Thursday, June 19, 2008
Philips BrightView XCT
Philips is expanding its portfolio of nuclear medicine products by introducing a new system called BrightView XCT that should enable "low patient dose levels, high-resolution localization and high-quality attenuation correction with the potential for fewer artifacts and shorter exam times." The system integrates Philips BrightView SPECT "in a co-planar design with advanced flat-detector X-ray CT technology to acquire low dose, high resolution CT images and to improve registration confidence," according to the company.
This is the first time a flat panel X-ray detector will be used for CT imaging in nuclear medicine. This system, along with the new GEMINI TF Big Bore and new NM Application Portfolio on the Extended Brilliance Workspace, is currently on display at the Society of Nuclear Medicine (SNM) annual meeting.
The BrightView XCT features technological advances that can enable low patient dose levels, high-resolution localization and high-quality attenuation correction with the potential for fewer artifacts and shorter exam times. This offers clinical advantages particularly in cardiology studies, the top procedure in nuclear medicine. In addition, the co-planar SPECT and CT capabilities limit, and in some cases eliminate, the need to move the table between scans. Reduced movement can help improve patient comfort and allow for more confidence in image registration, the process of comparing, matching and superimposing the SPECT and CT images on one another for analysis. The BrightView XCT is also the only scalable SPECT and SPECT/CT system that fits into a 12'x15.5' room and does not require special certification for nuclear medicine technicians.
Press release: New Philips systems deliver first-of-their-kind integrated solutions for nuclear medicine and radiation oncology ...
Product page: BrightView SPECT ...
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Thursday, June 19, 2008
Philips GEMINI TF Big Bore PET/CT Tomograph
Philips is introducing a larger bore model of its new GEMINI TF positron emission tomography/computed tomography (PET/CT) system, that we have reported on earlier.
With a full 85 cm bore for PET and CT scans, the new system allows for positioning flexibility and has a rigid table design to meet the accuracy requirements for treatment planning. The GEMINI TF Big Bore allows clinicians to image patients in the same position they are treated, expanding PET/CT capabilities beyond diagnosis, staging and follow-up to include therapy planning. The system combines Philips' GEMINI TF time-of-flight PET imaging technologies with its Brilliance Big Bore CT localization to consolidate radiation oncology procedures, increase potential for greater accuracy and improve scheduling. It is the first system that offers tools and protocols to easily integrate PET functional images into radiation oncology, helping to consolidate procedures while maintaining premium image quality.
Press release: New GEMINI TF Big Bore provides the accuracy needed for radiation oncology ...
Flashback: GEMINI TF from Philips
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Wednesday, June 18, 2008
Intego PET Infusion System Receives FDA 510(k) Clearance
Medrad's Intego automated fluorodeoxyglucose (FDG) Infusion System for Positron Emission Tomography/Computed Tomography (PET/CT) procedures has been given FDA clearance yesterday. It is the first automated FDG delivery system available in the US, and has some pretty impressive features that aim to increase safety, precision, and convenience for technicians, doctors, and patients.
Here is more from the press release:
The Intego System automatically extracts a patient dose from a multi-dose vial and delivers it directly to the patient, virtually eliminating manual dose preparation and handling, and the corresponding radiation exposure to the technologist. With the Intego System’s dose-on-demand capability, the prescribed dose can be delivered when the patient and technologist are ready, enabling technologists to easily and efficiently respond to schedule changes, patient delays, and add-on patients. Innovative features, including real-time dose availability information, an integrated ionization chamber, and an optional weight-based dose calculation, allow the healthcare provider to more precisely customize each patient’s dose. Safety features include a tungsten multi-dose vial shield, a fully lead-lined mobile cart, and an automated saline flush to remove residual FDG from the line after each infusion.
Product Page: Intego PET Infusion System...
Read the press release...
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PET Scanner With Semiconductor Detectors Shows Clinical Promise
Japanese researchers have been doing early clinical trials on new PET scanner technology from Hitachi, a system based on novel semiconductor detectors that are proving to be more sensitive at picking up gamma rays emitted indirectly by a positron-emitting radiotracers injected into the body.
From the Society of Nuclear Imaging statement:
Semiconductor-based detectors could improve PET imaging capabilities because the smaller, thinner semiconductors are easier to adjust and arrange than conventional scanners. The new technology allows for even higher spatial resolution and less "noise," or irrelevant images. The prototype semiconductor brain scanner also employs a depth of interaction (DOI) detection system, which reduces errors at the periphery of the field of view.Researchers evaluated the physical performance of the prototype scanner and studied the technology's clinical significance in patients suffering from partial epilepsy and nasopharyngeal cancer—a relatively rare form of cancer that develops at the top of the throat, behind the nose. The results indicate that the PET scanner is feasible for clinical use and has good potential for providing the higher spatial resolution and quantitative imaging required in nuclear medicine. This device, which has been installed in Hokkaido University Hospital, is a result of successful collaboration with staff from the Department of Nuclear Medicine at Hokkaido University in Sapporo, Japan.
Press release from the Society of Nuclear Imaging: First Semiconductor-Based PET Scanner Demonstrates Strong Potential to Aid in Early Diagnosis of Disease ...
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Monday, March 31, 2008
SIRTeX to Trial Radiation Spheres for Liver Cancer
Australian company SIRTeX has received FDA approval to begin trials of their injectable, beta radiating microspheres thought to directly target intrahepatic tumor sites.
From the product brochure:
SIR-Spheres microspheres consist of biocompatible microspheres containing yttrium-90 with a size between 20 and 60 microns in diameter. Yttrium-90 is a high-energy pure betaemitting isotope with no primary gamma emission. The maximum energy of the beta particles is 2.27MeV with a mean of 0.93MeV. The maximum range of emissions in tissue is 11mm with a mean of 2.5mm. The half-life is 64.1 hours. In therapeutic use, requiring the isotope to decay to infinity, 94% of the radiation is delivered in 11 days. The average number of particles implanted is 30 – 60 x 106. SIR-Spheres microspheres are a permanent implant.SIR-Spheres microspheres are implanted into a hepatic tumor by injection into either the common hepatic artery or the right or left hepatic artery via the chemotherapy catheter port. The SIRSpheres microspheres distribute non-uniformly in the liver, primarily due to the unique physiological characteristics of the hepatic arterial flow, the tumor to normal liver ratio of the tissue vascularity, and the size of the tumor. The tumor usually gets higher density per unit distribution of SIR-Spheres microspheres than the normal liver. The density of SIR-Spheres microspheres in the tumor can be as high as 5 to 6 times of the normal liver tissue. Once SIR-Spheres microspheres are implanted into the liver, they are not metabolized or excreted and they stay permanently in the liver.
Each device is for single patient use.
Press release: Sirtex receives US FDA approval for FAST clinical trial (.pdf)
Product page: Product Package Insert (PDF)
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Tuesday, January 29, 2008
Nanovector Trojan Horses (NTH): Drug That May Prevent Radiation Injury
The DoD's Defense Advanced Research Projects Agency (DARPA) is commissioning a nine-month study by Rice University chemists and investigators at the Texas Medical Center to "determine whether a new drug based on carbon nanotubes can help prevent people from dying of acute radiation injury following radiation exposure."
The drug, based on carbon nanotubes and two common food preservatives, has already shown huge promise in reducing the effects of radiation exposure:
The new study was commissioned after preliminary tests found the drug was greater than 5,000 times more effective at reducing the effects of acute radiation injury than the most effective drugs currently available...NTH is made at Rice's Chemistry Department and Carbon Nanotechnology Laboratory in the Richard E. Smalley Institute for Nanoscale Science and Technology. The drug is based on single-walled carbon nanotubes, hollow cylinders of pure carbon that are about as wide as a strand of DNA. To form NTH, Rice scientists coat nanotubes with two common food preservatives -- the antioxidant compounds butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) -- and derivatives of those compounds.
"The same properties that make BHA and BHT good food preservatives, namely their ability to scavenge free radicals, also make them good candidates for mitigating the biological affects that are induced through the initial ionizing radiation event," Tour said.
In preliminary tests at M.D. Anderson in July 2007, mice showed enhanced protection when exposed to lethal doses of ionizing radiation when they were given first-generation NTH drugs prior to exposure.
"Our preliminary results are remarkable, and that's why DARPA awarded us this grant with a very compressed timeline for delivery: nine months, which is almost unheard of for an academic study of this type," Tour said. "They are very interested in finding out whether this will work in a post-exposure delivery, and they don't want to waste any time."
Feds fund study of drug that may prevent radiation injury ...
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Friday, October 19, 2007
Symbia E Series SPECT Imager
This new spiffy gamma camera from Siemens AG is designed for a variety of clinical applications, including oncology, cardiology, neurology, and general imaging:
The new Symbia E is based on the success of Siemens' Symbia family of imagers. Based on state-of-the-art Symbia SPECT·CT technology and award-winning design, Symbia E leverages the strength of the industry's leading gamma camera, the e.cam. There are more than 4,000 e.cams installed in more than 120 countries, proving that the system is an industry icon. Siemens has redesigned the e.cam structure with an improved chassis and improved electronics. The Symbia E boasts features that will allow providers to work with increased confidence because of the system's improved image quality and increased reliability; these will lead to an accelerated workflow. The system is also versatile and it can be upgraded as a facility's workload grows.Siemens has taken the best detector technology that the Symbia family of SPECT and SPECT·CT imagers has to offer and made it available on Symbia E. A new generation of HD detector first introduced with the Symbia TruePoint SPECT·CT imager, with best in class performance and reliability is also included in the new Symbia E scanner. Using these new detectors, where Siemens achieved an 85 per cent reduction in wiring and a 75 per cent reduction in components, and Siemens' own crystal material, the reliability of this new system is significantly increased. Symbia E also imports the clinically validated c.clear attenuation correction, which was developed on the Siemens c.cam dedicated cardiac scanner. So Symbia E users will take advantage of high-end cardiac scanning features.
To ensure the highest customer satisfaction and system uptime, the Symbia E is equipped with Siemens' Remote Services capabilities. The Siemens Remote Services program enables Siemens to check the system status through full remote access and remote diagnostics. This level of proactive monitoring and trending of key performance indicators will allow Siemens to service and update the system before small problems turn into big downtime. The end result is that Symbia E users will experience interruption-free imaging while having the support of a network of nearly 1,000 trained field engineers.
The Symbia E offers features to accelerate the clinical workflow in acquisition, processing and reviewing with syngo workflow solutions such as an integrated physician worklist and it provides imaging in half the time for cardiology and oncology patients, when using cardio·Flash and onco·Flash reconstruction software packages. Users will realize time savings from the system's integrated, simultaneous Quality Control component. With the Symbia E, facilities will be able to see a wide range of patients from pediatrics to bariatrics and can also be equipped with special positioning pallets for mammography. It also sports a tilting detector for optimized planar imaging.
Press release: Siemens Unveils New Technology for Nuclear Medicine's Hardest Working Gamma Camera ...
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Monday, June 18, 2007
In the Works: Compact, Low-cost Proton Therapy System
It looks like proton therapy will be developed into a compact device, after a technology transfer agreement between Lawrence Livermore National Laboratory and TomoTherapy Inc., a Madison, Wisconsin company, was announced just a few days ago.
From the Lawrence Livermore NL press office:
"This technology has grown out of work to develop compact, high-current accelerators as flash X-ray radiography sources for nuclear weapons stockpile stewardship," said George Caporaso, the lead scientist on the project at Lawrence Livermore. "We are excited about applying this new technology to the field of cancer treatment, to make proton therapy widely available as a treatment option.""We have taken proton therapy and achieved major advances toward what we were told was impossible - to scale it down to a size and price that will bring it in reach of every major cancer center," said Ralph deVere White, director of UC Davis Cancer Center and associate dean for cancer programs. "Our research partnership with Lawrence Livermore National Laboratory has fulfilled the mission for which it was created: to deliver translational research in order to advance health care."
Conventional radiation therapy kills cancer cells using high-energy X-rays. These X-rays deliver energy to all the tissues they travel through, from the point they enter the body, until they leave it. Doctors therefore have to limit the dose delivered to the tumor to minimize damage to surrounding healthy tissue.
Unlike high-energy X-rays, proton beams deposit almost all of their energy on their target, with a low amount of radiation deposited in tissues from the surface of the skin to the front of tumor, and almost no "exit dose" beyond the tumor. This property enables doctors to hit tumors with higher, potentially more effective radiation doses than is possible with gamma radiation...
The compact system is expected to fit in standard radiation treatment suites and to cost less than $20 million. The compact system will be mounted on a gantry that rotates about the patient.
Caporaso's team overcame the size obstacle by using dielectric wall accelerator technology developed through defense research. The Livermore scientists have demonstrated in principle that this technology will enable proton particles to be accelerated to an energy of at least 200 million electron volts within a light-weight, novel, insulator-based structure about 6.5 feet long. It also won't use any bending magnets, and will be able to change the protons' energy and intensity between each burst that occurs many times per second.
Currently available proton therapy machines use cyclotrons or synchrotrons nearly 10 feet in diameter and weighing up to several hundred tons. This equipment includes the enormous gantry and bending magnets necessary to focus and direct the beams onto patients.
In addition to overcoming size and cost obstacles, the compact system will improve on existing full-scale systems by including the capability to vary the energy, intensity and "spot" size of the proton beam. Radiation will be produced in rapid pulses, creating small "spots" of dose throughout the tumor. Currently only one proton facility in the world, the Paul Scherrer Institute in Switzerland, is able to deliver this intensity-modulated proton therapy (IMPT). IMPT is generally considered the best way to destroy tumors while minimizing damage to surrounding healthy tissue.
Press release: First compact proton therapy machine for cancer treatment enters development ...
Press release: TomoTherapy Inc. and Lawrence Livermore National Laboratory to Develop Proton Therapy System ...
Flashbacks: Activate the Proton Beam ; The Physics of Proton Therapy; In the Works: Proton Treatment from MIT
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Friday, June 1, 2007
Improved Radiation Detectors Developed by DoE
Tovarisch Aleksey Bolotnikov (pictured), a physicist now working for Uncle Sam at the Brookhaven National Laboratory, developed a new radiation sensor that can function at normal temperatures, which is apparently a major improvement:
The improved sensors, for which the Laboratory has filed a U.S. provisional patent application, can be used at room temperature, which makes them more practical and cost-effective than existing detectors with similar performance, which must be operated at very cold temperatures using expensive liquid nitrogen. They can also more accurately detect the X-rays and gamma rays emitted by radiological sources such as dirty bombs and other illicit materials."Improving the performance of radiation detectors could improve the efficiency and accuracy of cargo screening at U.S. ports," said Brookhaven physicist Aleksey Bolotnikov, one of the inventors.
Radiation detectors work by detecting electrons and "holes" -- vacancies left by liberated electrons -- when ionizing radiation or high-energy particles strike the detector crystal. When the free electrons and holes flow toward electrodes (an anode and a cathode) at either end of the detector, they generate a signal that can be measured and recorded.
In an ideal detector, all of the electrons and holes created by the ionization process would arrive at the electrodes. But in reality, holes travel a very short distance before getting trapped by defects in the crystal. Also, because the electrostatic field inside the detector causes some of the electrons to drift, not all of them arrive at the anode. These losses lead to a subsequent inaccuracy in radiation measurements.
The Brookhaven-designed sensors improve on this situation by combining methods to shield the detector and focus the electrons toward the anode. In addition, the electrodes at each end of the detector give information about how many electrons/holes get trapped. This "correction factor" can then be used to reconstruct the number of electrons/holes originally created by incident gamma rays or high-energy particles.
"Together, these techniques enhance the energy resolution and efficiency of these detectors. In practical terms it means that the improved devices will be able to detect more minute quantities of radiation, detect radioactive materials more quickly or from greater distances, better identify the source of the radiation, and distinguish illicit sources of concern from common naturally occurring radioactive materials," Bolotnikov said.
Press release: New Method for Making Improved Radiation Detectors ...
Press release: NNSA Improves Technology for Radiation Detectors ...
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Tuesday, March 27, 2007
Fast Field-Cycled MRI
The University of Aberdeen researchers are developing a new generation magnetic resonance imaging technology called Field-Cycling MRI:
The new scanner will make visible features not currently seen in conventional MRI. This improved sensitivity and specificity should lead to a better understanding of key diseases, result in more rapid and accurate diagnosis, and eventually pave the way for new treatments.Professor Lurie, Chair in Biomedical Physics, University of Aberdeen, said: "We are tremendously excited about the potential for this scanner which uses new technology called Fast Field-Cycling MRI.
"We believe it has the potential to gain new insight into processes that give rise to disease, involving the complex interactions of atoms, molecules and cells in the body. Fast Field-Cycling MRI promises to be even more sensitive than conventional MRI at picking up these disease processes.
"This technology breaks the first rule of conventional MRI which is that the magnetic field is held constant while the image is being obtained.
"What we will do with our new scanner is to switch the magnetic field rapidly while the image is being obtained. In this way, we will be able to record information about how molecules behave at a whole range of magnetic fields.
"It is a bit like having at our disposal a hundred or more MRI scanners, each one operating at a different magnetic field - but all in the one scanner. The big advantage is that the new scanner will produce images of the body that will tell clinicians important information about disease processes at a much earlier stage.
"One area of research that will benefit in particular is the role of proteins in diseases. The malformation and malfunctioning of proteins is at the core of many diseases and disorders such as Alzheimer's, Parkinson's disease and Multiple Sclerosis. Aberdeen University's Institute of Medical Sciences has world-leading research teams in all of these areas, and the lead scientists are closely involved with the new MRI research.
"A clearer vision of the protein changes that occur in such disorders could lead not only to a better understanding of the disease process itself, but to more rapid and accurate diagnosis and eventually new treatments."
Press release: Pioneering Aberdeen again leads world with MRI...
Field-cycled MRI project page...
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Thursday, February 8, 2007
Radiation Rx Planning Algorithm
Teaching machines to learn? [insert joke about machines becoming self-aware and taking over the world] Being on the serious side, researchers at the Rensselaer Polytechnic Institute have developed a "machine learning" algorithm which can correctly determine appropriate radiation therapy in as little as 10 minutes.
A new computer-based technique could eliminate hours of manual adjustment associated with a popular cancer treatment. In a paper published in the Feb. 7 issue of Physics in Medicine and Biology, researchers from Rensselaer Polytechnic Institute describe an approach that has the potential to automatically determine acceptable radiation plans in a matter of minutes, without compromising the quality of treatment."Intensity Modulated Radiation Therapy (IMRT) has exploded in popularity, but the technique can require hours of manual tuning to determine an effective radiation treatment for a given patient," said Richard Radke, assistant professor of electrical, computer, and systems engineering at Rensselaer. Radke is leading a team of engineers and medical physicists to develop a "machine learning" algorithm that could cut hours from the process.
A subfield of artificial intelligence, machine learning is based on the development of algorithms that allow computers to learn relationships in large datasets from examples. Radke and his coworkers have tested their algorithm on 10 prostate cancer patients. They found that for 70 percent of the cases, the algorithm automatically determined an appropriate radiation therapy plan in about 10 minutes...
IMRT adds nuance and flexibility to radiation therapy, increasing the likelihood of treating a tumor without endangering surrounding healthy tissue. Each IMRT beam is composed of thousands of tiny "beamlets" that can be individually modulated to deliver the right level of radiation precisely where it is needed.
But the semi-automatic process of developing a treatment plan can be extremely time-consuming - up to about four hours for prostate cancer and up to an entire day for more complicated cancers in the head and neck, according to Radke.
A radiation planner must perform a CT scan, analyze the image to determine the exact locations of the tumor and healthy tissues, and define the radiation levels that each area should receive. Then the planner must give weight to various constraints set by a doctor, such as allowing no more than a certain level of radiation to hit a nearby organ, while assuring that the tumor receives enough to kill the cancerous cells.
This is currently achieved by manually determining the settings of up to 20 different parameters, or "knobs," deriving the corresponding radiation plan, and then repeating the process if the plan does not meet the clinical constraints. "Our goal is to automate this knob-turning process, saving the planner's time by removing decisions that don't require their expert intuition," said Radke.
The researchers first performed a sensitivity analysis, which showed that many of the parameters could be eliminated completely because they had little effect on the outcome of the treatment. They then showed that an automatic search over the smaller set of sensitive parameters could theoretically lead to clinically acceptable plans.
The procedure was put to the test by developing radiation plans for 10 patients with prostate cancer. In all 10 cases the process took between five and 10 minutes, Radke said. Four cases would have been immediately acceptable in the clinic; three needed only minor "tweaking" by an expert to achieve an acceptable radiation plan; and three would have demanded more attention from a radiation planner.
Full story @ Rensselaer. . .
Abstract . . .
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Tuesday, November 7, 2006
Panorama 1.0T R/T Simulator from Philips
At the ongoing annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO) in Philadelphia, Philips is introducing its new MR simulator:
The introduction of the Panorama 1.0T with R/T option--the first high field open MR simulator--builds on Philips experience in developing the first commercially available MR simulator, the Panorama 0.23T R/T.This option of the Panorama 1.0T is dedicated for radiation oncology and has received FDA clearance. The R/T option includes an external laser positioning system, an oncology tabletop with indexing, geometric distortion correction software and specialized imaging protocols.
The open gantry of Panorama 1.0T allows for patient scanning in treatment position with immobilization devices or supine inclined for breast imaging. Precise patient alignment is achieved with a flat and rigid oncology table top modeled after the LINAC table and a set of MR-compatible immobilization devices.
The Panorama 1.0T is the only high field open MR system featuring high performance whole body diagnostic imaging capabilities. Diffusion Weighted whole body Imaging with Background body signal Suppression (DWIBS) is a new whole body imaging technique unique to Philips systems and represents a breakthrough for identifying the presence of lesions without exposing the patient to radiation or radioactive isotopes.
Product page for Panorama 1.0T...
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Thursday, November 2, 2006
Antiproton Cell Experiment: Antimatter is a Better Killer
European Organization for Nuclear Research is reporting that results from a three year study of antiprotons for neoplasm irradiation showed a better cellular killer with a smaller lethal dose. From CERN announcement:
"We have taken the first step towards a novel treatment for cancer. The results show that antiprotons are four times more effective than protons at terminating live cells. Although it still has to be compared with other existing methods, it is a breakthrough in this area of investigation." says Michael Doser at CERN, one of the scientists collaborating on the experiment. ACE brings together a team of experts in the fields of physics, biology, and medicine from 10 institutes around the world.Current particle beam therapy commonly uses protons to destroy tumour cells inside a patient. The ACE experiment directly compared the effectiveness of cell irradiation using protons and antiprotons. To simulate a cross-section of tissue inside a body, tubes were filled with hamster cells suspended in gelatine. Researchers sent a beam of protons or antiprotons with a range of 2 cm depth into one end of the tube, and evaluated the fraction of surviving cells after irradiation along the path of the beam.
The results showed that antiprotons were four times more effective than protons. When comparing a beam of antiprotons with a beam of protons that cause identical damage at the entrance to the target, the experiment found the damage to cells inflicted at the end of the beam path to be four times higher for antiprotons than for protons. Michael Holzscheiter, spokesperson of the ACE experiment, summarises: "To achieve the same level of damage to cells at the target area one needs four times fewer antiprotons than protons. This significantly reduces the damage to the cells along the entrance channel of the beam for antiprotons compared to protons. Due to the antiproton's unsurpassed ability to preserve healthy tissue while causing damage to a specific area, this type of beam could be highly valuable in treating cases of recurring cancer, where this property is vital."
Antiprotons are antimatter; they have to be produced in small amounts in a laboratory with the help of a particle accelerator. When matter and antimatter particles meet, they annihilate, or destroy each other, transforming their mass into energy. The experiment makes use of this property as the antiproton would annihilate with a part of the nucleus of an atom in a tumour cell. The fragments produced from the energy released by the annihilation would be projected into adjacent tumour cells, which are in turn destroyed...
Researchers are currently conducting more tests to irradiate cells at a greater depth (about 15cm below the surface).
Clearly, a group of particle physicists is biased in favor of antimatter. Would you expect otherwise? C'mon, we are just kidding! The research seems to be a solid one.
Link ...
(hat tip: Membrana.ru)
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Friday, October 20, 2006
Hyperpolarized Xenon Makes MRI Hypersensitive
A new technique, reported in Science, uses xenon atoms attached to specific proteins or other biological molecules, to increase MRI's sensitivity. Investigators at Lawrence Berkeley National Laboratory and UC Berkeley are reporting MRI sensitivity able to detect bio-molecules at concentrations 10,000 less than the present MRI techniques.
This is how MRI with HYPER-CEST (hyperpolarized xenon chemical exchange saturation transfer) works:
... team of researchers report on a technique in which xenon atoms that have been hyperpolarized with laser light to enhance their MRI signal, incorporated into a biosensor and linked to specific protein or ligand targets. These hyperpolarized xenon biosensors generate highly selective contrast at sites where they are bound, dramatically boosting the strength of the MRI signal and resulting in spatial images of the chosen molecular or cellular target.This research was led by Alexander Pines and David Wemmer, who both hold joint appointments with Berkeley Lab and UC Berkeley. Their paper is entitled Molecular Imaging Using a Targeted Magnetic Resonance Hyperpolarized Biosensor. Co-authoring the paper with Pines and Wemmer were Leif Schröder and Thomas Lowery, plus Christian Hilty.
"Our HYPER-CEST molecular MRI technique makes optimum use of hyperpolarized xenon signals by creating a strong signal in regions where the biosensor is present, allowing for easy non-invasive determination of the target molecule," said Pines, one of the world's leading authorities on NMR/MRI technology, who holds a joint appointment as a chemist with Berkeley Lab's Materials Sciences Division and with UC Berkeley, where he is the Glenn T. Seaborg Professor of Chemistry. "This approach should be broadly applicable, potentially overcoming many shortcomings of currently used strategies for molecular imaging."
Added Wemmer, a chemist with Berkeley Lab's Physical Biosciences Division and UC Berkeley chemistry professor, "Other molecular MRI contrast agents provide small changes in big MRI signals, making the changes difficult to detect when the amount of contrast agent binding is small. Our HYPER-CEST contrast agent provides a big change in the xenon MRI signal, which means it is much easier to detect even though the xenon MRI signals are rather small."
In addition to its intrinsically higher contrast, another advantage with the HYPER-CEST technique is that its effects can be "multiplexed," meaning that the polarized xenon biosensors can be targeted to detect different proteins at the same time in a single sample. This capability, which is not shared by most conventional molecular MRI contrast agents, opens up a number of possibilities for future diagnostics.
Explained co-author Schröder, a member of the Pines' research group who is affiliated with Berkeley Lab's terials Sciences Division, "For example, as a diagnostic tool for the detection of cancer, with HYPER-CEST, we could perform multiple virtual biopsies on a single tissue sample, using different biosensors to screen for each potential form of cancer."
Link...
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Friday, October 13, 2006
TheraSphere® Yttrium 90 Glass Microspheres
The University of Cincinnati is reporting that its physicians are using "millions of glass beads" as a treatment for advanced hepatocellular carcinoma. The technology they are using is called TheraSphere® Yttrium 90 Glass Microspheres, designated as a "humanitarian device" (i.e. with no demonstrated effectiveness) by the FDA. The therapy is a product of MDS Nordion company.
Company explains:
TheraSphere® consists of insoluble glass microspheres where yttrium-90 is an integral constituent of the glass. The mean sphere diameter ranges from 20 to 30 µm. Each milligram contains between 22,000 and 73,000 microspheres...Yttrium 90, a pure beta emitter, decays to stable zirconium 90 with a physical half-life of 64.2 hours (2.67 days). The average energy of the beta emissions from yttrium 90 is 0.9367 MeV.
Following embolization of the yttrium 90 glass microspheres in tumorous liver tissue, the beta radiation emitted provides a therapeutic effect. The microspheres are delivered into the liver tumor through a catheter placed into the hepatic artery that supplies blood to the tumor. The microspheres, being unable to pass through the vasculature of the liver due to arteriolar capillary blockade, are trapped in the tumor and exert a local radiotherapeutic effect with some concurrent damage to surrounding normal liver tissue.
To advance its therapy, the company has recently launched a clinical trial to "further... clinical experience and knowledge of this treatment."
Clinical trial press release...
Product page...
More from the University of Cincinnati...
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Friday, September 15, 2006
Radiotracers for Addicts
Well, actually the radiotracers that are being developed at the U.S. Department of Energy's Brookhaven National Laboratory will be for the scientists, to study how the central nervous system is influenced by addictive drugs:
"Addiction is a brain disease that is devastating for families and society," said Fowler. [Chemist Joanna Fowler is the Director of the Center for Translational Neuroimaging at Brookhaven --ed.] "Chemistry -- through the development of radiotracers that can monitor the distribution and kinetics of drugs and receptors in the brain -- is at the core of understanding the addictive process and finding new ways to help people overcome it."In PET studies, radiotracers (compounds labeled with a radioactive form of certain chemical elements such as carbon or fluorine) are injected into a research subject's bloodstream. A PET scanner picks up the radioactive signal from the tracer and continuously tracks its concentration and movement through the body. The data can be used to reconstruct three-dimensional images that reveal where the compound goes in the body/brain and how long it stays, for example.
The Brookhaven group, led by Fowler, has developed radiotracers to track the movement of various addictive drugs including cocaine, nicotine, and methamphetamine, and also to measure the levels of certain "chemical messengers," or neurotransmitters, and their receptors in the brain. PET studies using these radiotracers have revealed, for example, that all addictive drugs elevate levels of a neurotransmitter called dopamine, a chemical that helps us experience feelings of pleasure, reward, and motivation -- and also plays a role in physical movement. Through the process of addiction, these studies show, the brain's ability to respond to pleasure signals becomes depleted as receptors for dopamine are lost. The research has also indicated that initial differences in people's dopamine systems may help explain why some people find drugs pleasurable and become addicted while others do not.
One of the challenges for the researchers has been developing extremely rapid methods for synthesizing the radiotracer compounds. The radioactive elements (isotopes) most commonly used, carbon-11 (11C) and fluorine-18 (18F), have very short half-lives (20 and 110 minutes, respectively). The half-life is the time it takes for half of the radioactive atoms in the sample to decay to a non-radioactive form. Since the PET scanner depends on the radioactive signal to detect the substance in the body, the compounds must be made and injected quickly to generate useful data.
"We are currently developing new ways to label complex molecules with carbon-11 and fluorine-18 to gain a better understanding of how different drugs of abuse disrupt brain function and how we may be able to treat addiction," said Fowler. "This is an area that benefits enormously from creative synthetic chemistry. It is also an area that desperately needs new talent to develop the scientific tools needed to solve this major public health problem."
FYI, Dr. Fowler knows what she is talking about: she is the inventor of 18F-fluorodeoxyglucose (FDG) radiotracer of brain glucose metabolism for PET scans, a chemical widely used today in clinical practice.
Link...
More at the Center for Translational Neuroimaging...
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Friday, September 8, 2006
The Precedence 64-slice SPECT/CT
At the ongoing annual meeting of the American Society of Nuclear Cardiology, Philips has introduced its Precedence 64-slice SPECT/CT. Described by the company as the world's only "hybrid-imaging system that delivers comprehensive cardiac management on a single imaging platform," the device now features new data software that integrates images from exams of all key cardiology subspecialties.
More about the system and the Philips Xcelera R2.1 information solution:
The Precedence SPECT/CT system unites high-end, multislice CT with an exceptionally flexible gamma camera- a true breakthrough in functional and molecular imaging that can aid diagnosis and treatment in cardiology and oncology. This merged system affords a comprehensive solution, providing registered SPECT, planar and CT images in addition to individual SPECT, CT, or attenuation-corrected nuclear medicine images. Clinicians can employ the fused SPECT/CT data sets to facilitate localization of pathology or alternatively, can acquire the individual datasets in a single imaging session, improving workflow and patient comfort...The Precedence 64-slice SPECT/CT can produce CT-based attenuation correction and perform advanced cardiac CT procedures such as calcium scoring and CTA in one episode of care, on one system. It can also produce SPECT myocardial perfusion imaging in half the time of conventional scanners...
[T]he Philips Xcelera R2.1, which now integrates exam results from all key cardiology subspecialties - interventional cardiology, cardiovascular ultrasound, ECG, nuclear cardiology, cardiac CT, cardiac MR and electrophysiology. This advanced cardiovascular solution for documentation, viewing, quantification and reporting tasks, provides clinicians with access to relevant images and information on patients across the hospital from a single workspace...
In addition to managing examination results in a patient centric-manner, the new release of Xcelera also brings a variety of new or enhanced clinical and reporting tools for 2D and 3D Echo, Cardiovascular X-Ray, Nuclear Cardiology (powered by AutoQuant), 2D and 3D Cardiac CT and MR, as well as for managing EP recording and mapping information. The new design of results management and availability of new and enhanced clinical tools enables cardiac professionals to more efficiently diagnose a patient's condition and subsequently make more informed decisions about the method of treatment.
The press release...
The product page...
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Thursday, August 31, 2006
Radilex™: Rx for Ionizing Radiation
ImmuneRegen BioSciences, a company out of Scottsdale, Arizona, has inititated a new study at the Oak Ridge National Laboratory (ORNL) to further evaluate its drug Radilex™, to support its submission to the FDA in the future. The drug is thought to be a possible treatment of the effects of acute radiation exposure. Radilex™ is an analog of Substance P (Sar9, Met (O2)11-Substance P), widely distributed throughout the body neuropeptide.
Read more about this interesting and promising product and its history on the company's product page...
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Tuesday, August 29, 2006
In the Works: Proton Treatment from MIT
MIT and Still River Systems Inc., a Littleton, Mass. company are working on developing proton treatment for radiation oncology:
The beauty of protons is that they are quite energetic, but their energy can be controlled so they do less collateral damage to normal tissues, compared to powerful x-ray beams. Protons enter the body through skin and tissue, hit the tumor and stop there, minimizing other damage.Protons are far more massive than the photons in x-rays, and the x-rays tend to pass directly through tissues and can harm living cells along the entire path. The side effects often include skin burns and other forms of tissue damage.
The new machines, in fact, should allow radiation specialists to deposit a far bigger dose of killing power inside the tumor, but spare more of the surrounding normal tissues. This is expected to increase tumor control rates while minimizing side effects.
Because of their high energy and controllability, protons have been used as anti-cancer bullets in the past, with promising results. But medical centers can't easily come up with the $100 million or more needed to build a proton machine dedicated to this medical use. That's because protons are produced inside the huge, expensive atomic accelerators that are usually employed at major atomic research centers, including national laboratories.
Now, Antaya [Timothy Antaya is a physicist at MIT's Plasma Science and Fusion Center --ed.] and his colleagues at MIT and at Still River Systems Inc. think they can provide the new machine for far less money, have it occupy just one moderate-size hospital treatment room, and achieve better results than x-ray therapy. MIT is licensing the technology to Still River Systems.
Industry is already showing acute interest in the new technology because more than half of all cancer patients are now treated with radiation, meaning there are two million radiation patients worldwide. That offers a huge market for an effective new radiation system, and the directors of major cancer research and treatment centers are already enthusiastic, Antaya said.
More...
Still River Systems' empty website...