve Falabella, Steven Hawkins, James Watson, Jan-Mark Zentler, and Kristin Sampayan of Opcondys Inc. were involved in the paper.
The Megavolt bremsstrahlung measurement from linear induction accelerators can be used to reduce acute toxicity. The DOI is 10.1038/s41598-021-95807-9.
Scientific reports are in the journal.
There is a news story about safe delivery of radiation to cancer patients.
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