A comparative study between xerographic, computer-assisted overlay generation and animated-superimposition methods in bite mark analyses.

This study was to compare the suitability and precision of xerographic and computer-assisted methods for bite mark investigations. Eleven subjects were asked to bite on their forearm and the bite marks were photographically recorded. Alginate impressions of the subjects' dentition were taken and their casts were made using dental stone. The overlays generated by xerographic method were obtained by photocopying the subjects' casts and the incisal edge outlines were then transferred on a transparent sheet. The bite mark images were imported into Adobe Photoshop® software and printed to life-size. The bite mark analyses using xerographically generated overlays were done by comparing an overlay to the corresponding printed bite mark images manually. In computer-assisted method, the subjects' casts were scanned into Adobe Photoshop®. The bite mark analyses using computer-assisted overlay generation were done by matching an overlay and the corresponding bite mark images digitally using Adobe Photoshop®. Another comparison method was superimposing the cast images with corresponding bite mark images employing the Adobe Photoshop® CS6 and GIF-Animator©. A score with a range of 0-3 was given during analysis to each precision-determining criterion and the score was increased with better matching. The Kruskal Wallis H test showed significant difference between the three sets of data (H=18.761, p<0.05). In conclusion, bite mark analysis using the computer-assisted animated-superimposition method was the most accurate, followed by the computer-assisted overlay generation and lastly the xerographic method. The superior precision contributed by digital method is discernible despite the human skin being a poor recording medium of bite marks.

Calciphylaxis in a patient with normal renal function: response to treatment with sodium thiosulfate.

Calciphylaxis is a rare, life-threatening cause of skin necrosis. The condition is primarily reported in patients with end-stage renal disease, and is associated with significant morbidity and mortality. Treatment has mainly been empirical. We report a case of calciphylaxis in a patient with normal renal function and hypoparathyroidism, who responded to treatment with sodium thiosulfate. To our knowledge, this is the first reported case of the use of sodium thiosulfate to treat calciphylaxis in a patient with normal renal function.

[Medical X-ray dryview photography and digitized diagnostic technique].

This paper introduces briefly xeroradiography, computed radiography system, x-ray dryview laser imaging series system and its products, digitized diagnostic technique, as well as the electronic radiography etc.

Estenosis subglótica adquirida: experiencia en 80 casos: Hospital Niños "J. M. de los Ríos" / Adquire subglotic stenosis: experience in cases: Hospital of Niños \"J. M.\" of the Rios

La Estenosis Subglótica Adquirida es una entidad que afecta a tejidos blandos y estructuras cartilaginosas del espacio subglótico. Desde enero de 1987 hasta agosto de 1995, ingresaron al servicio de ORL del Hospital de Niños "J.M de Los Ríos" 80 pacientes con esta patología. El 87 por ciento (70) ameritaron traqueotomía y el 13 por ciento (10) no necesito tratamiento alguno. De los 70 pacientes traqueotomisados el 77 por ciento (60), se les realizó dilatación más infiltración de esteroides. al 10 por ciento (8), se les practicó laringotraqueoplastia, 2 pacientes fallecieron. El 75 por ciento (45) de los traqueotomisados fueron decanulados y dados de alta. El 25 por ciento (15) de los pacientes se mantienen en tratamiento. Fueron decanulados el 75 por ciento (6) de los 8 pacientes a los cuales se les realizó laringotraqueoplastia; y el 25 por ciento (2) no han podido ser decanulados por regresión de la estenosis.

The location of hyoid fractures in strangulation revealed by xeroradiography.

The location of 19 fractures of 15 hyoid bones was studied from 13 cases of manual strangulation and two cases of hanging. The precise location of the fractures were determined by xeroradiography of isolated hyoid bones. To classify the location of the fractures, the greater cornu was divided into anterior, middle, and posterior thirds and the frequency of fracture occurrence in these locations was determined. In addition, the angle of curvature of the greater cornu was determined at the fracture site to ascertain if specific points along the greater cornu were more susceptible to fracture. Fractures were found with equal frequency in the posterior and middle thirds of the hyoid greater cornu (9/19, 47% for both posterior and middle) but were rare in the anterior portion (1/19, 5%). However, all fractures occurred between 30 degrees and 60 degrees of curvature of the hyoid and most fractures (approximately 60%) were found at approximately 50 degrees. These results indicate that fractures of the hyoid occur at vulnerable angles of curvature of the hyoid bone which, due to anatomic variation in hyoid shape, do not necessarily occur at specific segments of the hyoid bone. On this basis, although the presence of the hyoid fracture in strangulation is determined by the rigidity of the bone, the specific location is determined by the shape of the greater cornu.

[Xeroradiography and digital luminescence radiography in the study of the technics of manufacturing ancient ceramics. The advantages and limits]. / Xeroradiografia e radiografia digitale a luminescenza nello studio delle tecniche di manifattura della ceramica antica. Vantaggi e limiti.

This paper reports on the cooperative work of the Department of Radiology of the Catholic University, Rome, and of the Italian Institute for Middle and Far East. The study was aimed at using xeroradiography and digital luminescence radiography for the archeometric evaluation of ancient ceramics and at assessing the imaging potentials of the two techniques. Some manufacturing techniques are reported which were used in the ancient world and societies for pottery making--i.e., coil building (the superimposition of clay rings), paddle and anvil beating and throwing of the wheel. Such techniques leave, on the vessel's wall, clear traces which can be detected by X-ray imaging. After discussing the main semiologic features, we present 4 case studies from the project archive. Each vase underwent xeroradiography and digital luminescence radiography. The former technique was useful in detailing minor phase transitions--e.g., pores and inclusions--while the latter, thanks to both its wide dynamic range and its image processing potentials, was optimal in defining very gradual thickness transitions due to the different techniques used to join the clay parts. By combining the two techniques, the manufacturing technology of the artifacts could be defined. The interactive processing of radiographic images at the system console was seen to be of major importance: it allowed the best results to be obtained thanks to the integration of the radiologists' and archeologists' know-how during the actual analytical stages.

Effect of denture wax-pattern position on radial setting expansion.

Th dynamics of the setting expansion of gypsum-bonded investment is complicated by many variables and not well understood. The purposes of this study were to examine the fluid mechanics of the flow of investment during setting and to determine if the presence of wax patterns influences effective setting expansion. Mesial-occlusal-distal (MOD) inlay wax patterns were invested at six different radial positions and four different axial positions in plastics casting rings. Total expansion was determined by using xeroradiography. Combined results of radial expansion data at different axial and radial locations within casting rings suggest that expansion of gypsum-bonded investment may represent a variant of the laminar flow of a viscous fluid.

A comparison between xeroradiographs and conventional radiographs as an aid in root canal therapy for maxillary molars.

The purpose of this study was to compare the quality of images obtained with dental xeroradiography to that obtained with conventional dental radiography during performance of root canal therapy on maxillary molars. For each step requiring radiographic information during endodontic treatment of 12 maxillary molars, a conventional radiograph and a xeroradiograph were made. This produced four pairs of images for each tooth treated as follows: (1) preoperative, (2) initial files for length determination, (3) master cones fitted, and (4) completed obturation of the root canal systems. The same x-ray machine was used as the source of radiation for all exposures with a setting of 70 kVp and 15 mA and with near identical projection for each pair of images achieved through use of a modified film holder and a custom positioning occlusal index made for each patient. Exposure time for the radiographs was 60 impulses (1 impulse = 1/60 second) and for the xeroradiographs it was 42 impulses. Images of structures and items important in endodontic diagnosis and treatment were rated as unacceptable (0), poor (1), adequate (2), or optimal (3) by four independent evaluators. Analysis of data showed the following: images of bone trabeculae, periodontal ligament spaces, root morphology, root apices, and fine bony abnormalities were judged to be significantly better in the radiographs than in the xeroradiographs (p less than 0.01) whereas there were no significant differences in image quality of pulp chamber morphology, root canal morphology, metallic measuring instruments, or endodontic filling materials.

[Xeroradiographic scanning in clinical oncology]. / Elektrorentgenoskanirovanie v klinicheskoi onkologii.

A combined method of xeroradiographic scanning (ERS) was used for the recognition of tumors of different organs. Altogether 645 cancer patients were investigated: 98 with head and neck tumors, 102--with pulmonary and mediastinal tumors, 254--with liver tumors, 86--with renal tumors, 52--with bone tumors, and 53--with prostatic tumors. Special methods of investigation and tumoritropic radiopharmaceuticals 75Se-methionine, 67Ga-citrate, 85Sr, 113In, 99Tc, etc. were used. Statistical data processing was done using Olivetti computer M-24. ERS was shown to be the most effective method for the detection of cancer of the lung mediastinum (90%), head and neck (89%), and prostate (89%). The method is particularly valuable for tumors developing in anatomical regions inaccessible for examination, biopsy, and x-ray findings are not sufficiently clear. The use of ERS excludes possible errors in diagnosing disease on the edges of an organ, especially in liver and kidney investigation. The method also proved to be valuable for the assessment of therapeutic efficacy and correction of fields of irradiation.

Exposure times at which dental xeroradiographs and radiographs have comparable optical density.

Xeroradiographs and conventional radiographs were made of a dentulous human cadaver maxilla that was still covered with soft tissue. The times of exposure for the xeroradiographs started at 6 impulses (1 impulse = 1/60 second) and were increased by increments of 3 impulses through 48 for subsequent images, while the radiographs were made with D-speed film and exposure times of from 21 through 63 impulses, again at every third reading. The same x-ray machine, operated at 70 kVp and 15 mA, was used as the source of radiation for all images. Film/cassette-to-jaw relationship and focal-spot-to-film/cassette distance were standardized. Transmission optical density of the resulting images was determined. The results showed that radiographs with transmission optical densities comparable to those of xeroradiographs could be produced with exposure times approximately 3 times those used for xeroradiographs in the lower part of the range observed. This factor decreased to approximately 1.3 as optical density increased.

Use of a "sandwich" technique to control image geometry in clinical studies comparing intraoral xeroradiographs and E-speed films.

A method of superimposing a film on a xeroradiographic (XR) cassette for simultaneous intraoral exposure is evaluated for use as an imaging technique in clinical studies comparing Ektaspeed film and XR images. Sandwich images were indistinguishable from those produced by conventional technique. Pilot studies were conducted with 104 patients who had symptomatic dental problems. No significant differences were found in diagnostic usefulness or image quality between XR and film radiographs when sign test analysis was used. The sandwich technique yielded film and XR images with duplicate image geometry while reducing patient exposures to one half of that used in conventional image comparison protocols.

Clinical assessment of anatomic positioning and patient comfort for intraoral radiography: a comparison of xeroradiography versus film.

The Xerox 110 dental system employs rigid beveled-edge cassettes containing charged selenium-alloy plates for intraoral xeroradiography. This study evaluates the ability of a skilled operator to position these cassettes accurately within the oral cavity as compared to the ability to position conventional film packets using two types of image holders. Results indicate that xeroradiographic cassettes are significantly more difficult to use for complete-mouth radiographs than comparable conventional film packets. Also, the use of xeroradiographic cassettes causes a slight increase in patient discomfort. In addition, two types of rectangular collimating devices were shown to be useful. The greatest shortcoming of the xeroradiographic cassette is not its greater thickness or rigidity but the reduced dimensions of its internal surface area.