Harmfulness of Non-Ionizing and Ionizing Radiation - Research Paper Example

Radiation al Affiliation) Introduction to radiation Radiation is energy that has a particular source and travels through space. It has the ability to penetrate various materials whereas non ionizing radiation is potentially harmless; ionizing radiation is dangerous because it produces charged particles (ions) in matter. Types of Radiation There are two types of radiation i.e. solar and ionizing radiation. Solar radiation is largely optical radiation which includes ultraviolet (UV), visible (light) and infrared radiation, although ionizing radiation and radio-frequency radiation are also present in the electromagnetic spectrum. UV radiation comprises only about 5% of total solar radiation but is biologically important, as exposure to this part of the spectrum might lead to damage of cellular DNA and thereby increase the risk for skin cancer. Descriptive epidemiological data strongly indicate a link between solar radiation and malignant melanoma. Studies of have suggested that the risk for melanoma is related to exposure to solar rays at the place of residence in early life. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers (Edmund Kennet Karuth, 2011). Ionizing radiation is classified as either particulate or electromagnetic. Charged particles such as electrons (beta minus particles), protons, alpha particles (helium nuclei) and heavy ions can ionize directly. Uncharged particles, notably neutrons, interact with the nuclei of the atoms through which they pass and give up their energy to produce recoil protons, alpha particles and heavier nuclear fragments, which go on to produce ionizations. The important characteristic of ionizing radiation is the local release of large amounts of energy, sufficient to break strong chemical bounds that are biologically important. Electromagnetic ionizing radiation consists of X and gamma rays, which give up part or all of their energy to the orbital electrons of the atoms through which they pass, producing fast recoil electrons that have sufficient energy to be ionizing. X and gamma radiation differ only in the way in which they are produced, gamma being produced by the decay of radioactive isotopes and almost all X rays being made by electrical machines. How Radiation initiated or formed. For radiation initiated or formed, there is a process. To begin with, we classify radiation as either particulate or electromagnetic. Charged particles such as electrons (beta minus particles), protons, alpha particles (helium nuclei) and heavy ions can ionize directly. Uncharged particles, notably neutrons, interact with the nuclei of the atoms through which they pass and give up their energy to produce recoil protons, alpha particles and heavier nuclear fragments, which go on to produce ionizations. The important characteristic of ionizing radiation is the local release of large amounts of energy, sufficient to break strong chemical bounds that are biologically important. Electromagnetic ionizing radiation consists of X and gamma rays, which give up part all of their energy to the orbital electrons of the atoms through which they pass, producing fast recoil electrons that have sufficient energy to be ionizing (Gunderson, 2012). X and gamma radiation differ only in the way in which they are produced, gamma being produced by the decay of radioactive isotopes and almost all X rays being made by electrical machines weapons of mass destruction and subsequently in the generation of electricity by nuclear reactors. Nevertheless, natural sources still make the greatest contribution to the exposure of most of the population of the earth to radiation. The sources of natural and man-made ionizing radiation which includes the major characteristics of the respective sources: internal and external irradiation and particulate and electro-magnetic radiation. The natural radionuclides of significance in soil, air, water and living organisms include potassium-40 (40K) and the isotopes of the uranium (238U) and thorium (232Th) decay chains. Internal irradiation can occur after inhalation (radon) or ingestion (food), and external irradiation can occur from gamma radiation; cosmic radiation contributes to external irradiation Ionizing radiation used in diagnostic and therapeutic medicine represents the predominant source of manmade radiation. Major releases of manmade radionuclides to the environment resulted from the atomic bomb explosions over Hiroshima and Nagasaki in 1945, atmospheric atomic weapon testing during the 1960s and at the accident at Chernobyl in 1986. Still another man-made source is occupational exposure. How dangerous is Radiation and how it measured. Radiation is classified as being dangerous when people expose themselves to higher quantity. People need to know who radiation is first measured. The Absorbed dose is measured in Gy (Gray) and is quantified per unit mass. The energy deposition of 1J/kg is similar to 1 Gy. Not every radiation produces a similar biological effect, the dose equivalent is widely used compared to absorbed dose. We express radiation doses in medical imaging as milliSieverts (mSv). The average yearly background radiation dose (primarily from radon gas in a home) is around 5mSv Medical imaging procedures with x-ray, computed tomography (CT) and nuclear isotopes use ionizing radiation. On the other hand, ultrasound and magnetic resonance imaging (MRI) do not. When we expose biological tissues to radiation, the effects are related to the type of radiation and the amount absorbed. An average exposure from natural background radiation in the United States for an individual is 3–5 mSv/year. Also, a small amount of radiation exposure occurs with tobacco, the domestic water supply, building materials, and to a lesser extent televisions, and computer screens. The usual radiation dose of a chest radiograph is 0.02–0.1 mSv. These medical studies contribute up to 20% of the total annual radiation exposure to the population of the United States. Although radiological procedures are low risk for future cancers, we should be keep in mind potential risk versus benefit when ordering any radiological procedure involving ionizing radiation. Reducing radiation to a minimum for a particular procedure and use of other imaging modalities that do not use ionizing radiation (stress echocardiography or MRI) should be considered (Lin, 2011). Radiation dose from medical imaging has come under recent scrutiny in the medical and lay press. This is the result of recent articles on the increased cancer risks associated with CT as well as resent cases o excess radiation exposure from CT brain perfusion scans. Berrington de Gonzalez et al estimated that 29,000 future cancers could be related to CT performed I n the United States in 2007. This is comparable to the resent estimates of 1.5% to 2.0% by Brenner and Hall. These reviews provide a practical overview of the excess cancer risks related to radiation from imaging and suggest how clinicians can play a part in reducing these risks for their patients. How radiation can cause Cancer and treat it. Radiation can cause cancer and treat it as well. The relevant biological effect of the x-ray and gamma rays is secondary to ionization. Ionization of water molecules can create hydroxyl radicals that may interact with DNA to cause strand breaks or base damage; we can DNA ionize DNA directly. Although most radiation-induced damage is rapidly repaired, disrepair can lead to point mutations, chromosome translocations, and gene fusions that are linked to cancer induction. This effect typically to occurs at any level of radiation exposure, with the likelihood increasing as the dose increases. The typical lag period between radiation exposure and cancer diagnosis is at least five years, and in most cases, the lag period may be 1 or 2 decades or longer. Majority of radiation evidence on the radiation-induced risk arises from bomb survivors of Japanese Atomic, populations that are medically exposed, occupational exposed groud, and groups that are environmentally exposed. From the four groups, Japanese atomic bomb survivors is ranked to be the most robust. Radiation induced risk is more controversial at doses between 10 and 100mSv , the dose range relevant to medical imaging and in particular CT. A single CT of the abdomen may have a dose of around 10mSv, and patients undergoing multiple CTs or one multiple CT falls within the dose range. The examination of nuclear cardiology examinations also is one of the dose range. Some investigators suggest that direct epidemiological data from atomic bomb survivor and nuclear industry workers indicate increased cancer risk in this dosage range, whereas others contend that no data supports an increased cancer risk below 100mSv and that neutron irradiation and other co-founding factors may explain the putative carcinogenic effect at low doses seen in atomic bomb survivors Below 10mSv, which is a dose range relevant to radiography and some nuclear medicine and CT studies, no direct epidemiological studies data support increased cancer risk. However, this does not mean that this risk is not present, as even large epidemiological studies would not have the statistical power to detect increased risk, if present, at a low radiation dose. Given the paucity of direct epidemical data, the cancer risk from low dose radiation have been assessed using model based on the linear , no threshold theory .The theory holds that excess cancer risk related to low dose radiation are directly proportional to the dose. We use this model to extrapolate excess cancer risk at low doses from the known risk at higher doses (Mclean, 2011). However, some people do not have trust on the validity of the linear no-threshold literature and assume that under certain level, the carcinogenesis stops becoming a concern. Despite some of the controversy over the risk of cancer, the linear theory literature is used since it is an alternative technique to access the potential risk of dose radiation. In addition, epidemiological data directly suggests increase cancer risk in the 10mSv to 100mSv range, which is relevant to nuclear cardiac and many CT studies. A widely used figure is a 5% excess risk of death from cancer with a 1Sv(1000mSv)dose. We extrapolate this linearly for lower doses. A useful way to understand radiation doses from diagnostic examinations is to compare them to the average natural background radiation (3mSv per year). We sometimes use radiation doses as entrance skin doses, and skin doses, for conventional radiography: a dose estimate at 1 point in the beam allows estimate of organ doses and effective dose. To assess the health risks of low doses of ionizing radiation, the International Commission on Radiation Protection uses the concept of effective dose. Effective dose is not measured but is a theoretical dose based on the organs exposed by the applied radiation multiplied by the tissue-weighting factors. This dose can change over time because the tissue weighting factors can change with new data and continuing analysis of existing data. We make dose estimates for an adult of typical size and may vary subsequently depending on patient size and imaging technique. We use effective dose estimates to assess the general level of radiation dose from an imaging study. Effective dose estimates for individual patients are subject to a substantial level of uncertainty. Computed tomography and some nuclear medicine studies are associated with far higher radiation doses than radiography. In particular, the radiation doses of some CT and nuclear medicine studies fall in the range shown by direct epidemiological evidence to be associated with increased cancer risk. It is important to note that recent evidence suggested that radiation doses from CT might be highly variable between institutions. Radiography doses fall in the range for which no epidemiological evidence exists of increased cancer risk (but a very small increased cancer risk may be present if the no- threshold hypothesis is correct). Radiography of the spine and abdomen has substantially higher radiation doses than radiography of the chest and extremities (Watson, 2010). .Another useful way to express radiation risk is to compare it to common activities in daily life. For example, radiation doses from 0.1 to 1.0mSv carry an additional risk of death from cancer comparable to the risk of death associated with a flight of 4500 miles, whereas doses in the range of 1 to 10 mSvs have a higher risk, comparable to driving 2000miles. Radiation safety With all this harm potentially caused by radiation, several organizations have taken measures to ensure radiation safety. For instance, the US Food and Drug Administration (FDA) has launched an initiative to reduce unnecessary radiation as a result of medical imaging “The amount of radiation Americans are exposed to from medical imaging has dramatically increased over the past 20 years,” said Jeffrey Shuren, MD,JD, director of the FDA Centre for Devices and Radiological Health. “The goal of the FDA’s initiative is to support the benefits associated with medical imaging while minimizing the risks.”1 As a result of this initiative, health care providers should expect to receive information about radiation safety that promotes awareness of best practices for the use of medical imaging devices, supplies information regarding clinical decision-making, and increases awareness for the public regarding potential risks In promoting radiation safety, health care providers and surgical staff members should develop and implement procedures and protocols that emphasize risk reduction strategies to minimize radiation exposure and enhance patient safety. Protocols should be developed as a collaboration among preoperative team members, the facility’s radiation safety staff, and representatives from the radiology department. AORN recommends that ‘policies and procedures should include, but [not be] limited to, establishing authority, responsibility, and accountability for radiation safety; identifying measures for protecting patients and personnel from unnecessary exposure to ionizing radiation; developing procedures for handling and disposing of body fluids and tissue that may be radioactive; ensuring that appropriate personnel wear radiation monitoring devices; and scheduling radiographic testing of leaded protective devices’ Practice settings in which the potential exists for radiological exposure include the OR, ambulatory surgery centre, physician’s office, cardiac catheterization suite, endoscopy suite ,radiology department, and interventional radiology department, and other sites where invasive or surgical procedures may require radiological study. Following are some risk reduction strategies that focus on patient safety (Winther, 1997). Knowledge of the Radiation Safety Program-Preoperative nursing personnel should be aware of and able to implement a radiation safety program that is consistent with state regulations that govern the use of radiation-producing equipment and material. Regulatory agencies provide valuable patient safety information and risk reduction strategies to help prevent errors. Consider the Patient’s History of Radiation-For any procedure, the health care provider should consider the patient’s history of radiation exposure. Patients also should participate in their care by keeping records of radiation exposure and making them available to health care providers when a new study is ordered or a procedure is planned. Doing so may help to eliminate repetition of unnecessary studies and minimize excessive radiation exposure. Determine Whether the Patient is Pregnant-When anticipate use of radiation, the ordering provider should assess female patients to determine whether they are pregnant. If a patient is pregnant and a procedure that requires radiation exposure is necessary, then the surgeon must inform the patient of the risk to the developing foetus and discuss special precautions determined by facility policy that minimizes exposure to both the patient and the foetus. Lead Shielding-Facility policy and procedure will specify the individual responsible for assessing and applying lead shielding when appropriate to protect tissue sensitive to radiation (ie, eye, thyroid, ovaries, testes).We should base the specific policy and procedure on the patient and the study to be conducted. Finally, patient and staff member safety is a priority and a concern for every preoperative team member. Radiation safety requires policy and procedures based on evidence, which involves educational updates for the preoperative team on current issues and concerns, and staff member training on risk-reduction measures. The preoperative team is responsible for understanding the various radiological modalities, the risks and benefits, and risk-reduction strategies for operating equipment safely. . Bibliography Edmund Kennet Karuth, F. T. (2011). Echocardiography. Risk of Low-Level Ionizing Radiation from Medical, 593-595. Gunderson, L. L. (2012). Clinical radiation oncology. Radiation, 110-116. Lin, E. C. (2011). Radiation Risk from Medical Imaging. Concise Review for Clinicians, 1142-1146. Mclean, L. (2011). Mobile Phone Radiation. Is it Safe. ACNEM, 16-18. Watson, D. S. (2010). Patient Safety. Patient Safety First, 233-236. Winther, J. E. (1997). Radiation. APMIS Suppl., 83-89. Read More