Can the Incorporation of a Lead Foil on the Backside of Digital Receptors Produce a Better Endodontic Diagnosis?

Objectives: To access the influence of the addition of a lead foil to intraoral digital radiographic receptors on image contrast and approximal caries lesions diagnosis. Methods: 40 posterior teeth were distributed in silicone phantoms composed of two premolars, two molars and a non-test canine. Radiographic images of the phantoms were obtained with and without the incorporation of a lead foil, using the Digora Optime and Digora Toto systems. Four observers scored the images for the presence of caries lesions, using a 5-point scale. Images of an aluminum step wedge were acquired with and without the incorporation of a lead foil. Gray values and standard deviation of gray values were calculated in different thickness of the step wedge and, then, contrast variation was calculated. Results: Presence of a lead foil did not influence caries lesions diagnostic values, regardless of the type of digital system (p > 0.05). In general, the objective analysis was not influenced by the presence of a lead foil in any of the tested systems (p > 0.05). However, Digora Toto images showed greater gray values, lower standard deviation of gray values and lower contrast variation, regardless of the presence of the lead foil (p < 0.05). Conclusions: The addition of a lead foil to intraoral digital receptors did not influence image contrast nor caries lesions diagnosis.

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Permeation of Electrolytically Generated Hydrogen and Tritium Atoms through Lead

Canadian Journal of Chemistry ◽

10.1139/v71-392 ◽

1971 ◽

Vol 49 (14) ◽

pp. 2406-2411 ◽

Cited By ~ 1

Author(s):

Bansi L. Muju ◽

Frank R. Smith

Keyword(s):

Current Density ◽

Separation Factor ◽

Room Temperature ◽

Alkaline Media ◽

Gas Evolution ◽

Hydrogen Atoms ◽

Metal Lattice ◽

Acidic And Alkaline Media ◽

A Current ◽

Lead Foil

Radiochemical and electrochemical evidence is presented that electrochemically generated tritium and hydrogen atoms permeate through lead foil at measureable rates at room temperature. The permeation process is controlled by diffusion through the metal lattice, Fick's First Law being obeyed by both H and 3H atoms. Using earlier measurements of the diffusivity of H in Pb, H and 3H concentrations of 4 × 10−7 and 9 × 10−13 g-atom cm−3 are computed for a current density of 53 mA cm−2 at the Pb cathode surface.The overall hydrogen-tritium separation factor, ST is apparently 0.3 ± 0.15, in contrast to Bockris and Srinivasan's 6.7 and 7.2 for cathodic gas evolution from acidic and alkaline media, respectively. Reasons are suggested for this large difference.

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Gamma-ray sensitivity and shielding of a neutron imaging plate

Journal of Applied Crystallography ◽

10.1107/s0021889899005701 ◽

1999 ◽

Vol 32 (5) ◽

pp. 878-882 ◽

Cited By ~ 14

Author(s):

Y. Karasawa Haga ◽

S. Kumazawa ◽

N. Niimura

Keyword(s):

Thermal Neutron ◽

Energy Dependence ◽

Gamma Rays ◽

Gamma Ray ◽

Neutron Imaging ◽

Atomic Energy ◽

Imaging Plate ◽

Energy Research ◽

Experimental Hall ◽

Lead Foil

The energy dependence of gamma-ray sensitivity of a neutron imaging plate (NIP) has been measured. The gamma-ray sensitivity is equivalent to one half that of a thermal neutron at a gamma-ray energy less than 300 keV, and 1/40 at greater than 300 keV. The shielding of the NIP, by lead, from gamma rays in the experimental hall of the reactor JRR-3M of the Japan Atomic Energy Research Institute (JAERI) was measured. It was found that lead of thickness 40 mm is sufficient to reduce the gamma-ray background to 1/10 on a normalized scale. Covering the NIP with lead foil of thickness 1 mm results in a decrease of the gamma-ray background without reduction of the neutron signal.

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Influence of the incorporation of a lead foil to intraoral digital receptors on the image quality and root fracture diagnosis

Dentomaxillofacial Radiology ◽

10.1259/dmfr.20180369 ◽

2019 ◽

Vol 48 (6) ◽

pp. 20180369 ◽

Cited By ~ 3

Author(s):

Amanda Farias Gomes ◽

Yuri Nejaim ◽

Rocharles Cavalcante Fontenele ◽

Francisco Haiter-Neto ◽

Deborah Queiroz Freitas

Keyword(s):

Image Quality ◽

Control Group ◽

Human Teeth ◽

Radiographic Images ◽

Root Fracture ◽

Vertical Root Fracture ◽

Diagnostic Values ◽

Fracture Diagnosis ◽

Lead Foil

Objective: To evaluate the quality of images obtained with the addition of a lead foil to intraoral digital receptors. Methods: Radiographic images of 34 single-rooted human teeth - 19 with vertical root fracture (VRF) and 15 of the control group - were obtained with and without the addition of a lead foil, using the VistaScan, Express, Digora Optime and Digora Toto systems. Images were evaluated by five observers regarding the diagnosis of VRF, using a 5-point scale. In a second moment, an observer preference analysis related to the presence of the lead foil was performed. Images of an acrylic phantom were also obtained with and without the addition of a lead foil, and the quantities of uniformity, grey value and standard deviation of grey values were obtained. Results: There were no significant differences in the VRF diagnostic values, considering the presence of the lead foil. Regarding the image quality preference, the observers preferred images acquired with the lead foil for all systems tested, but with greater values for Digora Optime (61.33%) and Express (61.33%). The presence of the lead foil did influence the image uniformity in all systems tested ( p < 0.05). Moreover, the lead foil increased the mean of grey values for Digora Optime and Express images ( p < 0.05), however it did not influence the SD in any of the digital systems ( p > 0.05). Conclusion: The addition of a lead foil to intraoral digital receptors produces a positive effect in the image quality objectively detected by means of uniformity and subjective visual preference.

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