A series of permanent magnet chains designed by Brookhaven National Laboratory have successfully transported the proton beam that kills cancer into unprecedented energy ranges, opening up a pathway to ultra-fast “flash” radiation therapy, which can damage tumors while amplifying healthy tissue.
Magnetic array-guided proton beams range from 50 to 250 million electron volts, the highest energy range ever seen in this fixed field technology.
This innovation addresses the key limitations of current proton therapy: Today’s accelerators cannot switch quickly between energy levels, preventing doctors from providing research that can revolutionize the division of cancer care, high-dose treatments. Brookhaven designs remove this constraint using permanent magnets that do not require power yet without precise control of the beam path.
The promise of flash therapy
“It’s really like a flash, essentially a beam of ultra-high dose rate,” explained Samuel Ryu, director of the Department of Radiation Oncology at Stony Brook Medicine, who worked with Brookhaven researchers. “This ultra-high delivery method shows great promise because “adjacent normal tissue seems to be better preserved” when radiation is delivered in milliseconds rather than minutes.
Current proton therapy has already given advantages over conventional X-ray therapy. X-rays deposit energy throughout the path, including outside the tumor, but the protons stop and release most of the energy at precise depth determined by the energy level. This targeting capability reduces collateral damage, but existing systems lack the agility of fast energy switching.
“The main advantage of proton or other particle radiation therapy is that the beam stops and deposits most of the energy in one place,” notes Brookhaven physicist Dejan Trbojevic, who constructs the magnetic array with designer Stephen Brooks.
Engineering Accuracy
The breakthrough lies in Brooks’ clever permanent magnet design. Each of the nine magnets is composed of wedge-shaped fragments arranged in an elliptical configuration with horizontal openings for the beam passage. When arranged in slightly curved arcs, the magnets produce different field strengths – the most harsh on the outer edge and weaker toward the center.
This gradient allows different energy beams to follow different stable paths simultaneously. “All energy is all possibilities,” Brooks stressed. “That’s why we can offer high dose rates and fast energy scaling.”
The engineering challenges are enormous. Protons have a stronger magnetic field than the electrons used in Brookhaven’s early CBETA accelerator projects. “These magnets are about three times as big as the CBETA field, because for the hospital, you want it to be as small as possible,” Brooks explained.
Innovation in hospital scale
Compact design can reshape the cancer treatment infrastructure. A complete accelerator using this technology will measure approximately 30 feet by 10 feet, enough to accommodate typical hospital wings and larger than the current football field-sized proton therapy facility.
Rapid energy conversion will enable doctors to target tumors more effectively by immediately adjusting the depth of beam penetration. As Ryu points out, “Different energies give you different depths of proton energy deposits. You can choose these different energies right away, so you can cover large tumors, especially for deep tumors in the prostate, kidney, pancreas and brain.”
Key advantages of magnetic array systems include:
- Instant energy conversion without delay
- All energy levels are available simultaneously
- Compact design suitable for hospital environment
- Reduce infrastructure and operational costs
From physical laboratories to patient care
This project reflects the transformation method of basic physics research. The team worked with SABR Enterprises, LLC to manufacture precision magnet assemblies and tested them using the actual Proton Beams at NASA NASA Space Radiation Laboratory in Brookhaven.
“When Stephen reached out to produce these magnet arrays, we immediately knew we wanted to be involved,” said Robert Mercurio, president and technical director of SABR. Industrial partnerships require the development of dedicated tools to position individual magnet blocks with extremely high accuracy.
The tests confirmed the system functionality of the entire planned energy spectrum, with proton beams passing through the magnetic array exactly as predicted by the computer model. Future tests will be used to evaluate lower energy beams from 10-50 MEV using Brookhaven’s Tandem van de Graaff facility.
The path to clinical reality
Despite the promise, significant developments remain before patients can benefit from this technology. The current nine-piece array represents only one part of the proposed racing accelerator that requires two curved arcs connected through straight sections.
A complete system will require up to 6,000 cycle turns to maintain beam stability, almost 1000 times that of the CBETA system. However, basic physics has proven that the path forward seems obvious.
“The direct goal is to do some cell culture studies,” Ryu notes. “As a researcher and clinical investigator and doctor, I want to transfer this technology to patient care in my time.”
The study represents taxpayer-funded science, bringing direct social benefits, as Abhay Deshpande, associate director of Brookhaven’s laboratory, highlighted: “This work highlights important advances in accelerator science and technology obtained through years of building accelerator for basic physics research and how society can benefit directly.”
Related
If our report has been informed or inspired, please consider donating. No matter how big or small, every contribution allows us to continue to deliver accurate, engaging and trustworthy scientific and medical news. Independent news takes time, energy and resources – your support ensures that we can continue to reveal the stories that matter most to you.
Join us to make knowledge accessible and impactful. Thank you for standing with us!
