PubMed Health⌕ Search

Biomedical subjects

K H Thunthy

Publications and source records attributed to K H Thunthy.

52 records · Page 3Linked to original sources
PubMed1978

Effect of mAs and kVp on resolution and on image contrast.

Two clinical experiments were conducted to study the effect of kVp and mAs on resolution and on image contrast percentage. The resolution was measured with a "test pattern." By using a transmission densitometer, image contrast percentage was determined by a mathematical formula. In the first part of the experiment, the density of the film was kept constant by changing the kVp and mAs. In the second part of the experiment, different mAs's were chosen, and for each mAs, several kVp's were used. Five observers read the radiographs. The first experiment showed that, when the film density is kept constant, the higher the kVp, the lower the resolution and image contrast percentage; also, the higher the mAs, the higher the resolution and image contrast percentage. The second experiment showed that when the film density is not kept constant, the correlation between kVp and resolution and between kVp and image contrast percentage was the same as in the first experiment. However, there was negligible correlation between mAs and resolution and between mAs and image contrast percentage. A high positive correlation was found between resolution and image contrast percentage, but a high negative correlation was found between resolution and film density.

Absorptiometry, Photon↗
PubMed1978

Comparison of xeroradiographs with occlusal and screen films.

Since the advent of xeroradiography, many questions have been asked about its image quality and speed relative to that of periapical and screen films. The experiment reported here measures the "resolution" of occlusal film, screen film, and xeroradiographs at different k Vp and mAs settings. The occlusal film was used instead of the periapical film because it has the same speed as a periapical film and is sufficiently large for the placement of the measuring instrument (a test pattern).

Dental Equipment↗
PubMed1976

A study of the resolution of dental films and screens.

From the study of the resolution produced by 156 screen-film combinations at a film density between 1.41 and 1.59, the following conclusions are drawn: 1. Resolution is affected by screens, films, and observers. 2. The effect of screens on resolution is much greater than the effect of films. 3. Screens varied greatly in resolving ability. 4. Films did not differ greatly in resolving ability. 5. Cronex Lightning Plus screen and Radelin super high-speed screen produced the lowest resolution and Cronex detail screen produced the highest resolution. 6. In general, the slower the screen, the higher is the resolution and vice versa. 7. There were two groups of films with significant resolution differences. 8. Films designed to be processed automatically did not differ significantly in their resolving ability when processed manually. 9. There is significant interaction effect of screens and films on resolution. 10. Individual visual resolving ability plays a significant role in measuring resolution.

Radiographic Image Enhancement↗
PubMedDate not supplied

Everything you wanted to know about radiographic duplication.

If dental radiographs are not duplicated correctly, the resulting duplicates will be of inferior quality. This article discusses the characteristics of a duplicating film, the principle of radiographic duplication, a description of dental duplicators, the selection of optimum duplicating time, a technique of duplicating radiographs, an alternate technique of duplicating radiographs, errors in duplication and their correction, and the maintenance of duplicators.

Copying Processes↗
PubMedDate not supplied

Differential diagnosis of pericoronal radiolucencies with and without radiopacities.

Pericoronal radiolucencies, by definition, surround the crown of a tooth. They are encountered not only in pediatric patients but also in adults of all ages. It is likely that all clinicians, at some time or another, will be confronted with a radiograph showing a pericoronal radiolucent lesion. The differential diagnosis of such lesions is reviewed.

Adult↗
PubMedDate not supplied

Diseases of the maxillary sinus.

Dentists often encounter patients whose signs and symptoms are not related to any dental disease, but rather originate in the maxillary sinuses. To distinguish when dental care is appropriate, dentists must be familiar with the anatomic, physiologic, clinical, and radiographic aspects of the maxillary sinuses.

Cysts↗