1.0 INTRODUCTION.
The discovery of x-rays on November 8 by Professor W. C. Roentgen, a German physicist, gave rise to radiation medicine. Immediately after the discovery, ionizing radiation became a very useful tool in diagnostic medicine.
Electromagnetic (EM) radiation includes visible light, radio waves, microwaves, cosmic radiation and several other varieties of rays. X-rays are of short wavelength, and high frequency EM radiation. High frequency means, high energy and operate at energy level of ionizing radiation.1
Ionizing radiation is widely used in medicine and industries, and it presents a significant health hazard. The hazards of X-rays were reported few months after its discovery and it was later confirmed that X-rays have deleterious biological effects. It also causes microscopic damage to living tissues, resulting in skin burn and radiation sickness at high exposures and statistically elevated risk of cancer at low exposures. Examples of these effects are; dermatitis, alopecia, chronic ulceration, genetic effects. When patients undergo x-ray examinations, millions of photons pass through their bodies. These can damage any molecule by ionization, but damage to the DNA in the chromosome is of particular importance.2
The realization of these harmful effects has given rise to radiation protection practices. Radiation protection sometimes known as radiological protection is the protection of people and the environment from the harmful effects of ionizing radiation and high energy electromagnetic radiation. Radiation protection aims at the protection of individuals, their descendants and the human race in the environment against the potential risk of ionizing radiation.3
The harmful effects of ionizing radiation can be reduced through the filtration of x-ray beam, collimation/field size trimming, biological shielding like the use of lead apron, gonad shield, wall lead-lining which has to do with the room design.
The basic principles of radiation protection in every radiological department are time, distance and shielding. Personnel radiation monitoring is also a good measure of radiation protection which helps in measuring the radiation received by radiation workers. This involves the use of film badges, ionization chamber and thermoluminiscent dosimeter (TLD).
In as much as there are hazardous effects, ionizing radiation is of tremendous importance as it plays a useful role in medical imaging. Medical imaging procedures, which are used to view different areas inside the human body, can provide physicians with important clinical information. Imaging examinations can allow for non-invasive diagnosis of disease and monitoring of therapy, and can support medical and surgical treatment planning.4
Furthermore, this project is concentrated on the assessment of radiation protection in radiology department of hospitals in Kogi State.
MAIN OBJECTIVE
To evaluate radiation protection practices in radiology departments of hospitals in Kogi State.
SPECIFIC OBJECTIVES
1.4 SCOPE OF STUDY
This research was carried out among the hospitals that practice radiography in Kogi State.
ALARA: (acronym for As Low AsReasonably Achievable). Its aim is to make
every reasonable effort to maintain exposures to radiation as far below the dose limits as practical and consistent with the purpose for which the licensed activity is undertaken. ALARA also adheres to the principle of keeping radiation doses of patients As Low As Reasonably Achievable.
Absorbed dose: is the frequency or intensity of biological effects which is dependent upon the total energy of radiation absorbed (in joules) per unit mass (in kg) of a sensitive tissues or organs. This quantity is expressed in gray (Gy).
Alopecia: The absence of hair from where it normally grows.
Beam filtration:This is an invaluable means of reducing skin doses to patients.Filtration of the X-ray beam preferentially removes lower energy X-ray photons from the beam.Filtration by aluminium is a key method of reducing skin dose to patients. Additional filtration using materials (K-edge filters) other than aluminium, such as rare-earth materials, have been investigated as means of dose reduction.
Dermatitis: An inflammatory condition of the skin caused by outside agents.
Effective annual dose limit: is the limit which no radiation worker can receive more radiation. The aim is to reduce the risk of radiation workers to a level comparable to workers in other occupation.
Effective dose: This is the sum of the weighted equivalent doses in all the tissues and other organs of the body, i.e. multiplying the equivalent doses delivered to an organ by risk factor specific to that organ which is called the tissue weighting factor (wT).
Exposure: A measure of the ionization produced in air by x- or gamma radiation. The sum of electric charges on all ions of one sign produced in air when all electrons liberated by photons in a volume of air are completely stopped in air, divided by the mass of the air in the volume. The units of exposure in air are the international unit, coulomb per kilogram or the Roentgen.
Equivalent dose (Dose equivalent): The product of the absorbed dose in tissue, quality factor (i.e., rad x Q = rem) or organ dose weighting factors (i.e., Gy x wT = Sv), and all the necessary modifying factors at the location of interest. The units of dose equivalent are the international unit, Sievert (Sv) or the rem.
Field-size trimming: is the reduction of the size of the X-ray beam to the minimum size needed to image the object of interest. It is an obvious means of limiting dose to patients. Limiting beam area on the skin surface also limits the volume of the patient that is irradiated.
Ionizing and non-ionizing radiation: Ionizing radiation refers to electromagnetic or particulate radiation capable of producing ions directly or indirectly in its passage through matter. In general, it will refer to gamma rays and x-rays, alpha and beta particles, neutrons, protons, high speed electrons, and other nuclear particles. Ionizing radiations include X-rays, Gamma rays, cosmic rays, Alpha particles and Beta particles.
Non-ionizingradiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules, that is, to completely remove an electron from an atom or molecule. Instead of producing charged ions when passing through matter, the electromagnetic radiation has sufficient energy only for excitation, the movement of an electron to a higher energy state. Examples are: radio waves, visible, infrared, or ultraviolet light.
Necrosis: This is the death of some or all of the cells in an organ or tissue, caused by disease, chemical, loss of blood supply or physical interferences like radiation.
Occupational Dose: The dose received by an individual in a restricted area or
in the course of employment in which the individual’s assigned duties involve exposure to radiation and to radioactive material from licensed and unlicensed sources of radiation, whether in the possession of the licensee or other person. Occupational dose does not include dose received from background radiation, as a patient from medical practices, from voluntary participation in medical research programs, or as a member of the general public.
Public dose: Dose received by a member of the public from exposure toradiation and to radioactive material released by a licensee. It does not include occupational dose or doses received from background radiation, as a patient from medical practices, or from voluntary participation in medical research programs.
Radiation dose: is the quantitative expression of the physical effect produced by the radiation at a point in the irradiation medium. It has biological interest because the biological effect is related to it.
Quality assurance tests: These are plans and systematic actions necessary to provide confidence that the equipment is performing satisfactorily in the day to day services. The objective of the quality assurance programme is to ensure accurate diagnosis and to ensure that doses are kept as low as reasonably achievable.