Since the discovery of radiation and radioactivity more than 100 years ago, radiation protection standards and the philosophy governing those standards have evolved. Proper evaluation of these standards requires a good understanding of each requirement that differs for particular types of construction and the intended use.
This article discusses the most common requirements for X-ray diagnostic equipment that ensures the maximum imaging performance and minimal radiation dose to keep patients and operators safe.
X-Ray Beam Quality
X-Ray equipment produce a continuous spectrum of X-rays with energies ranging from near zero up to a maximum value, determined by the selected tube potential.
However, the spectral X-ray distribution of X-rays is not always desirable for diagnostic radiology for two reasons:
- Certain levels of effective energy – high or low – result in unnecessary skin exposure to radiation, but do not contribute any diagnostic information on the image receptor.
- The type of diagnostic information needed dictates the X-ray energy required. If the X-ray beam is not “tuned” to the appropriate energy range, it will not be effective in contrasting between various constituents in the body (i.e. bone and muscle).
Field Limitation and Alignment
Equally important to ensuring the patient is subjected to a minimal dose of radiation is ensuring that the X-ray beam passes through the region of the patient’s body of clinical interest, as well as aligning correctly with the image receptor. There are a variety of diagnostic X-ray systems, each with their own alignment criteria, which are laid out in the whitepaper.
The production of a diagnostic radio-graph of acceptable quality depends on several factors. One of those factors is the reproducibility of X-ray exposure at selected radio-graphic technique factors, such as X-ray tube voltage and current. Thus, for a given set of technique factor settings, the exposure should be consistent each time since the X-ray image depends on those factors. Any unexpected deviation could result in less than optimum diagnostic information or possibly a need to retake the radiograph.
Another factor that plays an important role in X-ray image quality is the “linear” response in X-ray dose to the changes in the X-ray tube current. The “linear” response between tube current and X-ray production is important to produce the radiographic image in a predictable manner.
Testing for Leakage Radiation
During X-ray examination, an operator is exposed to insignificant radiation levels as compared to what a patient receives during the same session. However, accumulated exposure by medical personnel over time could present a health hazard and therefore protection against this radiation is specified in the IEC 60601-1-3 standard clause 12.4 LEAKAGE RADIATION in the LOADING STATE.
There is some misunderstanding in testing leakage radiation when evaluating the X-ray systems in standby mode. In some X-ray systems, during standby mode. The X-ray tube is partially energised to improve dynamic ON/OFF characteristics of X-ray exposure. For those X-ray systems, no radiation should be present in standby mode, but because they are partially energised, some leakage radiation may occur.
Why Choose TÜV Rheinland as Your Testing Partner?
TÜV Rheinland has extensive experience with the entire catalogue of technologies and applications necessary to test for the range of issues that may arise from the use of X-ray equipment. Whether it’s understanding radiation leakage, electrical variance, attenuation issues or which particular products supersede the standard, every day TÜV Rheinland helps clients navigate the complicated and sometimes confusing path to attaining the highest degree of safety.
For more information on medical device testing, download our whitepaper, or speak to one of our experts: