Assessment of parameters of digital X-ray detectors using the method of exposure of the working area of the detector to uniform X-ray radiation
It is shown that the main parameters determining the imaging quality of digital X-ray image detectors can be assessed by the method of exposure of the working area of the detector to uniform X-ray radiation. This method makes unnecessary the expert evaluation and measurements using high-precision test objects. It can be used in clinical practice for effective monitoring of the quality of digital X-ray detectors.
Modulation Transfer Function of Radiographic Systems Using Fluorescent Screens
When radiographic film is exposed with fluorescent intensifying screens, the spatial x-ray quantum fluctuations are recorded on the film in the form of density fluctuations (“quantum mottle”). The x-ray quantum fluctuations can be regarded as the input and the quantum mottle as the output of the image-forming system. The Wiener spectrum of the quantum mottle has been used to determine the relative modulation transfer function of two radiographic systems.
Measurement of Sine-Wave Response of a Photographic Emulsion*
A method for experimentally determining the sine-wave response of a photographic emulsion is described. It consists in determining the sine-wave response of a lens, using the lens to photograph a sinusoidal test object on the emulsion under test, determining the response of the lens-emulsion combination, and dividing out the response of the lens. Since sine-wave response is defined in terms of relative exposure in the emulsion, it should be substantially independent of development conditions and the exposure level when adjacency effects are absent. This expectation has been confirmed experimentally. It is also shown that the sine-wave response of a lens and the response of an emulsion can be combined to predict the characteristics of the lens-emulsion combination.