Medical imaging is an important part of diagnosis of many diseases and also plays an important role in improving the public health. The diagnostic procedures involve the use of ionizing radiation which can cause a serious harm to operator and the patient, if it is not properly controlled. Although the radiation exposure connected with these procedures cannot be avoided, there are means to reduce it as much as possible. Therefore, the safety aspects of the radiation worker (operator) handling the equipment, the patient undergoing the test and others in the immediate vicinity of the installation is a major concern. The regulator and the government agency in every country takes necessary steps to protect the patients, staff and the general public by ensuring that only safe and properly installed X-ray equipments are used in the medical diagnostic X-ray facilities. This could be achieved through a proper Quality Assurance Program. The main objectives & needs of a Quality Assurance Program are to:
- Ensure proper functioning of the medical X-ray devices
- Reduce patient exposure
- Avoid unnecessary double exposures
- Reduce the costs of X-ray departments
The Quality Assurance Program consists of two activities:
- regular monitoring of diagnostic X-ray equipments by performing Quality Assurance (QA) and
- Area Surveillance of the diagnosis room.
- Quality Assurance consists of a series of standardized tests developed to detect changes in X-ray equipment function from its original level of performance. The objective of such tests, when carried out routinely, allows prompt corrective action to maintain X-ray image quality and to ensure that the dose delivered by the equipment over a period of time is as low as reasonably achievable (ALARA).
- Area Surveillance consists of a series of surveys performed near radioactive materials or radiation producing machines to ensure that the radioactive contamination and/or exposure levels are as low as reasonably achievable (ALARA).
To achieve this goal of ALARA principle, it is essential that a Quality Assurance and Area Surveillance program need to be developed and implemented in all medical diagnostic departments. It is important to note that the ultimate responsibility for quality assurance rests with the physician in charge of the x-ray facility. But at the same time, it is also the responsibility of the regulatory agency by placing proper regulations and guidelines to monitor these facilities.
Quality Assurance Testing include:
- 1. Congruence Test
- 2. Measurement of Kvp, Exposure Time, Dose
- 3. Linearity of mA Loading Stations, Timer
- 4. Total Filtration
- 5. Tube & Collimator Leakage Test
- 6. Focal Spot Test
- 7. Central Beam Alignment Test
- 8. Area Surveillance and Shielding Tests