Xeroradiography--its use in peripheral contrast medium angiography

A cephalometric appraisal of xeroradiography

The literature on the physics, the radiation hazard, and the current medicodental applications of xeroradiography is reviewed. A study is presented on estimating the effect of a xeroradiographic technique on the degree of inter- and intraobserver error in cephalometric landmark identification, as compared to a radiographic technique. This study involved identification by four observers of sixteen cephalometric landmarks on twelve xeroradiographs and twelve radiographs, on two separate occasions. The conclusions are that neither technique provided a significant reduction in interobserver differences. However, for eight of the thirty-two variables (nasion's Y axis, portion's X and Y axes, basion's X axis, Bolton point's X axis, anterior nasal spine's X axis, menton's Y axis, and the tip of the nose's X axis), as opposed to two (basion's Y axis and gonion's Y axis), xeroradiography produced a significant reduction in intraobserver error in comparison to radiography.

Xeroradiography of the hand in patients with renal osteodystrophy

The hands of 40 patients with chronic renal failure and varying degrees of renal osteodystrophy were studied. The xerograph and radiograph of each patient were compared, assessing the degree of subperiosteal erosion, and of vascular, capsular and ectopic calcification. While the changes of osteodystrophy were clearly demonstrated on the xeroradiographs, they were also seen on the radiographs, even when only minor changes were present. The authors prefer the xeroradiograph for the measurement of the metacarpal cortical thickness, because of the sharp medial border of the cortex afforded by the "edge enhancement" of this technique.

New methods of imaging in diagnostic radiology Sylvanus Thompson Memorial Lecture

A brief history of the recent developments in computer-assisted tomography (CAT) is presented. The development of whole-body scanners from the basic brain scanner, the trend towards higher-speed scanners using multiple detectors in a fan-type geometry, and some of the unsolved problems related to CAT scanners are discussed, as well as the potential use of whole-body scanning in radiotherapy treatment planning and in radiobiology. A review of recent developments in electrostatic imaging is presented and a new method of imaging called ionography is described in detail. It is shown how a single exposure can be used to produce a number of copies, each with a different amount of edge contrast, under the control of the radiologist. Further, it is shown how this can be done using a closed system so that the ionography chamber never needs to be opened. Some of the recent commercial developments in this field are described. It is suggested that in the future radiology departments may be replaced by departments of imaging, which will include all ways of obtaining diagnostic information and where such a department would be problem oriented rather than technique oriented. The need for basic scientific support by a medical physics and engineering group in such a department is emphasized.

Application of xeroradiography in sialography

Sialography was carried out in healthy volunteers and in patients with Sjögren's syndrome. A comparison was made between xeroradiography and conventional radiography. Superior images were obtained with xeroradiography and this technique also tended to reveal glandular structure which was obscured by overlying bone when using conventional radiography. In addition to this, there was considerably greater latitude in exposure and the skin dose of radiation using xeroradiography was slightly less.

Radiation exposure to the patient in xeroradiography

The paper presents measurements of the radiation exposure required in xeroradiography of the breast and of the extremities. The nature of the radiation hazard and the most appropriate quantity by which to assess it are discussed, and it is shown that for a number of radiological procedures xeroradiographs can be taken for about the same radiation exposure to the patient as that required by conventional film techniques.