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Biomedical subjects

S C White

Publications and source records attributed to S C White.

At least 91 records · Page 5Linked to original sources
PubMed1984

An evaluation of rare-earth imaging systems in panoramic radiography.

Panoramic radiographs were made of ninety-nine consenting adult patients who had image-analysis test devices placed within their oral cavities. Quantitative characteristics and perceived image quality of eight screen-film combinations were investigated. The quantitative characteristics of the images evaluated included contrast, resolution (in three regions), and bead detection (a measure of noise). Perceived image quality assessed similar characteristics. In addition, expert observers rated the resultant patient radiographs for both general and specific diagnostic tasks. Calcium tungstate screen-film systems were found to have the highest contrast but with resolution comparable to rare-earth screen-film systems under clinical test conditions. Calcium tungstate systems required up to twice the radiation exposure of the patient. It was found that some rare-earth screen-film combinations may produce clinically acceptable panoramic radiographs while reducing the patient's radiation exposure.

Adult↗
PubMed1984

Periodontal ligament changes in patients with progressive systemic sclerosis.

Progressive systemic sclerosis (PSS) is a generalized collagen disease which has oral manifestations, including widening of the periodontal ligament (PDL) space. The purpose of this study was to measure the extent of thickening of the PDL space in a group of 26 patients with PSS and in a similar group of age and sex-matched control patients. The width of the PDL was measured from periapical radiographs at four sites around seven selected teeth for every patient. The mean PDL width was found to be larger in all the patients with PSS than in the control patients, around both anterior and posterior teeth. One third of the teeth of patients with PSS had PDL widths thicker than the range observed in the control patients. When average thickness of PDL widths for each patient is compared, at least 65% of the patients with PSS have mean PDL widths which are greater than the range for control patients. The increased thickness of the PDL space associated with PSS is more pronounced in posterior teeth than in anterior teeth.

Adult↗
PubMed1984

Comparison of xeroradiographs and film for detection of periapical lesions.

Xeroradiographs and Kodak Ektaspeed film were compared with Kodak Ultraspeed film for their ability to reveal periapical lesions. Cadaver specimens containing teeth which were normal or demonstrated periapical inflammatory disease were used as the test objects. These specimens were first radiographed using xeroradiographic plates or film. Following radiography, histologic analysis revealed the true presence or absence of disease. Ten oral radiologists scored all xeroradiographic and film images of the specimens for the presence of periapical disease. In general, the observers detected about 70% of the cases with periapical disease, while simultaneously considering about 10 to 15% of the normal surfaces to be abnormal. Receiver-operating-characteristic (ROC) analysis of the radiographic decisions revealed little difference in the diagnostic performance of the observers using the various image receptors, although both types of film and low-contrast xeroradiographs viewed in transmitted light were all more useful than low-contrast xeroradiographs viewed in reflected light. In terms of patient dose, both xeroradiographic images and Ektaspeed film are preferred over Ultraspeed film.

Diagnosis, Differential↗
PubMed1982

Radiation safety for children.

In recent years there has been much public and professional concern about reducing patient exposure to radiation. This concern is especially appropriate for children because of their greater sensitivity to it. Exposure risks to children may be reduced by using radiography only when there is a specific clinical indication. Bitewing radiographs are indicated for detection of approximal caries in the child when the molar contacts are closed. The frequency of this examination should be determined on an individual basis. Other radiographs should be obtained only when there are clinical signs or symptoms suggesting disease. When a decision has been made to expose a patient to X-rays beam-restricting film holders, leaded aprons and thyroid collars should be employed. To minimize repeat radiographic examinations because of processing faults, the operator should use proper procedures coupled with an understanding of the film developing process. Further dose reduction may be anticipated with the advent of E-speed film, dental xeroradiography or rod-anode source radiography. Most importantly, dose reduction requires an awareness by the dentist and operator of its importance and the means available to accomplish it.

Child↗
PubMed1981

President's page.

Explore the source record for details and available documents.

Aerospace Medicine↗
PubMed1980

Xeroradiography for intraoral dental radiology. A process description.

A novel x-ray imaging system for intraoral dental radiography is described. The imaging process is based on xeroradiographic principles. The surface of a small selenium photoreceptor is electrically charged. After insertion into a light-tight cassette, the photoreceptor is placed intraorally and x-ray exposed like film. The resultant electrostatic charge image is developed in a processor using liquid toner. The toner image is then transferred from the photoreceptor and fixed to a white plastic substrate for viewing. After cleaning, the photoreceptor is available for reuse. In contrast to film images, xeroradiographic images are exposed and processed sequentially. Processing time is approximately 20 seconds. Two image characteristics--edge enhancement and deletion--are primarily responsible for many advantageous qualities of xeroradiographic images over film images. An experimental processor was tested successfully at two dental schools.

Alloys↗
PubMed1980

Xeroradiography of dental structures. IV. Image properties of a dedicated intraoral system.

Dental xeroradiography, a new imaging system designed specifically for intraoral use, provides a convenient, rapid, low-dose alternative to conventional film radiography. In this study the new imaging system was compared to conventional direct-exposure dental film technique for basic imaging characteristics of contrast, resolution, and noise. Dental xeroradiography proved to be a superior imaging system for demonstrating dental structures and did so at radiation doses one-third of those required for conventional dental (film) radiography.

Humans↗
PubMed1979

Absorbed bone marrow dose in certain dental radiographic techniques.

Dosages of radiation absorbed in the bone marrow of the calvaria, mandible, and cervical spine were measured during dental diagnostic exposures using intraoral, panoramic, and cephalometric radiographic techniques. The use of rectangular collimation in intraoral radiography reduced the total absorbed dose to the bone marrow of the mandible and cervical spine. Doses from the dental radiographic techniques are compared with environmental levels of background irradiation.

Bone Marrow↗
PubMed1979

Imaging properties of intraoral dental xeroradiography.

A prototype imaging system for intraoral dental xeroradiography has been described. In vivo evaluations of image quality show that intraoral xeroradiographs are superior to conventional intraoral film radiographs primarily because of the wide latitude and edge enhancement properties of xeroradiography. In addition, intraoral xeroradiography requires only a third of the radiation dose of corresponding intraoral film techniques.

Evaluation Studies as Topic↗
PubMed1979

Clinical trials of intraoral dental xeroradiography.

A new dental xeroradiographic processor was clinically tested. In comparison with conventional radiographs, xeroradiographs often showed more anatomic detail of teeth and bone and required approximately half the exposure time. These characteristics, the speed of operation and the added features for convenience, suggest that xeroradiography may be important to dental radiography in the future.

Alveolar Process↗