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mbaron2015

Radiotracer and Radiopharmaceutical Chemistry - Advancing Nuclear Medicine Through Inno... - 0 views

  • In fact, one can trace the major advances in nuclear medicine directly to research in chemistry.
  • 20 million nuclear medicine procedures using radiopharmaceuticals and imaging instruments are carried out in hospitals in the United States alone each year to diagnose disease and to deliver targeted treatments. These techniques have also been adopted by basic and clinical scientists in dozens of fields (e.g., cardiology, oncology, neurology, psychiatry) for diagnosis and as scientific tools. For example, many pharmaceutical companies are now developing radiopharmaceuticals as biomarkers for new drug targets to facilitate the entry of their new drugs into the practice of health care and to objectively examine drug efficacy at a particular target relative to clinical outcome (Erondu et al. 2006).
  • progress in synthetic organic and inorganic chemistry laid the groundwork for dozens of compounds labeled with positron emitters or single photon emitters, which are now used in many clinical specialties.
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  • FDG-PETTumors and some organs, such as the brain, use glucose as a source of energy. FDG (Sidebar 2.2) is a fluorine-18-labeled derivative of glucose (fluorodeoxyglucose) which is used with positron emission tomography (PET) to provide a map of where glucose is metabolized in the body. Because tumors, as well as the brain and the heart, all use glucose as a source of energy, FDG is widely used in cancer diagnosis and in cardiology, neurology, and psychiatry. FDG is now widely available to hospitals throughout the United States and the world from a network of regional commercial cyclotron/FDG distribution centers (Figure 6.1). With the current large infrastructure of commercial cyclotron/FDG distribution centers, many chemists are developing other highly targeted fluorine-18-labeled compounds to take advantage of this unique network to broaden the use of PET for making health care decisions. The translation of FDG from the chemistry laboratory into a practical clinical tool had its roots in government-supported research in hot atom chemistry (see Chapter 5), cyclotron targetry, biochemistry, synthetic chemistry, nuclear chemistry, and radiochemistry that was integrated with engineering and automation (Fowler and Ido 2002).
  • The first section (6.3.1) summarizes five priority areas with broad public health impact where radiopharmaceuticals could serve as scientific and clinical tools leading to major breakthroughs in health care and basic understanding of human biology. The second section (6.3.2) describes technologies and methods currently being explored that could enable innovations in radiopharmaceutical development and advances in these five priority areas.
  • Cancer Biology and Targeted Radionuclide Therapy.
  • Neuroscience, Neurology and Psychiatry
  • Drug Development.
  • Cardiovascular Disease
  • Genetics and Personalized Medicine.
  • Currently, chemists working in the areas of molecular imaging and targeted radionuclide therapy are focused on designing and synthesizing radiopharmaceuticals with the required bioavailability and specificity to act as true tracers targeting specific cellular elements (e.g., receptors, enzymes, transporters, antigens, etc.) in healthy human subjects and in patients. Goals are to make labeling chemistry occur faster, more efficiently, and at smaller and smaller scales to give labeled compounds of very high specific activity that can act as true tracers.4
  • specific activity is critical for imaging receptors present at a copy number of 1,000 per cell, but less of an issue with receptors such as the epidermal growth factor receptor that are present at a concentration of millions per cell.
  • Two high research priorities that are under investigation are carbon-11 and fluorine-18 chemistry and peptide and antibody labeling.
  • Of particular importance is research on the design and development of radiotracers that are more broadly applicable to common pathophysiological processes, which may be more useful and more readily commercialized (e.g., targets involved in inflammation and infection, angiogenesis, tissue hypoxia, mitochondrial targets, cell signaling targets, and targets associated with diabetes, obesity, metabolic syndrome, or liver disease).
  • For example, MIBG, used initially mainly for assessment of neuroendocrine tumors, is now showing promise in early diagnosis of heart failure, a major health and economic issue in the United States. It is important to keep in mind that any new developments in targeted radionuclide therapy require access to research radionuclides (see Chapters 4 and 5
  • Four major impediments—some of which are elaborated further in other chapters of the report—stand in the way of scientific and medical progress and the competitive edge that the United States has held for more than 50 years:
  • Lack of Support for Radiopharmaceutical R&D.
  • Shortage of Trained Chemists and Physician Scientists
  • Inappropriate Regulatory Requirements
  • Limited Radionuclide Availability
  • 6.5. RECOMMENDATIONSThe committee formulated two recommendations to meet the future needs for radiopharmaceutical development for the diagnosis and treatment of human disease and to overcome national impediments to their entry into the practice of health care. RECOMMENDATION 1 : Enhance the federal commitment to nuclear medicine research. Given the somewhat different orientations of the DOE and the National Institutes of Health (NIH) toward nuclear medicine research, the two agencies should find some cooperative mechanism to support radionuclide production and distribution; basic research in radio nuclide production, nuclear imaging, radiopharmaceutical/radiotracer and therapy development; and the transfer of these technologies into routine clinical use. Implementation Action 1A1: A national nuclear medicine research program should be coordinated by the DOE and NIH, with the former emphasizing the general development of technology and the latter disease-specific applications. Implementation Action 1A2: In developing their strategic plan, the agencies should avail themselves of advice from a broad range of authorities in academia, national laboratories and industry; these authorities should include experts in physics, engineering, chemistry, radiopharmaceutical science, commercial development, regulatory affairs, clinical trials, and radiation biology. RECOMMENDATION 2: Encourage interdisciplinary collaboration. DOE-OBER should support collaborations between basic chemistry and physics laboratories, as well as multi-disciplinary centers focused on nuclear medicine technology development and application, to stimulate the flow of new ideas for the development of next-generation radiopharmaceuticals and imaging instrumentation.
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    NuclearMedicine, Radiotracers
gabb_03

What is targeted therapy? | American Cancer Society - 0 views

  • What is targeted therapy?
  • As researchers have learned more about the gene changes in cells that cause cancer, they have been able to develop drugs that target these changes. Treatment with these drugs is often called targeted therapy. Targeted therapy drugs, like any drug used to treat cancer, are technically considered “chemotherapy.” But targeted therapy drugs do not work in the same ways as standard chemotherapy drugs. They are often able to attack cancer cells while doing less damage to normal cells by going after the cancer cells’ inner workings—the programming that sets them apart from normal, healthy cells. These drugs tend to have different (and often less severe) side effects than standard chemotherapy drugs. Targeted therapies are used to treat many kinds of diseases. Here we will focus on their use to treat cancer. In the past, only a few cancers could be treated with targeted therapy, but now these drugs are used to treat many different types of cancer. Targeted therapies are a major focus of cancer research today. Many future advances in cancer treatment will probably come from this field.
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    what is targeted therapy
gabb_03

How does targeted therapy work? | The American Cancer Society - 0 views

  • How does targeted therapy work?
  • Targeted therapy is used to keep cancer from growing and spreading. To become cancer cells, normal cells go through a process called carcinogenesis (car-sin-oh-JEN-eh-sis). Cancer cells may then grow into tumors or reproduce throughout a body system, like blood cancers do. Scientists have learned a lot about the molecules that are part of this process and the signals a cell gets to keep this process going. Targeted therapy disrupts this process. The drugs target certain parts of the cell and the signals that are needed for a cancer to develop and keep growing. These drugs are often grouped by how they work or what part of the cell they target.
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    how targeted therapy works
gabb_03

Types of stem cell transplants for treating cancer - 0 views

  • Types of stem cell transplants for treating cancer
  • In a typical stem cell transplant for cancer very high doses of chemo are used, often along with radiation therapy, to try to destroy all the cancer cells. This treatment also kills the stem cells in the bone marrow. Soon after treatment, stem cells are given to replace those that were destroyed. These stem cells are given into a vein, much like a blood transfusion. Over time they settle in the bone marrow and begin to grow and make healthy blood cells. This process is called engraftment
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    stem cell transplant
vikram1997

The Iran Case: Addressing Why Countries Want Nuclear Weapons | Arms Control Association - 0 views

  • Iran’s possible development of nuclear weapons has now come front and center in U.S. foreign policy, as well as in consideration overall of preventing the spread of weapons of mass destruction. It has assumed particular importance because of its potential to reshape the security and politics of an already turbulent and critical region. In the middle of the Middle East, such a capability would at the very least lead to a basic reassessment by countries near and far of a full range of security, political, and other issues. As the saga of a widely presumed but not admitted Iranian nuclear weapons program unfolds, with its on-again, off-again character, something else is happening: the need for a reassessment of nonproliferation—both how to prevent proliferation and what to do if prevention fails. There is dwindling confidence that a country bent on developing nuclear weapons can forever be prevented from doing so by the now-traditional technological safeguards. In particular, it appears less possible to block the indigenous development of either plutonium or highly enriched uranium, the essential materials for nuclear weapons. Talent and knowledge are not a constraint, and access to fissionable materials may be an ever decreasing one to a country’s nuclear ambitions.
  • Most importantly, we need to ask why Iran or any other country would want to acquire nuclear weapons in the first place. Then we must see whether and, within appropriate limits, how the country in question can be dissuaded from developing those weapons. The recent Iranian pause in its enrichment activities allows the West, particularly the United States, the opportunity to explore this possibility before either resorting to military force or merely fretting that Iran is on the path to the destabilizing development of nuclear weapons.
  • To be sure, the United States and its allies have reasons to be bothered about Iran’s behavior, such as its support for terrorist groups such as Hezbollah. But Iran also has reason to be concerned about its security. Its principal antagonist, the United States, for many years not only practiced its dual containment policy against Iran (and Iraq) but also supported expatriate groups bent on overthrowing the regime in Tehran, including through violent means. Regime change in Tehran has been a recurrent theme in U.S. policy as it has been consistently in the policy of Israel, which also strongly supported the U.S. invasion of Iraq. Iran was accorded a place in the U.S. “axis of evil” and is now even more vulnerable than only a few years ago to nearby U.S. military power. However legitimate these U.S. policies and actions may be, along with the animosity toward Iran of some key regional countries, they do provide an objective basis for Iranian security concerns.
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  • One frequently expressed concern is that Iran would consider its nuclear weapons capability to be held in trust for the Islamic world or would give custody of a weapon to someone else, perhaps even a terrorist group. Such an outcome is theoretically possible, but not very probable. With one notable and quickly regretted exception—Soviet transfer of some U-235 to China in the 1950s—no country with bomb-making fissionable materials has knowingly transferred them to anyone else.
  • More useful to consider is the role that nuclear weapons would play in shaping post-nuclear Iran’s relationships with its neighbors—friends and foes. When all is said and done, such weapons would have little military utility except for deterrence. This would operate at four levels: to deter a conventional attack from a non-nuclear regional power; to deter an openly nuclear regional state—today only including Pakistan and India; to deter Israel; or to deter a major external power, notably the United States but, in theory at least, also including Russia.
  • The first case is obvious: no country with just conventional arms is likely to try the patience of a nuclear power. But in the other three cases, “proportional deterrence” would come into play. Originally developed by France, this doctrine holds that a relatively less-capable nuclear power such as Iran can deter a much stronger nuclear power (the United States, Russia, Pakistan, India, Israel) if it is viewed as able and willing to destroy “value targets” in the attacking nation even while it is being obliterated. This complex doctrine can be summarized as the “death throes” of a country under nuclear or even extreme conventional attack
  • Such a doctrine depends on the potential attacker such as the United States or Israel calculating that the targets in its own country that would be destroyed in retaliation would be more “valuable” to it than the benefit (military or political) of annihilating Iran. Of course, proportional deterrence can only succeed if the potential retaliation is credible, hence the need for a survivable second-strike capability. The threat of retaliation must not be so precise that the original attacking nation can calculate with precision whether the game is worth the candle (uncertainty principle). There should also be a margin for the leadership of the attacked nation to over-respond (irrationality principle). All these ideas were worked out in detail during the Cold War.
  • Nevertheless, as with all issues involving nuclear weapons, psychology and politics are critical elements. Indeed, if they were not—if the world had not witnessed Hiroshima and Nagasaki—we would likely have seen much more proliferation over the past 60 years, as many analysts long predicted, or even the further use of nuclear weapons in war.
  • As things now stand in the Middle East and are likely to stand for the foreseeable future, a nuclear-armed Iran would change the politics and the security of the region dramatically in terms of perceptions. The point need hardly be spelled out. Further, even if regional and outside countries could in time adjust to a nuclear-armed Iran, judged from today, it is highly unlikely that Iran would be permitted to gain such a capability. The United States, Israel, or perhaps some third-party would likely use whatever means necessary to prevent Iran from ever getting into that position.
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    What happens if Iran gets bomb?
ferriska2015

Nuclear Ventriculography: Purpose, Procedure & Risks - 1 views

  • You will be asked to walk or run on a treadmill until a target heart rate has been reached.
  • sive test with very low risk. The test exposes you to a small amount of radiation from th
  • lower dose of radiation than an occurs from an X-ray
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  • noninvasive test with very low risk
  • electrocardiogram
  • (ECG), a test that detects electrical activity in the heart
  • different intervals in the heart’s cycle
  • an (MUGA) or radionuclide ventriculography (RNV).
  • , which shows the strength of the heart’s contraction
  • determine the location of a pumping problem in your heart chambers.
  • gain information about or diagnose other conditions.
  • avoid caffeine for 48 hours before the test.
  • The nuclear substance used during the test may be passed to the fetus or excreted in breast milk.
  • metal plate or screw in your body, inform your doctor and the technician.
  • remove all metal from your body
  • hospital gown so the technican has access to your ches
  • metal plate or screw in your body
  • It is normal to feel flushed or chilled as the radioactive tracer makes its way into your body
  • The technician will apply electrodes to different areas on your chest for the electrocardiogram.
  • special type of camera and begin taking pictures.
  • change positions in order to get certain images
  • exercise stress test in
  • heart performs during activity
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