External-beam radiotherapy systems that that employ real-time or near real-time MRI guidance show much promise as a new technique to treat cancer. Prototype hybrid MRI-Linac systems are being evaluated as modalities to deliver high precision ablative radiotherapy.

Researchers at Sunnybrook Health Sciences Centre in Toronto are investigating the feasibility of using an MRI-Linac to treat breast cancer patients, using hypofractionated partial breast irradiation (HPBI). Sunnybrook’s Odette Cancer Centre is evaluating a clinical prototype of Elekta’s MRI-Linac. Its clinical staff believe that the system’s online visualization and tumour contouring capabilities, combined with the ability to reduce internal motion margins using multileaf collimator tracking or exception gating from real-time MR images, will be advantageous for treating intact breast tumours.

However, one concern is that treatment with an MRI-Linac can cause elevated radiation doses to the skin. The ever-present magnetic field can create electron return effects (ERE), in which electrons liberated at tissue–air and tissue–lung interfaces curl back on themselves and deposit larger radiation doses in tissue at these interfaces.

Sunnybrook’s Anthony Kim and colleagues

Medical physicist Anthony Kim and colleagues conducted a simulation study to determine the impact of the magnetic field on HPBI dose distributions. After evaluating a tangential beam arrangement (TAN), 5-beam intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT), the researchers confirmed their hypothesis that the magnetic field increases the skin dose. The magnetic field had clinically negligible effects on radiation dose to the heart and the lung (J. Appl. Clin. Med. Phys. doi: 10.1002/acm2.12182).

Impact of the magnetic field

The researchers developed treatment plans for five patients who did not have surgery due to metastatic disease or severe medical comorbidities. They analysed a total of seven tumours close to the skin, with planning target volumes (PTV) of between 37.3 cc and 341.1 cc. For each tumour, treatment plans for the three beam geometries were optimized with and without a 1.5 T magnetic field, using the same PTV isocoverage for all six plans.

The authors used the same patient image data and target contours as used clinically. They evaluated two skin depths, 3 and 5 mm, to determine whether magnetic dose effects were more prevalent closer to the patient’s external surface.

All plans had acceptable PTV coverage. The authors reported that with the magnetic field on, the skin dose was considerably higher for the TAN plan compared with the IMRT plan, which in turn delivered a higher dose to the skin than the VMAT plan.

The skin dose correlated with the number of beam angles used. Specifically, skin dose can be reduced by increasing the number of beam entry angles. Hence, in the presence of a magnetic field, VMAT spared the skin more than IMRT, which in turn spared more than the TAN beam arrangement. Also, the researchers found that the ERE due to the magnetic field was greatest very near the surface of the skin.

The authors explain these phenomena by the fact that the ERE tends to have much less impact at the entry points compared with the beam exit points. Only the beam angles near the tumour created a higher magnetic field dose. The ERE had a much larger impact with TAN radiation delivery compared with IMRT or VMAT delivery when the beam angles were spread far more apart.

Based on their analyses, the authors stated, “The number of beam angles matter, and it is likely that beam arrangement also matters… Skin dose is significantly impacted not only by the magnetic field, but also varies with depth and when increasing the number of beam angles.”

The MRI-Linac is currently being installed at Odette Cancer Centre. “The installation will be completed soon, and in the early part of 2018 we will be conducting basic physics research and volunteer MR imaging, to evolve our understanding of this device ahead of treating patients,” Kim told medicalphysicsweb. “We have been able to do some basic groundwork with respect to how to best optimize these plans without adverse effects. This groundwork has been possible because of our access to the radiation treatment planning system (Elekta’s Monaco) that can simulate the MRI-Linac beam on actual patient data.”

Original Source: medicalphysicsweb.org/cws/article/research/70214

Original Author: Cynthia E Keen

Original Date: Oct 17 2017

CERN, the European nuclear physics research organization, is contemplating the development of a particle accelerator three times larger than the Large Hadron Collider that confirmed the existence of the Higgs boson, a move intended to match growing Chinese ambitions in particle physics.

Fabiola Gianotti, CERN’s director general, said in an interview that the organization has begun design studies for a new circular super-collider that would be between 90 to 100 kilometers long. CERN’s Large Hadron Collider, currently the world’s highest energy particle accelerator, measures 27 kilometers.

The collider is famous for finding the Higgs boson in 2012, considered one of the most important discoveries in particle physics in decades. The particle helps explain how the visible universe holds together.

Chinese scientists would like to build a electron-positron circular collider twice the size of the LHC, which smashes protons together. After building this initial accelerator, China would eventually expand it into an even bigger proton collider. But initial plans to start construction in 2021 suffered a setback when the Chinese government opted not to fund the collider in its 2016 five-year plan. The research team will now to need to wait until 2020 to apply again.

The effort is controversial. Chinese-born physics Nobel winner Chen Ning Yang, a U.S. citizen, argued last year that China, as a still developing country, could not afford the project, which is expected to cost as much as $6 billion in its initial phase.

Gianotti, who is the first woman to head the European nuclear research agency, said she welcomed the Chinese proposals. “I think it is very good to have competition,” she said. “It is very good to have different regions of the world that are interested in fundamental physics and consider that the outstanding questions today in particle physics are worth building the next generation particle collider.”

But Gianotti said it was unlikely that both CERN and the Chinese would actually complete construction of their massive projects. “I don’t think the world can afford two such colliders,” she said, adding it was important to “optimize” available scientific expertise and financial resources for the sake of advancing science.

“There is no point having two similar accelerators,” she said.

She said that while CERN has begun initial planning for its own massive super-collider, it had not yet produced cost estimates. The growing interest from China could help Gianotti make the case for its 100-kilometer ring or for alternative proposals, such as a high-energy electron and positron accelerator known as the Compact Linear Collider. Gianotti said which project CERN will pursue would be decided in a review of Europe’s particle physics strategy in 2019.

Gianotti described the relationship with China as being collaborative as well competitive. Three CERN scientists sit on the international advisory panel for China’s electron-positron accelerator. Gianotti said discussions had taken place about strengthening CERN’s work with China and that she plans to travel to China next year for further talks.

Higgs Discovery

After discovering the Higgs boson, an elementary particle that the so-called Standard Model of physics postulates is fundamental to giving objects mass, the LHC underwent a two-year retrofit. CERN upgraded the electro-magnets that allow the collider to accelerate particles to velocities approaching the speed of light, as well as the cryogenic refrigerators that keeps those magnets cooled. The new machine, which has been running since April 2015, operates at energy levels about 75 percent greater than the LHC did when it found the Higgs in 2012 and it produces almost triple the number of collisions per second.

Many hoped the upgrade would allow the LHC to move beyond the visible universe and find evidence of dark matter and exotic new particles that are not accounted for by the Standard Model. But so far, Gianotti said, the LHC has not found any conclusive evidence.

“The Higgs boson behaves very much like the Standard Model predicts,” she said, while cautioning that the experimental precision of the LHC is not yet high enough to exclude that Higgs is part of a broader theory beyond the Standard Model.

The LHC is due to undergo another major upgrade starting in 2024. This turbo-boosted collider is known as the High Luminosity LHC.

“At the moment, large uncertainties still exist,” Gianotti said referring to the precision of the LHC results. “We hope that with more data and the advantage of the luminosity upgrade of the LHC, which will extend the full program of the Large Hadron Collider to 2035, by that time we will reduce the uncertainty on several measurements by some large factor.”

Processing all the information the High Luminosity LHC produces will pose a monumental challenge of its own. CERN scientists this week released a paper in which they forecast that by 2026 the computing capacity required for experiments run on the collider will be 50 to 100 times greater than today, with data storage needs running into many exabytes. (By way of comparison, all the words ever spoken by humans are estimated to be about 5 exabytes, according to a 2003 report from the University of California at Berkeley’s School of Information Management and Systems.)

The CERN scientist think improvements in computing technology will be able to meet only 10 to 20 percent of these needs without additional cost. So the physics agency is calling for a major research and development effort to solve the bottleneck with more efficient software coding, changes in data center infrastructure and more use of advance machine learning techniques. CERN works with partners such as Intel Corp., Oracle Corp., Huawei Technologies Co. Ltd., and Siemens AG, on many of these efforts.

CERN, which has a budget of about 1 billion Swiss francs ($1.04 billion) per year, is funding this upgrade to the LHC out of its existing finances, Gianotti said.

“For a researcher like me, perhaps the best reward is a surprise,” she said. “Nature is always more clever, and perhaps also more simple and more elegant, than the human brain. So it may be the all the models that mankind have developed, these are not what Nature has finally chosen.”

CERN has collaboration with U.S. physicists, with American researchers running experiments at CERN’s LHC and CERN scientists working on neutrino and dark matter research at the Stanford Underground Research Facility in South Dakota. Some are concerned this research could be jeopardized by an almost 20 percent funding cut for high energy physics research and nuclear research proposed by President Trump in his 2018 budget.

Gianotti said she was optimistic that this funding would be restored by the U.S. Congress before it passes a final spending bill. “I remain pretty positive things will be okay,” she said.

Original Source: https://www.bloomberg.com/news/articles/2017-09-21/europe-is-designing-a-new-particle-collider-to-take-on-china

Original Author: Jeremy Kahn and Thomas Mulier

Original Date: Sept 21 2017

The rise in a number of people suffering from cancer along with the increasing investment in healthcare has resulted in new diagnostics and treatment options. Innovation in technologies such as imaging technologies, linear accelerators and diagnostic devices have made the radiotherapy treatment highly effective. However, to introduce more cost-effective and better treatments, radiotherapy device manufacturers are using software solutions and are also combining technologies to improve outcome and provide better patient care.

Companies are working towards introducing cost-effective solutions. While researchers are studying the various mode of treatment that will offer the best outcome. Researchers are trying to reach the point where it will be easy to suggest particular treatment for the specific type of cancer.

According to the latest report by Future Market Insights (FMI), North America radiotherapy device market is anticipated to gain 34% market share between 2017 and 2027. While Western Europe is expected to have 30% market share by the end of 2027. The North America market is projected to exceed $3,500 million market valuation by 2027 end. By the end of 2027, Western Europe is estimated to exceed $3,100 market value. Radiotherapy device market is a well-structured market and poses a good opportunity for growth. As the market is governed by strict regulations such as the U.S. Food and Drug Administration (FDA) Medical Device Regulatory Approval Process and more such regulations in different countries.

New technologies to drive demand for radiotherapy devices

New devices made using innovative technologies are gaining popularity among healthcare providers and patients. However, more research is being conducted to validate these devices before being used. For instance, IsoRay, a medical technology company has received a response from FDA for its GammaTile radiation therapy system. FDA has asked the company to submit additional data to secure clearance for GammaTile device. According to the company, additional testing of the device is expected to be completed by 2017 end. Once the clearance is received, GammaTile device will be able to address the need for the treatment of recurrent brain tumors. In the clinical trials, around 80 patients have been treated using the GammaTile device.

Elekta, an equipment and software provider to improve cancer and brain disorders, along with clinicians developed Venezia, an advanced gynecological applicator to be used in the treatment of advanced stage cervical cancer.

Next-gen MRI guided radiation therapy device

FDA recently approved ViewRay’s MRIdian Linac system, the first kind of device combining MRI guidance along with linear accelerator radiation. This device helps to visualize the movement of tumors and organs in real time during radiation treatment. The new device can be used to plan treatment during radiation procedures. The device uses magnetic resonance imaging to differentiate between different types of tissue while delivering more radiation to the tumor than to the surrounding tissue.

Governments of various countries are also allocating budget for cancer research and treatment. This is resulting in the development of new radiotherapy devices using advanced technology. This is also leading to the development of cost-effective solutions with enhanced treatment capabilities.

Original Source: http://www.editiontruth.com/smart-radiotherapy-devices-provide-better-cancer-treatment/

Original Author: Abhishek Bhudoliya

Original Date: Sept 13 2017