X-Ray Spectrogram Film Densitometer

The increased emphasis on mass screening for early detection of cancer has created a demand for effective quality assurance of medical radiography equipment. This is particularly true in mammography where indications of cancer are subtle and the image quality varies strongly with the x-ray technique used for the examination. Many studies clearly indicate that well calibrated and aligned equipment is a key to producing the high quality images required for effective screening. The measurement of x-ray tube voltage calibration is an important part of quality assurance for medical diagnostic examinations such as mammography. A new method, recently developed by NIST, gives a direct measurement of the tube voltage from the x-ray spectrum of the tube. An instrument is required to measure the spectrometric image and transfer the data to a portable computer which can then compute the high energy limit and hence the tube voltage. We propose a new densitometer approach for this application. The new approach proposed allows the use of inexpensive, commonly available components while producing the required wide dynamic range and high spatial resolution. If the research is successful, it will be the basis for a low cost, high performance scanner.