Biomedical subjects

A Tsirlis

Publications and source records attributed to A Tsirlis.

3 recordsLinked to original sources

PubMed2005

Conventional radiographs vs digitized radiographs: image quality assessment.

OBJECTIVES: The aim of this study was to compare image quality characteristics of conventional radiographs and their digital counterparts. METHODS: 100 conventional radiographs (E-speed) were used for the evaluation of density and contrast. The radiographs were made using a range of exposures under standardized conditions and were compared with digital images that resulted from scanning the above radiographs with a commercially available scanner. Resolution was evaluated with an experiment using 50 film packets and a resolution target exposed with different exposure times, using both the original radiographs and their scanned equivalents. RESULTS: The digitized radiographs appeared to be of higher density than the conventional ones. Moreover, they demonstrated a narrower density range. Resolution was similar for both types of images. CONCLUSIONS: Although there is an agreement with the literature that the digitized radiographs are of higher density, further investigation is required to detect the various factors that may have an effect on the quality of the digitized images.

Radiography, Dental↗

PubMed1994

Radiopacity of elastomeric impression materials.

The purpose of this study was to measure and classify the radiopacity of various elastomeric impression materials available on the open market and to compare their appearance in radiographs of the oral tissues. In order to measure and classify their radiopacity, twenty-eight specimens of various materials were placed and exposed on film together with an aluminium stepwedge. A dummy head was used to investigate the radiographic density of the above specimens in comparison with that of simulated oral tissues.

Absorptiometry, Photon↗

PubMed1989

[Arterial pressure variation following an intravenous and submucous injection of local anaesthetic solutions with vasoconstrictor].

This paper deals with the control, registration and statistical evaluation of blood pressure variations (systolic, diastolic and average) after an i.v. and submucous injection of fixed quantity local anaesthetic solutions (0.05 ml) in white hamsters. The solutions used were: lidocaine 2% with adrenaline 1/80,000, lidocaine 3% with noradrenaline 1/25,000. The intravenous injection of all three local anaesthetic solutions has caused an increase of the arterial pressure parameters which was statistically significant (P less than 0.01). The submucous injection of lidocaine 2% solution with adrenaline 1/80,000 and lidocaine 2% with noradrenaline 1/80,000 has not caused mentionworthy arterial pressure variations. On the contrary, the submucous injection of lidocaine 3% solution with noradrenaline 1/25,000 has led to an increase of the arterial pressure which is statistically important (P less than 0.05). The research results have led to the following conclusions: 1) Intravascular injection of local anaesthetics with adrenaline or noradrenaline has immediate negative consequences on the circulatory system, a fact which renders necessary a test respiration prior to any stem anaesthesia. 2) The submucous injection of lidocaine solutions with adrenaline or noradrenaline 1/80,000 may be described as harmless with respect to cardiovascular toxicity, and 3) The 3% lidocaine solution with noradrenaline 1/25,000 has proved to be capable of producing significant increase of the arterial pressure following a submucous injection. Anaesthetic solutions with 1/25,000 noradrenaline concentration should not be used, while they must be considered as extremely hazardous for patients with cardiovascular problems.

Administration, Buccal↗