Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Films”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed1994

Sensitometric and archival evaluation of Kodak RA films in dental automatic processing.

The Kodak Rapid Access System is an extension of the T-grain technology (T-Mat film). Unlike the T-Mat film, the T-Mat/Rapid Access film is forehardened by the addition of more hardener to the film emulsion. It can thus be processed rapidly in a Kodak Rapid Access medical processor in only 45 seconds dry-to-dry cycle by using the Kodak X-Omat RA/30 developer that does not contain a hardener. The absence of the hardener, glutaraldehyde, in the developer also makes this solution environmentally safer. In medical radiography, the T-Mat film has been replaced by the T-Mat/Rapid Access film. However, in dental extraoral radiography the T-Mat film is still being used because the processing solutions and the comparatively low temperatures of dental automatic processors are different from those used in medical radiography. This report shows that, for panoramic and other dental extraoral radiography, T-Mat films can be replaced by T-Mat/RA films by processing them in conventional Kodak X-Omat RP solutions using a dental automatic processing cycle. The differences in the sensitometric properties of the T-Mat and T-Mat/rapid Access films were negligible and therefore clinically insignificant. All films tested well for archival quality.

Dental Records↗
PubMed1997

A sensitometric comparison of four dental X-ray films and their diagnostic accuracy.

OBJECTIVES: To compare the sensitometric properties and accuracy in the diagnosis of approximal caries of two E-speed (Ektaspeed Plus and EV 57) and two D-speed (Ultra-speed and DV 57) films. METHODS: Speed and contrast for the four films were determined following 30 exposures for each film. Base plus fog density was measured on unexposed films and the increase was studied over a 18-month period. Seventy-five extracted premolars with known pathology were radiographed under standardized conditions and the radiographs assessed by nine observers for approximal caries. Receiver Operating Characteristic (ROC) curve technique was used to analyse the diagnostic accuracy. RESULTS: The sensitometric analysis showed that the Ektaspeed Plus film had the highest speed of the four films. At a density of 1.0 it was 2.28 times faster than Ultra-speed. The contrast of Ektaspeed Plus was comparable with that of the other films and base plus fog density plateaued at 0.4 ten months before expiry date. There were no statistically significant differences in diagnostic accuracy for white spot lesions between the four films. For cavitations there was a significant difference between EV 57 and DV 57 and Ektaspeed Plus (P = 0.005) but not between Ultra-speed and Ektaspeed Plus nor between Ultra-speed and EV 57 and DV 57. CONCLUSION: Ektaspeed Plus film is comparable with D-speed and a conventional E-speed film. Since it is at present the fastest available dental film it should be recommended for general dental practice.

Analysis of Variance↗
PubMed2002

The value of radiographic film for the characterization of intensity-modulated beams.

In this paper the performance of radiographic film (KODAK X-Omat V) for analysing intensity-modulated (IM) beams in a plane at reference depth (5 cm for 6 MV, 10 cm for 18 MV) was investigated. The field size dependence of the film response was studied for small and medium field sizes. The dose rate dependence of the response and possible effects of fractionating the dose were assessed. In the end, profiles were measured for two clinically delivered IM beams, and the results were compared with diamond detector data. We found that the response of the radiographic film increases with field size, but for field sizes up to 15 x 15 cm the deviations remain within 3% for measurements with the films in a plane at reference depth. We found that the response of the films decreases with decreasing dose rate, and that the extent of this effect differs from film batch to film batch. For clinical IM beams the effect can amount to about 9% at the location of shielded organs at risk. Also, fractionating the dose reduces the net optical density, but this effect is normally small when assessing IM beams. In low-dose regions low-energy photons have an important contribution, resulting in a higher response at these positions. This may counteract the dose rate dependence of the response. In the high-dose regions of the two IM beams that were studied, the relative dose measurements with film are within 1% of those obtained with a diamond detector, when the results of three films are averaged. In shielded organs at risk the deviations can mount to about 3%, depending on the film batch. In conclusion, radiographic film is a suitable detector for characterizing IM beams in a plane at reference depth.

Dose-Response Relationship, Radiation↗
PubMed1992

An evaluation of the effect of processing conditions on mammographic film contrast, fog levels and speed.

While it is well established that extended development times and temperatures will increase mammographic film contrast and speed (1), little work has been done to date in extending this work to encompass all common screen-film types and to study the effect of processing chemistry variations on contrast speed results. This paper reports on four locally available mammographic films which, after exposure in conditions that closely simulate clinical conditions, have been developed with four different development chemicals as a function of development temperature and time. Three development times were used (23, 32 and 42 seconds) in combination with four development temperatures (32, 34, 36 and 38 degrees). The results support the previously published result of increased speed and contrast with extending development time and temperature. It was further found that, for some film types, the film contrast varied significantly over film density when developed with extended processing. Other film types, however, maintained high contrasts over large film density ranges. In some cases the increased contrast was accompanied by elevated film fog levels. The development of mammographic films in non recommended chemistries produced varying results, mostly detrimental, which demonstrated that selection of development chemistry as well as optimal development times and temperatures, is critical for good film performance.

Absorptiometry, Photon↗
PubMed1998

Effects of inserting a pressensor film into articular joints on the actual contact mechanics.

Fuji film has been widely used in studies aimed at obtaining the contact mechanics of articular joints. Once sealed for practical use in biological joints, Fuji Pressensor film has a total effective thickness of 0.30 mm, which is comparable to the cartilage thickness in the joints of many small animals. The average effective elastic modulus of Fuji film is approximately 100 MPa in compression, which is larger by a factor of 100-300 compared to that of normal articular cartilage. Therefore, inserting a Pressensor film into an articular joint will change the contact mechanics of the joint. The measurement precision of the Pressensor film has been determined systematically; however, the changes in contact mechanics associated with inserting the film into joints have not been investigated. This study was aimed at quantifying the changes in the contact mechanics associated with inserting sealed Fuji Pressensor film into joints. Spherical and cylindrical articular joint contact mechanics with and without Pressensor film and for varying degrees of surface congruency were analyzed and compared by using finite element models. The Pressensor film was taken as linearly elastic and the cartilage was assumed to be biphasic, composed of a linear elastic solid phase and an inviscid fluid phase. The present analyses showed that measurements of the joint contact pressures with Fuji Pressensor film will change the maximum true contact pressures by 10-26 percent depending on the loading, geometry of the joints, and the mechanical properties of cartilage. Considering this effect plus the measurement precision of the film (approximately 10 percent), the measured joint contact pressures in a joint may contain errors as large as 14-28 percent.

Animals↗
PubMed2002

Film dosimetry for intensity modulated radiation therapy: dosimetric evaluation.

X-ray film has been used for the dosimetry of intensity modulated radiation therapy (IMRT). However, the over-response of the film to low-energy photons is a significant problem in photon beam dosimetry, especially in regions outside penumbra. In IMRT, the radiation field consists of multiple small fields and their outside-penumbra regions; thus, the film dosimetry, for it involves the source of over-response in its radiation field. In this study we aim to verify and possibly improve film dosimetry for IMRT. Two types of modulated beams were constructed by combining five to seven different static radiation fields using 6 MV x rays. For verifying film dosimetry, x-ray films and an ion chamber were used to measure dose profiles at various depths in a phantom. The film setups include both parallel and perpendicular arrangements against the beam incident direction. In addition, to reduce an over-response, we placed 0.01 in. (0.25 mm) thick lead filters on both sides of the film. Compared with ion-chamber measurement, measured dose profiles showed the film over-response at outside-penumbra and low-dose regions. The error increased with depths and approached 15% as a maximum for the field size of 15 cm x 15 cm at 10 cm depth. The use of filters reduced the error down to 3%. In this study we demonstrated that film dosimetry for IMRT involves sources of error due to its over-response to low-energy photons, with the error most transparent in the low-dose region. The use of filters could enhance the accuracy in film dosimetry for IMRT. In this regard, the use of an optimal filter condition is recommended.

Humans↗
PubMed2002

Interinstitutional variations of sensitometric curves of radiographic dosimetric films.

Depth and field size dependence of the sensitometric curves of radiographic films have been studied by various groups. Limited information is, however, available on the magnitude of the variations in sensitometric curves applied in clinical practice in different institutions. In this study we assessed in a systematic way the effect of the various parameters influencing the shape of the sensitometric curve: batch composition, irradiation conditions, film processing, and film scanning. Two types of film, Kodak X-Omat V and CEA TVS, were irradiated, processed, and analyzed in three different institutions. The interinstitutional variation of the sensitometric curves, expressed as the OD variation at 50 cGy, can be up to 32% and is mainly caused by differences in film processing and to a lesser degree to differences in batch composition, film scanning, and irradiation conditions. For the Kodak films, the average OD difference at 50 cGy between the three institutions is 17% as a result of differences in batch composition and 25% due to differences in processing conditions. For the CEA films these data are 6% and 24%, respectively. The long-term variation of the sensitometric curves of KODAK films in one institution was smaller than the differences in batch composition between the three institutions. The sensitometric curves of CEA films showed in one institution a large variation with time; the shape gradually varied from sigmoidal to quasilinear. By using relative OD values rather than absolute OD values, variations in sensitometric curves of KODAK films can be reduced to 2%. Consequently, one sensitometric curve is sufficient to derive relative dose values. If processing conditions are well controlled, it might therefore be advantageous to determine the absolute OD only at one or two dose values, in combination with a "universal" relative sensitometric curve.

Arizona↗
PubMed2003

The response of Kodak EDR2 film in high-energy electron beams.

Kodak XV2 film has been a key dosimeter in radiation therapy for many years. The advantages of the recently introduced Kodak EDR2 film for photon beam dosimetry have been the focus of several IMRT verification dosimetry publications. However, no description of this film's response to electron beams exists in the literature. We initiated a study to characterize the response and utility of this film for electron beam dosimetry. We exposed a series of EDR2 films to 6, 9, 12, 16, and 20 MeV electrons in addition to 6 and 18 MV x rays to develop standard characteristic curves. The linac was first calibrated to ensure that the delivered dose was known accurately. All irradiations were done at dmax in polystyrene for both photons and electrons, all films were from the same batch, and were developed at the same time. We also exposed the EDR2 films in a solid water phantom to produce central axis depth dose curves. These data were compared against percent depth dose curves measured in a water phantom using an IC-10 ion chamber, Kodak XV2 film, and a PTW electron diode. The response of this film was the same for both 6 and 18 MV x rays, but showed an apparent energy-dependent enhancement for electron beams. The response of the film also increased with increasing electron energy. This caused the percent depth dose curves using film to be shifted toward the surface compared to the ion chamber data.

Calibration↗
PubMed1992

Improved radiology film library operations.

An interdisciplinary task force at the authors' institution developed a design for a new film library that placed heavy emphasis on service to its customers. The task force established locations and staffing for "satellite" inpatient film libraries organized by clinical specialties. Inpatient films were not permitted to be taken from the radiology department but were available for 24-hour viewing. Film locations were recorded in the radiology information system. Reorganization led to important improvements in film library operations and in the clinical staff's opinion of film library service. Objective measures of performance, such as the fraction of requested films available for conferences, showed significant improvement (P less than .001). Closer working relationships developed between film librarians, radiologists, and their clinical colleagues. Film library personnel were recruited more easily and stayed on the job longer. Several hundred thousand film-tracking transactions per year were recorded. The authors conclude that decentralization of certain film library activities improved many critical aspects of performance.

Libraries↗
PubMed1992

Assessment of mammographic film processor performance in a hospital and mobile screening unit.

In contrast to the majority of mammographic breast screening programmes, film processing at this centre occurs on site in both hospital and mobile trailer units. Initial (1989) quality control (QC) sensitometric tests revealed a large variation in film processor performance in the mobile unit. The clinical significance of these variations was assessed and acceptance limits for processor performance determined. Abnormal mammograms were used as reference material and copied using high definition 35 mm film over a range of exposure settings. The copies were than matched with QC film density variation from the mobile unit. All films were subsequently ranked for spatial and contrast resolution. Optimal values for processing time of 2 min (equivalent to film transit time 3 min and developer time 46 s) and temperature of 36 degrees C were obtained. The widespread anomaly of reporting film transit time as processing time is highlighted. Use of mammogram copies as a means of measuring the influence of film processor variation is advocated. Careful monitoring of the mobile unit film processor performance has produced stable quality comparable with the hospital based unit. The advantages of on site film processing are outlined. The addition of a sensitometric step wedge to all mammography film stock as a means of assessing image quality is recommended.

Breast Neoplasms↗
PubMed2006

Image quality and breast dose of 24 screen-film combinations for mammography.

In this study the effect of different mammographic screen-film combinations on image quality and breast dose, and the correlation between the various image quality parameters, breast dose and the sensitometric parameters of a film were investigated. Three Agfa (MR5-II, HDR, HT), two Kodak (Min-R M, Min-R 2000), one Fuji (AD-M), one Konica (CM-H) and one Ferrania (HM plus) single emulsion mammographic films were combined with three intensifying screens (Agfa HDS, Kodak Min-R 2190 and Fuji AD-MA). The film characteristics were determined by sensitometry, while the image quality and the dose to the breast of the resulting 24 screen-film combinations were assessed using a mammography quality control phantom. For each combination, three images of the phantom were acquired with optical density within three different ranges. Two observers assessed the quality of the 72 phantom images obtained, while the breast dose was calculated from the exposure data required for each image. Large differences among screen-film combinations in terms of image quality and breast dose were identified however, that, could not be correlated with the film's sensitometric characteristics. All films presented the best resolution when combined with the HDS screen at the expense of speed, and the largest speed when combined with the AD-MA screen, without degradation of the overall image quality. However, an ideal screen-film combination presenting the best image quality with the least dose was not identified. It is also worth mentioning that the best performance for a film was not necessarily obtained when this was combined with the screen provided by the same manufacturer. The results of this study clearly demonstrate that comparison of films based on their sensitometric characteristics are of limited value for clinical practice, as their performance is strongly affected by the screens with which they are combined.

Breast↗
PubMed1993

A study of the effects of lead foil in dental X-ray film packets on radiographic image quality.

The role of lead foil in protecting film from image degradation due to back-scattered radiation was studied. The effects of low-scattering (polystyrene foam) and tissue-equivalent (Lucite) materials on relative speed and modulation transfer factor (MTF) of the front and back films from Kodak DF-57 double film packets were evaluated. The relative speed of the back film with polystyrene foam behind the film was about 10% faster with lead foil. However, when Lucite was placed behind the film, lead foil eliminated the effect of scattered radiation on film density, MTF, was decreased by the presence of lead foil when polystyrene foam was placed behind the film. With Lucite, however, lead foil improved the MTF value, which was decreased by the scattered radiation at spatial frequencies over 5 cycle mm-1. These results suggest that lead foil itself causes scattered or secondary radiation and affects film speed and resolution. However, it also protects the film from scattered radiation from tissue behind the film and results in improvement in resolution.

Analysis of Variance↗
PubMed2006

Sensitometric comparisons of Insight and Ektaspeed Plus films: effects of chemical developer depletion.

The aim of this study was to compare the sensitometric properties of Insight and Ektaspeed Plus radiographic films manually and automatically processed using fresh and depleted chemical solutions. Ten sets of each type of film were obtained (1 set = 5 films), 5 sets being manually processed and 5 sets being automatically processed. A total of 100 films (50 Ektaspeed Plus and 50 Insight film) were exposed and developed. The first two sets of each film type were developed in fresh chemicals (one set per each type of processing), on the first day of the experiment. The other sets were processed in the same progressively depleted solutions once a week until the end of experiment, which was completed within 4 weeks. Characteristic curves were constructed to compare the sensitometric properties of the films: contrast, latitude and speed. Processing solution depletion had different effects on manually and automatically developed films, which was confirmed by the changes in the form of the characteristic curves in the third week of the automatic processing and fourth week of the manual processing. Ektaspeed Plus showed 11% reduction in contrast values for manual processing and 53% for automatic processing, while Insight contrast values showed a reduction of 25% and 59%, respectively. Insight film, however, showed lesser loss of speed and lesser increase of latitude than Ektaspeed Plus. In conclusion, chemical depletion in automatic film processing was faster than in manual developing. In depleted chemicals, both types of films had an increase in latitude values and a decrease in speed and contrast. Insight was more resistant than Ektaspeed Plus to decrease in speed and latitude when processed using older chemicals, whereas contrast in Ektaspeed Plus was comparatively more stable.

Solutions↗
PubMed2000

[Comparison of mammographic and industrial films in dialysis patients].

PURPOSE: To optimize the technique for radiographic studies of bone and joint damage in renal osteodystrophy. MATERIAL AND METHODS: Sixty-four patients with chronic renal failure on dialysis for 0-10 years, were divided into two homogeneous groups and submitted to two different radiographic examinations of the nondominant hand. Group A patients were examined with a conventional radiological unit and an industrial film and a conventional radiological unit with a mammographic film with a dedicated screen, while group B patients with a mammographic with an industrial film and a conventional radiologic unit with a mammographic film with a dedicated screen. The examinations were evaluated by three radiologists in a double-blind fashion. RESULTS: Bone conditions such as osteoporomalacia, trabecular rarefaction, channel enlargement and intracortical absorption were equally demonstrated by mammographic films and the mammograph with industrial films. The mammographic film was superior to the mammograph with an industrial film in 8 cases, comparable in 25 and inferior in 6, but when compared with the conventional radiological unit with an industrial film it was superior in 19 cases, comparable in 2 and never inferior. CONCLUSIONS: The industrial film without a screen combined with a mammograph is considered the gold standard to study fine bone alterations in renal osteodystrophy. However the conventional radiological unit with a mammographic film with a dedicated screen provides the same results with lower irradiation doses and can therefore be considered a good alternative.

Adult↗
PubMed2004

Evaluation of the diagnostic advantage of intraoral D and E film for detecting interproximal caries.

Clinicians strive to reduce the exposure of patients to X-ray radiation in an effort to decrease its harmful effects on the body. A potential strategy for achieving this goal is the use of high-speed films that require less exposure to radiation to generate a diagnostic image. There are two film types commonly used in intraoral radiography: high speed or "Ekta-speed" film (Type E) and normal speed or Ultra-speed film (Type D). Type E film requires nearly half of the exposure time that is required by Type D films to produce an acceptable diagnostic image; however, the diagnosis quality and usability of these film types are under question. The purpose of this research is to compare the diagnostic quality of Type E with Type D film when used to diagnose proximal caries. In this study 40 pairs of extracted maxillary premolar teeth were chosen and divided into four groups of 10 pairs. Cavities were made on proximal surfaces at different depths (0.5, 1, 1.5, and 2 mm) for each group. Bitewing radiographs were then taken on each pair of teeth using Type E film and then again using Type D film. Radiographs were evaluated by two oral radiologists and two operative dentistry specialists who recorded the perceived diagnostic depth of the prepared cavities. Our data showed both Type D and E films are suitable for use in diagnosing proximal caries, and despite a minor discrepancy between them no significant difference was found with regard to their value in diagnosing proximal caries.

Dental Caries↗
PubMed1999

Storage of partially deacetylated chitosan films.

Chitosan has wide-ranging applications as a biomaterial, but its stability in storage is not widely known. The objective of this study was to evaluate the storage stability of films prepared from chitosan of 77% deacetylation. Both the neutralized and acetate films were evaluated, as chitosan salts offer the advantage of being soluble in water at the neutral-to-basic pH range. Aqueous solutions containing 0.5-5% acetic acid were used as solvents. The X-ray diffraction pattern, the IR spectrum, water uptake, and solubility of the films were influenced by the presence of the N-acetyl functionality, the acetate ions, and storage of the films. The anhydrous chitosan crystal in the neutralized films was unstable to storage at 4 degrees C and 28 degrees C. Its formation, as well as that of the hydrated crystal, were further hindered by the presence of even small quantities of the acetate ions. The resultant amorphous nature of the acetate films, coupled with the acidifying action of the acetic acid, led to greater water uptake and solubility compared to the neutralized films. Storage reduced the differences between the neutralized and acetate films. It also minimized the influence of the initial acetic acid content on the IR absorption and water uptake of the acetate films, exerting its leveling effects mainly within the first week of storage. Using a lower storage temperature of 4 degrees C or heating the films for 2 h at 120 degrees C prior to storage did not significantly modify the results. A pertinent factor appears to be the degree of deacetylation of the chitosan that was used to prepare the films.

Anesthetics, Local↗
PubMed1999

Bioadhesion of gelatin films crosslinked with glutaraldehyde.

The present study was carried out in an attempt to make a gelatin film strongly bioadhesive by introducing free dangling aldehyde groups. When gelatin films were treated with 0.5M of glutaraldehyde (GA) solution at 60 degrees C, free aldehyde groups (up to 150 micromol/g) were introduced in the film. The bonding strength of GA-crosslinked gelatin films (GA gelatin films) with biological tissue was assessed using porcine skins. It was found that bonding strength increased with increasing aldehyde content in the film. The GA gelatin films had bonding strength as high as 250 gf/cm2 whereas the native gelatin film (before GA treatment) showed bonding strength of 40 gf/cm2. When the aldehyde groups introduced in the gelatin films were quenched with glycine or reduced by NaBH4, the films no longer demonstrated such high bonding strength. These facts suggest that a Schiff base was formed between the free dangling aldehyde in the GA gelatin films and the amino groups of the natural tissue, which strongly contributed to a marked bioadhesion.

Adhesives↗
PubMed2005

Interaction of heme proteins with poly(propyleneimine) dendrimers in layer-by-layer assembly films under different pH conditions.

With the isoelectric point at pH 7.4, hemoglobin (Hb) has net positive surface charges at pH 5.0 and overall negative charges at pH 9.0, and is essentially neutral at pH 7.0. The fifth-generation poly(propyleneimine) (PPI) dendrimer is usually positively charged in aqueous solution. The {PPI/Hb}n films under different pH conditions have been successfully fabricated on various solid surfaces by the layer-by-layer assembly technique, and the growth of films was monitored by ultraviolet-visible (UV-vis) spectroscopy, quartz crystal microbalance (QCM), and cyclic voltammetry (CV). Not only was the negatively charged Hb at pH 9.0 alternately adsorbed with positively charged PPI onto solid substrates by electrostatic attraction between them, but the positively charged Hb at pH 5.0 was also successfully assembled with like charged PPI into layer-by-layer {PPI/Hb(pH 5.0)}n films. For the latter, the localized electrostatic interaction or the charge reversal of proteins on PPI surface may be the main driving force. For {PPI/Hb(pH 7.0)}n films, however, the hydrophobic/hydrophilic interaction may play a more important role in the assembly, making the amount of adsorbed Hb even less than that of {PPI/Hb(pH 5.0)}n films. For comparison, negatively charged catalase (Cat) at pH 8.0 was used to assemble layer-by-layer films with positive PPI, but {PPI/Cat}n films showed quite different properties from {PPI/Hb}n films. UV-vis and infrared (IR) spectroscopy, QCM, ellipsometry, and voltammetry were utilized to characterize the {PPI/protein}n films. The results suggest that the proteins in the multilayer films retain their near-native structure and display good voltammetric response for heme Fe(III)/Fe(II) redox couples at underlying pyrolytic graphite (PG) electrodes. Electrocatalysis of oxygen and hydrogen peroxide based on direct electrochemistry of heme proteins at {PPI/protein}n film electrodes was also demonstrated.

Animals↗