Hybrid x-ray luminescence and optical imaging

X-ray diagnostic imaging is a major worldwide activity. In the United States, approximately 250 million x-ray examinations are performed annually, and in Europe, a similar level of radiological activity is undertaken. This results in the fact that the largest contribution to radiation exposure to the population as a whole is known to be from manmade radiation sources arising in the form of diagnostic x-ray (UNSCEAR 2012). For diagnostic radiology, the image is generated by the interaction of x-ray photons, which have transmitted through the patient, with a photon detector. These photons can either be primary photons, which have passed through the tissue without interacting, or secondary photons, which result from an interaction along their 118path through the patient. The secondary photons will in general be deflected from their original direction and result in scattered radiation. The basic principles of projection radiography are that path through the patient. The secondary photons will in general be deflected from their original direction and result in scattered radiation. The basic principles of projection radiography are that 1. X-rays are produced in an x-ray tube. 2. The energy distribution of the photons is modified by inherent and additional filtration. 3. The x-rays are attenuated differently by the various body tissues. 4. Scattered radiation, which impairs image contrast, is reduced. 5. The transmitted photons are detected. The x-ray image is a two-dimensional (2-D) projection of the attenuating properties of all the tissues along the paths of the x-rays. The photons emitted by the x-ray tube are collimated by a beam-limiting device. Then they enter the patient, where they may be scattered, absorbed, or transmitted without interaction. The primary photons recorded by the image receptor form the image. The secondary photons create a certain amount of background radiation which degrades contrast. If necessary, the majority of the scattered photons can be removed by placing an antiscatter device between the patient and the image receptor. This device can simply be an air gap or a so-called antiscatter grid formed from a series of parallel metal strips.