Physics of Atom PDF

PHYSICS OF ATOM Milad Hatamian PhD of Medical Physics Department of Medical physics Radiobiology, Radioprotection and Radiotherapy  THE ATOM STRUCTURE An atom is the smallest unit of matter that retains all of the chemical properties of an element. In Bohr’s theory the poten...

PHYSICS OF ATOM Milad Hatamian PhD of Medical Physics Department of Medical physics Radiobiology, Radioprotection and Radiotherapy  THE ATOM STRUCTURE An atom is the smallest unit of matter that retains all of the chemical properties of an element. In Bohr’s theory the potential energy of an electron at a position is 2 1 BE   K Ze 2 r 3  AN ELECTROMAGNETIC WAVE When an electron jumps from higher energy state to the lower energy state, it emits radiations in form of photons. The energy of a photon emitted or absorbed is given by using Planck's relation. The energy of the photon (emitted or absorbed) is given as : c 12.4 E (keV )  h  h    (A ) 4 AN ELECTROMAGNETIC WAVE 5  Life is short appreciate each day like it was your last 6  What is Radiobiology?  Radiobiology is the study of the effects of radiation on biological systems.  How does radiation damage cells?  Radiation damages cells by causing breaks within the structure of DNA. There are two primary mechanisms by which this damage occurs.  Direct Radiation Damage  Radiation impacts sufficient energy to DNA bonds to directly cause breaks.  Indirect Radiation Damage  Indirect damage occurs when radiation interactions outside of the DNA to produce free radicals which in turn damage DNA.  A free radical is an atom or molecule carrying an unpaired electron in an outer shell.  Hydroxide (OH-) is the most common free radical produced by radiation within the body. Hydroxide is produced in the body through interaction of water (H2O). 7  Ionizing radiation  Ionizing radiation is a type of energy released by atoms that travels in the form of electromagnetic waves (gamma or X-rays) or particles (neutrons, beta or alpha). The spontaneous disintegration of atoms is called radioactivity, and the excess energy emitted is a form of ionizing radiation. Unstable elements which disintegrate and emit ionizing radiation are called radionuclides.  All radionuclides are uniquely identified by the type of radiation they emit, the energy of the radiation, and their half-life.  The activity — used as a measure of the amount of a radionuclide present — is expressed in a unit called the becquerel (Bq): one becquerel is one disintegration per second. The half-life is the time required for the activity of a radionuclide to decrease by decay to half of its initial value. The half-life of a radioactive element is the time that it takes for one half of its atoms to disintegrate. This can range from a mere fraction of a second to millions of years (e.g. iodine-131 has a half-life of 8 days while carbon-14 has a half-life of 5730 years). 8  Sources and types of ionizing radiation  People are exposed to natural radiation sources as well as human-made sources on a daily basis. Natural radiation comes from many sources including more than 60 naturally-occurring radioactive materials found in soil, water and air. Radon, a naturally-occurring gas, emanates from rock and soil and is the main source of natural radiation. Every day, people inhale and ingest radionuclides from air, food and water.  People are also exposed to natural radiation from cosmic rays, particularly at high altitude. On average, 80% of the annual dose of background radiation that a person receives is due to naturally occurring terrestrial and cosmic radiation sources. Background radiation levels vary geographically due to geological differences. Exposure in certain areas can be more than 200 times higher than the global average.  Exposure to radiation also comes from human-made sources ranging from nuclear power generation to medical uses of radiation for diagnosis or treatment. Today, the most common human-made sources of ionizing radiation are medical devices, including x-ray machines and Computed Tomography (CT) scanners. 9  Exposure to ionizing radiation  People can be exposed to ionizing radiation under different circumstances, at home or in public places (public exposures), at their workplaces (occupational exposures), or in a medical setting (medical exposures).  Exposure to radiation may occur through internal or external pathways.  Internal exposure to ionizing radiation occurs when a radionuclide is inhaled, ingested or otherwise enters into the bloodstream (for example, by injection or through wounds). Internal exposure stops when the radionuclide is eliminated from the body, either spontaneously (such as through excreta) or as a result of a treatment.  External exposure may occur when airborne radioactive material (such as dust, liquid, or aerosols) is deposited on skin or clothes. This type of radioactive material can often be removed from the body by washing. Exposure to ionizing radiation can also result from irradiation from an external source, such as medical radiation exposure from x-rays. External irradiation stops when the radiation source is shielded or when the person moves outside the radiation field. 10  Exposure to ionizing radiation  Exposure to ionizing radiation can be classified for radiation protection purposes into three exposure situations, i.e. planned, existing and emergency situations. Planned exposure situations result from the deliberate introduction and operation of radiation sources with specific purposes, as is the case with the medical use of radiation for diagnosis or treatment of patients, or the use of radiation in industry or research. Existing exposure occurs where radiation already exists and a decision on control must be taken – for example, exposure to radon in homes or workplaces or exposure to natural background radiation from the environment. Emergency exposure situations result from unexpected events requiring prompt response, such as nuclear accidents or malicious acts.  Medical use of radiation accounts for 98 % of the population dose contribution from all human-made sources, and represents 20% of the total population exposure. Annually worldwide, more than 4200 million diagnostic radiology examinations are performed, 40 million nuclear medicine procedures are carried out, and 8.5 million radiotherapy treatments are given. 11  Health effects of ionizing radiation  Radiation damage to tissue and/or organs depends on the dose of radiation received, or the absorbed dose which is expressed in a unit called the gray (Gy). The potential damage from an absorbed dose depends on the type of radiation and the sensitivity of the different tissues and organs.  The effective dose is used to measure ionizing radiation in terms of the potential for causing harm. The sievert (Sv) is the unit of effective dose that takes into account the type of radiation and sensitivity of tissues and organs. It is a way to measure ionizing radiation in terms of the potential for causing harm. In addition to the amount of radiation (dose), the rate at which the dose is delivered (dose rate), described in microsieverts per hour (μSv/hour) or millisievert per year (mSv/year), is an important parameter.  Beyond certain thresholds, radiation can impair the functioning of tissues and/or organs and can produce acute effects such as skin redness, hair loss, radiation burns, or acute radiation syndrome. These effects are more severe at higher doses and higher dose rates. For instance, the dose threshold for acute radiation syndrome is about 1 Sv (1000 mSv). 12  Health effects of ionizing radiation  If the radiation dose is low and/or it is delivered over a long period of time (low dose rate), the risk is substantially low because there is a greater likelihood of repairing the damage. There is still a risk of long-term effects such as cataract or cancer, however, that may appear years or even decades later. Effects of this type will not always occur, but their likelihood is proportional to the radiation dose. This risk is higher for children and adolescents as they are significantly more sensitive to radiation exposure than adults.  Epidemiological studies on populations exposed to radiation, such as the survivors of the atomic bombings or radiotherapy patients, showed a significant increase of cancer risk at doses above 100 mSv. More recently, some epidemiological studies in individuals exposed to medical exposure during childhood (paediatric CT) have suggested that cancer risk may increase even at lower doses (between 50-100 mSv).  Prenatal exposure to ionizing radiation may induce brain damage in foetuses following an acute dose exceeding 100 mSv between weeks 8-15 of pregnancy and 200 mSv between weeks 16-25 of pregnancy. Before week 8 or after week 25 of pregnancy human studies have not shown radiation risk to fetal brain development. Epidemiological studies indicate that the cancer risk after fetal exposure to radiation is similar to the risk after exposure in early childhood. 13  Key facts  Ionizing radiation is a type of energy released by atoms in the form of electromagnetic waves or particles.  People are exposed to natural sources of ionizing radiation, such as in soil, water, and vegetation, as well as in human-made sources, such as x-rays in medical devices.  Ionizing radiation has many beneficial applications, including uses in medicine, industry, agriculture and research.  As the use of ionizing radiation increases, so does the potential for health hazards if not properly used or contained.  Acute health effects such as skin burns or acute radiation syndrome can occur when doses of radiation exceed very high levels.  Low doses of ionizing radiation can increase the risk of longer term effects such as cancer. 14  LET  Linear energy transfer (LET) is the average (radiation) energy deposited per unit path length along the track of an ionizing particle. Its units are keV/μm.  Linear energy transfer describes the energy deposition density of a particular type of radiation, which largely determines the biological consequence of radiation exposure.  High linear energy transfer radiations: linear energy transfer 3-200 keV/μm- commonly mediated by:  α-particles  protons  neutrons  greater density of interactions at cellular level  more likely, than low linear energy transfer, to produce biological damage in a given volume of tissue  Low linear energy transfer radiations: linear energy transfer 0.2-3 keV/μm-commonly mediated by:  electrons  positrons  gamma rays  x-rays  less likely than high linear energy transfer to produce tissue damage in the same volume of tissue 15  Radiation Dose  Absorbed dose is a measure of the energy deposited in a medium by ionizing radiation. It is equal to the energy deposited per unit mass of a medium, and so has the unit joules (J) per kilogram (kg), with the adopted name of gray (Gy) where 1 Gy = 1 J.kg-1.  The absorbed dose is not a good indicator of the likely biological effect. 1 Gy of alpha radiation would be much more biologically damaging than 1 Gy of photon radiation for example. Appropriate weighting factors can be applied reflecting the different relative biological effects to find the equivalent dose.  The risk of stochastic effects due to radiation exposure for the population can be quantified using the effective dose, which is a weighted average of the equivalent dose to each organ depending upon its radiosensitivity.  Other related values include:  absorbed dose rate (Gy.s-1): amount of radiation delivered over a time period  rad: the international unit of absorbed dose pre-1980 where 1 Gy = 100 rad  kerma (Gy): kinetic energy released per unit mass 16  Weighting factor  The radiation weighting factor (WR) is a dimensionless constant that accounts for the relative biological effectiveness (RBE) of various types of ionizing radiation.  The radiation weighting factor is used to calculate the equivalent dose (HT) by the following equation:  Absorbed dose (DT) x radiation weighting factor (WR) = equivalent dose (HT)  The International Commission on Radiological Protection (ICRP) has published the latest set of numerical values of radiation weighting factors as below (as of 2007):  WR = 1: photons, electrons  WR = 2: protons  WR = 20: alpha particles, fission fragments, heavy ions  WR = variable: neutrons (determined by complex equations) 17  Equivalent Dose  Equivalent dose (symbol HT) is a measure of the radiation dose to tissue where an attempt has been made to allow for the different relative biological effects of different types of ionizing radiation. In quantitative terms, equivalent dose is less fundamental than absorbed dose, but it is more biologically significant. Equivalent dose is measured using the Sievert but rem is still commonly used  (1 Sv = 100 rem).  Equivalent dose= absorbed dose*WR  Equivalent dose (HT) is calculated by multiplying the absorbed dose to the organ or tissue (DT) with the radiation weighting factor, WR. This factor is dependent on the type and energy of the incident radiation. The value of wR is 1 for x-rays, gamma rays and beta particles, but higher for protons (WR = 5), neutrons (WR is between 5 and 20 depending on energy), alpha particles and heavy fragments (WR = 20) etc. 18  Permissible dose  Permissible dose  occupational exposure: 20 mSv/year (effective dose)  lens of eye: 20 mSv/year (updated in ICRP 2011 - previously 150 mSv/year)  skin (average dose over 1 cm2 of the most highly irradiated area of skin): 500 mSv/year  hands and feet: 500 mSv/year  females of reproductive capacity: 13 mSv/any three month period (additional restriction is to protect a recently conceived foetus within a female who may be unaware of her pregnancy)  fetus (during declared term of pregnancy): 1 mSv/over declared term of pregnancy 19  Genetic Effects of Radiation  When ionizing radiation causes DNA damage (mutations) in male or female reproductive (“germ”) cells, that damage can be transmitted to the next generation. This is in contrast to mutations in somatic cells, which are not transmitted.  Detection of human germ cell mutations is difficult, especially at low doses. While high doses in experimental animals can cause various disorders in offspring (birth defects, chromosome aberrations, etc.). 20  Radiation effects on fetal  Due to rapid cell proliferation, migration and differentiation, the developing embryo is extremely radiosensitive. Additionally, as with ionizing radiation exposure in children compared to adults; the potential time available for stochastic effects to manifest is typically greater.  The response after exposure to ionizing radiation depends on:  total dose, dose rate and radiation quality  stage of development at the time of exposure  Radiation effects related to the stage of development  Radiation risks to the fetus are dependent on the developmental period the embryo/fetus is at upon exposure. The risks are most significant during organogenesis and the early fetal stage. 21  Radiation effects on fetal  Pre-conception pre-conception radiation of either parents' gonads has not been shown to result in an increased risk of malformations or cancer in children  Pre-implantation stage fertilisation to day 9 "all-or nothing‟ phenomenon, i.e. either intrauterine death and resorption (usually undetected) or normal fetal risk threshold dose ≈ 100 mSv  Organogenesis stage 3rd-8th week after conception risk of fetal death decreases substantially, whereas the risk of congenital malformation coincides with the peak developmental periods of various organ systems growth retardation can also occur if irradiated >4 weeks gestation deterministic effect with a probable threshold of >100 mSv 22  Radiation effects on fetal  Fetal growth stage begins after the end of organogenesis (>8 weeks) and continues until term poses little risk of congenital malformations, but CNS abnormalities (reduced intelligence quotient (IQ) is the main risk at 8-25 weeks) 2, growth retardation and risk of childhood cancer (main risk after 25 weeks) can be significant  Congenital malformations may occur if the embryo irradiated during organogenesis (3rd-8th week), especially at 20-40 days greatest probability of malformation in a specific organ system (critical period) exists when the radiation exposure is received during the period of peak differentiation of that system response of each organ system depends on gestational age, radiation quantity, quality and dose rate, oxygen tension and cell type probable threshold of ≥100 mSv: these doses are rarely, if ever reached with routine diagnostic examinations, but may be reached with interventional pelvic procedures or radiation therapy most malformations at the 100 mSv threshold will be CNS-related 23  Background radiation Background radiation is the radiation that is present in the natural environment. Natural background radiation is all around us, all of the time. It makes up over half of our yearly This image shows the different exposure to radiation. The amount of pieces of an ecosystem and the background radiation is different at every different things that could affect it, like solar radiation, disturbances, location. nutrients, minerals, and organisms. Source: U.S. National Park Service (NPS) 24  Background radiation  It depends on many factors, including:  Radionuclides present in Earth’s crust.  Radionuclides created by cosmic rays hitting atoms in Earth’s atmosphere. If we are closer to outer space, we are more likely to interact with these radionuclides.  Human activity and industry, including byproducts and wastes from processes like water filtration and treatment.  Weather, which can help radionuclides from nuclear weapons testing settle back to Earth from the atmosphere. 25  Radionuclides in Earth’s Crust  Some radionuclides have been present in rocks since the formation of the Earth. All radionuclides go through radioactive decay until they reach a stable state. Radioactive decay is the process in which a radioactive element turns into another element, releasing radiation in the process. Natural radionuclides found in the Earth’s crust include uranium and thorium. As they decay, they become other radionuclides such as radium and radon. These radionuclides end up naturally in soil, water and air.  Rocks containing natural radionuclides are broken down into soil by the weather, bacteria and fungi. When radionuclides are in soil particles, they can be blown around by wind. Some radionuclides dissolve in water and end up in surface or groundwater. 26  Radionuclides in Earth’s Crust  More than half of the average annual radiation exposure of people in the United States comes from natural sources. The natural radionuclide, radon, which is produced from the decay of uranium and thorium, is the largest natural source of exposure. Radon is a natural radioactive gas that gets into homes and buildings. It is important to test your home for radon to reduce your exposure to radiation. Learn more about RadTown’s Radon in Homes, Schools and Buildings. 27  Radionuclides in Earth’s Crust Radiation from Space  About 5% of the average annual radiation exposure for people in the United States comes from outer space. Our solar system’s sun, and other stars in the galaxy, emit a constant stream of cosmic radiation, which then regularly hits the Earth. When cosmic rays collide with atoms, they can make atoms radioactive. These radioactive atoms are called cosmogenic radionuclides. They are rare, but some of them do reach Earth’s surface and mix with soil and water. Learn more about Cosmic Radiation. 28  Radionuclides in Earth’s Crust Radionuclides from Human Uses of Radioactive Material  Most radioactive material in the environment comes from natural sources. Much smaller amounts of radionuclides come from sources developed by humans. For example, uranium mines, nuclear power plants, and research facilities that use radionuclides sometimes add small amounts of radionuclides to the ecosystem. For most people, the annual exposure from these sources is very low. There may be a serious health hazard only in certain areas where open uranium, hard rock metal mines, other mineral mines or mining wastes are present. 29  Radionuclides in Earth’s Crust Nuclear weapons testing  Mostly in the 1950s and 1960s, nuclear weapons tests released large amounts of radionuclides that spread and remained in ecosystems until the radionuclides decayed away. The Comprehensive Nuclear-Test Ban Treaty Organization (CTBTO)has a network of radionuclide monitoring stations that detect radionuclide particles and noble gases, like xenon, which would indicate a nuclear test. 30  Radionuclides in Earth’s Crust Nuclear facility releases  The small amounts of airborne radionuclides released from facilities that handle and process radioactive materials can get into the soil, water or air. The EPA regulates how much radioactive materials can be released from these facilities. Learn more about Nuclear Power Plants. Radioactive waste Improper disposal of radioactive waste is another way radionuclides can enter an ecosystem. For example, water seeping thorough mining wastes can dissolve some radionuclides and carry them into the water system. Public water systems are carefully monitored by your state, and must meet federal standards, to make sure the drinking water is safe. 31  IAEA International Atomic Energy Agency  The use of ionizing radiation in medicine, energy production, industry, and research brings enormous benefits to people when it is used safely. However, the potential radiation risk must be assessed and controlled. The IAEA develops safety standards to protect the health and minimize the danger to people’s life and property associated with such use. 32 ‫آﺛﺎر زودرس و دﯾﺮرس ﺗﺸﻌﺸﻊ‬ ‫‪33‬‬  ‫ﻣﻘﺪﻣﻪ‬ ‫ رادﯾﻮ ﯿﻮﻟـﻮژی آﻣ ـ ﻩ ای از دو ﻋﻠــﻢ ﻓ ﯾـﮏ رادﯾﻮﻟـﻮژی و ز ﺴــﺖ ﺷﻨﺎ ـ اﺳـﺖ ﮐــﮫ ﮐـﮫ او ـ ﭼ ــﻮﻧ ﯽ‬ ‫ﭘﺨﺶ اﻧﺮژی در ﻓﻀﺎ و ﺟﺬب آن در ﻣﻮاد زﻧﺪﻩ و دوﻣﯽ ﺳﺎﺧﺘﻤﺎن ﺑﺪن ﻣﻮﺟﻮدات زﻧﺪﻩ را ﻣﻄﺎﻟﻌﮫ‬ ‫ﻣﯽ ﮐﻨﺪ‪.‬‬ ‫در ﭘ ﺸﺮﻓﺖ ﻋﻠﻢ رادﯾﻮ ﯿﻮﻟﻮژی ﻧﻘﺶ داﺷﺘﮫ اﻧﺪ‪...‬‬ ‫ ﺣﻮادث ﻣ‬ ‫ ﺑﮑﺮل اوﻟ ن ﻓﺮدی ﺑﻮد ﮐﮫ ﺑﮫ اﺛﺮ ﺑﯿﻮﻟﻮژ ﮏ ﭘﺮﺗﻮ ﺎی ﯾﻮ ﺴﺎز ﯽ ﺑﺮد‪.‬‬ ‫ از ﻣ ﻤ ـ ﯾﻦ اﯾ ــﻦ ﺣ ــﻮادث درﺳ ــﺎل ‪ 1906‬ﻣ ــﯽ ﺗ ــﻮان ﺑ ــﮫ ﻗ ــﺎﻧﻮن ﺑﺮ ﻮﻧﯿ ــﮫ و ﺗﺮ ﺒﺎﻧ ــﺪو اﺷ ــﺎرﻩ ﮐ ــﺮد ‪.‬اﯾ ــﻦ‬ ‫دا ﺸ ــﻤﻨﺪان ﺑ ــﺎ ﺗ ــﺎ ﺶ ﺑﯿﻀ ــﮫ ﺧﺮ ــﻮش ﺑ ــﺎ اﺷ ــﻌﮫ اﯾﮑ ــﺲ‪ ،‬اﺛﺮ ﺸﻌﺸ ــﻊ ﺑ ــﺮ روی ﺳ ــﻠﻮﻟ ﺎی ﺟ ـ را‬ ‫ﺑﺮر ﮐﺮدﻧﺪ‪.‬‬ ‫‪34‬‬ ‫ﻋﻤﻞ ﻣﺴﺘﻘﯿﻢ و ﻏﯿﺮ ﻣﺴﺘﻘﯿﻢ‬ ‫‪35‬‬  ‫ﻋﻤﻞ ﻣﺴﺘﻘﯿﻢ‬ ‫اﻧﺪرﮐ ﺸـ ﺎی ﺣﺎﺻــﻞ از ﺑﺮاﻧﮕﯿﺨﺘ ــﯽ و ﯾــﺎ ﯾﻮﻧ اﺳــﯿﻮن در ﻣﺎﮐﺮوﻣﻮﻟ ﻮﻟ ــﺎی ﺑﺤﺮا ــﯽ)‪ (DNA‬و ﯾــﺎ در‬ ‫ﺣﻼﻟ ﺎی آ ﺎ )آب( را ﺑﮫ دو ﮔﺮوﻩ ﻣﺴﺘﻘﯿﻢ و ﻏ ﻣﺴﺘﻘﯿﻢ دﺳﺘﮫ ﺑﻨﺪی ﻣﯽ ﮐﻨﻨﺪ‪.‬‬ ‫‪ -‬ﻋﻤﻞ ﻣﺴﺘﻘﯿﻢ درو ﻠﮫ اول ﺑﺮای ﭘﺮﺗﻮ ﺎی ﺑﺎ ‪ LET‬ز ﺎد ﻣﺜﻞ ﻧﻮﺗﺮون ﺎل ﺳﺮ ﻊ روی ﻣﯿﺪ ﺪ‪.‬‬ ‫ زﻣﺎ ﯽ اﺗﻔﺎق ﻣـﯽ اﻓﺘـﺪ ﮐـﮫ ﯾـﮏ ﻣﻮﻟ ـﻮل ﮐـﮫ از ﻧﻈـﺮ ز ﺴـﺖ ﺷـﻨﺎﺧ ﺣـﺎﺋﺰ ا ﻤﯿـﺖ اﺳـﺖ ‪ ،‬ﻣﺴـﺘﻘﯿﻤﺎ‬ ‫ﻣﻮرد اﺻﺎﺑﺖ ﭘﺮﺗﻮ ﻗﺮار ﮔﺮﻓﺘﮫ و ﺑﮫ اﺟﺰای ﻏ ﻣﻔﯿﺪ ز ﺴﺖ ﺷﻨﺎﺧ ﺗﻘﺴﯿﻢ ﺷﻮد‪.‬‬ ‫ اﺣﺘﻤــﺎﻻ ﻣ ﻤ ـ ﯾﻦ ﻣﻮﻟ ــﻮل ‪ DNA‬ﻣــﯽ ﺑﺎﺷــﺪ ز ـﺮا ﻧ ﯿﺠــﮫ ﻧــﺎﺑﻮدی ﯾــﮏ ﻣﻮﻟ ــﻮل ‪ DNA‬اﯾــﻦ اﺳــﺖ‬ ‫ﮐﮫ ﺳﻠﻮل دﯾﮕﺮﻗﺎدرﺑﮫ ﺗﻘﺴﯿﻢ ﻧﺒﻮدﻩ و ﺑﮫ اﻋﻤﺎل ﻏ ﻋﺎدی و ﺎﯾﺘﺎ ﻣﺮگ ﺑﺎﻓﺖ ﻣﻨﺘ ﻣﯽ ﺷﻮد‪.‬‬ ‫‪36‬‬  ‫ﻋﻤﻞ ﻏﯿﺮﻣﺴﺘﻘﯿﻢ‬ ‫آب ﯾﮑﯽ از ﺗﺮﮐﯿﺒﺎت ﻏﯿﺮآﻟﯽ ﺳﻠﻮل ﻣﯽ ﺑﺎﺷﺪ ﮐﻪ در ﺳﻠﻮل ﺑـﯿﺶ از ﻫـﺮ ﻣـﺎده‬ ‫دﯾﮕﺮ ‪ ،‬آب وﺟﻮد دارد‪.‬ﻣﻘﺪار ﺳﻠﻮﻟﻬﺎ از ‪ 70‬ﺗﺎ ‪ 85‬درﺻﺪ ﻣﺘﻐﯿﺮ ﻣﯽ ﺑﺎﺷﺪ‪.‬‬ ‫ از آﻧﺠﺎ ﮐﻪ ﺣﺪود ‪ 80‬درﺻﺪ ﺟـﺮم ﺑـﺪن را آب ﺗﺸـﮑﯿﻞ ﻣـﯽ دﻫـﺪ ﺑﯿﺸـﺘﺮ‬ ‫ﯾﻮﻧﯿﺰاﺳﯿﻮن ﻫﺎي اوﻟﯿﻪ در آب ﺻﻮرت ﻣﯽ ﮔﯿﺮد‪.‬اﻧﺮژي ﺟﺬب ﺷﺪه ﺗﻮﺳـﻂ‬ ‫ﻣﻮﻟﮑﻮل آب ‪ ،‬ﺑﺎ اﯾﺠﺎد واﮐﻨﺶ ﻫﺎي ﺷـﯿﻤﯿﺎﯾﯽ‪ ،‬ﺑﻄـﻮر ﻏﯿﺮﻣﺴـﺘﻘﯿﻢ ﻣﻮﺟـﺐ‬ ‫ﺑﺮوز ﺗﻐﯿﯿﺮات در ﮐﺎر ﯾﺎﺧﺘﻪ ﻫﺎ ﻣﯽ ﺷﻮد‪.‬‬ ‫ ﺗﺠﺰﯾﻪ ﯾﮏ ﻣﻮﻟﮑﻮل آب ﺑﺪﻧﺒﺎل ﺟﺬب ﭘﺮﺗﻮ ﺻﻮرت ﻣﯽ ﮔﯿﺮد‬ ‫‪37‬‬ ‫ﯾﮏ رادﯾﮑﺎل آزاد ﺑﻪ ﻋﻠﺖ وﺟﻮد ﯾﮏ اﻟﮑﺘﺮون ﺟﻔﺖ ﻧﺸﺪه در ﻻﯾﻪ ﺧـﺎرﺟﯽ ﺧـﻮد از ﻧﻈـﺮ واﮐـﻨﺶ ﺷـﯿﻤﯿﺎﯾﯽ‬ ‫ﺑﺴﯿﺎر ﻓﻌﺎل ﺑﻮده ‪ H2O+‬ﻣﻮﻟﮑﻮﻟﯽ ﺑﺎردار ﺑﺎ ﯾﮏ اﻟﮑﺘﺮون ﺟﻔﺖ ﻧﺸﺪه اﺳﺖ ‪.‬‬ ‫‪ H2O+‬ﯾﮏ ﯾﻮن رادﯾﮑﺎل اﺳﺖ‪.‬ﯾﮏ ﯾﻮن اﺗﻢ ﯾﺎ ﻣﻮﻟﮑﻮﻟﯽ ﺑﺎ ﺑﺎراﻟﮑﺘﺮﯾﮑﯽ ﻣﯽ ﺑﺎﺷﺪ زﯾﺮا ﯾﮏ اﻟﮑﺘـﺮون از دﺳـﺖ‬ ‫داده اﺳﺖ ‪.‬‬ ‫در ﻣﻮرد آب‪ ،‬ﯾﻮ ن رادﯾﮑﺎل ﺑﺎ ﻣﻮﻟﮑـﻮل دﯾﮕـﺮ آب اﻧـﺪرﮐﻨﺶ اﻧﺠـﺎم ﻣـﯽ دﻫـﺪ ﺗـﺎ رادﯾﮑـﺎل ﺑﺴـﯿﺎر ﻓﻌـﺎل‬ ‫ﻫﯿﺪروﮐﺴﯿﻞ ‪ HO‬ﺗﺸﮑﯿﻞ ﻣﯽ ﺷﻮد‪.‬‬ ‫ﺗﺨﻤﯿﻦ زده ﻣﯽ ﺷﻮد ﮐـﻪ ﺣـﺪود دو ﺳـﻮم آﺳـﯿﺐ اﺷـﻌﻪ اﯾﮑـﺲ ﺑـﻪ ﻣﻮﻟﮑـﻮل ‪ DNA‬ﻧﺎﺷـﯽ از رادﯾﮑـﺎل‬ ‫ﻫﯿﺪروﮐﺴﯿﻞ اﺳﺖ‪.‬‬ ‫‪38‬‬  ‫ﺣﺴﺎﺳﯿﺖ ﭘﺮﺗﻮﯾﯽ ﺑﺎﻓﺖ و اﻧﺪام‬ ‫‪ ‬ﺑﺎﻓﺘﻬﺎ ﻣﺘﺸﮑﻞ از ﺳﻠﻮﻟﻬﺎ ﻣﯽ ﺑﺎﺷﻨﺪ و ﺑﺴﯿﺎري از آﻧﻬﺎ از اﻧﻮاع ﻣﺨﺘﻠﻒ ﺳﻠﻮﻟﻬﺎ ﺗﺸﮑﯿﻞ ﻣﯽ ﺷـﻮﻧﺪ‪ ،‬ﮐـﻪ اﯾـﻦ‬ ‫ﺳﻠﻮﻟﻬﺎ را ﻣﯽ ﺗﻮان ﺑﺴﺎدﮔﯽ ﺑﻪ ﺻﻮرت زﯾﺮ ﺗﻘﺴﯿﻢ ﺑﻨﺪي ﮐﺮد ‪:‬‬ ‫‪ ‬ﺳﻠﻮل ﻫﺎي ﭘﺎﯾﻪ ‪ :‬ﺑﺮاي ﺧﻮدﺳﺎزي وﺟﻮد دارﻧﺪ و ﻣﻮﻟّﺪ ﺳﻠﻮﻟﻬﺎي دﯾﮕﺮ ﺑﺮاي ﺟﻮاﻣﻊ ﺳـﻠﻮﻟﯽ دﯾﮕﺮﻧـﺪ‪.‬ﻣﺎﻧﻨـﺪ‬ ‫اﺳﭙﺮﻣﺎﺗﻮوﮔﻮﻧﯽ‬ ‫‪ ‬ﺳﻠﻮﻟﻬﺎي ﻋﺒﻮري ‪ :‬ﺳﻠﻮﻟﻬﺎ در ﺣﺮﮐﺖ ﺑﻪ ﺳﻮي ﺟﻤﻌﯿﺖ ﺳﻠﻮﻟﯽ دﯾﮕﺮ ﻣﯽ ﺑﺎﺷﻨﺪ‪.‬ﻣﺎﻧﻨﺪ رﺗﯿﮑﻮﻟﻮﺳﯿﺖ ﻫﺎ ﮐﻪ‬ ‫در ﺣﺎل ﺗﻤﺎﯾﺰ ﺑﺮاي ﺗﺒﺪﯾﻞ ﺑﻪ ﯾﮏ ارﯾﺘﺮوﺳﯿﺖ اﺳﺖ‬ ‫‪ ‬ﺳﻠﻮﻟﻬﺎي ﺛﺎﺑﺖ ‪ :‬ﺳﻠﻮﻟﻬﺎﯾﯽ ﮐﻪ ﮐﺎﻣﻼ ﻣﺘﻤﺎﯾﺰﻧﺪ و ﻫﯿﭻ ﻓﻌﺎﻟﯿﺖ ﻣﯿﺘﻮزي اﻧﺠـﺎم ﻧﻤـﯽ دﻫﻨـﺪ‪.‬ﺳـﻠﻮﻟﻬﺎي ﺑـﺎﻟﻎ‬ ‫ﻋﻀﻼﻧﯽ و ﻋﺼﺒﯽ‬ ‫‪39‬‬ ‫‪ ‬ﺣﺴﺎﺳﯿﺖ ﭘﺮﺗﻮﯾﯽ ﺑﺎﻓﺖ و اﻧﺪام را ﻣﯽ ﺗﻮان ﺑﻪ ﺣﺴﺎﺳﯿﺖ ﭘﺮﺗﻮﯾﯽ ﺳﻠﻮﻟﻬﺎ و اﺟﺰاي ﺑﺎﻓﺘﻬﺎي ﻓﺮد ﻧﺴﺒﺖ داد‪.‬‬ ‫‪ - ‬ﺑﻪ ﻃﻮرﮐﻠﯽ ﺑﺎﻓﺖ ﻫﺎ و اﻧﺪام ﻫﺎي ﺣﺎوي ﺳﻠﻮﻟﻬﺎي ﺣﺴﺎس ﺑﻪ ﺗﺸﻌﺸﻊ ‪ ،‬ﺧﻮد ﻧﯿـﺰ ﺑـﻪ اﺷـﻌﻪ ﺣﺴﺎﺳـﯿﺖ‬ ‫ﺑﯿﺸﺘﺮي ﻧﺸﺎن ﻣﯽ دﻫﻨﺪ و ﺑﺮﻋﮑﺲ‪...‬‬ ‫‪ - ‬ﺑﺮﺧﯽ از اﻧﺪام ﻫﺎ واﺑﺴﺘﮕﯽ زﯾﺎدي ﺑﻪ ﺳﻠﻮﻟﻬﺎي ﺗﮑﺜﯿﺮﺷﻮﻧﺪه ي ﺳﺮﯾﻊ دارﻧﺪ‪.‬ﻫﺮ اﻧـﺪازه ﺗﻌـﺪاد ﺳـﻠﻮﻟﻬﺎي‬ ‫ﺗﻘﺴﯿﻢ ﺷﻮﻧﺪه ي ﺑﯿﺸﺘﺮي آﺳﯿﺐ دﯾﺪه ﺑﺎﺷﻨﺪ‪ ،‬زﻣﺎن ﺑﺮوز اﺛﺮ ﮐﻮﺗﺎه ﺗﺮ ﺧﻮاﻫﺪ ﺑﻮد‪.‬ﺳﯿﺴﺘﻢ ﻣﻐـﺰ اﺳـﺘﺨﻮان‪،‬‬ ‫ﺳﯿﺴﺘﻢ ﮔﻮارﺷﯽ ‪ ،‬ﭘﻮﺳﺖ و ﺑﯿﻀﻪ ﻫﺎ‬ ‫‪ - ‬ﺑﺮﺧﯽ از اﻧﺪام ﻫﺎ واﺑﺴﺘﮕﯽ زﯾﺎدي ﺑﻪ ﺳﻠﻮﻟﻬﺎي ﺗﮑﺜﯿﺮﺷﻮﻧﺪه ي ﺳﺮﯾﻊ ﻧﺪارﻧﺪ و ﺗﻘﺴﯿﻢ ﺳﻠﻮﻟﯽ ﺑﺴﯿﺎرﮐﻤﯽ‬ ‫در ﻣﻘﺎﯾﺴﻪ ﺑﺎ دﯾﮕﺮ اﻧﺪام ﻫﺎي ذﮐﺮ ﺷﺪه دارد‪.‬ﮐﻠﯿﻪ ﻫﺎ و رﯾﻪ ﻫﺎ‬ ‫‪40‬‬  ‫ﻣﻄﺎﻟﻌﮫ اﺛﺮ ﺎی ﺑﯿﻮﻟﻮژ ﯽ‬ ‫‪ ‬اﯾﻦ ﺑﺮرﺳﯽ ﻫﺎ ﺷﺎﻣﻞ آزﻣﺎﯾﺸﻬﺎﯾﯽ ﺑﺎ ﺣﯿﻮاﻧﺎت آزﻣﺎﯾﺸﮕﺎﻫﯽ و ﺟﻮاﻣﻊ اﻧﺴﺎﻧﯽ ﻣﯽ ﺑﺎ ﺷﺪ ‪.‬‬ ‫‪ ‬در ﻣﻮرد ﺑﺮرﺳﯽ ﺟﻮاﻣﻊ اﻧﺴﺎﻧﯽ ‪ 4‬ﻣﺤﺪودﯾﺖ وﺟﻮد دارد ‪:‬‬ ‫‪ ‬اﺣﺘﻤﺎل دارد ﮔﺮوﻫﯽ ﺑﻪ ﻋﻨﻮان ﺷﺎﻫﺪ اﻧﺘﺨﺎب ﺷﻮد ﮐﻪ ﮐﺎﻣﻼ ﺑﺎ ﮔﺮوه ﻣﻮرد ﻣﻄﺎﻟﻌﻪ ﻣﻄﺎﺑﻘﺖ ﻧﺪاﺷﺘﻪ ﺑﺎﺷﺪ‪.‬‬ ‫‪ ‬در ﺻﻮرت ﻣﺸﺎﻫﺪه اﻓﺰاﯾﺶ ﺷﯿﻮع ﺳﺮﻃﺎن‪ ،‬ﺷﺎﯾﺪ از ﻧﻈﺮ آﻣﺎري ﻣﻌﻨﯽ دار ﻧﺒﺎﺷﺪ‪.‬‬ ‫‪ ‬اﻣﮑﺎن ﺟﺪاﺳﺎزي ﺗﻤﺎم ﻋﻮاﻣﻞ ﻣﺪاﺧﻠﻪ ﮔﺮ وﺟﻮد ﻧﺪارد‪.‬‬ ‫‪ ‬ﻣﺸﮑﻞ دُزﯾﻤﺘﺮي‬ ‫‪Dr Milad Hatamian‬‬ ‫‪41‬‬ ‫اﺛﺮﻫﺎي دﯾﺮرس ﺗﺸﻌﺸﻊ‬ ‫‪ ‬ﻟﻮﺳﻤﯽ‬ ‫‪ ‬ﺑﯿﻤﺎري ﻫﺎي ﺑﺪﺧﯿﻢ‬ ‫اﻟﻒ‪.‬ﺳﺮﻃﺎن اﺳﺘﺨﻮان‬ ‫‪‬‬ ‫ب‪.‬ﺳﺮﻃﺎن رﯾﻪ‬ ‫‪‬‬ ‫ج‪.‬ﺳﺮﻃﺎن ﭘﻮﺳﺖ‬ ‫‪‬‬ ‫د‪.‬ﺳﺮﻃﺎن ﺗﯿﺮوﺋﯿﺪ‬ ‫‪‬‬ ‫ه‪.‬ﺳﺮﻃﺎن ﭘﺴﺘﺎن‬ ‫‪‬‬ ‫‪ ‬آﺳﯿﺐ ﻣﻮﺿﻌﯽ ﺑﺎﻓﺖ ﻫﺎ‬ ‫اﻟﻒ‪.‬ﭘﻮﺳﺖ‬ ‫‪‬‬ ‫ب‪.‬ﮔﻮﻧﺎدﻫﺎ‬ ‫‪‬‬ ‫ج‪.‬ﭼﺸﻤﻬﺎ‬ ‫‪‬‬ ‫‪ ‬ﮐﻮﺗﺎﻫﯽ ﻋﻤﺮ‬ ‫‪ ‬ﺗﺎﺑﺶ ﮔﯿﺮي ﺟﻨﯿﻦ‬ ‫‪42‬‬  ‫در ﻣﻮرد ﺳﺮﻃﺎﻧﺰاﯾﯽ ﺗﺸﻌﺸﻊ ﺑﺎﯾﺪ ﺑﻪ ﻣﻮارد زﯾﺮ ﺗﻮﺟﻪ داﺷﺖ ‪:‬‬ ‫‪ ‬ﯾﮏ ﻣﻮرد ﺗﺎﺑﺶ ﮔﯿﺮي ﻣﯽ ﺗﻮاﻧﺪ ﺑﺮاي اﻓﺰاﯾﺶ ﺷﯿﻮع ﺳﺮﻃﺎن‪ ،‬ﺳﺎﻟﻬﺎ ﺑﻌﺪ از ﺗﺎﺑﺶ ﮔﯿﺮي ﮐﺎﻓﯽ ﺑﺎﺷﺪ‪.‬‬ ‫‪ ‬ﻫﯿﭻ ﺳﺮﻃﺎﻧﯽ وﺟﻮد ﻧﺪارد ﮐﻪ ﻣﻨﺤﺼﺮا ﺑﺎ ﺗﺸﻌﺸﻊ اﯾﺠﺎد ﺷﻮد‪.‬‬ ‫‪ ‬ﺗﻘﺮﯾﺒﺎ ﺷﯿﻮع ﺗﻤﺎم ﺳﺮﻃﺎﻧﻬﺎ ﺑﺎ ﺗﺎﺑﺶ ﮔﯿﺮي اﻓﺰاﯾﺶ ﻣﯽ ﯾﺎﺑﺪ‪.‬‬ ‫‪ ‬اﻧﺪام ﻫﺎي ﻣﺎﻧﻨﺪ ﺗﯿﺮوﺋﯿﺪ‪ ،‬ﻣﻐﺰاﺳﺘﺨﻮان و ﭘﺴﺘﺎن ﺣﺴﺎﺳﯿﺖ ﺑﯿﺸﺘﺮي ﺑﻪ ﺗﺸﻌﺸﻊ ﻧﺸﺎن ﻣﯽ دﻫﻨﺪ‪.‬‬ ‫‪ ‬ﻟﻮﺳﻤﯽ‪ ،‬ﺑﯿﺸﺘﺮﯾﻦ ﻓﺮاواﻧﯽ را در ﻣﯿﺎن ﺗﻮﻣﻮرﻫﺎي ﻣﺸﺎﻫﺪه ﺷﺪه ﻧﺎﺷﯽ از ﺗﺎﺑﺶ ﮔﯿﺮي ﺑﺮﺧﻮردار اﺳﺖ‪.‬‬ ‫‪ ‬دوره ﻧﻬﻔﺘﻪ ﺗﻮﻣﻮرﻫﺎي ﺟﺎﻣﺪ ﺣﺪاﻗﻞ ‪ 10‬ﺳﺎل اﺳﺖ‪.‬‬ ‫‪ ‬ﺳﻦ اﻓﺮاد ﺗﺎﺑﺶ دﯾﺪه ﯾﮑﯽ ازﻣﻬﻤﺘﺮﯾﻦ ﻋﻮاﻣﻞ اﺳﺖ‪.‬‬ ‫‪ ‬درﺻﺪ اﻓﺰاﯾﺶ ﺑﺮوز ﺳﺮﻃﺎن ‪ ،‬ﺑﻪ ازاي ﻫﺮ راد ﺗﺎﺑﺶ ﮔﯿﺮي ﺑﺮاي اﻧﺪاﻣﻬﺎ و ﺳﺮﻃﺎﻧﻬﺎي ﻣﺨﺘﻠﻒ‪ ،‬ﻣﺘﻐﯿﺮ اﺳﺖ‪.‬‬ ‫‪43‬‬ ‫ﮐﺎﺗﺎراﮐﺖ‬ ‫‪44‬‬  ‫‪ ‬ﭼﺸﻢ ﻫﺎ‬ ‫‪ ‬ﮐﺎﺗﺎراﮐﺖ زاﯾﯽ ﺗﺸﻌﺸﻊ )ﺗﺸﮑﯿﻞ آب ﻣﺮوارﯾﺪ در ﻧﺘﯿﺠﻪ ي ﺗﺎﺑﺶ ﮔﯿﺮي ( ﺗﺎ ﺣﺪي ﻣﻮﺿﻮﻋﯽ ﺑﺤﺚ ﺑﺮاﻧﮕﯿـﺰ‬ ‫ﺑﺎﻗﯽ ﻣﺎﻧﺪه اﺳﺖ‪.‬‬ ‫‪ ‬ﺑﯿﻤﺎران ﭘﺮﺗﻮدرﻣﺎﻧﯽ و ﻣﺘﺨﺼﺼﺎن ﻓﯿﺰﯾﮏ ﺳﯿﮑﻠﻮﺗﺮون از ﺗﺎﺑﺶ دﯾﺪه ﻣﺒﺘﻼ ﺑﻪ ﮐﺎﺗﺎراﮐﺖ ﻣﯽ ﺷﻮﻧﺪ‪.‬‬ ‫‪ ‬دز آﺳﺘﺎﻧﻪ ﺑﺮاي اﯾﺠﺎد ﮐﺎﺗﺎراﮐﺖ ‪ 200‬راد ﺑﺮآورد ﺷﺪه اﺳﺖ‪ ،‬اﻣـﺎ دﻗﯿـﻖ ﻧﯿﺴـﺖ‪.‬ﺑـﺮاي دز ﻫـﺎي ﺗﻘﻄﯿﻌـﯽ‬ ‫ﻣﻤﮑﻦ اﺳﺖ ﺗﺎ ‪ 1000‬راد ﺑﺎﻟﻎ ﺷﻮد‪.‬‬ ‫‪ ‬ﺑﺮﺧﯽ از ﻓﻨﺎوران و ﭘﺰﺷﮑﺎن ﺑﻮﯾﮋه آﻧﻬﺎﯾﯽ ﮐﻪ ﺑﺎ دز ﻧﺴﺒﺘﺎً ﺑﺎﻻ ﻣﺜﻞ اﺗﺎق آﻧﮋﯾﻮﮔﺮاﻓﯽ ﮐﺎر ﻣﯽ ﮐﻨﻨﺪ‪ ،‬از ﻋﯿﻨﮏ‬ ‫ﻫﺎي ﻣﺤﺎﻓﻆ ﻋﺪﺳﯽ ﻫﺎي ﭼﺸﻢ ﺑﻬﺮه ﻣﯽ ﺑﺮﻧﺪ‪ ،‬اﮔﺮ ﭼﻪ ﻣﻤﮑﻦ اﺳﺖ ﻏﯿﺮ ﺿﺮوري ﺑﺎﺷﺪ‪.‬‬ ‫‪ ‬ﻫﺮ ﻓﺮد ﺑﺎﯾﺪ ﺣﻔﺎﻇﺖ ﺷﺨﺼﯽ ﺧﻮد را آن ﻃﻮر ﮐﻪ ﻣﻨﺎﺳﺐ ﻣﯽ داﻧﺪ ﻋﻤﻞ ﻣﯽ ﮐﻨﺪ‪.‬ﻣـﺜﻼً در ﯾـﮏ ﺑﺮرﺳـﯽ‬ ‫ﻧﺸﺎن داده ﺷﺪ ﮐﻪ ﭘﺰﺷﮑﺎن در ﺣﺎل ﺗﻌﻠﯿﻢ )رزﯾﺪﻧﺖ ﻫﺎي رادﯾﻮ ﻟﻮژي( دزﻫﺎي زﯾـﺎدي را ﺑـﺎ ﻋﺪﺳـﯽ ﻫـﺎي‬ ‫ﭼﺸﻢ درﯾﺎﻓﺖ ﻣﯽ ﮐﻨﻨﺪ اﯾﻦ ﻣﺴﺎﻟﻪ ي اﻟﺰاﻣﯽ ﺑﺮاي اﺳﺘﻔﺎده از ﻋﯿﻨﮏ ﻫﺎي ﻣﺤﺎﻓﻆ اﺳﺖ‪.‬‬ ‫‪45‬‬  ‫‪ ‬ﮐﻮﺗﺎﻫﯽ ﻋﻤﺮ‬ ‫‪ ‬اﻃﻼﻋﺎت ﻣﺴﺘﻨﺪي ﮐﻪ ﻧﺸﺎن دﻫﺪ ﺗﺸﻌﺸﻊ ﻣﻮﺟﺐ ﮐﻮﺗﺎﻫﯽ ﻋﻤﺮ ﻣﯽ ﺷﻮد‪ ،‬وﺟﻮد ﻧﺪارد‪.‬‬ ‫‪ ‬ﯾﻌﻨﯽ اﺛﺮ آن در ﮐﻮﺗﺎﻫﯽ ﻋﻤﺮ‪ ،‬ﻧﺎﻣﺸﺨﺺ اﺳﺖ وﻟﯽ ﻣﯽ ﺗﻮاﻧﺪ ﻧﺎﺷﯽ از اﺛﺮ ﻫﺎي دﯾﮕﺮ ﺗﺸﻌﺸﻊ ﻣﺎﻧﻨﺪ ﺑﺮوز ﻟﻮﺳﻤﯽ ﺑﺎﺷﺪ‪.‬‬ ‫‪ ‬در دﻫﻪ ي ‪ 1930‬ﻋﻤﺮ رادﯾﻮﻟﻮژﯾﺴﺖ ﻫﺎ ﻧﺴﺒﺖ ﺑﻪ دﯾﮕﺮ ﭘﺰﺷﮑﺎن ‪ 5‬ﺳﺎل ﮐﻤﺘﺮ ﮔﺰارش ﺷﺪ‪.‬ﺑﻪ دﻟﯿﻞ ﻣﺴـﺎﺋﻞ اﻗﺘﺼـﺎدي‬ ‫و اﺟﺘﻤﺎﻋﯽ اﻧﺘﻈﺎر ﻣﯽ رودﭘﺰﺷﮑﺎن از ﻃﻮل ﻋﻤﺮ ﻣﺸﺎﺑﻬﯽ ﺑﺮﺧﻮردار ﺑﺎﺷﻨﺪ‪ ،‬ﺑﻨﺎﺑﺮاﯾﻦ اﺛﺮ ﺗﺸﻌﺸﻊ ﺛﺎﺑﺖ ﺷﺪ‪.‬‬ ‫‪ ‬ﺑﻪ ﻫﺮ ﺣﺎل‪ ،‬ﺗﮑﺮار اﯾﻦ ﺑﺮرﺳﯽ در دﻫﻪ ي ‪ 1960‬ﻧﺸﺎن دادﮐﻪ دﯾﮕﺮ ﭼﻨﯿﻦ ﺗﻔﺎوﺗﯽ وﺟﻮد ﻧﺪارد و در ﺣﺎل ﺣﺎﺿـﺮ ﻓﻘـﺪان‬ ‫ﺗﻔﺎوت ﺑﻪ ﺗﻮﺟﻪ ﺑﯿﺸﺘﺮ ﺑﻪ ﺣﻔﺎﻇﺖ در ﺑﺮاﺑﺮ ﺗﺸﻌﺸﻊ ﻧﺴﺒﺖ داده ﻣﯽ ﺷﻮد‪.‬‬ ‫‪ ‬ﺑﺮاي ﺑﺎزﻣﺎﻧﮕﺎن ﺑﻤﺐ اﺗﻤﯽ‪ ،‬ﻧﻘﺎﺷﺎن اﻋﺪاد ﺑﺎ رادﯾﻢ ﯾﺎ ﺑﯿﻤﺎراﻧﯽ ﮐﻪ ﺗﺤﺖ ﺗﺎﺑﺶ ﺗﺸﺨﯿﺼﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﻧـﺪ‪ ،‬ﮐﻮﺗـﺎﻫﯽ ﻋﻤـﺮ‬ ‫ﻣﺸﺎﻫﺪه ﻧﺸﺪه اﺳﺖ‪.‬‬ ‫‪46‬‬ ‫آﺳﯿﺐ ژﻧﺘﯿﮑﯽ‬ ‫‪47‬‬  ‫زن‬ ‫ﻣﺮد‬ ‫ﺗﺎ ‪ 3‬روز ﭘﺲ از ﺗﻮﻟﺪ‪ ،‬ﻫﻤﻪ ﺳﻠﻮﻟﻬﺎ ﺗﺎ ﻣﺮﺣﻠﻪ‬ ‫اﺳﭙﺮﻣﺎﺗﻮﮔﻮﻧﯽ