After weeks of assiduous work studying the properties of a new type of radiation that was able to go through screens of notable thickness, Professor Dr. W.C. Röntgen astounded the world with the discovery of X-rays in 1895. He named them X-rays to underline the fact that their nature was unknown. X-rays were used on patients to investigate the skeleton, lung, skin, lesions, and other organs; hence, arose the birth of radiology. From radiology came radioscopy, which has firmly established itself in a wide range of industrial applications that of necessity depend on instant evaluation. ASTM E1255-23: Standard Practice For Radioscopy provides details for applying radioscopic examination.
Radiographic Examination Vs Radioscopic Examination
Essentially, radiography is an off-line, static examination technique, while radioscopy is a dynamic, real-time examination technique with the potential for on-line examination and process control. Radiography achieves a very high level of stationary imaging performance through the use of high-performance X-ray equipment and X-ray film. It is used to diagnose or treat patients by recording images of the internal structure of the body to assess the presence or absence of disease, foreign objects, and structural damage or anomaly. During a radiographic procedure, an x-ray beam is passed through the body. A portion of the x-rays are absorbed or scattered by the internal structure and the remaining x-ray pattern is transmitted to a detector so that an image may be recorded for later evaluation.
According to ASTM E1255-23, radioscopy may be either a dynamic, filmless technique allowing the examination part to be manipulated and imaging parameters optimized while the object is undergoing examination, or a static, filmless technique wherein the examination part is stationary with respect to the X-ray beam. It is broadly applicable to any material or examination object through which a beam of penetrating radiation may be passed and detected including metals, plastics, ceramics, composites, and other nonmetallic materials. It can used to understand internal structures (statues, mummies, musical instruments, archaeological objects, etc.). Radioscopic systems are also used in industrial applications for the continuous inspection of objects since these systems allow for flexible settings of the incident beam direction and the inspection perspective as well as for on-line viewing of the radioscopic image.
ASTM E1255-23 is the first radioscopy standard with general applicability to a wide range of real-time X-ray examination environments.
What Is ASTM E1255?
ASTM E1255-23 establishes the basic parameters for the application and control of the radioscopic examination method. It covers application details for radioscopic examination using penetrating radiation that utilizes an analog component such as an electro-optic device (for example, X-ray image intensifier (XRII) or analog camera, or both) or a Digital Detector Array (DDA) used in dynamic mode radioscopy. It establishes the minimum requirements for radioscopic examination of metallic and non-metallic materials using X-ray or gamma radiation. The standard specifies that radioscopy is a radiographic technique that can be used in the following ways:
- Dynamic mode radioscopy to track motion or optimize radiographic parameters in real-time, or both (25 to 30 frames per second), near real-time (a few frames per second), or high speed (hundreds to thousands of frames per second)
- Static mode radioscopy where there is no motion of the object during exposure as a filmless recording medium.
The requirements of this standard and ASTM E1411, which provides the performance qualification and long-term stability test procedures for the radioscopic system, should be used together.
The standard is not to be used for static mode radioscopy using DDAs. If static radioscopy using a DDA (that is, DDA radiography) is being performed, use ASTM E2698.
History of Radioscopy
In 1895, X-rays were first discovered by fluorescence, meaning that radioscopy, or fluoroscopy as it was formerly called, pre-dates film radiographic examination. Here is a timeline of the advancements of radioscopy:
- Late 1930s and early 1940s: Radioscopy with fluorescent screens was widely known as a non-destructive test method.
- Late 1940s: Closed cabinets were used to examine aluminum castings for the automotive industry.
- Mid 1950s: X-ray image intensifiers with a binocular were introduced to radioscopic inspection.
- Early 1960s: The image intensifier / TV camera chain was launched.
- Early 1970s: Continuing advancement of the imaging components and the inspection techniques led to a marked increase in the demand for radioscopic systems, especially for those that are intended for the examination of castings and welds.
- Early 1980s: Digital image processing techniques were increasingly applied in radioscopy.
ASTM E1255-23: Standard Practice For Radioscopy is available on the ANSI Webstore.