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At least 775 records · Page 43Linked to original sources
PubMed2006

An ex vivo characterization of Paclitaxel loaded chitosan films after implantation in mice.

The objective of present investigation was the characterization of chitosan films after in vivo implantation. Chitosan films were prepared at three dose loadings of paclitaxel by classical casting method. They were implanted subcutaneously in Swiss mice in the neck region and were removed at 7, 15, 21 and 30 days post implantation for characterization. In vitro release studies on explanted films were done to observe the influence of the time of implantation and loading on paclitaxel release, which were correlated with amount of paclitaxel remaining in films. Residual amount of paclitaxel remaining in explanted films decreased with increase in loading i.e. after 30 days, the % residual content of drug at 25, 20 and 15 mg loadings (per film) were 13, 20 and 45 % of the initial loading. The in vivo release of paclitaxel from films with higher loadings was higher, indicating that paclitaxel, per se, altered biodegradation of chitosan. Light microscopy and SEM studies of films removed from mice provided qualitative information on the loss of integrity and biodegradation of films with time. Further, FTIR and ATR-FTIR spectra revealed the changes in the film matrix that occur after implantation.

Animals↗
PubMed2006

Digital and screen-film mammography: comparison of image acquisition and interpretation times.

OBJECTIVE: The objective of our study was to compare acquisition times and interpretation times of screening examinations using screen-film mammography and soft-copy digital mammography. MATERIALS AND METHODS: Technologist study acquisition time from examination initiation to release of the screenee was measured for both screen-film and digital mammography (100 cases each) in routine clinical practice. The total interpretation time for screening mammography was also measured for 183 hard-copy screen-film cases and 181 soft-copy digital cases interpreted by a total of seven breast imaging radiologists, four experienced breast imagers, and three breast imaging fellows. RESULTS: Screening mammography acquisition time averaged 21.6 minutes for screen-film and 14.1 minutes for digital, a highly significant 35% shorter time for digital than screen-film (p < 10(-17)). The average number of images per case acquired with digital mammography was higher than that for screen-film mammography (4.23 for screen-film, 4.50 for digital; p = 0.047). The total interpretation time averaged 1.4 minutes for screen-film mammography and 2.3 minutes for digital mammography, a highly significant 57% longer interpretation time for digital (p < 10(-11)). In addition, technical problems delaying interpretation were encountered in none of the 183 screen-film cases but occurred in nine (5%) of the 181 digital cases. CONCLUSION: Compared with screen-film mammography, the use of digital mammography for screening examinations significantly shortened acquisition time but significantly increased interpretation time. In addition, more technical problems were encountered that delayed the interpretation of digital cases.

Female↗
PubMedDate not supplied

[Boleslas Matuszewki--pioneer of medical film-making].

Boleslas Matuszewski, born in 1856, was a pioneer in medical film-making. He worked simultaneously on improving his movie camera, film-making, collecting film documentation, and the idea of establishing an archive of medical films. Although his first attempts at filming and showing surgical operations didn't gain widespread approval, he was not discouraged, and succeeded in garnering support from a number of French doctors, who realised the importance of his ideas, not only in filming and forming medical film documentation, but also in the use of film for educative purposes. His visionary ideas gained acceptance when Dr. Doyen, on the occasion of the 66th Convention of the British Medical Society, in 1898, used film material as part of his lecture. Shortly afterwards, the Medical Academy took steps to show certain operative techniques, which represented both the confirmation and fruition of Matuszewski's ideas about filmmaking and the establishment of an archive of medical films.

Famous Persons↗
PubMedDate not supplied

Effect of tear film stability on fluctuation of vision after photorefractive keratectomy.

PURPOSE: To evaluate the difference in tear film break-up between normal eyes and eyes after photorefractive keratectomy (PRK) and its impact on quality of vision in PRK eyes. METHODS: Seventy-seven normal eyes and 76 eyes with no ocular pathology except refractive error that had PRK were enrolled. Tear film break-up time was determined under slit-lamp microscopy with fluorescent staining. Two videokeratographs (TMS-1) were taken before and immediately after tear film break-up. Surface asymmetry index, surface regularity index, and subtractive maps were analyzed to evaluate corneal topographic changes before and after tear film break-up. RESULTS: The distribution of tear film break-up in the central cornea was different in PRK eyes than in normal eyes (P < .0001). Distributions of tear film break-up after PRK were localized more in the upper and lower temporal regions than in normal eyes; incidence of tear film break-up in the central cornea was decreased. There were no significant differences in tear film break-up between normal eyes and eyes after PRK (P = .69). Twelve PRK patients (24 eyes, 32%) experienced fluctuation of vision and fatigue during normal activities after PRK. We divided eyes after PRK into two groups (with and without fluctuation of vision) and found a statistically significant difference in surface asymmetry index before tear film break-up between the two groups (P = .0092). CONCLUSION: The distribution of tear film break-up is changed after PRK. Eyes after PRK experienced more fluctuation of vision than normal eyes.

Adult↗
PubMed1999

Electron density imaging of protein films on gold-particle surfaces with transmission electron microscopy.

BACKGROUND: Surface bound proteins on colloid particles are widely used in biotechnological applications such as diagnostics or separation. Analysis of colloid surfaces by imaging methods provides information on the structure of these protein films, and an understanding of the functional relationships of biomolecules immobilised on solid surfaces. METHODS: In order to visualise protein molecules organised in films on surfaces of nano-sized gold-particles, an electron-microscopic approach based on the scattering absorption contrast of the specimen was applied. RESULTS: Analysing protein conjugated gold particles with a transmission electron microscope, protein films on gold particle surfaces cause a significant scattering absorption contrast based on the materials' electron density. Thus, the thickness of such films becomes directly measurable in planar projection and the shape of these films are visualised without negative staining methods. The insertion of Ruthenium-labelled antibodies instead of non-labelled antibodies as a marker with increased electron-density in these films yields a contrast enhancement of the whole film. Additional labelling with anti-Mouse IgG Gold conjugates localises the position of the surface bound antibodies in such protein films. CONCLUSIONS: The power of transmission electron microscopy to resolve protein-films on colloid surfaces without staining or labelling as a sample preparation procedure has been demonstrated. Thus, this direct method provides an analytical tool for studying protein films and their structural features on particle surfaces.

Animals↗
PubMed2003

Bone bonding strength of sputtered hydroxyapatite films subjected to a low temperature hydrothermal treatment.

Hydroxyapatite (HA) was coated onto titanium substrates using radio frequency sputtering, and the coated HA films were crystallized in an autoclave at 110 degrees C using a low temperature hydrothermal method. The crystallite size, the Ca/P ratio, and the surface of the films were observed using XRD, EDS, and SEM, respectively. An immersion test was carried out in physiological saline solution, and the film-to-substrate adhesion strength was measured using a pull-out test. From the XRD patterns, a sputtered film subjected to the hydrothermal treatment had crystallized after 24 h, and the crystallite size increased from 38.0+/-8.7 to 81.4+/-19.1 nm. In immersion tests, an as-sputtered film completely dissolved after 1 d, whereas a sputtered film subjected to the hydrothermal treatment survived to 18.7+/-5.8% of the initial film thickness after four weeks. In pull-out tests, the adhesion strength of the sputtered film to the substrate increased from 1.9+/-0.2 to 5.3+/-1.6 MPa after the hydrothermal treatment. A sputtered film subjected to the hydrothermal treatment and a plasma-sprayed coating on titanium columns were implanted in the diaphysis of the femora of six adult dogs, and a pull-out test was carried out after two, four, and 12 weeks. The sputtered film showed higher bone bonding strength than the plasma-sprayed coating at any period.

Animals↗
PubMed2004

[Characterizing methods of structure and character for silane film on metal surface].

Surface analysis methods for structure and characters of silane film on metal surface were reviewed in this paper. Many instrumental methods, such as XPS, ATR-FTIR, RA-FTIR, SIMS, ellipsometry, EIS and so on, were applied to characterizing different silane films on different metal base surfaces. According to the research on silane film formation mechanism, silane film state, silane film structure, silane film thickness, silane film corrosion resistance and so on, factors which affect silane film properties were discussed. Various parameters were proposed for characterizing silane film. Merits and defects of various surface analysis methods were expressed. In order to acquire more chemical information, different surface analysis methods can be combined for detection at the same time. Regarding the results from these detection and analysis, new silane treatment technique for metal surface can be optimized and improved greatly. Some other kinds of surface analysis methods were also mentioned in this paper. More advanced researches in the field of silane film analysis on metal surface were prospected.

English Abstract↗
PubMed2006

[The reliability of digital periapical films in diagnosis of root resorption].

OBJECTIVE: To investigate the difference between digital periapical film and conventional film in the evaluation of tooth length and root resorption. METHODS: A standard for root resorption in vitro was developed based on 20 extracted upper central incisors. Digital periapical films and conventional periapical films were taken before and after the process of simulating root resorption at six different projection angles respectively. The tooth length and root resorption were measured on these films. The results were analyzed by paired-samples rank sum test. RESULTS: Significant difference on tooth length measurement was found between two types of films on the same projection angle. No significant difference on the length of root resorption calculated on digital and conventional films was found. CONCLUSIONS: The accuracy of the digital periapical film was greater than that of conventional periapical films. The conventional periapical film can still be used in the evaluation of root resorption.

Humans↗
PubMed1978

Transferred pulmonary surfactant film: chemical analysis and contact angle study.

The Langmuir dip plate transfer technique was adapted to isolate the interfacial film formed at the surface of lung wash. The chemical analysis of the film showed that the weight ratio of lipid to protein of this surfactant film and its content of surface active substances were higher than those of lung wash. It was found that the wettability of the surfactant film could be simulated by a Dipalmitoyl lecithin and albumin film. When the surfactant film was transferred at condensed state (one of low air-lung-wash surface tension), we found the film exhibited a low critical surface tension which indicates the dominance of the lipid in the outer most layer of the film. On the other hand, insignificant amount of lipid was found in the film transferred at expanded state (one of high surface tension) and its surface behavior was shown to be similar to that of a protein film.

Animals↗
PubMed1997

Radiochromic film dosimetry for clinical proton beams.

Depth doses and lateral profiles for proton beams with energies of 100-250 MeV were measured with a high-sensitivity GafChromic MD-55 film, which requires no post-irradiation development. The exposed MD-55 films were evaluated with the RIT 113 film dosimetry system. Depth doses measured with MD-55 film were compared with those obtained with a plane-parallel ionization chamber. The GafChromic film was found to be less sensitive at the distal edge for both modulated and unmodulated beams compared with an ionization chamber, however, the difference in penetration of the beam at the depth of 80-50% distal fall-off measured with this film and the ionization chamber is within 0.1-0.2 mm for studied beams. The lateral beam profiles measured with MD-55 film were in a good agreement with profiles obtained from Kodak XV-2 radiographic film, scanned with the Wellhofer densitometer. It is concluded that MD-55 film, with some limitations, is a useful detector for dosimetry measurements in a single proton beam and can be employed for verification dosimetry in multiple-beam radiation therapy.

Evaluation Studies as Topic↗
PubMed1983

High-yield radiography of the maxillofacial complex using the free focus and conventional imaging concepts. The resolution performance of nonscreen and screen-film combinations.

Free focus radiography with miniaturized dental x-ray machines may be a valuable source of "high-yield" diagnostic information in dentistry. This study evaluated the resolution performance of conventional image receptors, including nonscreen and screen-film combinations which were available in sizes suitable for panoramic free focus radiography or conventional extraoral radiography. Results with nonscreen films produced resolution performances ranging from about 10 lp/mm. to about 20 lp/mm. For each film tested, the performances in conventional radiography as well as in free focus radiography with the film in the buccal fold approached the maximum measurable of 20 lp/mm. In a mode of free focus radiography with the film positioned extraorally, there were significant variations in performance according to film brand. A significant reduction in resolution performance occurred when screen-film combinations were tested; resolution ranged between 4.0 lp/mm. and 7.4 lp/mm., with the better performance obtained with free focus radiography. The performance of a rare earth system was similar to other screen-film combinations tested in conventional radiography. In free focus radiography the performance of the rare earth system was slightly below the mean resolution for conventional screen-film combinations at 4.0 lp/mm. and 4.3 lp/mm. An example of a small cassette adapted for intraoral use was given.

Face↗
PubMed1998

Technique charts for Kodak's new film-screen systems for portal localization.

In July 1996, Kodak released new film-screen systems with enhanced contrast (EC) for portal localization with megavoltage therapeutic beams. This study presents the generation of general-purpose technique charts for Kodak's new film-screen combinations: the Enhanced-Contrast localization (EC-L) film in EC-L cassette and the EC-L film in fast ECL (fECL) cassette for use with cobalt-60, 6 MV, 10 MV, and 18 MV beams. These technique charts were based on the assumption that a film with an optical density (OD) of 1.8 provides the best viewing density. The doses to produce such as OD, Dexp, were obtained from the H & D curves and were 1.5, 1.6, 1.7, and 1.8 cGy for cobalt-60, 6 MV, 10 MV, and 18 MV beams, respectively, with the EC-L-film + EC-L-cassette combination. The corresponding values were 1.3, 1.3, 1.3, and 1.4 cGy, respectively, for the above four beams with the EC-L-film + fEC-L-cassette combination. The dose to the film is assumed to be proportional to the calibrated dose rate (D0), field size factor (FSF), inverse square factor relative to 100.0 cm (INV), and the transmission factor through the patient, which is equal to e-uT, where u is the broad beam attenuation coefficient and T is the patient thickness. With the above assumptions, the exposure time or monitor unit, t, is then calculated from the following equation: t = Dexp/(D0*FSF*INV*e-uT). For an average port size of 15 x 15 cm, the attenuation coefficients were obtained from the fitting of TAR (cobalt-60) or TMR (6 MV, 10 MV, and 18 MV) as a function of depth from 10 to 30 cm and were 0.0564 cm-1, 0.03714 cm-1, and 0.02271 cm-1 for cobalt-60, 6 MV, 10 MV, and 18 MV beams, respectively. The FSF were explicitly obtained from the clinical physics data books and were 1.028, 1.032, 1.036, and 1.053 for cobalt-60, 6 MV, 10 MV, and 18 MV, respectively. For cobalt-60 beam, the D0 was assumed to be 100.0 cGy/min. For the 6 MV, 10 MV, and 18 MV beams, the D0 in cGy per monitor unit is 1.030, 1.051, and 1.061, respectively. Technique charts were then generated as a function of patient thickness from 10 to 45 cm for filming distance from 110 to 140 cm for all four beams. These technique charts can be easily customized to portal localization practices in a radiation therapy department.

Film Dosimetry↗
PubMed2003

Conversion of teaching file cases from film to digital format: a comparison between use of a diagnostic-quality digitizer and use of a flatbed scanner with transparency adapter.

RATIONALE AND OBJECTIVES: The authors' institution had decided to convert its radiology teaching files from film to digital media. This study was performed to determine the simplest method for converting the analog film images to digital images without a subsequent loss in diagnostic accuracy. MATERIALS AND METHODS: Twenty chest radiographs that demonstrated interstitial lung disease were randomly selected from the departmental teaching files and matched with 20 control radiographs from healthy adults. Analog film images were converted with both a diagnostic-quality film image digitizer (digitized) and a flatbed scanner equipped with a transparency adapter (scanned). Three radiology faculty members reviewed a mixed set of corresponding analog film, digitized, and scanned images. Reviewers judged whether each image depicted interstitial lung disease, indicated their level of confidence in the diagnosis, and rated each image for quality. Image quality was assessed by each reviewer subjectively at the time of viewing the individual image, without regard to other images. A one-way analysis of variance was performed to determine whether there was a statistically significant difference in diagnostic accuracy between the three image formats. Agreement in diagnosis between corresponding images in the three different formats was evaluated for each reviewer with the McNemar test. RESULTS: There was no statistically significant difference in diagnostic accuracy between analog film and scanned images, but there was such a difference between these two groups and digitized images. Accuracy was 97% for analog film, 94% for scanned, and 89% for digitized images. Results of the McNemar test showed no statistically significant difference in agreement between the analog film images and the scanned images for any of the reviewers (P > .05). CONCLUSION: A high-end flatbed scanner with transparency adapter provided accurate, simple, and inexpensive conversion of analog film teaching files to digital format, with no loss of the ability to detect or diagnose subtle abnormalities such as interstitial lung disease.

Adult↗
PubMed2003

Endodontic measurement accuracy and perceived radiograph quality: effects of film speed and density.

OBJECTIVES: This study sought to determine the effects of direct exposure x-ray film speed and background density on observer assessment of endodontic working lengths and on perceived radiographic image quality. STUDY DESIGN: A human cadaver maxilla section with surrounding soft tissues was used for the study. The canal length to the radiographic apex was determined on 4 canals in maxillary posterior teeth by using Trophy RVG images and adjusting the position of a No. 15 file in each canal until the file tip coincided with the radiographic apex in images made at 3 different vertical angulations. The files were measured with a micrometer from the file stop to the file tip to obtain the length to the radiographic apex. Then No. 10 files were placed in the 4 canals at varying lengths short of this previously determined length, and 5 observers assessed the distance from the file tip to the radiographic apex on radiographs made with Kodak D-, E-, and F-speed and Flow D- and E-speed direct exposure x-ray films that were exposed to produce background densities of 1.5, 2.0, and 3.0. Subjective appraisal of radiographic quality was also assessed. RESULTS: Analysis of variance and Tukey honestly significantly different post-hoc analysis results concerning measurement errors made with each film type revealed significantly less error for Kodak Ektaspeed Plus (E-speed) intraoral x-ray film than for Kodak InSight (F-speed) and Flow E; however, no difference was detected among Kodak Ektaspeed Plus (E-speed), Kodak Ultra-Speed (D-speed), and Flow D. Films with a background optical density of 3.0 received 98% favorable ratings; radiographs with a background optical density of 2.0 received 77% favorable ratings; and those with background optical density of 1.5 received only 18% favorable ratings at the 95% confidence level. Flow D film received the most favorable ratings, but there was no statistically significant difference among other film types at the 95% confidence level. CONCLUSIONS: Underexposed radiographs are perceived as inferior to slightly overexposed radiographs for endodontic file length assessment regardless of the film speed used. Current Flow and Kodak E-speed and F-speed radiographs appear to be as accurate as other accepted radiographs used in determining endodontic working lengths. Image background density should be kept constant when making comparisons among x-ray films.

Absorptiometry, Photon↗
PubMed1995

Densitometric comparisons of Ultra-speed, Ektaspeed, and Ektaspeed Plus intraoral films for two processing conditions.

This study compared film speed, contrast, exposure latitude, and resolution of Ultra-speed, Ektaspeed, and Ektaspeed Plus films (Eastman Kodak Co., Rochester, N.Y.). Densitometric curves were generated for each film type under processing conditions of fresh and used chemistry to observe their effect on factors associated with diagnostic quality. Ektaspeed Plus film displayed the least variability due to processing condition of any film; it also demonstrated the fastest speed and was twice as fast as Ultra-speed film. Ektaspeed exhibited the greatest relative exposure latitude followed by Ektaspeed Plus and Ultra-speed. Average gradient over a clinically useful range of densities was greatest for Ultra-speed in fresh processing solutions, but greatest for Ektaspeed Plus in used processing solutions. All film types were able to resolve more than 16.6 line pairs per millimeter regardless of processing conditions. The results of this study suggest that dental practitioners who have refrained from using E-speed film because of the sensitivity of this film to variations in processing may now consider providing this dose-reducing technology for their patients with the expectation of obtaining consistent image quality.

Absorptiometry, Photon↗
PubMed1995

Objective and subjective evaluations of Kodak Ektaspeed Plus dental x-ray film.

A new dental x-ray film, Kodak Ektaspeed Plus (Eastman Kodak Co., Rochester, N.Y.), was compared with Kodak Ektaspeed and Ultraspeed films. The comparison was based on objective measures (film contrast, speed, and fog levels) and subjective appraisals (film graininess and appearance). Ektaspeed Plus had higher contrast than Ektaspeed and in general similar contrast to Ultraspeed. Ektaspeed Plus was faster than Ektaspeed. Films were stored in various locations and base + fog determinations were made during a 16-week period. Ektaspeed Plus and Ultraspeed films were generally stable within this period. There were no meaningful differences in fog buildup based on storage location. Ektaspeed Plus had the least rate of buildup. Ektaspeed demonstrated the greatest rate of buildup and the greatest sensitivity to environmental factors. Periapical exposures were made of the molars of a manikin. These radiographs were subjectively assessed by three observers. The Ektaspeed Plus film was judged to appear less grainy than the Ektaspeed and to have a pleasing appearance. On the basis of the evaluations performed in this initial investigation, it was concluded that Ektaspeed Plus was superior to Ektaspeed film and was superior or equivalent to Ultraspeed film for dental radiography.

Absorptiometry, Photon↗
PubMed1999

Sensitometric evaluation of four dental X-ray films using five processing solutions.

OBJECTIVES: To compare the sensitometric properties of four dental films: Ektaspeed Plus and Ultra-speed (Kodak Eastman Co, Rochester, USA) and new and previous Dentus M2 (Agfa-Gevaert, Mortsel, Belgium) in five different processing solutions. METHODS: Characteristic curves were constructed for four dental X-ray films using five different processing solutions. All films were processed manually in three sets of chemicals for manual processing: Agfa (Heraeus Kulzer, Dormagen, Germany), Kodak (Kodak-Pathé, Paris, France) and Demat (Viscopac, Athens, Greece) and two sets of chemicals for automatic processing: Dürr XR and Periomat (Dürr Dental, Bietigheim-Bissingen, Germany). Analysis of variance and regression analysis was performed to examine the factors significantly affecting film density. RESULTS: The new Dentus M2 film had comparable gradient, higher speed and lower base-plus-fog than its predecessor. It had comparable speed with Ektaspeed Plus in chemicals for automatic processing. All films had a higher speed and lower gradient when processed in the chemicals for automatic processing. The highest film speed was achieved using Dürr XR chemicals. CONCLUSIONS: The new Agfa Dentus M2 film is an E-speed film and can be considered an alternative to Ektaspeed Plus: both can be recommended for use in dental practice as they contribute to dose reduction.

Absorptiometry, Photon↗
PubMed1999

Effects of developer exhaustion on the sensitometric properties of four dental films.

OBJECTIVES: To examine the effects of exhaustion of five different processing solutions on the sensitometric properties of four dental X-ray films: Ektaspeed Plus and Ultra-speed (Kodak Eastman Co. Rochester, USA) and new and previous Dentus M2 (Agfa-Gevaert, Mortsel, Belgium). METHODS: An aluminum stepwedge was used to construct characteristic curves for the four films. All films were processed manually using three sets of chemicals for manual processing: Agfa (Heraeus Kulzer, Dormagen, Germany), Kodak (Kodak-Pathé, Paris, France) and Demat (Viscopac, Athens, Greece) and two sets for automatic processing: Dürr XR and Periomat (Dürr Dental, Bietigheim-Bissingen, Germany). Film speed and gradient were evaluated until the chemicals were completely exhausted. An analysis of variance was performed separately for each set of chemicals for manual and automatic processing. RESULTS: Ektaspeed Plus was the fastest film in the manual processing solutions. The new Dentus M2 and Ektaspeed Plus films had similar speed using the chemicals for automatic processing. Ultra-speed had the lowest speed in all solutions, but it had the greatest consistency. Exhaustion of the developer caused a comparable decrease in speed of Ektaspeed Plus and the two Dentus M2 films. In fresh chemistry Agfa was the strongest manual processing solution, but it had the highest exhaustion rate. The Dürr XR chemical was stronger than Periomat over the whole test period. CONCLUSIONS: The combination of film and processing solution is an important factor for achieving constant sensitometric properties. Ektaspeed Plus and the new Dentus M2 film should be used in dental practice, as they require lower exposure and have equivalent or superior properties compared with Ultra-speed.

Analysis of Variance↗