FMRI Accurately Predicts which Patients can Recover from Vegetative State…

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According to new research published in The Lancet, a functional brain imaging (fMRI) method known as positron emission tomography (PET) is a promising tool for determining which severely brain damaged individuals in vegetative states have the potential to recover full consciousness. It is the very first time that researchers have tested the diagnostic accuracy of fMRI techniques in clinical practice.   "Our findings suggest that PET imaging can reveal cognitive processes that aren't visible through traditional bedside tests, and could substantially complement standard behavioral assessments to identify unresponsive or "vegetative" patients who have the potential for long-term recovery," said study leader Professor StevenLaureys from the University of Liége in Belgium.   In gravely brain-damaged individuals, evaluating the level of consciousness has proved quite difficult. Conventionally, bedside clinical examinations have been utilized to determine whether patients are in a minimally conscious state (MCS), in which there is some evidence of awareness and response to stimuli, or are in a vegetative state (VS) also known as unresponsive wakefulness syndrome, where there is neither, and the chance of recovery is much lower. But up to 40% of patients are misdiagnosed using these examinations.   "In patients with substantial cerebral oedema [swelling of the brain], prediction of outcome on the basis of standard clinical examination and structural brain imaging is probably little better than flipping a coin," writes Jamie Sleigh from the University of Auckland, New Zealand, and Catherine Warnaby from the University of Oxford, UK.   The study evaluated whether two new fMRI methods, PET with the imaging agent fluorodeoxyglucose (FDG) and fMRI during mental imagery tasks, could differentiate between vegetative and MCS in 126 patients with severe brain injury (81 in a MCS, 41 in a VS, and four with locked-in syndrome, a behaviorally unresponsive but conscious control group) referred to the University Hospital ofLiége, in Belgium, from across Europe.   The researchers then juxtaposed their results with the well-established standardized Coma Recovery Scale-Revised (CSR-R)behavioral test, considered the most authenticated and sensitive method for discerning very low awareness levels.   Overall, FDG-PET was better than fMRI in distinguishing conscious from unconscious patients. Mental imagery fMRI was less sensitive at diagnosis of a MCS than FDG-PET (45% vs. 93%), and had less agreement with behavioral CRS-R scores than FDG-PET (63% vs. 85%). FDG-PET was about 74% accurate in predicting the extent of recovery within the next year, as opposed to 56% for fMRI.   Notably, a third of the 36 patients diagnosed as behaviorallyunresponsive on the CSR-R test who were scanned with FDG-PETdemonstrated brain activity consistent with the presence of some consciousness. Nine patients of this cohort later recovered a reasonable level of consciousness.   "We confirm that a small but substantial proportion of behaviorallyunresponsive patients retain brain activity compatible with awareness. Repeated testing with the CRS-R complemented with a cerebral FDG-PET examination provides a simple and reliable diagnostic tool with high sensitivity towards unresponsive but aware patients. fMRI during mental tasks might complement the assessment with information about preserved cognitive capability, but should not be the main or sole diagnostic imaging method,” saidLaureys.   The authors note that the study was conducted in a specialist unitconcentrating on the diagnostic neuroimaging of disorders of consciousness and therefore roll out might be more challenging in less specialist units.   "From these data, it would be hard to sustain a confident diagnosis of unresponsive wakefulness syndrome solely on behavioral grounds, without PET imaging for confirmation. This work serves as a signpost for future studies. Functional brain imaging is expensive and technically challenging, but it will almost certainly become cheaper and easier. In the future, we will probably look back in amazement at how we were ever able to practice without it,” commented Sleigh ... Read more

Shared Decision Making During Radiation Therapy …

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Based on a recent study by researchers from the Perelman School of Medicine at the University of Pennsylvania, playing an active role in their radiation treatment decisions puts cancer patients at ease and has them feeling more satisfied with their care, and may even alleviate psychological distress around the circumstance.   In the study, which was published in the journal Cancer, 305 patients receiving radiation treatment, Neha Vapiwala, MD, an associate professor in the department in Radiation Oncology at Penn Medicine, and colleagues at Penn's Abramson Cancer Center discovered a connection between patient satisfaction and patient-perceived control and shared decision making (SDM), the process that enables patients and providers to make health care decisions together, taking into account scientific evidence as well as the patient's values and preferences.   Patients who experienced SDM or perceived some control over their treatments were more satisfied with their care as opposed to those who did not experience SDM or perception of control, a difference of almost 17 percent and 26 percent, respectively. Additionally, increased anxiety, depression and fatigue were reported in patients who desired control over treatments, but did not distinguish this control.   "Most importantly, our findings emphasize the value of patient-physician relationships and communication specifically in radiation oncology, and their impact on patient experience in a way that hasn't been shown before. No matter where cancer patients are in the treatment process, there is always an opportunity to improve patient satisfaction, something hospitals and providers have consciously and increasingly been making a priority," said Vapiwala.   Previous studies of SDM in patients receiving chemotherapy, as well as treatments for other medical conditions such ashypertension and diabetes, have demonstrated a correlation with improved satisfaction and quality of life. Taking into account, the Institute of Medicine recently recognized its importance, and theAffordable Care Act even devotes a whole section to establishing a program for SDM. Though, no group has assessed its impact on patients going through radiation. Frequently, radiation oncology is viewed as a treatment specialty that is ultimately left up to the physician to determine the course of action. However, there are tailored options, decisions, and discussions that can apply to individual patients, even if they all have similar diagnoses. There are varying radiation regimens, dosages, risks and benefits, as well as pain control managementissues, that should be part of the ongoing conversation. Amongst the patients enrolled in the study, 31 percent of patients experienced SDM, 32 percent perceived control in decisions, and 76 percent reported feeling very satisfied with their radiation treatment course overall. There was a prominent link between patient satisfaction with his/her radiation treatments and patient-perceived experience of SDM (84.4 percent vs. 71.4 percent) or perceived control over one's treatment (89.7 percent vs. 69.2 percent). Patients who particularly desired control over their treatment decisions, but did not perceive this control, experienced a higher rate of anxiety (44 percent vs. 20 percent), depression (44 percent vs. 15 percent), and fatigue (68 percent vs. 39.2 percent), as opposed to patients who did not perceive a sense of control in their treatment decisions. One of the advantages of the study is its assorted group of patients. Ages ranged from 18 to 87 years old, with patients of varying ethnic and racial backgrounds, and having diverse cancers at all stages, as long as they were well enough to participate in the study. The next phase in the research is to determine both physician and patient barriers to SDM and to determine methods and techniques to break down such barriers. "As providers, it doesn't matter what treatment you are offering, or how complicated it is, or how busy you may be. It’s worth taking even a few minutes to talk to patients about seemingly minor decisions in which they can provide some input. It's not only critical in today's health care setting where both information and misinformation are rampant, but will very likely lead to the patient feeling positively about the encounter," ... Read more

New Canadian Mammography Study Sparks Controversy…

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A recent report from the Canadian National Breast Screening Study (CNBSS) determined that mammography screening does not reduce deaths from breast cancer. The findings reignited the much heated debate that started in 2009 when the U.S. Preventive ... Read more

Comparison of Dose-escalated Hypofractionated IMRT and …

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According to a study published in the International Journal of Radiation Oncology, Biology, Physics (Red Journal), which also serves as the official scientific journal of the American Society for Radiation Oncology (ASTRO); dose-escalated intensity ... Read more

Better-targeted Treatment in Pediatric Radiotherapy…

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According to a recent study, for the very first time researchers have been able to show that the use of helium ions in radiation therapy could provide proper treatment to tumors, all the while sparing healthy organs. A treatment planning study presented at the ESTRO 33 congress has been able to demonstrate that helium may have effects that are better to radiotherapy using protons, themselves a significant advance on traditional photon beam radiotherapy. Mr. Hermann Fuchs, a PhD student at the Medical University of Vienna/AKH Vienna, Austria, in collaboration with Dr. Barbara Knäusl, and Professor Dietmar Georg, set out to develop a method of calculating the best possible dose of helium ions for use in radiation treatment. The dose calculation algorithm was then implemented for treatment plan calculation for ten pediatric patients, five with neuroblastoma (tumors arising in cells of the hormonal and nervous system), and five with Hodgkin's lymphoma. "Particle beam therapy involving protons or carbon ions has advantages over conventional radiotherapy. Helium ions may represent another kind of particle that can improve radiotherapy treatment. Due to their increased mass, spreading of the beam is reduced by a factor of two as compared with protons. Moreover helium ions have an increased biological effectiveness at the end of their range," explained Fuchs. “Heavier ions like carbon have the potential to kill cancer cells more effectively due to their underlying biology. But by modeling these biological processes, large uncertainties are introduced, and these can be reduced by using lighter ions like helium. "Helium ions reside in the low Linear Energy Transfer (LET) area. LET is a physical quantity describing how much energy of a particle is deposited at a given range, and this measure is important when looking at the biological effects of therapy,” he added. Such higher accuracy and sparing of normal tissue is crucial in the case of children, the researchers note. When treating children it is mainly important to ensure that as little dose of radiation as possible is placed outside the area to be treated, since an increased area treated with a low dose can lead to the development of secondary cancers. And since children have a potentially long lifespan ahead of them, this probability must be reduced as much as possible through the functions of therapies that are targeted as accurately as possible to the tumor, while sparing the dose to surrounding areas, and particularly to healthy organs especially sensitive to radiation located nearby (the organs at risk). "After three years of extensive research and validation efforts, we were able to produce a treatment planning algorithm that enabled us to investigate the possibilities for using helium ion therapy in children treated with low dose radiation. We would now like to investigate its potential in patients being treated with higher doses, for example, those with brain tumors. The good results that have been achieved so far warrant the verification of the model in order to investigate the real clinical potential of helium ions. In the long term, clinical trials of this therapy will be needed to substantiate the effects of our treatment planning model," said Fuchs. "Particle beam therapy has already advanced care and treatment options for cancer patients. We hope that the use of helium ions may help to bring about further improvements," he ... Read more

Radiotherapy in Addition to Six Months of Hormone …

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According to a recent study’s findings, most men with prostate cancer that is small and restricted to the prostate gland, yet is at risk of growing and spreading, get better if they are treated with radiotherapy, in accordance with androgen deprivation therapy, which lowers their levels of the male hormone, testosterone. The study’s findings, which were presented at the 33rd conference of the European Society for Radiotherapy and Oncology (ESTRO33) in Vienna, are expected to change medical practice and treatment options for prostate cancer. "Although we need longer follow-up to assess the impact on these men's overall survival, these findings need to be taken into account in daily clinical practice. They show that three-dimensional conformal radiotherapy, whether intensity modulated or not, and regardless of the dose level, has to be combined with short-term androgen deprivation therapy in order to obtain a significant decrease in the risk of relapse. Therefore, during multidisciplinary team meetings to discuss a patient's treatment, this combined treatment approach should be one of the options proposed for men with localized prostate cancer that has an intermediate or high risk of growing and spreading,” said professor of radiation oncology at Grenoble University Hospital, Grenoble, France, Michel Bolla. Bolla and his team from 37 centers in 14 countries recruited 819 men to a clinical trial. The patients had early stage prostate tumors, as verified by analyses of biopsy samples and levels of prostate specific antigen (PSA), that were in-between or high risk of metastasizing to other parts of the body. Patients were randomized to undergo either radiotherapy alone or radiotherapy and two injections under the skin of hormone drugs called luteinizing hormone-releasing hormone analogues (LH-RH analogues), which lower levels of testosterone to cause reversible chemical castration. Each drug injection lasted three months; the first was administered on the first day of irradiation and the second three months later. When LH-RH analogues are first administered, testosterone levels go up temporarily before falling to very low levels. This effect is called flare and, in order to prevent it, the patients received an oral anti-androgen (bicalutamide, 50 mg per day) for 15 days prior to the first injection. Physicians could select between one of three irradiation doses, 70, 74 or 78 Grays (Gy). They followed up the men for a mean of 7.2 years and discovered that, regardless of the radiotherapy dose and whether it was intensity modulated or not, the 403 men who had been treated with radiotherapy in conjunction with hormone treatment were considerably less likely to have suffered a relapse and progression of their cancer than the 407 men who had been treated with radiotherapy alone; whereas nine men did not receive the planned treatment. Men undergoing the joint treatment had nearly half the risk (47%) of biochemical progression of their disease as opposed to men treated with radiotherapy alone. In the combined treatment group, 118 men had a biochemical progression of their disease as opposed to 201 men in the radiotherapy only group; biochemical progression was evaluated according to whether or not PSA values had risen above the lowest level plus two nanograms per milli-litre; if it had risen, then this required confirmation in subsequent checks. Five years following treatment, the men in the joint treatment group were doing considerably better. "They had better survival without biochemical progression. Among those receiving the combined treatment, 17.5% had progressed compared to 30.7% receiving radiotherapy alone,” said Bolla. When the researchers examined clinical progression of the disease, whether the cancer had recurred, spread to other parts of the body (proven by biopsies and imaging) or the patients had died, they discovered that five years following their treatment 88.7% of the men in the combined treatment group had not progressed, as opposed to 80.8% of men undergoing radiotherapy only. Over the course of the study, 152 patients have died, of which 25 died from prostate cancer. Side-effects, relating mainly to problems with urination, were accounted for in 5.9% of patients receiving the combined treatment compared to 3.6% of patients on radiotherapy alone. Problems with sexual function were higher in the combined treatment group: 27% versus 19.4%. "These results show that, in men with localized prostate cancer that is at risk of recurring and spreading, the addition of six months of hormonal treatment to radiotherapy improves the time these men survive without their disease progressing. It is important to ensure that the radiation treatment is of the best quality; further clinical research is required to optimize radiation techniques and to find new hormonal treatments,” concluded ... Read more

Non-invasive Imaging used in Monitoring Prostate …

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A University of Colorado Cancer Center study presented at the American Association for Cancer Research (AACR) Annual Meeting 2014 illustrates a ground-breaking method to "manipulate the lipid metabolism in the cancer cell to trick them to use more radiolabeled glucose, the basis of PET scanning," said lead investigator at the CU Cancer Center Department of Pharmacology, and recipient of a 2014 Minority Scholar Award in Cancer Research from AACR, Isabel Schlaepfer, PhD. “Your body's cells have two major interconnected energy sources: the lipid metabolism and the glucose metabolism. Most cancers feed themselves by metabolizing glucose, and thus can be seen in Positron Emission Topography (PET) scans that detect radiolabeled glucose. However, prostate cancers tend to use the lipid metabolism route and so cannot be imaged in this way effectively,” explained Schlaepfer. The current study applied the clinically safe drug etomoxir to obsturct prostate cancer cells' capability to oxidize lipids. With the lipid energy source detached, cells switched to glucose metabolism and both cells and mouse models roughly doubled their uptake of radiolabeled glucose. "Because prostate cancer can be a slow-growing disease, instead of immediate treatment, many men choose active surveillance, they watch and wait. But that requires repeated prostate biopsies. Instead, now we could use this metabolic technique to allow PET imaging to monitor prostate cancer progression without the need for so many biopsies," said Schlaepfer. Schlaepfer also notes that possible therapeutic application of the technique, while instantaneously useful for imaging, it may be that cutting off a prostate cancer cell's capacity to provide itself with energy from lipids could make it difficult for these cells to ... Read more

Risk of Developing Lung Cancer for Breast Cancer …

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According to a recent study, women who undergo radiotherapy treatment for breast cancer have a small but significantly increased risk of developing a primary lung tumor following treatment, to which further research has confirmed that this risk increases with the amount of radiation absorbed by the tissue over time.   The study’s findings were presented by Dr Trine Grantzau, M.D., at the 33rd conference of the European Society for Radiotherapy and Oncology (ESTRO33) in Vienna: "We found that for each Gray delivered to the lung as part of radiotherapy for a breast tumor, the relative risk of developing a subsequent primary lung cancer increased. This increased risk was similar to the reported increased risk of heart disease after radiotherapy for breast cancer.”   "Our findings suggest that any reduction in the dose of radiation to the lung would result in a reduction in the risk of radiation-induced subsequent lung cancers. With the advances in breast cancer treatment and the introduction of breast cancer screening, a growing number of women are becoming long-term survivors, and so we need to have an increased awareness of treatment-induced second cancers and take steps to reduce those risks by using radiotherapy techniques that spare normal tissue as much as possible." Grantzau, who is a doctor in the department of experimental clinical oncology at Aarhus University Hospital , Aarhus, Denmark, and her colleagues examined the occurrence of second primary lung cancers, a new lung cancer and not a secondary tumor that has spread from the original breast cancer, in a group of 23,627 women in Denmark who had been treated with post-operative radiotherapy for early breast cancer between 1982 and 2007. Among this large group of women, 151 (0.6%) were diagnosed with a new lung cancer (the case group) and were matched with 443 women who had not developed lung cancer (the control group). A prior study including the 23,627 irradiated women and, additionally, 22,549 unirradiated breast cancer patients, results showed that the risk of developing a radiation-induced second lung cancer was around one in every 200 women treated with postoperative radiotherapy.  "In the current study, we wanted to see if there was a dose-response correlation for second primary lung cancer after breast cancer irradiation. We further wished to estimate the excess relative risk per delivered Gray to the lung. As smoking is strongly correlated to lung cancer, we also looked into the effect of radiation and smoking," explained Grantzau. The researchers attained radiotherapy records of the previous breast cancer radiation treatment, including the delivered dose, field size and treatment technique, together with the smoking habits for all cases and controls. For the case group they also acquired radiographic images of the lung cancers. With this data they were able to recreate the ways that the women had been treated for the original breast cancer and to determine the amount of radiation that was delivered to the part of the lung where the tumour subsequently developed. They tested the accuracy of their calculated radiation doses on a model, or "phantom", and made the necessary adjustments to take into consideration the higher doses that they found were actually delivered to areas outside the main field of radiation. The average age of the women when they were first diagnosed with breast cancer was 54 (with a range of 34-74) and the average age when a second primary lung cancer was diagnosed was at 68 (range 46-90). Seventy percent of the lung cancers were diagnosed five or more years following radiotherapy for breast cancer, ranging from five to 26 years. The majority (91%) of the lung cancer cases were smokers, whereas 40% of the controls were smokers. The average dose of radiotherapy during breast cancer treatment that had been delivered to the site of the lung tumor was 8.7 Gy, while it was 5.6 Gy to the comparable site in the women who had not developed lung cancer. Even though the absolute risk of developing a second lung cancer is tiny, the researchers demonstrated that among women who had survived breast cancer for at least five years, the relative risk of subsequently developing a lung cancer increased by 8.5% per delivered Gy to the lung. "These results show that the risk of second lung cancer after radiotherapy in early breast cancer patients is associated with the delivered dose to the lung. It is, however, important to place the risk of getting a radiation-induced second lung cancer in a perspective that is balanced with the known benefits of radiotherapy in the adjuvant treatment of breast cancer. Post-operative radiotherapy in breast cancer patients decreases the likelihood of breast cancer recurrence and improves overall survival. The challenge for radiation oncologists is to reduce the delivered dose of radiotherapy in a way that minimizes the dose to the normal tissue to avoid radiation-induced malignancies, without compromising its efficacy in the cancerous breast tissue," said Grantzau.  "Furthermore, clinicians should be continually advising breast cancer patients to quit smoking in order to reduce their risk of developing lung cancer. It's important to emphasize that the risk of getting a tobacco-induced lung cancer is much higher than the risk of getting a radiation-induced second lung cancer,” she added. "This research shows the importance of monitoring the safety of radiotherapy procedures so that we can use the information gained to achieve a good balance between the risks and benefits of a particular treatment. Reducing the radiation dose to normal tissue is always beneficial, and knowing the exact target and the best radiation dose will help to reduce any long-term side-effects of a therapy that research has long shown to be instrumental in helping to save the lives of women with breast cancer. Dr Grantzau's research suggests there is a small increased risk of lung cancer in the years after radiotherapy for breast cancer, particularly in women who smoke. This underlines the importance to women of not smoking, as this increases the risk of a range of diseases. We, as radiation oncologists, will continue to work to monitor and improve the safety and efficacy of our therapies,” noted President of ESTRO and a radiation oncologist at the Policlinico Universitario A. Gemelli, Rome, Italy, Professor Vincenzo ... Read more

Blocking DNA Repair Mechanisms may Improve Radiation …

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Based on a recent study, researchers at the UT Southwestern Medical Center have exhibited in both cancer cell lines and in mice that blocking vital DNA repair mechanisms could improve the overall efficiency of radiation therapy (RT) for often fatal brain tumors known as glioblastomas. RT leads to double-strand breaks in DNA that must be repaired for tumors to keep growing. Scientists have long theorized that if they could find a way to block or obstruct repairs from being made, they then could prevent tumors from developing or at least slow down the growth, thus extending patients' survival. Blocking DNA repair is a particularly appealing tactic for treating glioblastomas, as these tumors are known to be highly resistant to RT. In the study, UT Southwestern researchers demonstrated that the theory does in fact work when placed in the context of glioblastomas. "This work is informative because the findings show that blocking the repair of DNA double-strand breaks could be a viable option for improving radiation therapy of glioblastomas," said Associate Professor of Radiation Oncology in the division of Molecular Radiation Biology at UT Southwestern Dr. Sandeep Burma. Burma’s lab works on understanding basic mechanisms by which DNA breaks are mended, with the main objective of improving cancer therapy with DNA damaging agents. Recent research from his lab has shown how a cell makes the choice between two major trails that are used to fix DNA breaks - non-homologous end joining (NHEJ) and homologous recombination (HR). His lab discovered that enzymes involved in cell division called cyclin-dependent kinases (CDKs) set off HR by phosphorylating a major protein, EXO1. In this scenario, the use of HR is joined to the cell division cycle, which has significant signs for cancer therapeutics. The study’s findings were published in the April issue of Nature Communications. While the study explains how the cell chooses between NHEJ and HR, a translational study from the Burma lab shows how blocking both repair pathways can improve RT of glioblastomas. Researchers in the lab first were able to demonstrate in glioblastoma cell lines with a drug called NVP-BEZ235, which is undergoing clinical trials for other solid tumors, can also hamper two major DNA repair enzymes, DNA-PKcs and ATM, which are vital for NHEJ and HR, respectively. While the drug alone had a limited effect, when joined with RT, the tumor cells could not hastily mend their DNA, stunting their growth. While understandably encouraged by the preliminary findings in cell lines, the researchers remained vigilant due to previous efforts to identify DNA repair inhibitors was unsuccessful when applied in living organisms, mice with glioblastomas. In addition, drugs developed to treat brain tumors must also go through, what's known as the blood-brain-barrier in living organisms. However, the NVP-BEZ235 drug could successfully cross the blood-brain-barrier, and when administered to mice with glioblastomas in accordance with radiation, the tumor growth in mice was stalled and the mice survived for much longer , up to 60 days as opposed to around 10 days with the drug or RT alone. The findings were published in a recent issue of Clinical Cancer Research. "The consequence is striking," remarked Burma. "If you irradiate the tumors, nothing much happens because they grow right through radiation. Give the drug alone, and again, nothing much happens. But when you give the two together, tumor growth is delayed significantly. The drug has a very striking synergistic effect when given with radiation." The combination effect is key because the standard therapy for glioblastomas in humans RT, therefore discovering a drug that enhances overall efficiency of RT could eventually have significant clinical importance. For instance, such drugs may allow lower doses of X-rays and gamma rays to be used for conventional therapies, thus causing fewer side effects. "Radiation is still the mainstay of therapy, so we have to have something that will work with the mainstay of therapy," said Burma. While the findings provide evidence that the notion of "radiosensitizing" glioblastomas works in mice, further research and clinical trials will be needed in order to demonstrate whether the combination of radiation with DNA repair inhibitors would be effective in humans, Burma warned. "Double-strand DNA breaks are a double-edged sword. On one hand, they cause cancer. On the other, we use ionizing radiation and chemotherapy to cause double-strand breaks to treat the disease,” he said.Another recent publication from his lab highlights this apparent paradox by demonstrating how radiation can actually trigger glioblastomas in mouse models. This research, supported by NASA, is focused on understanding cancer risks from particle radiation, the type faced by astronauts on deep-space missions and now being used in cutting-edge cancer therapies such as proton and carbon ion therapy. Burma's lab uses the high-tech facilities and large particle accelerator of the NASA Space Radiation Laboratory at the Brookhaven National Laboratory in New York to produce heavy ions, which can be utilized to irradiate glioblastoma-prone mice to test both the cancer-inducing potential of particle radiation as well as its potential therapeutic use. "Heavy particles cause dense tracks of damage, which are very hard to repair. With gamma or X-rays, which are used in medical therapy, the damage is diffuse and is repaired within a day. If you examine a mouse brain irradiated with heavy particles, the damage is repaired slowly and can last for months," noted Burma “These findings, published March 17 in Oncogene, suggest that glioblastoma risk from heavier particles is much higher compared to that from gamma or X-rays. This study is relevant to the medical field, since ionizing radiation, even low doses from CT scans, have been reported to increase the risk of brain tumors,” he ... Read more

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