الفهرس 
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Abstract
Radiation is a form of energy in motion. It is emitted by one object and absorbed by another. Regarding their nature, Radiations are of two types:-
1. Particulate radiations: Examples of these radiations are energetic electrons, protons, neutrons, and so forth. They have mass and charge, except neutrons, which are neutral particles. The velocity of their motion depends on their kinetic energy. The particulate radiations originate from radioactive decay, cosmic rays, nuclear reactions, and so forth.
2. Electromagnetic radiations: These radiations are a form of energy in motion that does not have mass and charge and can propagate as either waves or discrete packets of energy, called the photons or quanta. These radiations travel with the velocity of light. Various examples of electromagnetic radiations include radio waves, visible light, heat waves, radiations, and so forth, and they differ from each other in wavelength and hence in energy. It should be pointed out that the sound waves are not electromagnetic radiations.
Each time a charged particle ionizes or excites an atom, it loses energy until it no longer has enough energy to interact; the final result of these energy losses is a minute rise in the temperature of the material of which the atom is a part. In this way, all the energy deposited in biological tissues by ionizing radiation is eventually dissipated as heat through increased vibrations of the atomic and molecular structures. It is the initial ionization and the resulting chemical changes that cause harmful biological effects. The nucleus of the cell is the most sensitive part to radiation and this sensitivity has been attributed to the DNA molecule. To understand the effect of radiation on the DNA molecule, a knowledge of its structure is essential. It has a double helicalstructure consisting of two strands, which are like the two rails of a ladder.The strands are composed of sugars interlinked by phosphate bonds.
These radiation effects on DNA molecules changes result in so called mutations, which have adverse effects on the genetic codes. The number of mutations increases with increasing radiation exposure. At low-dose exposures, the breaks are single stranded and can be repaired by joining the broken components in the original order. At higher exposures, however, double strand breaks occur and the odds for repair decrease. Also, high LET radiations cause more damage to the DNA molecule. If the cell is not repaired, it may suffer a minor functional impairment or a major consequence (cell death). If DNA damage occurs in germ cells, future offspring may be affected.
The effects of radiation can be classified into two groups: deterministic effects and stochastic effects. Harmful tissue reactions (deterministic effects) resulting from the killing/malfunctioning of cells is characterized by a certain dose called “threshold.” The reason for the threshold is that a serious malfunction or death of a critical population of cells in a given tissue should be sustained before injury is expressed in a clinically relevant form.stochastic effect results from the mutagenic action of ionizing radiation, which can lead to the loss of control over the cell division. It eventually results in the induction of cancer as a result of mutagenic disturbance. On the other hand, if it happens to be a germ cell, the mutated information can be passed on to the progeny leading to genetic effects. The most important and widely discussed effect of chronic exposure to radiation is cancer. It is not known at present whether there is a real threshold for cancer induction. When studying epidemiological data for many populations, a clear increase of the probability of contracting cancer is seen with increasing dose.
The risk of stochastic effects is the primary reason for limiting doses to both the public and radiation workers. For the purposes of radiation protection, it is assumed that the probability of a stochastic effect increases linearly as the dose increases and that there is no threshold dose. For this reason, a stochastic effect is called a Linear or Zero-Threshold Dose-Response Effect. If there is no threshold dose then it is considered that even small doses of radiation might cause cancer.
ALARA - As Low As Reasonably Achievable – is usually considered as a way of thinking, a philosophy, continuously questioning whether all reasonable action has been done to reduce exposures and whether the best has been done in the facility. The radiation protection program at any institution must not be a static entity, but one that is continually being scrutinized and evaluated to introduce continuous quality improvements.
The aim of this study is to evaluate radiological protection of workers. Occupationally exposed to Radiation and it’soptinization. Worker protection may be achieved by a good and organized protection program. The Radiation protection program aims to reduce the personal dose and protect the workers from hazards of radiation not only by reducing the time, increasing The distance and using shield but also by achieving the factors of the program .
Types of places that needs evaluation are medical, research and industrial.In medicine where it is used for imaging in diagnostic radiology and nuclear medicine; for treatment of cancer in radiotherapy. In research where Universities, colleges, high schools, and other academic and scientific institutions use nuclear materials in course work, laboratory demonstrations, experimental research, and a variety of health physics applications. Research workers in educational establishments use radioactive sources, X-ray equipment and unsealed radioactive sources for a wide range of activities. In industry Because radiation has the ability to penetrate matter, industrial measurements can be made using radioisotopes without the need for direct physical contact of either the source or sensor. Engineers use gauges containing radioactive substances to measure the thickness of paper products, fluid levels in oil and chemical tanks, and the moisture and density of soils and material at construction sites. They also use an x-ray process, called radiography, to find otherwise imperceptible defects in metallic castings and welds. Radiography is also used to check the flow of oil in sealed engines and the rate and way that various materials wear out.
Components of protection program are caution signs and labels, radioactive waste disposal, calibration of survey instruments, classification of areas, protective equipment and tools, individual monitoring and exposure assessment, monitoring the workplace, health surveillance, records, training, emergency procedures, responsibilities of and licensees.
The study included 3 types of facilities that use radioactivity or radiation; namely; medical, research and industrial, with a total number of 10 facilities in the 3 groups; 5 medical, 3 research and 2 industrial facilities. The analysis was carried out through a check list, and the factors involved were evaluated through a score for each factor that adds up to a total score that should reflect the degree of protection of workers and the efficiency of the protection program, if present.
The medical category involved five places (M1-M5), M1,M2 used X-ray in C-arm device for endoscopy and heart catheterization purpose. Their total score in the check list were 9 and 11 respectively. Third place M3 used X-ray tube ( CT device ) for radiology and scored 9. The fourth place M4 used 99Tc, 192Ir, 60Co for gamma camera and 60Co for brachytherapy and it scored 50. The fifth place M5 used 131I, 99Tc for treatment of thyroid and examining of heart, bones, kidney and scored 53.
The research category involved three places (R1- R3). The first place R1 used 125I,129I, 60Co, 90Srfor research and teaching and it’s score was 53. The second place R2 was radioisotopes production facility which produced 192Ir, 60Co, 137Cs, 131I, 125I, Mo99 and scored 57. The third place R3 used 60Co, 152Eu, 137Cs, 133Ba, 241Am for calibration of semiconductor and scintillation detectors and scored 48.
The industrial category involved two places (D1, D2), The first place DI used 85Kr for Thickness gauging and it’s score was 51. The second place D2 used 192Ir, for Industrial Radiography and scored 51.
Some topics as ”individual monitoring and dose”, ”personal protective equipment”, ”responsibilities and accountability” were consistently well attended in all categories, while ”Environmental surveillance” was missing in all categories. The remaining topics showed high discrepancy of data among categories, but in most cases, research and industrial categories scored much higher than the medical categories.
We can understand from this the radiation protection program is applied completely in place R2 while in M1, M2, M3 we can observe the absence of the protection and safety for workers and there is an extreme careless case in these places, other places ranged from 48-53 and these results is acceptable but not satisfactory.
According to the data the difference between three categories is observed so we can say the medical category is the lowest one with a median of 11.0 and the research is the highest between them with a median of 53.0 and the median of industrial is 51.0.
The Egyptian Code for regulating nuclear and radiation activities and its implementing regulations were issued on 2010, to regulate and control all activities involving the use of radiation or radioactivity. The code is comprehensive and it paid very special attention to workers safety and protection and to the environmental protection. These two issues are, by law, required for licensing the workplace.
Any facility that uses radiation should get a license from ENRRA to be able to practice its activities. As a matter of fact, the organization is applying the code well; in addition to its role in monitoring and follow up of facilities already licensed. So, workplaces licensed by this authority are well in compliance with all codes and regulations that would ensure the presence of a good protection program and its application.
The code however, has a major drawback, in Chapter 13, article 16, page 16, that states that “It is not allowed to found, own possess or operate any facility gamma irradiation, or electron or ionic cyclotrons, except for those used in medical field which comply for the regulations and monitoring of the Ministry of Health.” It was in fact the medical workplaces authorized and licensed by the ministry of health, that were of very low score.
from this information we can notify that according to the code, the conditions which are needed to get the license for the facility to practice its nuclear activities achieve and cover all factors of radiation protection program which should be applied by the facility.