Radiation that knocks electrons out and down, one after anotherDecember 06, 2016
Researchers at Japan's Tohoku University are investigating novel ways by which electrons are knocked out of matter. Their research could have implications for radiation therapy.
Exposing a small cluster of neon atoms to a very short and intense burst of extreme ultraviolet light initiates a novel mechanism that produces a large number of electrons and ions.
A team of researchers led by physical chemist Kiyoshi Ueda of Tohoku University used a free electron laser (FEL) at Japan's SPring-8 Compact SASE Source test accelerator to investigate how electrons are 'knocked out' of neon atom clusters. Intense extreme ultraviolet FEL pulses were directed at the clusters and the resultant energy distribution of electrons knocked out of the clusters was measured using a 'velocity map imaging spectrometer'.
Electrons inside a material absorb energy when the material is exposed to light. Normally, this energy is used to 'knock electrons out' of the material. This can only happen, however, if the energy of the light particle, or 'photon', absorbed by the electron is higher than the amount of energy needed by the material, or its 'work function', to eject the electron. In 1921, Albert Einstein won a Nobel Prize for describing this 'photoelectric effect'.
The team tested what would happen when they set the photon energy of the FEL light below the work function of clusters of neon atoms. Instead of being knocked out, when an electron tightly bound to a neon atom absorbs the lower energy photon, it becomes loosely bound, causing the atom to become 'excited'. Since the FEL pulse is so intense, many electrons become loosely bound in the clusters at the same time; meaning many atoms become excited. Electrons are then knocked out of the clusters even though the photon energy is below their work function.
The team discovered that loosely bound electrons are knocked out of the clusters in a novel 'cascading' process.
The process begins when an atom with a loosely bound electron interacts with a nearby atom that also has a loosely bound electron. The first transfers energy to its neighbour, which 'knocks down' its own loosely bound electron hovering in a 'high-energy' orbit into a 'low-energy' orbit closer to the atom's core. At the same time, the energy transferred to the neighbouring atom knocks a loosely bound electron out of it. The first atom, which is now 'less excited', then interacts with another neighbouring excited atom, also giving it energy and thus 'de-exciting' itself even further while knocking an electron out of another neighbour. This cascading process occurs in many pairs of excited atoms, resulting in the emission of a large number of low-energy electrons.
"The cascades of knocking electrons out and down produce more electrons and more ions, damaging the sample more. I am convinced these cascades might play a crucial role in future radiation therapy," says Lorenz Cederbaum of Germany's Heidelberg University, one of the study's co-authors.
The release of low-energy electrons exposed to intense light can damage DNA. This concept is used in cancer radiation therapy. The findings could have implications for the use of radiation therapy in the future.
The researchers published their findings in the journal Nature Communications.
Related Radiation Therapy Articles:
Massachusetts General Hospital investigators report finding finding how appropriately timed radiation therapy can significantly improve the delivery of cancer nanomedicines by attracting macrophages to tumor blood vessels, which results in a transient 'burst' of nanoencapsulated drugs from capillaries into the tumor.
The researchers are able to use the radiosensitivity index within a mathematical framework to select the optimum radiotherapy dose for each patient based on their individual tumor biology.
Childhood cancer survivors are living longer. Now research shows they are also less likely to develop second cancers while still young.
A new study shows that repeated radiation therapy used to target tumors in the brain may not be as safe to healthy brain cells as previously assumed.
Investigators from Brigham and Women's Hospital (BWH) and the Dana-Farber Cancer Institute have found that a set of easily measurable risk factors can predict the magnitude of survival benefit offered by radiation therapy following breast cancer surgery.
Nearly two-thirds of US women age 70 or older with stage I breast cancer who undergo lumpectomy and are eligible to safely omit subsequent radiation therapy according to national cancer guidelines still receive this treatment, according to new study results.
An antiscarring paste when applied to the skin of mice halts fibrosis caused by the radiation used in cancer therapy.
The characteristic blue glow from a nuclear reactor is present in radiation therapy, too.
Therapy dogs may improve the emotional well-being of some cancer patients, according to results of a clinical study, the first to document the benefits of animal-assisted therapy in adult cancer patients.
Among men undergoing radiation therapy for prostate cancer, daily use of the erectile dysfunction drug tadalafil, compared with placebo, did not prevent loss of erectile function, according to a study in the April 2 issue of JAMA.
Related Radiation Therapy Reading:
Radiation Therapy (Quick Study Academic)
by Inc. BarCharts (Author)
Radiation therapy (RT) is a dynamic but complex medical profession. Our comprehensive 3-panel (6-page) guide will make it all easy to understand, including the differences between RT and x-ray tech. All key aspects of RT―from basic radiophysics and radiobiology to radiotherapy safety and procedures―are covered in-depth, with up-to-date information that is enhanced by useful charts, tables and images of cutting-edge equipment. Each section features “The Tech Knows” summary of critical points, set off graphically for easy reference. View Details
Principles and Practice of Radiation Therapy, 4e
by Charles M. Washington MBA RT(T) FASRT (Author), Dennis T. Leaver MS RT(R)(T) FASRT (Author)
Learn everything you need to know about radiation therapy with the only comprehensive text written for radiation therapy students by radiation therapists. Principles and Practice of Radiation Therapy is designed to help you understand cancer management, improve clinical techniques for delivering doses of radiation, and apply complex concepts to treatment planning and delivery. This edition features enhanced learning tools and thoroughly updated content, including three new chapters to inform you of increasingly important technologies and practices. The up-to-date and authoritative coverage of... View Details
Mosby’s Radiation Therapy Study Guide and Exam Review (Print w/Access Code), 1e
by Leia Levy MAdEd(Masters in Adult Education) RT(T) (Author)
Reinforce your understanding of radiation therapy and prepare for the Registry exam! Mosby's Radiation Therapy Study Guide and Exam Review is both a study companion for Principles and Practice of Radiation Therapy, by Charles Washington and Dennis Leaver, and a superior review for the certification exam offered by the American Registry for Radiologic Technology (ARRT). An easy-to-read format simplifies study by presenting information in concise bullets and tables. Over 1,000 review questions are included in the book, with an additional 1,000 questions available online on... View Details
Khan's The Physics of Radiation Therapy
by Faiz M. Khan PhD (Author), John P. Gibbons PhD (Author)
Expand your understanding of the physics and practical clinical applications of advanced radiation therapy technologies with Khan's The Physics of Radiation Therapy, 5th edition, the book that set the standard in the field. This classic full-color text helps the entire radiation therapy team—radiation oncologists, medical physicists, dosimetrists, and radiation therapists—develop a thorough understanding of 3D conformal radiotherapy (3D-CRT), stereotactic radiosurgery (SRS), high dose-rate remote afterloaders (HDR), intensity modulated radiation therapy (IMRT), image-guided radiation... View Details
The Physics & Technology of Radiation Therapy
by Patrick N. McDermott (Author), Colin G. Orton (Author)
This book is the outgrowth of a course taught to residents in radiation oncology at Wayne State University, at the suggestion of residents who saw a need for a technically accurate text set at the correct mathematical level. It is intended to be a book to learn from, not a comprehensive compendium. It is written for members of the radiation therapy community such as radiation therapy technologists, dosimetrists, and radiation oncologists who may have taken college physics several years previously but still need to know the basic physics of radiation therapy. For graduate students in medical... View Details
Radiation Therapy Study Guide: A Radiation Therapist's Review
by Amy Heath (Author)
This book is a comprehensive review and study aid for radiation therapists. Organized in a question-and-answer format, it present clinical features and principles of treatment. Topics include radiation therapy physics, radiobiology, treatment and simulation equipment, principles of patient care, clinical components of cancer care, and cancers of the brain, head and neck region, and respiratory, digestive, urinary, and male and female reproductive systems. It offers over 500 multiple-choice questions with detailed answers and rationales. Radiation Therapy Study Guide is a valuable... View Details
Radiation Therapy Planning
by Gunilla C. Bentel (Author)
A Doody's Core Title for 2011!All new expanded edition provides step-by-step guidelines on performing the technical aspects of radiation therapy. Important new coverage includes treatment preparation, 3-D treatment planning, dosimetry, new technologies, documentation, and quality assurance. In addition, you'll find added treatment planning guidelines by body region, and an expanded art program including many new 4-color illustrations. View Details
Radiation Therapy in Hematologic Malignancies: An Illustrated Practical Guide
by Bouthaina Shbib Dabaja (Editor), Andrea K. Ng (Editor)
This book is designed to assist practitioners in managing patients who present with difficult cases of the most common hematological malignancies. The scenarios covered are those that are likely to be encountered in patients with the various forms of Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, and leukemia. In each of the three sections devoted to these malignancies, multiple cases are presented. The case discussions follow a standard format. A clinical description is followed by a pathological description documenting information relevant to diagnosis and by details of staging work-up,... View Details
Confessions of a Radiation Oncologist: What you don't know about Cancer and Radiation Therapy.
by MD Bobby N. Koneru (Author), Alla Zarifyan (Editor), Carolyn Wittstone (Editor)
CONFESSIONS OF A RADIATION ONCOLOGIST: What You Don't Know About Cancer and Radiation Therapy. An Illustrated Guide for Patients. BOOK HIGHLIGHTS: Starting with how radiation therapy works, Confessions of a Radiation Oncologist informs patients of what to expect before, during and after treatment. Special attention is paid to radiation therapy for different kinds of cancers, empowering patients with the knowledge they need about the specific cancer they are fighting. Patients will find a whole host of resources at their fingertips including: (1) Detailed infographics that explain clearly,... View Details
The Physics of Radiation Therapy
by Faiz M. Khan PhD (Author)
Dr. Khan's classic textbook on radiation oncology physics is now in its thoroughly revised and updated Fourth Edition. It provides the entire radiation therapy team—radiation oncologists, medical physicists, dosimetrists, and radiation therapists—with a thorough understanding of the physics and practical clinical applications of advanced radiation therapy technologies, including 3D-CRT, stereotactic radiotherapy, HDR, IMRT, IGRT, and proton beam therapy. These technologies are discussed along with the physical concepts underlying treatment planning, treatment delivery, and... View Details