Researchers use MRI scanner to image damage in the lung due to second-hand smoke.They presented this work at RSNA 2007
K.S.Parthasarathy
Public release date: 26-Nov-2007
Contact: Rachel Salis-Silverman
Salis@email.chop.edu
267-426-6063
Children's Hospital of Philadelphia
Secondhand smoke damages lungs, MRIs show
The apparent diffusion coefficient (ADC) measures lung injury, indicated by different colors.
Click here for more information.
It’s not a smoking gun, but it’s smoking-related, and it’s there in bright medical images: evidence of microscopic structural damage deep in the lungs, caused by secondhand cigarette smoke. For the first time, researchers have identified lung injury to nonsmokers that was long suspected, but not previously detectable with medical imaging tools.
The researchers suggest that their findings may strengthen public health efforts to restrict secondhand smoke.
“We used a special type of magnetic resonance imaging to find these structural changes in the lungs,” said study leader Chengbo Wang, Ph.D., a magnetic resonance physicist in the Department of Radiology at The Children’s Hospital of Philadelphia. “Almost one-third of nonsmokers who had been exposed to secondhand cigarette smoke for a long time developed these structural changes.” Formerly at the University of Virginia, Wang collaborated with radiology researchers at that institution, where they acquired the MRIs from adult smokers and nonsmokers.
Wang presented the team’s findings in Chicago at the annual meeting of the Radiological Society of North America. Although the participants in the research study were adults, Wang said the results have implications for the 35 percent of American children who live in homes where regular smoking occurs.
The researchers studied 60 adults between ages 41 and 79, 45 of whom had never smoked. The 45 non-smokers were divided into groups with low and high exposure to secondhand smoke; the high-exposure subjects had lived with a smoker for at least 10 years, often during childhood. The 15 current or former smokers formed a positive control group.
The research team prepared an isotope of helium called helium-3 by polarizing it to make it more visible in the MRI. Researchers diluted the helium in nitrogen and had research subjects inhale the mixture. Unlike ordinary MRIs, this MRI machine measured diffusion, the movement of helium atoms, over 1.5 seconds. The helium atoms moved a greater distance than in the lungs of normal subjects, indicating the presence of holes and expanded spaces within the alveoli, tiny sacs within the lungs.
The researchers found that almost one-third of the non-smokers with high exposure to secondhand smoke had structural changes in their lungs similar to those found in the smokers. “We interpreted those changes as early signs of lung damage, representing very mild forms of emphysema,” said Wang. Emphysema, a lung disease that is a major cause of death in the U.S., is commonly found in heavy smokers.
The researchers also found a seemingly paradoxical result among two-thirds of the high-exposure group of non-smokers—diffusion measurements that were lower than those found in the low-exposure group. Although these findings require more study, said Wang, they may reflect a narrowing in airways caused by early stages of another lung disease, chronic bronchitis.
“To our knowledge, this is the first imaging study to find lung damage in non-smokers heavily exposed to secondhand smoke,” said Wang. “We hope our work strengthens the efforts of legislators and policymakers to limit public exposure to secondhand smoke.”
###
The study received financial support from the National Heart, Lung and Blood Institute, the Flight Attendant Medical Research Institute, the Commonwealth of Virginia Technology Research Fund, and Siemens Medical Solutions.
Wang’s co-authors were Talissa A. Altes, M.D., and Kai Ruppert, Ph.D., now of the Children’s Hospital Radiology Department; and G. Wilson Miller, Ph.D., Eduard E. deLange, M.D., Jaime F. Mata, Ph.D., Gordon D. Cates, Jr., Ph.D., and John P. Mugler III, Ph.D., all of the University of Virginia Department of Radiology. Drs. Wang, Altes, and Ruppert were previously at the University of Virginia as well.
About The Children's Hospital of Philadelphia: The Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country, ranking third in National Institutes of Health funding. In addition, its unique family-centered care and public service programs have brought the 430-bed hospital recognition as a leading advocate for children and adolescents. For more information, visit http://www.chop.edu.
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Tuesday, November 27, 2007
Wednesday, November 21, 2007
Post-treatment PET scans can reassure cervical cancer patients
PET scanner is a very powerful tool which can pinpoint secondary cancers , if any, in patients who underwent radiation treatment
K.S.Parthasarathy
Public release date: 20-Nov-2007
Contact: Gwen Ericson
ericsong@wustl.edu
314-286-0141
Washington University in St. Louis
Post-treatment PET scans can reassure cervical cancer patients
St. Louis, Nov. 20, 2007 — Whole-body PET (positron emission tomography) scans done three months after completion of cervical cancer therapy can ensure that patients are disease-free or warn that further interventions are needed, according to a study at Washington University School of Medicine in St. Louis.
"This is the first time we can say that we have a reliable test to follow cervical cancer patients after therapy," says Julie K. Schwarz, M.D., Ph.D., a Barnes-Jewish Hospital resident in the Department of Radiation Oncology. "We ask them to come back for a follow-up visit about three months after treatment is finished, and we perform a PET scan. If the scan shows a complete response to treatment, we can say with confidence that they are going to do extremely well. That's really powerful."
Schwarz and colleagues published their study in the Nov. 21, 2007 issue of the Journal of the American Medical Association (JAMA).
Without a test like PET, it can be difficult to tell whether treatment has eliminated cervical tumors, Schwarz says. That's because small tumors are hard to detect with pelvic exams, and overt symptoms, such as leg swelling, don't occur until tumors grow quite large. Furthermore, CT and MRI scans often don't differentiate tumor tissue from surrounding tissues, Pap tests can be inaccurate because of tissue changes induced by radiation therapy, and no blood test exists to detect the presence of cervical cancer.
Cancerous tumors glow brightly in the PET scans used in the study, called FDG-PET scans, which detect emissions from radioactively tagged blood sugar, or glucose. Tumor tissue traps more of the glucose than does normal tissue, making tumors readily discernable.
Not only can post-treatment PET scans reassure those patients whose tumors respond well to therapy, they can also identify those patients whose tumors have not responded so that their physicians can explore other treatment options before the cancer advances further. These options can include surgery to remove tissue, standard chemotherapy or experimental therapies available through clinical trials.
"Follow-up PET scans can also be very useful tools for physicians conducting clinical trials of new therapies," Schwarz says. "Our study has shown that the scans are predictive of long-term survival. Using PET scans, clinical researchers can get an early readout of how effective experimental treatments might be."
Schwarz and colleagues also have a project to compare follow-up PET results with tumor biology to find out why some tumors don't respond well to therapy. In a study that won her a Resident Clinical Basic Science Research Award from the American Society for Therapeutic Radiation and Oncology, a global organization of medical professionals, Schwarz found differences in gene activity between tumors from patients that responded well and those that had persistent disease. Ongoing research will look for the significance of these differences.
The study's senior author, Perry Grigsby, M.D., professor of radiation oncology, of nuclear medicine and of obstetrics and gynecology and a radiation oncologist with the Siteman Cancer Center at Washington University School of Medicine and Barnes-Jewish Hospital, has overseen a patient database that now has PET images and tumor samples from hundreds of cervical cancer patients.
"We have a tremendous database of PET images collected from patients in the department since 1998," Schwarz says. "We want to combine these results with analyses of tumor biopsies so that we can more effectively choose additional therapies for patients who haven't responded to the initial treatment."
###
Schwarz JK, Siegel BA, Dehdashti F, Grigsby PW. Association of posttherapy positron emission tomography with tumor response and survival in cervical carcinoma. Journal of the American Medical Association, November 21, 2007.
Funding from the Department of Radiology and the Department of Radiation Oncology at Washington University School of Medicine in St. Louis supported this research.
Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
Siteman Cancer Center is the only federally-designated Comprehensive Cancer Center within a 240-mile radius of St. Louis. Siteman Cancer Center is composed of the combined cancer research and treatment programs of Barnes-Jewish Hospital and Washington University School of Medicine. Siteman has satellite locations in West County and St. Peters, in addition to its full-service facility at Washington University Medical Center on South Kingshighway.
K.S.Parthasarathy
Public release date: 20-Nov-2007
Contact: Gwen Ericson
ericsong@wustl.edu
314-286-0141
Washington University in St. Louis
Post-treatment PET scans can reassure cervical cancer patients
St. Louis, Nov. 20, 2007 — Whole-body PET (positron emission tomography) scans done three months after completion of cervical cancer therapy can ensure that patients are disease-free or warn that further interventions are needed, according to a study at Washington University School of Medicine in St. Louis.
"This is the first time we can say that we have a reliable test to follow cervical cancer patients after therapy," says Julie K. Schwarz, M.D., Ph.D., a Barnes-Jewish Hospital resident in the Department of Radiation Oncology. "We ask them to come back for a follow-up visit about three months after treatment is finished, and we perform a PET scan. If the scan shows a complete response to treatment, we can say with confidence that they are going to do extremely well. That's really powerful."
Schwarz and colleagues published their study in the Nov. 21, 2007 issue of the Journal of the American Medical Association (JAMA).
Without a test like PET, it can be difficult to tell whether treatment has eliminated cervical tumors, Schwarz says. That's because small tumors are hard to detect with pelvic exams, and overt symptoms, such as leg swelling, don't occur until tumors grow quite large. Furthermore, CT and MRI scans often don't differentiate tumor tissue from surrounding tissues, Pap tests can be inaccurate because of tissue changes induced by radiation therapy, and no blood test exists to detect the presence of cervical cancer.
Cancerous tumors glow brightly in the PET scans used in the study, called FDG-PET scans, which detect emissions from radioactively tagged blood sugar, or glucose. Tumor tissue traps more of the glucose than does normal tissue, making tumors readily discernable.
Not only can post-treatment PET scans reassure those patients whose tumors respond well to therapy, they can also identify those patients whose tumors have not responded so that their physicians can explore other treatment options before the cancer advances further. These options can include surgery to remove tissue, standard chemotherapy or experimental therapies available through clinical trials.
"Follow-up PET scans can also be very useful tools for physicians conducting clinical trials of new therapies," Schwarz says. "Our study has shown that the scans are predictive of long-term survival. Using PET scans, clinical researchers can get an early readout of how effective experimental treatments might be."
Schwarz and colleagues also have a project to compare follow-up PET results with tumor biology to find out why some tumors don't respond well to therapy. In a study that won her a Resident Clinical Basic Science Research Award from the American Society for Therapeutic Radiation and Oncology, a global organization of medical professionals, Schwarz found differences in gene activity between tumors from patients that responded well and those that had persistent disease. Ongoing research will look for the significance of these differences.
The study's senior author, Perry Grigsby, M.D., professor of radiation oncology, of nuclear medicine and of obstetrics and gynecology and a radiation oncologist with the Siteman Cancer Center at Washington University School of Medicine and Barnes-Jewish Hospital, has overseen a patient database that now has PET images and tumor samples from hundreds of cervical cancer patients.
"We have a tremendous database of PET images collected from patients in the department since 1998," Schwarz says. "We want to combine these results with analyses of tumor biopsies so that we can more effectively choose additional therapies for patients who haven't responded to the initial treatment."
###
Schwarz JK, Siegel BA, Dehdashti F, Grigsby PW. Association of posttherapy positron emission tomography with tumor response and survival in cervical carcinoma. Journal of the American Medical Association, November 21, 2007.
Funding from the Department of Radiology and the Department of Radiation Oncology at Washington University School of Medicine in St. Louis supported this research.
Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.
Siteman Cancer Center is the only federally-designated Comprehensive Cancer Center within a 240-mile radius of St. Louis. Siteman Cancer Center is composed of the combined cancer research and treatment programs of Barnes-Jewish Hospital and Washington University School of Medicine. Siteman has satellite locations in West County and St. Peters, in addition to its full-service facility at Washington University Medical Center on South Kingshighway.
Saturday, November 17, 2007
Remote-control nanoparticles deliver drugs directly into tumors
Public release date: 16-Nov-2007
Contact: Elizabeth Thomson
thomson@mit.edu
617-258-5402
Massachusetts Institute of Technology
MIT: Remote-control nanoparticles deliver drugs directly into tumors
CAMBRIDGE, MA--MIT scientists have devised remotely controlled nanoparticles that, when pulsed with an electromagnetic field, release drugs to attack tumors. The innovation, reported in the Nov. 15 online issue of Advanced Materials, could lead to the improved diagnosis and targeted treatment of cancer.
In earlier work the team, led by Sangeeta Bhatia, M.D.,Ph.D., an associate professor in the Harvard-MIT Division of Health Sciences & Technology (HST) and in MIT's Department of Electrical Engineering and Computer Science, developed injectable multi-functional nanoparticles designed to flow through the bloodstream, home to tumors and clump together. Clumped particles help clinicians visualize tumors through magnetic resonance imaging (MRI).
With the ability to see the clumped particles, Bhatia’s co-author in the current work, Geoff von Maltzahn, asked the next question: “Can we talk back to them?”
The answer is yes, the team found. The system that makes it possible consists of tiny particles (billionths of a meter in size) that are superparamagnetic, a property that causes them to give off heat when they are exposed to a magnetic field. Tethered to these particles are active molecules, such as therapeutic drugs.
Exposing the particles to a low-frequency electromagnetic field causes the particles to radiate heat that, in turn, melts the tethers and releases the drugs. The waves in this magnetic field have frequencies between 350 and 400 kilohertz—the same range as radio waves. These waves pass harmlessly through the body and heat only the nanoparticles. For comparison, microwaves, which will cook tissue, have frequencies measured in gigahertz, or about a million times more powerful.
The tethers in the system consist of strands of DNA, “a classical heat sensitive material,” said von Maltzahn, a graduate student in HST. Two strands of DNA link together through hydrogen bonds that break when heated. In the presence of the magnetic field, heat generated by the nanoparticles breaks these, leaving one strand attached to the particle and allowing the other to float away with its cargo.
One advantage of a DNA tether is that its melting point is tunable. Longer strands and differently coded strands require different amounts of heat to break. This heat-sensitive tuneability makes it possible for a single particle to simultaneously carry many different types of cargo, each of which can be released at different times or in various combinations by applying different frequencies or durations of electromagnetic pulses.
To test the particles, the researchers implanted mice with a tumor-like gel saturated with nanoparticles. They placed the implanted mouse into the well of a cup-shaped electrical coil and activated the magnetic pulse. The results confirm that without the pulse, the tethers remain unbroken. With the pulse, the tethers break and release the drugs into the surrounding tissue.
The experiment is a proof of principal demonstrating a safe and effective means of tunable remote activation. However, work remains to be done before such therapies become viable in the clinic.
To heat the region, for example, a critical mass of injected particles must clump together inside the tumor. The team is still working to make intravenously injected particles clump effectively enough to achieve this critical mass.
“Our overall goal is to create multifunctional nanoparticles that home to a tumor, accumulate, and provide customizable remotely activated drug delivery right at the site of the disease,” said Bhatia.
###
Co-authors on the paper are Austin M. Derfus, a graduate student at the University of California at San Diego; Todd Harris, an HST graduate student; Erkki Ruoslahti and Tasmia Duza of The Burnham Institute in La Jolla, CA; and Kenneth S. Vecchio of the University of San Diego.
The research was supported by grants from the David and Lucile Packard Foundation, the National Cancer Institute of the National Institutes of Health. Dervis was supported by a G.R.E.A.T fellowship from the University of California Biotechnology Research and Educational Program.
Written by Elizabeth Dougherty, Harvard-MIT Division of Health Sciences and Technology
Tuesday, November 13, 2007
Scientists discover record-breaking hydrogen storage materials for use in fuel cells
UVa researchers found materials that absorb hydrogen up to 14 percent by weight at room temperature. By absorbing twice as much hydrogen, the new materials could help make the dream of a hydrogen economy come true.
K.S.Parthasarathy
Public release date: 12-Nov-2007
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Contact: Bellave Shivaram
bss2d@virginia.edu
434-806-9582
University of Virginia
Scientists discover record-breaking hydrogen storage materials for use in fuel cells
Scientists at the University of Virginia have discovered a new class of hydrogen storage materials that could make the storage and transportation of energy much more efficient — and affordable — through higher-performing hydrogen fuel cells.
Bellave S. Shivaram and Adam B. Phillips, the U.Va. physicists who invented the new materials, will present their finding at 8 p.m., Monday, Nov. 12, at the International Symposium on Materials Issues in a Hydrogen Economy at the Omni Hotel in Richmond, Va.
“In terms of hydrogen absorption, these materials could prove a world record,” Phillips said. “Most materials today absorb only 7 to 8 percent of hydrogen by weight, and only at cryogenic [extremely low] temperatures. Our materials absorb hydrogen up to 14 percent by weight at room temperature. By absorbing twice as much hydrogen, the new materials could help make the dream of a hydrogen economy come true.”
In the quest for alternative fuels, U.Va.’s new materials potentially could provide a highly affordable solution to energy storage and transportation problems with a wide variety of applications. They absorb a much higher percentage of hydrogen than predecessor materials while exhibiting faster kinetics at room temperature and much lower pressures, and are inexpensive and simple to produce.
“These materials are the next generation in hydrogen fuel storage materials, unlike any others we have seen before,” Shivaram said. “They have passed every litmus test that we have performed, and we believe they have the potential to have a large impact.”
The inventors believe the novel materials will translate to the marketplace and are working with the U.Va. Patent Foundation to patent their discovery.
“The U.Va. Patent Foundation is very excited to be working with a material that one day may be used by millions in everyday life,” said Chris Harris, senior licensing manager for the U.Va. Patent Foundation. “Dr. Phillips and Dr. Shivaram have made an incredible breakthrough in the area of hydrogen absorption.”
###
Phillips’s and Shivaram’s research was supported by the National Science Foundation and the U.S. Department of Energy.
K.S.Parthasarathy
Public release date: 12-Nov-2007
[ Print Article | E-mail Article | Close Window ]
Contact: Bellave Shivaram
bss2d@virginia.edu
434-806-9582
University of Virginia
Scientists discover record-breaking hydrogen storage materials for use in fuel cells
Scientists at the University of Virginia have discovered a new class of hydrogen storage materials that could make the storage and transportation of energy much more efficient — and affordable — through higher-performing hydrogen fuel cells.
Bellave S. Shivaram and Adam B. Phillips, the U.Va. physicists who invented the new materials, will present their finding at 8 p.m., Monday, Nov. 12, at the International Symposium on Materials Issues in a Hydrogen Economy at the Omni Hotel in Richmond, Va.
“In terms of hydrogen absorption, these materials could prove a world record,” Phillips said. “Most materials today absorb only 7 to 8 percent of hydrogen by weight, and only at cryogenic [extremely low] temperatures. Our materials absorb hydrogen up to 14 percent by weight at room temperature. By absorbing twice as much hydrogen, the new materials could help make the dream of a hydrogen economy come true.”
In the quest for alternative fuels, U.Va.’s new materials potentially could provide a highly affordable solution to energy storage and transportation problems with a wide variety of applications. They absorb a much higher percentage of hydrogen than predecessor materials while exhibiting faster kinetics at room temperature and much lower pressures, and are inexpensive and simple to produce.
“These materials are the next generation in hydrogen fuel storage materials, unlike any others we have seen before,” Shivaram said. “They have passed every litmus test that we have performed, and we believe they have the potential to have a large impact.”
The inventors believe the novel materials will translate to the marketplace and are working with the U.Va. Patent Foundation to patent their discovery.
“The U.Va. Patent Foundation is very excited to be working with a material that one day may be used by millions in everyday life,” said Chris Harris, senior licensing manager for the U.Va. Patent Foundation. “Dr. Phillips and Dr. Shivaram have made an incredible breakthrough in the area of hydrogen absorption.”
###
Phillips’s and Shivaram’s research was supported by the National Science Foundation and the U.S. Department of Energy.
Thursday, November 1, 2007
World's smallest radio uses single nanotube to pick up good vibrations
Public release date: 31-Oct-2007
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Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
World's smallest radio uses single nanotube to pick up good vibrations
Berkeley -- Physicists at the University of California, Berkeley, have built the smallest radio yet - a single carbon nanotube one ten-thousandth the diameter of a human hair that requires only a battery and earphones to tune in to your favorite station.
The scientists successfully received their first FM broadcast last year - Derek & The Dominos' "Layla" and the Beach Boys' "Good Vibrations" transmitted from across the room. In homage to last year's 100th anniversary of the first voice and music radio transmission, they also transmitted and successfully tuned in to the first music piece broadcast in 1906, "Largo" from George Frederic Handel's opera "Xerxes."
"We were just in ecstasy when this worked," said team leader Alex Zettl, UC Berkeley professor of physics. "It was fantastic."
The nanoradio, which is currently configured as a receiver but could also work as a transmitter, is 100 billion times smaller than the first commercial radios, and could be used in any number of applications - from cell phones to microscopic devices that sense the environment and relay information via radio signals, Zettl said. Because it is extremely energy efficient, it would integrate well with microelectronic circuits.
"The nanotube radio may lead to radical new applications, such as radio-controlled devices small enough to exist in a human's bloodstream," the authors wrote in a paper published online today by the journal Nano Letters. The paper will appear in the print edition of Nano Letters later this month.
Authors of the nanoradio paper are Zettl, graduate student Kenneth Jensen, and their colleagues in UC Berkeley's Center of Integrated Nanomechanical Systems (COINS) and in the Materials Sciences Division at Lawrence Berkeley National Laboratory (LBNL). COINS is a Nanoscale Science and Engineering Research Center supported by the National Science Foundation (NSF).
Nanotubes are rolled-up sheets of interlocked carbon atoms that form a tube so strong that some scientists have suggested using a nanotube wire to tether satellites in a fixed position above Earth. The nanotubes also exhibit unusual electronic properties because of their size, which, for the nanotubes used in the radio receiver, are about 10 nanometers in diameter and several hundred nanometers long. A nanometer is one billionth of a meter; a human hair is about 50,000-100,000 nanometers in diameter.
In the nanoradio, a single carbon nanotube works as an all-in-one antenna, tuner, amplifier and demodulator for both AM and FM. These are separate components in a standard radio. A demodulator removes the AM or FM carrier frequency, which is in the kiloHertz and megaHertz range, respectively, to retrieve the lower frequency broadcast information.
The nanoradio detects radio signals in a radically new way - it vibrates thousands to millions of times per second in tune with the radio wave. This makes it a true nanoelectromechanical device, dubbed NEMS, that integrates the mechanical and electrical properties of nanoscale materials.
In a normal radio, ambient radio waves from different transmitting stations generate small currents at different frequencies in the antenna, while a tuner selects one of these frequencies to amplify. In the nanoradio, the nanotube, as the antenna, detects radio waves mechanically by vibrating at radio frequencies. The nanotube is placed in a vacuum and hooked to a battery, which covers its tip with negatively charged electrons, and the electric field of the radio wave pushes and pulls the tip thousands to millions of times per second.
While large objects, like a stiff wire or a wooden ruler pinned at one end, vibrate at low frequencies - between tens and hundreds of times per second - the tiny nanotubes vibrate at high frequencies ranging from kiloHertz (thousands of times per second) to hundreds of megaHertz (100 million times per second). Thus, a single nanotube naturally selects only one frequency.
Although it might seem that the vibrating nanotube yields a "one station" radio, the tension on the nanotube also influences its natural vibration frequency, just as the tension on a guitar string fine tunes its pitch. As a result, the physicists can tune in a desired frequency or station by "pulling" on the free tip of the nanotube with a positively charged electrode. This electrode also turns the nanotube into an amplifier. The voltage is high enough to pull electrons off the tip of the nanotube and, because the nanotube is simultaneously vibrating, the electron current from the tip is an amplified version of the incoming radio signal. This is similar to the field-emission amplification of old vacuum tube amplifiers used in early radios and televisions, Zettl said. The amplified output of this simple nanotube device is enough to drive a very sensitive earphone.
Finally, the field-emission and vibration together also demodulate the signal.
"I hate to sound like I'm selling a Ginsu knife - But wait, there's more! It also slices and dices! - but this one nanotube does everything; it performs all radio functions simultaneously and extremely efficiently," Zettl said. "It's ridiculously simple - that's the beauty of it."
Zettl's team assembles the nanoradios very simply, too. From nanotubes copiously produced in a carbon arc, they glue several to a fixed electrode. In a vacuum, they bring the electrode within a few microns of a second electrode, close enough for electrons to jump to it from the closest nanotube and create an electrical circuit. To achieve the desired length of the active nanotube, the team first runs a large current through the nanotube to the second electrode, which makes carbon atoms jump off the tip of the nanotube, trimming it down to size for operation within a particular frequency band. Connect a battery and earphones, and voila!
Reception by the initial radios is scratchy, which Zettl attributes in part to insufficient vacuum. In future nanoradios, a better vacuum can be obtained by insuring a cleaner environment, or perhaps by encasing the single nanotube inside a second, larger non-conducting nanotube, thereby retaining the nanoscale.
Zettl won't only be tuning in to oldies stations with his nanoradio. Because the radio static is actually the sound of atoms jumping on and off the tip of the nanotube, he hopes to use the nanoradio to sense the identity of atoms or even measure their masses, which is done today by cumbersome large mass spectrometers.
###
Coauthors with Jensen and Zettl are UC Berkeley post-doctoral fellow Jeff Weldon and physics graduate student Henry Garcia. The work was supported by NSF and the U.S. Department of Energy.
[ Print Article | E-mail Article | Close Window ]
Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
World's smallest radio uses single nanotube to pick up good vibrations
Berkeley -- Physicists at the University of California, Berkeley, have built the smallest radio yet - a single carbon nanotube one ten-thousandth the diameter of a human hair that requires only a battery and earphones to tune in to your favorite station.
The scientists successfully received their first FM broadcast last year - Derek & The Dominos' "Layla" and the Beach Boys' "Good Vibrations" transmitted from across the room. In homage to last year's 100th anniversary of the first voice and music radio transmission, they also transmitted and successfully tuned in to the first music piece broadcast in 1906, "Largo" from George Frederic Handel's opera "Xerxes."
"We were just in ecstasy when this worked," said team leader Alex Zettl, UC Berkeley professor of physics. "It was fantastic."
The nanoradio, which is currently configured as a receiver but could also work as a transmitter, is 100 billion times smaller than the first commercial radios, and could be used in any number of applications - from cell phones to microscopic devices that sense the environment and relay information via radio signals, Zettl said. Because it is extremely energy efficient, it would integrate well with microelectronic circuits.
"The nanotube radio may lead to radical new applications, such as radio-controlled devices small enough to exist in a human's bloodstream," the authors wrote in a paper published online today by the journal Nano Letters. The paper will appear in the print edition of Nano Letters later this month.
Authors of the nanoradio paper are Zettl, graduate student Kenneth Jensen, and their colleagues in UC Berkeley's Center of Integrated Nanomechanical Systems (COINS) and in the Materials Sciences Division at Lawrence Berkeley National Laboratory (LBNL). COINS is a Nanoscale Science and Engineering Research Center supported by the National Science Foundation (NSF).
Nanotubes are rolled-up sheets of interlocked carbon atoms that form a tube so strong that some scientists have suggested using a nanotube wire to tether satellites in a fixed position above Earth. The nanotubes also exhibit unusual electronic properties because of their size, which, for the nanotubes used in the radio receiver, are about 10 nanometers in diameter and several hundred nanometers long. A nanometer is one billionth of a meter; a human hair is about 50,000-100,000 nanometers in diameter.
In the nanoradio, a single carbon nanotube works as an all-in-one antenna, tuner, amplifier and demodulator for both AM and FM. These are separate components in a standard radio. A demodulator removes the AM or FM carrier frequency, which is in the kiloHertz and megaHertz range, respectively, to retrieve the lower frequency broadcast information.
The nanoradio detects radio signals in a radically new way - it vibrates thousands to millions of times per second in tune with the radio wave. This makes it a true nanoelectromechanical device, dubbed NEMS, that integrates the mechanical and electrical properties of nanoscale materials.
In a normal radio, ambient radio waves from different transmitting stations generate small currents at different frequencies in the antenna, while a tuner selects one of these frequencies to amplify. In the nanoradio, the nanotube, as the antenna, detects radio waves mechanically by vibrating at radio frequencies. The nanotube is placed in a vacuum and hooked to a battery, which covers its tip with negatively charged electrons, and the electric field of the radio wave pushes and pulls the tip thousands to millions of times per second.
While large objects, like a stiff wire or a wooden ruler pinned at one end, vibrate at low frequencies - between tens and hundreds of times per second - the tiny nanotubes vibrate at high frequencies ranging from kiloHertz (thousands of times per second) to hundreds of megaHertz (100 million times per second). Thus, a single nanotube naturally selects only one frequency.
Although it might seem that the vibrating nanotube yields a "one station" radio, the tension on the nanotube also influences its natural vibration frequency, just as the tension on a guitar string fine tunes its pitch. As a result, the physicists can tune in a desired frequency or station by "pulling" on the free tip of the nanotube with a positively charged electrode. This electrode also turns the nanotube into an amplifier. The voltage is high enough to pull electrons off the tip of the nanotube and, because the nanotube is simultaneously vibrating, the electron current from the tip is an amplified version of the incoming radio signal. This is similar to the field-emission amplification of old vacuum tube amplifiers used in early radios and televisions, Zettl said. The amplified output of this simple nanotube device is enough to drive a very sensitive earphone.
Finally, the field-emission and vibration together also demodulate the signal.
"I hate to sound like I'm selling a Ginsu knife - But wait, there's more! It also slices and dices! - but this one nanotube does everything; it performs all radio functions simultaneously and extremely efficiently," Zettl said. "It's ridiculously simple - that's the beauty of it."
Zettl's team assembles the nanoradios very simply, too. From nanotubes copiously produced in a carbon arc, they glue several to a fixed electrode. In a vacuum, they bring the electrode within a few microns of a second electrode, close enough for electrons to jump to it from the closest nanotube and create an electrical circuit. To achieve the desired length of the active nanotube, the team first runs a large current through the nanotube to the second electrode, which makes carbon atoms jump off the tip of the nanotube, trimming it down to size for operation within a particular frequency band. Connect a battery and earphones, and voila!
Reception by the initial radios is scratchy, which Zettl attributes in part to insufficient vacuum. In future nanoradios, a better vacuum can be obtained by insuring a cleaner environment, or perhaps by encasing the single nanotube inside a second, larger non-conducting nanotube, thereby retaining the nanoscale.
Zettl won't only be tuning in to oldies stations with his nanoradio. Because the radio static is actually the sound of atoms jumping on and off the tip of the nanotube, he hopes to use the nanoradio to sense the identity of atoms or even measure their masses, which is done today by cumbersome large mass spectrometers.
###
Coauthors with Jensen and Zettl are UC Berkeley post-doctoral fellow Jeff Weldon and physics graduate student Henry Garcia. The work was supported by NSF and the U.S. Department of Energy.
Wednesday, October 24, 2007
Nuclear power worldwide: status and outlook
Nuclear power is expected to raise to a maximum of 679MWe to a minimum of 447MWe from the present 370MWe by 2030.Nuclear power's share of worldwide electricity production rose from less than 1 percent in 1960 to 16 percent in 1986, and that percentage has held essentially constant in the 21 years since 1986.The IAEA report released on October 23, 2007 reviews the status of nuclear power worldwide.
K.S.Parthasarathy
Public release date: 23-Oct-2007
Contact: Press Office
press@iaea.org
0043-126-002-1273
International Atomic Energy Agency
Nuclear power worldwide: status and outlook
A report from the IAEA
The IAEA makes two annual projections concerning the growth of nuclear power, a low and a high. The low projection assumes that all nuclear capacity that is currently under construction or firmly in the development pipeline gets completed and attached to the grid, but no other capacity is added. In this low projection, there would be growth in capacity from 370 GW(e) at the end of 2006 to 447 GW(e) in 2030. (A gigawatt = 1000 megawatts = 1 billion watts)
In the IAEA's high projection -- which adds in additional reasonable and promising projects and plans -- global nuclear capacity is estimated to rise to 679 GW(e) in 2030. That would be an average growth rate of about 2.5%/yr.
"Our job is not so much to predict the future but to prepare for it, " explains the IAEA's Alan McDonald, Nuclear Energy Analyst. "To that end we update each year a high and low projection to establish the range of uncertainty we ought to be prepared for."
Nuclear power's share of worldwide electricity production rose from less than 1 percent in 1960 to 16 percent in 1986, and that percentage has held essentially constant in the 21 years since 1986. Nuclear electricity generation has grown steadily at the same pace as overall global electricity generation. At the close of 2006, nuclear provided about 15 percent of total electricity worldwide.
The IAEA's other key findings as of the end of 2006 are elaborated below.
There were 435 operating nuclear reactors around the world, and 29 more were under construction. The US had the most with 103 operating units. France was next with 59. Japan followed with 55, plus one more under construction, and Russia had 31 operating, and seven more under construction.
Of the 30 countries with nuclear power, the percentage of electricity supplied by nuclear ranged widely: from a high of 78 percent in France; to 54 percent in Belgium; 39 percent in Republic of Korea; 37 percent in Switzerland; 30 percent in Japan; 19 percent in the USA; 16 percent in Russia; 4 percent in South Africa; and 2 percent in China.
Present nuclear power plant expansion is centred in Asia: 15 of the 29 units under construction at the end of 2006 were in Asia. And 26 of the last 36 reactors to have been connected to the grid were in Asia. India currently gets less than 3% of its electricity from nuclear, but at the end of 2006 it had one-quarter of the nuclear construction - 7 of the world's 29 reactors that were under construction. India's plans are even more impressive: an 8-fold increase by 2022 to 10 percent of the electricity supply and a 75-fold increase by 2052 to reach 26 percent of the electricity supply. A 75-fold increase works out to an average of 9.4 percent/yr, about the same as average global nuclear growth from 1970 through 2004. So it's hardly unprecedented.
China is experiencing huge energy growth and is trying to expand every source it can, including nuclear power. It has four reactors under construction and plans a nearly five-fold expansion by just 2020. Because China is growing so fast this would still amount to only 4 percent of total electricity.
Russia had 31 operating reactors, five under construction and significant expansion plans. There's a lot of discussion in Russia of becoming a full fuel-service provider, including services like leasing fuel, reprocessing spent fuel for countries that are interested, and even leasing reactors.
Japan had 55 reactors in operation, one under construction, and plans to increase nuclear power's share of electricity from 30 percent in 2006 to more than 40 percent within the next decade.
South Korea connected its 20th reactor just last year, has another under construction and has broken ground to start building two more. Nuclear power already supplies 39 percent of its electricity.
Europe is a good example of "one size does not fit all." Altogether it had 166 reactors in operation and six under construction. But there are several nuclear prohibition countries like Austria, Italy, Denmark and Ireland. And there are nuclear phase-out countries like Germany and Belgium.
There are also nuclear expansion programmes in Finland, France, Bulgaria and Ukraine. Finland started construction in 2005 on Olkiluoto-3, which is the first new Western European construction since 1991. France plans to start its next plant in 2007.
Several countries with nuclear power are still pondering future plans. The UK, with 19 operating plants, many of which are relatively old, had been the most uncertain until recently. Although a final policy decision on nuclear power will await the results of a public consultation now underway, a White Paper on energy published in May 20071 concluded that "…having reviewed the evidence and information available we believe that the advantages [of new nuclear power] outweigh the disadvantages and that the disadvantages can be effectively managed. On this basis, the Government's preliminary view is that it is in the public's interest to give the private sector the option of investing in new nuclear power stations."
###
1 http://www.dti.gov.uk/energy/whitepaper/page39534.html
The US had 103 reactors providing 19 percent of the country's electricity. For the last few decades the main developments have been improved capacity factors, power increases at existing plants and license renewals. Currently 48 reactors have already received 20-year renewals, so their licensed lifetimes are 60 years. Altogether three-quarters of the US reactors either already have license renewals, have applied for them, or have stated their intention to apply. There have been a lot of announced intentions (about 30 new reactors' worth) and the Nuclear Regulatory Commission is now reviewing four Early Site Permit applications.
For further information, please contact: IAEA Division of Public Information, Media & Outreach Section 43-1-2600-21273 .
For further details on the current status of the nuclear industry, go to IAEA's "Power Reactor Information System,"(PRIS).
Video B-roll is available on request.
Audio Q & A with IAEA Nuclear Energy Analyst, Alan McDonald and UN language editions of this press release are available under the following link http://www.iaea.org/NewsCenter/PressReleases/2007/prn200719.html
K.S.Parthasarathy
Public release date: 23-Oct-2007
Contact: Press Office
press@iaea.org
0043-126-002-1273
International Atomic Energy Agency
Nuclear power worldwide: status and outlook
A report from the IAEA
The IAEA makes two annual projections concerning the growth of nuclear power, a low and a high. The low projection assumes that all nuclear capacity that is currently under construction or firmly in the development pipeline gets completed and attached to the grid, but no other capacity is added. In this low projection, there would be growth in capacity from 370 GW(e) at the end of 2006 to 447 GW(e) in 2030. (A gigawatt = 1000 megawatts = 1 billion watts)
In the IAEA's high projection -- which adds in additional reasonable and promising projects and plans -- global nuclear capacity is estimated to rise to 679 GW(e) in 2030. That would be an average growth rate of about 2.5%/yr.
"Our job is not so much to predict the future but to prepare for it, " explains the IAEA's Alan McDonald, Nuclear Energy Analyst. "To that end we update each year a high and low projection to establish the range of uncertainty we ought to be prepared for."
Nuclear power's share of worldwide electricity production rose from less than 1 percent in 1960 to 16 percent in 1986, and that percentage has held essentially constant in the 21 years since 1986. Nuclear electricity generation has grown steadily at the same pace as overall global electricity generation. At the close of 2006, nuclear provided about 15 percent of total electricity worldwide.
The IAEA's other key findings as of the end of 2006 are elaborated below.
There were 435 operating nuclear reactors around the world, and 29 more were under construction. The US had the most with 103 operating units. France was next with 59. Japan followed with 55, plus one more under construction, and Russia had 31 operating, and seven more under construction.
Of the 30 countries with nuclear power, the percentage of electricity supplied by nuclear ranged widely: from a high of 78 percent in France; to 54 percent in Belgium; 39 percent in Republic of Korea; 37 percent in Switzerland; 30 percent in Japan; 19 percent in the USA; 16 percent in Russia; 4 percent in South Africa; and 2 percent in China.
Present nuclear power plant expansion is centred in Asia: 15 of the 29 units under construction at the end of 2006 were in Asia. And 26 of the last 36 reactors to have been connected to the grid were in Asia. India currently gets less than 3% of its electricity from nuclear, but at the end of 2006 it had one-quarter of the nuclear construction - 7 of the world's 29 reactors that were under construction. India's plans are even more impressive: an 8-fold increase by 2022 to 10 percent of the electricity supply and a 75-fold increase by 2052 to reach 26 percent of the electricity supply. A 75-fold increase works out to an average of 9.4 percent/yr, about the same as average global nuclear growth from 1970 through 2004. So it's hardly unprecedented.
China is experiencing huge energy growth and is trying to expand every source it can, including nuclear power. It has four reactors under construction and plans a nearly five-fold expansion by just 2020. Because China is growing so fast this would still amount to only 4 percent of total electricity.
Russia had 31 operating reactors, five under construction and significant expansion plans. There's a lot of discussion in Russia of becoming a full fuel-service provider, including services like leasing fuel, reprocessing spent fuel for countries that are interested, and even leasing reactors.
Japan had 55 reactors in operation, one under construction, and plans to increase nuclear power's share of electricity from 30 percent in 2006 to more than 40 percent within the next decade.
South Korea connected its 20th reactor just last year, has another under construction and has broken ground to start building two more. Nuclear power already supplies 39 percent of its electricity.
Europe is a good example of "one size does not fit all." Altogether it had 166 reactors in operation and six under construction. But there are several nuclear prohibition countries like Austria, Italy, Denmark and Ireland. And there are nuclear phase-out countries like Germany and Belgium.
There are also nuclear expansion programmes in Finland, France, Bulgaria and Ukraine. Finland started construction in 2005 on Olkiluoto-3, which is the first new Western European construction since 1991. France plans to start its next plant in 2007.
Several countries with nuclear power are still pondering future plans. The UK, with 19 operating plants, many of which are relatively old, had been the most uncertain until recently. Although a final policy decision on nuclear power will await the results of a public consultation now underway, a White Paper on energy published in May 20071 concluded that "…having reviewed the evidence and information available we believe that the advantages [of new nuclear power] outweigh the disadvantages and that the disadvantages can be effectively managed. On this basis, the Government's preliminary view is that it is in the public's interest to give the private sector the option of investing in new nuclear power stations."
###
1 http://www.dti.gov.uk/energy/whitepaper/page39534.html
The US had 103 reactors providing 19 percent of the country's electricity. For the last few decades the main developments have been improved capacity factors, power increases at existing plants and license renewals. Currently 48 reactors have already received 20-year renewals, so their licensed lifetimes are 60 years. Altogether three-quarters of the US reactors either already have license renewals, have applied for them, or have stated their intention to apply. There have been a lot of announced intentions (about 30 new reactors' worth) and the Nuclear Regulatory Commission is now reviewing four Early Site Permit applications.
For further information, please contact: IAEA Division of Public Information, Media & Outreach Section 43-1-2600-21273 .
For further details on the current status of the nuclear industry, go to IAEA's "Power Reactor Information System,"(PRIS).
Video B-roll is available on request.
Audio Q & A with IAEA Nuclear Energy Analyst, Alan McDonald and UN language editions of this press release are available under the following link http://www.iaea.org/NewsCenter/PressReleases/2007/prn200719.html
Quantitative PET imaging finds early determination of effectiveness of cancer treatment
PET imaging can demonstrate the effectiveness of cancer treatment.This imaging modality will reveal reduction in metabolism of cells killed by chemotherapeutic agents
K.S.Parthasarathy
Public release date: 23-Oct-2007
Contact: Maryann Verrillo
mverrillo@snm.org
703-652-6773
Society of Nuclear Medicine
Quantitative PET imaging finds early determination of effectiveness of cancer treatment
Visual analysis of PET Scans for non-Hodgkin lymphoma may be improved by using standardized uptake value in monitoring response to treatment, say researchers in October Journal of Nuclear Medicine
RESTON, Va.—With positron emission tomography (PET) imaging, seeing is believing: Evaluating a patient’s response to chemotherapy for non-Hodgkin lymphoma (NHL) typically involves visual interpretation of scans of cancer tumors. Researchers have found that measuring a quantitative index—one that reflects the reduction of metabolic activity after chemotherapy first begins—adds accurate information about patients’ responses to first-line chemotherapy, according to a study in the October issue of the Journal of Nuclear Medicine.
“In our study, we demonstrated that a quantitative assessment of therapeutic response for patients with diffuse large B-cell lymphoma (DLBCL) is more accurate than visual analysis alone when using the radiotracer FDG (fluorodeoxyglucose) with PET scans,” said Michel Meignan, professor of nuclear medicine at Henri Mondor Hospital in Creteil, France. “The ability to predict tumor response early in the course of treatment is very valuable clinically, allowing intensification of treatment in those patients who are unlikely to response to first-line chemotherapy,” he added. “Similarly, treatment could possibly be shortened in those patients who show a favorable response after one or two cycles of chemotherapy, and quantification also may help identify the disease’s transformation from low-grade to aggressive stage,” he explained. “However, visual interpretation of PET scans will always be the first step of analysis and will prevail in case of difficulties to quantify images,” added Meignan.
Diffuse large B-cell lymphoma is a fast-growing, aggressive form of non-Hodgkin lymphoma, a cancer of the body’s lymphatic system. Although there are more than 20 types of NHL, DLBCL is the most common type, making up about 30 percent of all lymphomas. In the United States, about 63,190 people are expected to be diagnosed with non-Hodgkin lymphoma in 2007, according to recent statistics.
Ninety-two patients with DLBCL were studied before and after two cycles of chemotherapy, and tumor response was assessed visually and by various quantitative parameters, explained the co-author of “Early 18F-FDG PET for Prediction of Prognosis in Patients With Diffuse Large B-Cell Lymphoma: SUV-Based Assessment Versus Visual Analysis.” Meignan said, “We found that quantification of tumor FDG uptake (the ratio of tissue radioactivity concentration) can markedly improve the accuracy of FDG PET for prediction of patient outcome.” Additional studies need to be done, said Meignan, reiterating that the future monitoring of cancer tumor response will probably include a combination of quantitative analysis and visual assessment.
PET is a powerful molecular imaging procedure that uses very small amounts of radioactive materials that are targeted to specific organs, bones or tissues. When PET is used to image cancer, a radiopharmaceutical (such as FDG, which includes both a sugar and a radionuclide) is injected into a patient. Cancer cells metabolize sugar at higher rates than normal cells, and the radiopharmaceutical is drawn in higher amounts to cancerous areas. PET scans show where FDG is by tracking the gamma rays given off by the radionuclide tagging the drug and producing three-dimensional images of their distribution within the body. PET scanning provides information about the body’s chemistry, metabolic activity and body function.
###
“Early 18F-FDG PET for Prediction of Prognosis in Patients With Diffuse Large B-Cell Lymphoma: SUV-Based Assessment Versus Visual Analysis” appears in the October issue of the Journal of Nuclear Medicine, which is published by SNM, the world’s largest molecular imaging and nuclear medicine society. Additional co-authors include Chieh Lin, Alain Luciani and Alain Rahmouni, Department of Radiology; Emmanuel Itti and Gaetano Paone, Department of Nuclear Medicine; and Corinne Haioun and Jehan Dupuis, Department of Hematology, all at Henri Mondor Hospital in Créteil, France; and Yolande Petegnief and Jean-Noël Talbot, Department of Nuclear Medicine, Tenon Hospital in Paris, France.
Credentialed press: To obtain a copy of this article—and online access to the Journal of Nuclear Medicine— please contact Maryann Verrillo by phone at (703) 652-6773 or send an e-mail to mverrillo@snm.org. Current and past issues of the Journal of Nuclear Medicine can be found online at http://jnm.snmjournals.org. Print copies can be obtained by contacting the SNM Service Center, 1850 Samuel Morse Drive, Reston, VA 20190-5316; phone (800) 513-6853; e-mail servicecenter@snm.org; fax (703) 708-9015. A subscription to the journal is an SNM member benefit.
About SNM—Advancing Molecular Imaging and Therapy
SNM is an international scientific and professional organization of more than 16,000 members dedicated to promoting the science, technology and practical applications of molecular and nuclear imaging to diagnose, manage and treat diseases in women, men and children. Founded more than 50 years ago, SNM continues to provide essential resources for health care practitioners and patients; publish the most prominent peer-reviewed journal in the field (Journal of Nuclear Medicine); host the premier annual meeting for medical imaging; sponsor research grants, fellowships and awards; and train physicians, technologists, scientists, physicists, chemists and radiopharmacists in state-of-the-art imaging procedures and advances. SNM members have introduced—and continue to explore—biological and technological innovations in medicine that noninvasively investigate the molecular basis of diseases, benefiting countless generations of patients. SNM is based in Reston, Va.; additional information can be found online at http://www.snm.org.
K.S.Parthasarathy
Public release date: 23-Oct-2007
Contact: Maryann Verrillo
mverrillo@snm.org
703-652-6773
Society of Nuclear Medicine
Quantitative PET imaging finds early determination of effectiveness of cancer treatment
Visual analysis of PET Scans for non-Hodgkin lymphoma may be improved by using standardized uptake value in monitoring response to treatment, say researchers in October Journal of Nuclear Medicine
RESTON, Va.—With positron emission tomography (PET) imaging, seeing is believing: Evaluating a patient’s response to chemotherapy for non-Hodgkin lymphoma (NHL) typically involves visual interpretation of scans of cancer tumors. Researchers have found that measuring a quantitative index—one that reflects the reduction of metabolic activity after chemotherapy first begins—adds accurate information about patients’ responses to first-line chemotherapy, according to a study in the October issue of the Journal of Nuclear Medicine.
“In our study, we demonstrated that a quantitative assessment of therapeutic response for patients with diffuse large B-cell lymphoma (DLBCL) is more accurate than visual analysis alone when using the radiotracer FDG (fluorodeoxyglucose) with PET scans,” said Michel Meignan, professor of nuclear medicine at Henri Mondor Hospital in Creteil, France. “The ability to predict tumor response early in the course of treatment is very valuable clinically, allowing intensification of treatment in those patients who are unlikely to response to first-line chemotherapy,” he added. “Similarly, treatment could possibly be shortened in those patients who show a favorable response after one or two cycles of chemotherapy, and quantification also may help identify the disease’s transformation from low-grade to aggressive stage,” he explained. “However, visual interpretation of PET scans will always be the first step of analysis and will prevail in case of difficulties to quantify images,” added Meignan.
Diffuse large B-cell lymphoma is a fast-growing, aggressive form of non-Hodgkin lymphoma, a cancer of the body’s lymphatic system. Although there are more than 20 types of NHL, DLBCL is the most common type, making up about 30 percent of all lymphomas. In the United States, about 63,190 people are expected to be diagnosed with non-Hodgkin lymphoma in 2007, according to recent statistics.
Ninety-two patients with DLBCL were studied before and after two cycles of chemotherapy, and tumor response was assessed visually and by various quantitative parameters, explained the co-author of “Early 18F-FDG PET for Prediction of Prognosis in Patients With Diffuse Large B-Cell Lymphoma: SUV-Based Assessment Versus Visual Analysis.” Meignan said, “We found that quantification of tumor FDG uptake (the ratio of tissue radioactivity concentration) can markedly improve the accuracy of FDG PET for prediction of patient outcome.” Additional studies need to be done, said Meignan, reiterating that the future monitoring of cancer tumor response will probably include a combination of quantitative analysis and visual assessment.
PET is a powerful molecular imaging procedure that uses very small amounts of radioactive materials that are targeted to specific organs, bones or tissues. When PET is used to image cancer, a radiopharmaceutical (such as FDG, which includes both a sugar and a radionuclide) is injected into a patient. Cancer cells metabolize sugar at higher rates than normal cells, and the radiopharmaceutical is drawn in higher amounts to cancerous areas. PET scans show where FDG is by tracking the gamma rays given off by the radionuclide tagging the drug and producing three-dimensional images of their distribution within the body. PET scanning provides information about the body’s chemistry, metabolic activity and body function.
###
“Early 18F-FDG PET for Prediction of Prognosis in Patients With Diffuse Large B-Cell Lymphoma: SUV-Based Assessment Versus Visual Analysis” appears in the October issue of the Journal of Nuclear Medicine, which is published by SNM, the world’s largest molecular imaging and nuclear medicine society. Additional co-authors include Chieh Lin, Alain Luciani and Alain Rahmouni, Department of Radiology; Emmanuel Itti and Gaetano Paone, Department of Nuclear Medicine; and Corinne Haioun and Jehan Dupuis, Department of Hematology, all at Henri Mondor Hospital in Créteil, France; and Yolande Petegnief and Jean-Noël Talbot, Department of Nuclear Medicine, Tenon Hospital in Paris, France.
Credentialed press: To obtain a copy of this article—and online access to the Journal of Nuclear Medicine— please contact Maryann Verrillo by phone at (703) 652-6773 or send an e-mail to mverrillo@snm.org. Current and past issues of the Journal of Nuclear Medicine can be found online at http://jnm.snmjournals.org. Print copies can be obtained by contacting the SNM Service Center, 1850 Samuel Morse Drive, Reston, VA 20190-5316; phone (800) 513-6853; e-mail servicecenter@snm.org; fax (703) 708-9015. A subscription to the journal is an SNM member benefit.
About SNM—Advancing Molecular Imaging and Therapy
SNM is an international scientific and professional organization of more than 16,000 members dedicated to promoting the science, technology and practical applications of molecular and nuclear imaging to diagnose, manage and treat diseases in women, men and children. Founded more than 50 years ago, SNM continues to provide essential resources for health care practitioners and patients; publish the most prominent peer-reviewed journal in the field (Journal of Nuclear Medicine); host the premier annual meeting for medical imaging; sponsor research grants, fellowships and awards; and train physicians, technologists, scientists, physicists, chemists and radiopharmacists in state-of-the-art imaging procedures and advances. SNM members have introduced—and continue to explore—biological and technological innovations in medicine that noninvasively investigate the molecular basis of diseases, benefiting countless generations of patients. SNM is based in Reston, Va.; additional information can be found online at http://www.snm.org.
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