The sharpness of the image x-ray


Fig. 1. The influence of the value of focus x-ray tube on the sharpness of the image. If the same object of research (or) value of confusion (And) decreases with decreasing sizes of tube focus (CFT).

Fig. 2. The impact of the focal length on the sharpness of the image. The designations are the same as in Fig. 1. With longer focal lengths blur (H) decreases.

2. The sharpness of the image is called the clarity of the shadow of items on the x-ray, and if to speak about the internal structure of the object, the structure (for example, bone, lung picture, and so on). Soft x-rays are different smudged, fuzzy image contours and details.
There are two types of confusion: the geometric and dynamic. Geometric blur (Fig. 1 and 2) depends on the focus x-ray tube (the sharper focus, not the less sharpness); distance-focus tube - film (the higher the percentage, the blur less) finally, from grain film and intensifying screens (the lower the grain size, the less blur). Therefore, to minimize the geometric blur, should be radiograph weight fine-focus x-ray tube, apply a sufficiently large focal length, to ensure a tight fit subject to the cassette to use fine-grain films and screens.
Dynamic blur depends mainly on the movements of the subject. In order to avoid reflections on the radiograph, or to minimize the influence of the dynamic of confusion, when you radiography physiologically moving organs (heart, lungs, stomach) to use short excerpts at the pictures and produce x-rays with the detainee breath, and in all other cases, to provide reliable fixation of the object in radiography, thereby eliminating a blur from his voluntary and involuntary movements.