Radiopacity Testing

Radiopacity is the ability of a material to impede the passage of x-rays, thus allowing for visibility in an xray. This allows for devices to be tracked in vivo during a medical procedure. Radiopacity of a test article can be determined either qualitatively or quantitatively. Qualitative radiopacity compares visibility of a test article to a reference, such as a predicate device. Quantitative radiopacity calculates the difference in pixel intensity between the test article and the reference. Pixel intensity is defined as the greyscale value of a pixel between 0 and 255, with 0 representing black and 255 representing white. The lower the pixel intensity, the higher the radiopacity, and the more visible your device. Evaluating the radiopacity of medical devices is important to the development process since it verifies that the device will be adequately visible during a procedure. Figure 1 shows an example of medical devices arranged on a phantom, which mimics a portion of the body during radiopacity evaluation.