ABSTRACT
It has been observed that during x-ray equipment failure, radiographers seem not to know what to do, there is usually a display of distress observed by radiographers and an immediate call for the services of a technician is made by the radiographers. This work is aimed at assessing the knowledge of radiographers in knowing their equipments, knowing what they do when an equipment fails, assessing their capability in fixing simple faults and assessing their knowledge on quality assurance testing. Questionnaires were shared to the various government hospitals in the southeastern Nigeria using a sample size of one government hospital in four south eastern states. Data were collected and analysed and it was realized that radiographers were familiar with their equipment and they possessed basic knowledge in troubleshooting and quality assurance but they lacked practice in troubleshooting and quality assurance testing, and basic facilities used in maintaining x-ray equipment failures such as faults and maintenance logbooks and simple tools used in carrying out quality assurance testing and troubleshooting were unavailable in the various departments.
INTRODUCTION
An x-ray machine is an equipment that provides the source of x-rays which utilizes electromagnetic radiation to penetrate objects to produce images or used in therapy to treat cancers and other diseases1. The earliest equipment used in the production of x-rays was the Crookes tube, a discharge tube invented in 1875 and used by Wilhelm Conrad Roentgen, who discovered x-rays using this simple equipment in 1895. Crookes tubes created free electrons by ionisation of the residual air in the tube by a high DC voltage of between a 10 kilovolts and 100kilovolts, this voltage accelerated the electrons coming from the cathode to a high enough velocity that created x-rays when they struck the glass wall of the tube. In 1913, William D Coolidge invented the Coolidge tube, which consisted of a vacuum tube (an evacuated tube) and a hot cathode that permitted current to flow into the tube, this allowed the continuous production of x-rays. The Coolidge tube was the first x-ray tube and it stands as the model in which all x-ray tubes for medical applications are based. As years passed, the x-ray equipment was modified in various ways to ensure optimum output and to ensure the safety of the patient and the operator.
An x-ray machine is a complex device used in a variety of circumstances around the world. With the ability of x-rays to penetrate hard objects, they are used for purposes such as in the medical community to check for fractures of bones or pathologies within the body and in airport security checkpoints to see into bags for concealed weapons or other contrabands2. Regardless of the type of x-ray equipment, there are three major components that are vital to the inner workings of an x-ray machine, and they include;
1.Vacuum Tube: X-ray tubes are more commonly referred to as vacuum tubes. They are integral parts of the x-ray machine, and work by electrons accelerating along the vacuum tube to hit the target for x-ray production. A cathode within the machine emits electrons into the vacuum tube, at which point an anode receives the electrons and establishes an electrical current through the tube. A high voltage is used to accelerate the electrons, and the current flow is pulsed until the required amount of x-ray exposure has occurred. The radiation formed leaves the tube port and is used in producing final images.
2. Power Source: A high voltage power source is required to operate an x-ray machine. The voltage is used to accelerate the electrons within the vacuum tube, and is usually pulsed from 1 microsecond to 1 full second. The high voltage power source of an x-ray machine controls the penetration of the x-ray itself, and thus the overall contrast of the image, with the voltage of the current and exposure time affecting the dose and darkening of the image.
3. Control Unit: The control unit of the x-ray machine is necessary to manage the current, voltage, and time of exposure. Radiation intensity can change dramatically depending on whether you are using the machine to render x-ray stills of body parts or using it as a security monitor, for example. In addition there is a voltage control with a display, allowing you to make adjustments in the anode itself to change the type of radiation energy being released. The control unit also has a timer to control the pulses and duration of the exposure, shutting the current off when the radiation exposure has been completed3.
The X-ray tube contains either a filament or cathode emitter that expels accelerated electrons and leads them to a metal anode, where current is now flowing. The electrons that have been emitted toward the anode make up an electron beam. The beam hits a focal point in the anode, where a small percentage is converted into X-ray photons. The photons are discharged in all directions, and once the control unit is put to use, the adjusted currents and voltage result in a beam of X-rays that is projected onto a visible substance. An X-ray machine essentially acts as a camera, but without the visible light. Instead, it uses the X-rays that were produced to expose the film. X-rays use electromagnetic waves that can break through several layers due to the energy held inside of them. If the body is being X-rayed, the skin tissue will not absorb the waves coming from the X-ray but the dense parts of the body will, which is why bones, tendons and ligaments are able to be examined4.
An equipment failure can be defined as a cessation of normal operation of the equipment; it is a breakdown or decline in the performance of an equipment, or an occasion when something stops working adequately5. Such equipment failure could be due to different causes ranging from simple broken wires in the generator handswitch cable and faults in plugs and switches to oil leakage in the x-ray tube or a crooked or distorted anode in the anode tube.
Effects of equipment failure
These include:
• Poor quality output leading to increased patient waiting time and hampers effective diagnosis
• Total disruption of work in the x-ray department leading to financial loss in the department and delayed diagnosis of pathologies in patients.
• Pose serious mechanical risks to the patient and operator such as injuries or even death.
• Inadvertent radiation exposure to the patient and the operator6.
Usually, it is the duty of equipment engineers to fix such problems, but before they arrive at the x-ray department to ascertain the exact fault of the machine and effect repairs, a lot of time is lost. However before the arrival of the engineers, the radiographer should be able to ascertain the faults characteristics and malfunctioning component for speedy repairs. Therefore radiographers should have knowledge on how to handle minor equipment faults and the ability to manage such equipments via quality assurance tests and troubleshooting.
