Showing posts with label Physics:HEP. Show all posts
Showing posts with label Physics:HEP. Show all posts
September 11, 2014
May 9, 2011
The National Association for Proton Therapy
Supporting operating center members:
James M. Slater, M.D. Proton Treatment and Research Center at Loma Linda University Medical Center
The University of Florida Proton Therapy Institute
M.D. Anderson Cancer Center's Proton Center, Houston
ProCure Proton Therapy Center, Oklahoma City
The Roberts Proton Therapy Center at University of PA Health System
Hampton University Proton Therapy Institute
CDH Proton Center, A ProCure Center, Chicago Area, Illinois
Other operating centers:
Indiana University Health Proton Therapy
Francis H. Burr Proton Center at Mass. General Hospital
Supporting members under construction:
ProCure Proton Therapy Center in partnership with Princeton Radiation Oncology Group and CentraState Healthcare System, Somerset, N.J.
ProCure Proton Therapy Center in partnership with the Seattle Cancer Care Alliance, Seattle, WA
The McLaren Proton Therapy Center, Flint, Michigan
Supporting members in development:
The Proton Therapy Center, Knoxville, in partnership with the University of Tennessee Medical Center
Proton Institute of New York
Mayo Clinic Proton Beam Therapy Program with locations in Rochester, Minnesota and Phoenix, Arizona
©
April 18, 2011
Taiwan, US to jointly develop next-generation PET technology
The China Post
April 15, 2011
TAIPEI -- Taiwan's National Cheng Kung University (NCKU) announced yesterday a cooperation plan with a U.S. laboratory and manufacturer to jointly develop next-generation positron emission tomography (PET) technology that will significantly advance the diagnosis of breast cancer.
Under the terms of the project with the Brookhaven National Laboratory (BNL) and Aurora Imaging Technology Inc., the new PET technology will be used in combination with magnetic resonance imaging (MRI) to create the world's most progressive breast cancer diagnosis system, said NCKU officials.
According to Gene-Jack Wang, chairman of BNL's Medical Department, the new PET/MRI system will be able to accurately identify breast cancer tumors even when they are only 0.2 cm in size. Existing technology is unable to identify such tumors until they reach 4 cm.
The time required for an accurate diagnosis will also be shortened from 30 minutes to under 5 minutes, NCKU said.
©
April 15, 2011
TAIPEI -- Taiwan's National Cheng Kung University (NCKU) announced yesterday a cooperation plan with a U.S. laboratory and manufacturer to jointly develop next-generation positron emission tomography (PET) technology that will significantly advance the diagnosis of breast cancer.
Under the terms of the project with the Brookhaven National Laboratory (BNL) and Aurora Imaging Technology Inc., the new PET technology will be used in combination with magnetic resonance imaging (MRI) to create the world's most progressive breast cancer diagnosis system, said NCKU officials.
According to Gene-Jack Wang, chairman of BNL's Medical Department, the new PET/MRI system will be able to accurately identify breast cancer tumors even when they are only 0.2 cm in size. Existing technology is unable to identify such tumors until they reach 4 cm.
The time required for an accurate diagnosis will also be shortened from 30 minutes to under 5 minutes, NCKU said.
©
March 23, 2011
Engineers Unveil Particle Accelerator on a Chip
IEEE Spectrum
Zipping ions down a MEMS racetrack could lead to portable particle beams
By Joseph Calamia / March 2011
Image: Yue Shi
This article was modified on 22/02/2011
3 February 2011—Forget for a moment about the quest to build bigger high-energy particle accelerators. Last week, at the MEMS 2011 conference, in Cancun, Mexico, researchers instead explained their efforts to create a smaller one.
Their chip-size cyclotron can guide argon ions with around 1.5 kiloelectronvolts of energy down a 5-millimeter accelerating track before whipping them around a 90-degree turn. The system boosts the ions’ energy by 30 electronvolts. That’s not very much energy, but unlike its larger cousins, this accelerator has no need for bulky magnets and instead uses an electric field set up between parallel electrode guide rails to accelerate and steer its particle beam. The device’s designers at Cornell University, in Ithaca, N.Y., say that with more research, similar electrostatic mini-accelerators might be used in shoebox-size scanning electron microscopes or portable particle-ray guns for cancer treatment.
The Large Hadron Collider, the world’s largest particle accelerator, which is buried underneath the border of France and Switzerland, can slam particles together in collisions that have nine or ten orders of magnitude more energy than the ions that traveled through the tiny Cornell device. "They need that to break open the nucleus and see what’s inside," says Yue Shi, an electrical and computer engineering graduate student who developed the accelerator on a chip.
Instead, Shi, funded by the U.S. Defense Advanced Research Projects Agency, is working to create a device that might accelerate ions to energies of hundreds of kiloelectronvolts on a chip not much bigger than a few square centimeters, and a suitcase-size device capable of accelerating ions to hundreds of megaelectronvolts, in the hopes of developing portable particle accelerators.
Shi constructed three versions of the accelerator—two on silicon-on-insulator (SOI) chips and one on a printed circuit board. Each had a straight, segmented acceleration track and either a 1-, 2-, or 4-mm turning radius. To test the design, she fired a stream of argon ions with around 1.5 keV of energy from a commercial ion source into each chip’s tracks. Electric fields between four segments in each chip’s acceleration track gave the ions a kick before they raced into the turn. Then another electric potential between two electrode curbs pulled ions around the bend. Only those ions with just the right amount of energy made it through. So, by detecting ions at the finish line, Shi confirmed that they truly got a boost.
If a small accelerator based on this design could bestow 1 MeV of energy to ion beams, it would have a broad range of applications, says Amit Lal, who worked with Shi and leads Cornell’s SonicMEMS Laboratory. Lal’s group works to create chip-scale power sources, such as a radioisotope-based generator for powering the electronics in cyborg insects. This particle accelerator is an offshoot of that research.
Lal also foresees more fantastic uses for the device. Doctors already use high-energy particle beams to kill cancer cells, he says, explaining that protons shot at living tissue give off heat as they slow down. Such radiation therapy requires devices that take up an entire room, he says, but tinier accelerators might make treatments more feasible for smaller clinics or allow more localized beams to irradiate fewer healthy cells. "Think of a scalpel with a proton beam coming out of it," he says.
Developing this proof-of-concept device into a commercial tool will first require overcoming some technical hurdles. Right now, the chip accelerates ions from a commercial argon ion source with a 75-micrometer-wide beam. Shi compares shooting that wide source into the accelerating channel to threading a needle, and much of the beam is lost. In the future, she hopes to use on-chip plasma sources to ionize atoms and energize them to around 100 eV before they even enter the electrostatic accelerator. She also notes that the accelerator she presented last week doesn’t focus the beam, which also leads to lost ions. Finally, she points out that the fastest ions that coursed through the accelerator during this initial research only had around 2 keV of energy—not much more than their starting energy of 1.5 keV from the commercial ion source—and that’s still three orders of magnitude lower than what she seeks.
Reaching the 1 MeV goal is certainly possible, she says. Having now shown that the ions can execute tight turns, Shi believes that future designs could navigate the ions repeatedly through accelerating strips for more energy.
The Cornell device is not the only mini-accelerator in development, or even the smallest. Instead of electrostatics, Gil Travish, who is developing a "micro-accelerator platform" at the University of California, Los Angeles, wants to use the electric fields in laser light to speed particles on their way. Travish’s group is starting to build a device that he describes as a 1-µm-thick "sandwich" with two mirrors above and below a gap only one wavelength of light high and several hundred wavelengths wide. As the light from a laser oscillates in that gap, an electron passing through the peak electric field will receive a tremendous boost—around a gigaelectronvolt per meter or a megaelectronvolt per millimeter. His team hopes to start beam tests in a prototype device in the next six months.
Travish says that it’s important to have multiple approaches, such as Cornell’s electrostatic work, for building these tiny particle accelerators. The high frequency of the laser light planned for use in the UCLA device means that only the zippiest of particles would make it through before the oscillating, light-wave-induced electric field reverses. That’s fine for electrons, but the argon ions that Cornell has accelerated, he notes, would need to be moving very quickly to make it through any laser accelerator. Otherwise, "the wave would just wash over the particle, and it would gain almost nothing," he says.
Funded in part by the U.S. Defense Threat Reduction Agency, which protects against the threat of weapons of mass destruction, the UCLA team imagines that their particle beam might also one day appear in medical devices or in unmanned aerial vehicles that could examine suspicious buildings using X-rays. "I think that in the next half decade you’ll start to see a real awakening," Travish says about the possibilities in particle accelerators’ new realm.
This article appeared in print as “A Chip-Scale Particle Accelerator."
©
Zipping ions down a MEMS racetrack could lead to portable particle beams
By Joseph Calamia / March 2011
This article was modified on 22/02/2011
3 February 2011—Forget for a moment about the quest to build bigger high-energy particle accelerators. Last week, at the MEMS 2011 conference, in Cancun, Mexico, researchers instead explained their efforts to create a smaller one.
Their chip-size cyclotron can guide argon ions with around 1.5 kiloelectronvolts of energy down a 5-millimeter accelerating track before whipping them around a 90-degree turn. The system boosts the ions’ energy by 30 electronvolts. That’s not very much energy, but unlike its larger cousins, this accelerator has no need for bulky magnets and instead uses an electric field set up between parallel electrode guide rails to accelerate and steer its particle beam. The device’s designers at Cornell University, in Ithaca, N.Y., say that with more research, similar electrostatic mini-accelerators might be used in shoebox-size scanning electron microscopes or portable particle-ray guns for cancer treatment.
The Large Hadron Collider, the world’s largest particle accelerator, which is buried underneath the border of France and Switzerland, can slam particles together in collisions that have nine or ten orders of magnitude more energy than the ions that traveled through the tiny Cornell device. "They need that to break open the nucleus and see what’s inside," says Yue Shi, an electrical and computer engineering graduate student who developed the accelerator on a chip.
Instead, Shi, funded by the U.S. Defense Advanced Research Projects Agency, is working to create a device that might accelerate ions to energies of hundreds of kiloelectronvolts on a chip not much bigger than a few square centimeters, and a suitcase-size device capable of accelerating ions to hundreds of megaelectronvolts, in the hopes of developing portable particle accelerators.
Shi constructed three versions of the accelerator—two on silicon-on-insulator (SOI) chips and one on a printed circuit board. Each had a straight, segmented acceleration track and either a 1-, 2-, or 4-mm turning radius. To test the design, she fired a stream of argon ions with around 1.5 keV of energy from a commercial ion source into each chip’s tracks. Electric fields between four segments in each chip’s acceleration track gave the ions a kick before they raced into the turn. Then another electric potential between two electrode curbs pulled ions around the bend. Only those ions with just the right amount of energy made it through. So, by detecting ions at the finish line, Shi confirmed that they truly got a boost.
If a small accelerator based on this design could bestow 1 MeV of energy to ion beams, it would have a broad range of applications, says Amit Lal, who worked with Shi and leads Cornell’s SonicMEMS Laboratory. Lal’s group works to create chip-scale power sources, such as a radioisotope-based generator for powering the electronics in cyborg insects. This particle accelerator is an offshoot of that research.
Lal also foresees more fantastic uses for the device. Doctors already use high-energy particle beams to kill cancer cells, he says, explaining that protons shot at living tissue give off heat as they slow down. Such radiation therapy requires devices that take up an entire room, he says, but tinier accelerators might make treatments more feasible for smaller clinics or allow more localized beams to irradiate fewer healthy cells. "Think of a scalpel with a proton beam coming out of it," he says.
Developing this proof-of-concept device into a commercial tool will first require overcoming some technical hurdles. Right now, the chip accelerates ions from a commercial argon ion source with a 75-micrometer-wide beam. Shi compares shooting that wide source into the accelerating channel to threading a needle, and much of the beam is lost. In the future, she hopes to use on-chip plasma sources to ionize atoms and energize them to around 100 eV before they even enter the electrostatic accelerator. She also notes that the accelerator she presented last week doesn’t focus the beam, which also leads to lost ions. Finally, she points out that the fastest ions that coursed through the accelerator during this initial research only had around 2 keV of energy—not much more than their starting energy of 1.5 keV from the commercial ion source—and that’s still three orders of magnitude lower than what she seeks.
Reaching the 1 MeV goal is certainly possible, she says. Having now shown that the ions can execute tight turns, Shi believes that future designs could navigate the ions repeatedly through accelerating strips for more energy.
The Cornell device is not the only mini-accelerator in development, or even the smallest. Instead of electrostatics, Gil Travish, who is developing a "micro-accelerator platform" at the University of California, Los Angeles, wants to use the electric fields in laser light to speed particles on their way. Travish’s group is starting to build a device that he describes as a 1-µm-thick "sandwich" with two mirrors above and below a gap only one wavelength of light high and several hundred wavelengths wide. As the light from a laser oscillates in that gap, an electron passing through the peak electric field will receive a tremendous boost—around a gigaelectronvolt per meter or a megaelectronvolt per millimeter. His team hopes to start beam tests in a prototype device in the next six months.
Travish says that it’s important to have multiple approaches, such as Cornell’s electrostatic work, for building these tiny particle accelerators. The high frequency of the laser light planned for use in the UCLA device means that only the zippiest of particles would make it through before the oscillating, light-wave-induced electric field reverses. That’s fine for electrons, but the argon ions that Cornell has accelerated, he notes, would need to be moving very quickly to make it through any laser accelerator. Otherwise, "the wave would just wash over the particle, and it would gain almost nothing," he says.
Funded in part by the U.S. Defense Threat Reduction Agency, which protects against the threat of weapons of mass destruction, the UCLA team imagines that their particle beam might also one day appear in medical devices or in unmanned aerial vehicles that could examine suspicious buildings using X-rays. "I think that in the next half decade you’ll start to see a real awakening," Travish says about the possibilities in particle accelerators’ new realm.
This article appeared in print as “A Chip-Scale Particle Accelerator."
©
December 13, 2010
Particle accelerators: think small
MedicalPhysicsWeb
Aug 7, 2007
Proton therapy offers a number of advantages over conventional X-ray radiotherapy. Most importantly, protons deliver all of the energy at the end of their path - unlike X-rays. This means they can be "tuned" to dump all of their killing power in the tumour, which considerably reduces the damage incurred by surrounding healthy tissue as well as offering the possibility of upping the dose.
Trouble is, conventional proton accelerators require a space the size of a basketball court and can cost well in excess of $100 million, once all the necessary infrastructure is factored in. That alone provides strong motivation for physicists to develop smaller, cheaper accelerators that will make proton therapy accessible to many more clinics - and many more patients.
By the sound of things, they have been rising to the challenge. During a symposium entitled "Novel particle acceleration techniques" at last month's annual meeting of the American Association of Physicists in Medicine (AAPM) in Minneapolis, MN, a number of physicists from around the world presented their latest work on compact particle accelerators.
Chang-Ming Charlie Ma from Fox Chase Cancer Center (Philadelphia, PA) kicked off the session with a reminder about why all of this effort is necessary. "Proton/ion therapy has great potential for improving local control and normal-tissue sparing because of its superior dose distributions," he explained.
One option for shrinking the cost of proton therapy is simply to build a smaller, lighter accelerator using conventional technology. This is the approach being taken by Still River Systems, a Littleton, MA-based start-up that's developing a compact proton-therapy system powered by a synchrocyclotron (a cyclotron in which the frequency of the driving RF electric field is varied to compensate for the mass gain of the accelerated particles). "When you scale a 2 T cyclotron to 10 T, it goes from weighing 450 tonnes to less than 20 tonnes," said Kenneth Gall, co-founder and CEO of Still River Systems.
Essentially this is what Gall and his team have done, using superconductors as the basis for the 10 T electromagnet. The result will be an accelerator, just a couple of metres across, which can be mounted on a gantry in a similar fashion to the familiar linac set-up. So far, Gall reported, the ion source is operating successfully at 10 T, the RF system has been tested, and the vacuum system is complete. A prototype system is set to be installed at Washington University (St Louis, MO) next year.
Laser focus
Elsewhere, researchers are trying a more radical approach. In recent years, an increasing number of scientists have become interested in the idea of laser-energized proton acceleration. Focusing a high-power laser pulse onto a thin target causes massive ionization in the target and expels a large number of relativistic electrons. This leaves the target with a strong positive charge and so creates a transient electric field. Any protons present will then be accelerated to high energies by this field.
However, there are several challenges to overcome before laser-generated proton beams become a ready-to-go clinical technology. For starters, therapists need a beam of at least 60 MeV; that beam also has to be monoenergetic. Neither of these specifications is currently easy to achieve with laser acceleration. Nevertheless, Toshi Tajima of the Japan Atomic Energy Agency (Kizugawa, Japan) is confident that this is the route to affordable proton therapy. "My goal is to 'compactify' the laser accelerators into the size of a hospital photon machine," he told AAPM delegates.
His team believes it can solve both the MeV and "monoenergy" challenges by combining a technique known as adiabatic acceleration with a specially designed graded target. Add in a PET scanner for confirming the irradiation and you have the basis of a clinical proton-therapy system, Tajima claims. The project has just been given funding equivalent to $100 million by the Japanese government. It remains to be seen whether the researchers can make their ideas work in practice, though.
Electrons, not protons
Laser-based accelerators could also facilitate the clinical uptake of very-high-energy electron therapy (VHEET). Compared to photons, electrons are little-used therapeutically. When they are, it is usually at the low energies a conventional linac is capable of producing, which in turn restricts their usefulness to superficial tumours. By and large, electron-beam therapy is most commonly employed in conjunction with photon radiotherapy to boost the dose.
VHEET, on the other hand, requires a dedicated accelerator, though current technology is bulky and expensive. Too bulky and too expensive for the clinical mainstream, despite the fact that that high-energy electrons offer dosimetric advantages over photons. According to Victor Malka of the Laboratoire d'Optique Appliquée (Palaiseau, France), electrons have a narrower penumbra compared to photons, a characteristic which improves the sparing of sensitive structures by as much as 20%.
"The lack of compact and cost-efficient electron accelerators could be overcome by laser-plasma systems," Malka claimed. In such an accelerator, a high-intensity pulsed laser is fired into a jet of dense, ionized gas. The subsequent interaction creates plasma waves, and electrons caught in these waves are pushed to high speeds and emitted as a high-energy electron beam. Using this technique, electrons can be accelerated to therapeutic energies in a few millimetres, rather than hundreds of metres.
The question is: will any of these technologies actually deliver what that their proponents claim? Some members of the audience expressed scepticism during the ensuing debate. For their part, most of the speakers were more than a little vague about what their systems might cost if they ever make it to market. Clearly, this remains a watching brief for the time being.
About the author
Michelle Jeandron is science and technology reporter on medicalphysicsweb.
©
Aug 7, 2007
Proton therapy offers a number of advantages over conventional X-ray radiotherapy. Most importantly, protons deliver all of the energy at the end of their path - unlike X-rays. This means they can be "tuned" to dump all of their killing power in the tumour, which considerably reduces the damage incurred by surrounding healthy tissue as well as offering the possibility of upping the dose.
Trouble is, conventional proton accelerators require a space the size of a basketball court and can cost well in excess of $100 million, once all the necessary infrastructure is factored in. That alone provides strong motivation for physicists to develop smaller, cheaper accelerators that will make proton therapy accessible to many more clinics - and many more patients.
By the sound of things, they have been rising to the challenge. During a symposium entitled "Novel particle acceleration techniques" at last month's annual meeting of the American Association of Physicists in Medicine (AAPM) in Minneapolis, MN, a number of physicists from around the world presented their latest work on compact particle accelerators.
Chang-Ming Charlie Ma from Fox Chase Cancer Center (Philadelphia, PA) kicked off the session with a reminder about why all of this effort is necessary. "Proton/ion therapy has great potential for improving local control and normal-tissue sparing because of its superior dose distributions," he explained.
One option for shrinking the cost of proton therapy is simply to build a smaller, lighter accelerator using conventional technology. This is the approach being taken by Still River Systems, a Littleton, MA-based start-up that's developing a compact proton-therapy system powered by a synchrocyclotron (a cyclotron in which the frequency of the driving RF electric field is varied to compensate for the mass gain of the accelerated particles). "When you scale a 2 T cyclotron to 10 T, it goes from weighing 450 tonnes to less than 20 tonnes," said Kenneth Gall, co-founder and CEO of Still River Systems.
Essentially this is what Gall and his team have done, using superconductors as the basis for the 10 T electromagnet. The result will be an accelerator, just a couple of metres across, which can be mounted on a gantry in a similar fashion to the familiar linac set-up. So far, Gall reported, the ion source is operating successfully at 10 T, the RF system has been tested, and the vacuum system is complete. A prototype system is set to be installed at Washington University (St Louis, MO) next year.
Laser focus
Elsewhere, researchers are trying a more radical approach. In recent years, an increasing number of scientists have become interested in the idea of laser-energized proton acceleration. Focusing a high-power laser pulse onto a thin target causes massive ionization in the target and expels a large number of relativistic electrons. This leaves the target with a strong positive charge and so creates a transient electric field. Any protons present will then be accelerated to high energies by this field.
However, there are several challenges to overcome before laser-generated proton beams become a ready-to-go clinical technology. For starters, therapists need a beam of at least 60 MeV; that beam also has to be monoenergetic. Neither of these specifications is currently easy to achieve with laser acceleration. Nevertheless, Toshi Tajima of the Japan Atomic Energy Agency (Kizugawa, Japan) is confident that this is the route to affordable proton therapy. "My goal is to 'compactify' the laser accelerators into the size of a hospital photon machine," he told AAPM delegates.
His team believes it can solve both the MeV and "monoenergy" challenges by combining a technique known as adiabatic acceleration with a specially designed graded target. Add in a PET scanner for confirming the irradiation and you have the basis of a clinical proton-therapy system, Tajima claims. The project has just been given funding equivalent to $100 million by the Japanese government. It remains to be seen whether the researchers can make their ideas work in practice, though.
Electrons, not protons
Laser-based accelerators could also facilitate the clinical uptake of very-high-energy electron therapy (VHEET). Compared to photons, electrons are little-used therapeutically. When they are, it is usually at the low energies a conventional linac is capable of producing, which in turn restricts their usefulness to superficial tumours. By and large, electron-beam therapy is most commonly employed in conjunction with photon radiotherapy to boost the dose.
VHEET, on the other hand, requires a dedicated accelerator, though current technology is bulky and expensive. Too bulky and too expensive for the clinical mainstream, despite the fact that that high-energy electrons offer dosimetric advantages over photons. According to Victor Malka of the Laboratoire d'Optique Appliquée (Palaiseau, France), electrons have a narrower penumbra compared to photons, a characteristic which improves the sparing of sensitive structures by as much as 20%.
"The lack of compact and cost-efficient electron accelerators could be overcome by laser-plasma systems," Malka claimed. In such an accelerator, a high-intensity pulsed laser is fired into a jet of dense, ionized gas. The subsequent interaction creates plasma waves, and electrons caught in these waves are pushed to high speeds and emitted as a high-energy electron beam. Using this technique, electrons can be accelerated to therapeutic energies in a few millimetres, rather than hundreds of metres.
The question is: will any of these technologies actually deliver what that their proponents claim? Some members of the audience expressed scepticism during the ensuing debate. For their part, most of the speakers were more than a little vague about what their systems might cost if they ever make it to market. Clearly, this remains a watching brief for the time being.
About the author
Michelle Jeandron is science and technology reporter on medicalphysicsweb.
©
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