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PubMed2002

Predicting film dose to aid in cassette placement for radiation therapy portal verification film images.

EC film has improved portal localization images with better contrast and improved distinction of bony structures and air-tissue interfaces. A cassette with slower speed screens was used with EC film to image the treatment portal during the entire course of treatment (verification) instead of taking separate films after treatment. Measurements of film density vs source to film distance (SFD) were made using 15 and 25 cm thick water phantoms with both 6 and 18 MV photons from I to 40 cm past the phantom. A characteristic (H & D) curve was measured in air to compare dose to film density. Results show the reduction in radiation between patient and cassette more closely follows an "inverse cube law" rather than an inverse square law. Formulas to calculate radiation exposure to the film, and the desired SFD were based on patient tumor dose, calculation of the exit dose, and the inverse cube relationship. A table of exposure techniques based on the SFD for a given tumor dose was evaluated and compared to conventional techniques. Although the film has a high contrast, there is enough latitude that excellent films can be achieved using a fixed SFD based simply on the tumor dose and beam energy. Patient diameter has a smaller effect. The benefits of imaging portal films during the entire treatment are more reliability in the accuracy of the portal image, ability to detect patient motion, and reduction in the time it takes to take portal images.

Dose-Response Relationship, Radiation↗
PubMed1995

Plain X-ray films and air enema films reflect severe mucosal inflammation in acute ulcerative colitis.

In a prospective study of 34 patients with active ulcerative colitis, the findings of inflammation on plain abdominal films and air enema films were compared to those at colonoscopy including biopsy within 10 days. The degree of inflammation on X-ray films was graded independently by two radiologists, at colonoscopy by one gastroenterologist and from histological slides from 6 different colon segments by one pathologist for each patient. Air enema films had a high sensitivity for endoscopically confirmed friable or ulcerated mucosa (0.91). There was a high specificity (0.86) when excluding inflammation in individual colon segments. Absence of fecal residue as an indication of active inflammation had the same positive predictive value, 0.95, as an abnormal air enema film, 0.98 for endoscopically confirmed inflamed mucosa. The presence of fecal residue or a normal air enema film excluded a friable or ulcerated mucosa at endoscopy with negative predictive values of 0.83 and 0.86, respectively. Patients who had had a complete colonoscopy (n = 16) were divided into groups with total, extensive or distal colitis. Air enema films underestimated the extent of inflammation in 8 of 16 patients compared to colonoscopy. Of 6 patients with distal disease only on air enema films, 5 had disease above the splenic flexure at endoscopy. In patients with ulcerative colitis (1) the presence of fecal residue and a normal air enema film exclude a friable or ulcerated mucosa with a high degree of certainty, and (2) the absence of fecal residue and an abnormal air enema film are predictors of the presence of endoscopically confirmed inflammation.

Adult↗
PubMed1986

Radiographic quality control measurements comparing D-speed film, E-speed film, and xeroradiography.

This study evaluated quality control (QC) measurements of D-speed film, E-speed film, and xeroradiography under clinical conditions. Automatic and manual (wet-tank) film-processing techniques were assessed. The results of QC tests (speed index, contrast index, and base + fog measurements) indicated that D-speed film and E-speed film react similarly under clinical conditions with regard to speed and contrast when processed automatically. E-speed film had an elevated base + fog measurement over D-speed film in both processing methods. Manually processed D-speed film had a greater contrast than did manually processed E-speed film. Xeroradiography maintained a consistent level of image processing under clinical conditions during this 90-day trial.

Quality Control↗
PubMed2000

Evaluation of a new F speed dental X-ray film. The effect of processing solutions and a comparison with D and E speed films.

OBJECTIVE: To compare the properties of a new speed group F intra-oral X-ray film with those of three well established types both from groups D and E, and evaluate the impact of six commercially available processing solutions. METHODS: Four types of dental X-ray film, Flow (Flow X-ray, West Hempstead, NY, USA), speed group F, Ektaspeed Plus (Eastman Kodak, Rochester NY, USA) and M2 Comfort (AgfaGevaert, Morstel, Belgium), both speed group E, and Ultra-speed (Eastman Kodak), speed group D, were exposed under standardised conditions and processed in six different processing solutions. Base plus fog density, characteristic curves, film density, speed, average gradient, contrast and latitude and spatial resolution were calculated. RESULTS: The choice of processing chemistry affected radiographic characteristics including speed grouping. The new F film was consistently the fastest. M2 Comfort could achieve F speed and Ultra-speed achieved E speed using Automat XR chemicals. The speed of Ektaspeed Plus was independent of the automatic processing solution used. Ultra-Speed film had the lowest base plus fog density and the widest latitude. Film contrast was similar irrespective of the film and solution combination. CONCLUSIONS: The choice of processing chemistry can affect radiographic characteristics. The new F film reduces patient exposure by one-half compared with E speed film with no detriment to image quality.

Absorptiometry, Photon↗
PubMedDate not supplied

Technical aspects of screen-film radiography, film processing, and quality control.

The broad goal of quality control (QC) of screen-film radiography and film processing is to provide radiographs of consistent, high quality. Achievement of this goal requires attention to several areas, including QC of the screen-film system and photographic processor, acceptance testing of all components, and skill in analysis of film artifacts to "diagnose" the processor problems causing the aberrations. Methods to reduce waste, recycle by-products, and reuse resources such as silver are also part of the QC process. To optimize the photographic process, one should use the film, chemical solutions, processor, and screens and cassettes produced by one manufacturer or the combination recommended by the film manufacturer. Important variables in film processing (eg, density, density difference, and base plus fog) are recorded on control charts, which plot the variables as a function of time and allow easy analysis of changes in operating levels. Many variables can affect any component in the screen-film imaging system; problems caused by manufacturing batch-to-batch variation, which is perhaps the most pervasive variable, can be lessened by purchasing film, screens, and cassettes in large batches and of the same batch and by purchasing photographic chemicals in concentrated form and mixing them as needed. Acceptance testing ensures that the product meets expectations, ensures that its performance meets specifications, and establishes the operating level for the ongoing QC program.

Artifacts↗
PubMed2001

Laser-tissue soldering with biodegradable polymer films in vitro: film surface morphology and hydration effects.

BACKGROUND AND OBJECTIVE: Previous research introduced the concept of using biodegradable polymer film reinforcement of a liquid albumin solder for improvement of the tensile strength of repaired incisions in vitro. In this study, the effect of creating small pores in the PLGA films on the weld breaking strength is studied. Additionally, the effect of hydration on the strength of the reinforced welds is investigated. STUDY DESIGN/MATERIALS AND METHODS: A 50%(w/v) bovine serum albumin solder with 0.5 mg/mL Indocyanine Green dye was used to repair an incision in bovine aorta. The solder was coagulated with an 806-nm CW diode laser. A poly(DL-lactic-co-glycolic acid) (PLGA) film was used to reinforce the solder (the controls had solder but no reinforcement). Breaking strengths were measured acutely and after hydration in saline for 1 and 2 days. The data were analyzed by ANOVA (P < 0.05) and multiple comparisons of means were performed using the Newman-Keuls test. RESULTS: The creation of pores in the PLGA films qualitatively improved the film flexibility without having an apparent adverse effect on the breaking strength, while the actual technique of applying the film and solder had more of an effect. The acute maximum average breaking strengths of some of the film reinforced specimens (114.7 g-134.4 g) were significantly higher (P < 0.05) than the acute maximum average breaking strength of the unreinforced control specimens (68.3 g). Film reinforced specimens were shown to have a statistically significantly higher breaking strength than unreinforced controls after 1- and 2-day hydration. CONCLUSIONS: Reinforcement of liquid albumin solders in laser-assisted incision repair appears to have advantages over conventional methods that do not reinforce the cohesive strength of the solder in terms of acute breaking strength and after immersion in moist environments for short periods of time. Using a film with the solder applied to one surface only may be advantageous over other techniques.

Animals↗
PubMed2002

Cognitive engineering of film library transition from film medium to digital environment in a Texas teaching hospital.

Digital imaging technology promises efficient, economical, and fast service for patient care, but the challenges are great in the transition from film to a filmless (digital) environment. This change has a significant impact on the film library's personnel (film librarians) who play a leading roles in storage, classification, and retrieval of images. The objectives of this project were to study film library errors and the usability of a physical computerized system that could not be changed, while developing an intervention to reduce errors and test the usability of the intervention. Cognitive and human factors analysis were used to evaluate human-computer interaction. A workflow analysis was performed to understand the film and digital imaging processes. User and task analyses were applied to account for all behaviors involved in interaction with the system. A heuristic evaluation was used to probe the usability issues in the picture archiving and communication systems (PACS) modules. Simplified paper-based instructions were designed to familiarize the film librarians with the digital system. A usability survey evaluated the effectiveness of the instruction. The user and task analyses indicated that different users faced challenges based on their computer literacy, education, roles, and frequency of use of diagnostic imaging. The workflow analysis showed that the approaches to using the digital library differ among the various departments. The heuristic evaluation of the PACS modules showed the human-computer interface to have usability issues that prevented easy operation. Simplified instructions were designed for operation of the modules. Usability surveys conducted before and after revision of the instructions showed that performance improved. Cognitive and human factor analysis can help film librarians and other users adapt to the filmless system. Use of cognitive science tools will aid in successful transition of the film library from a film environment to a digital environment.

Cognitive Science↗
PubMed2001

Corn starches as film formers in aqueous-based film coating.

The purpose of this study was to evaluate the film formation ability and mechanical stress-strain properties of aqueous native corn starches, using free films and film coatings applied to tablets. Free films were prepared from high-amylose corn (Hylon VII), corn and waxy corn starches, using sorbitol and glycerol as plasticizers. The tablets and pellets were film-coated using an air-suspension coater, and characterized with respect to the film coating surface topography, cross-sectional structure and thickness (SEM), and dissolution in vitro. The amylose content of the starch film formers affected both the tensile strength and the elongation. The elongations were under 5% for even the plasticized starches, and in most cases, no plasticization effect was seen by either of the plasticizers. Dissolution of native corn starch film-coated tablets (weight gain 1%) did not differ from uncoated ones. A notable delay in dissolution of the drug was found by increasing Hylon VII film coating thickness, suggesting controlled-release characteristics.

Amylose↗
PubMed1986

Mammographic microcalcifications: detection with xerography, screen-film, and digitized film display.

Pulverized bone specks and aluminum oxide specks were measured by hand into sizes ranging from 0.2 mm to 1.0 mm and then arranged in clusters. These clusters were superimposed on a human breast tissue phantom, and xeromammograms and screen-film mammograms of the clusters were made. The screen-film mammograms were digitized using a high-resolution laser scanner and then displayed on cathode ray tube (CRT) monitors. Six radiologists independently counted the microcalcifications on the xeromammograms, the screen-film mammograms, and the digitized-film mammograms. The xeromammograms were examined with a magnifying glass; the screen-film images were examined with a magnifying glass and by hot light; and the digitized-film images were examined by electronic magnification and image processing. The bone speck size that corresponded to a mean 50% detectability level for each technique was as follows: xeromammography, 0.550 mm; digitized film, 0.573 mm; and screen-film, 0.661 mm. We postulate that electronic magnification and image processing with edge enhancement can improve the capability of screen-film mammography to enhance the detection of microcalcifications.

Breast Diseases↗
PubMed1987

Is E-speed dental film more sensitive to storage than D-speed dental film?

Two types of films with different speed, D-speed (Kodak Ultraspeed) and E-speed (Kodak Ektaspeed), were compared regarding film fogging under different storage conditions. The films were stored during one year at room temperature (+21 degrees C) without shielding, with 3 mm lead or with 200 mm iron shielding and in a refrigerator (+8 degrees C) without shielding. The films were processed in a standardised way and the film fog measured densitometrically each month. The film fog increased insignificantly with time for both film types under all storage conditions except in the refrigerator, where it reached unacceptably high levels and the faster film type (Kodak Ektaspeed) became unusable after 4 months storage in the refrigerator.

Radiography, Dental↗
PubMed1992

Relationship of film properties to drug release from monolithic films containing adjuvants.

The rate of drug release from a polymeric matrix system was influenced by the physical and chemical properties of the monolithic films. The model drugs, salicylic acid and chlorpheniramine maleate, and two poly(methyl methacrylate) copolymers of different permeabilities (Eudragit RL and Eudragit RS), with and without additional adjuvants, were used to form monolithic matrix films for controlled drug release. Adjuvants, including polyethylene glycols (PEG 400 and PEG 8000) and poly(vinylpyrrolidones) (PVP-K15 and PVP-K90), were incorporated into films of Eudragit RL PM and Eudragit RS PM. The moisture permeation constant, glass transition temperature (Tg), tensile strength, and drug release profiles were determined for each acrylic resin slab to correlate the physicochemical and physicomechanical film properties to observed drug release. Faster rates of drug diffusion were observed with the addition of PEG 400 to the films, because of its plasticizing effect and the resultant increased moisture permeability of the matrix. An exception existed with the Eudragit RL PM film containing salicylic acid where drug-polymer interactions inhibited drug diffusion. The small changes in moisture permeability, Tg, and tensile strength observed with incorporation of the PVPs had an insignificant influence on the dissolution results for salicylic acid from Eudragit RS PM films. Increases in the tensile strength and Tg after addition of PVP to the Eudragit RS PM matrix support the observed decreased rate of diffusion for chlorpheniramine maleate. The pores formed by migration of the hydrophilic adjuvants from the films altered the diffusion kinetics of the matrix, compared with that of the nonporous polymer, when only the antihistamine was present.

Acrylic Resins↗
PubMed1998

Effect of film composition and various penetration enhancers concentrations on prazosin release from acrylic polymeric films.

An investigation was conducted to evaluate the effect of changing the Eudragit RL 100 ratio and the influence of different penetration enhancers in various concentrations on the release of prazosin from Carboset 525:Eudragit RL 100 polymeric films using improved Franz diffusion cells, to choose the most suitable polymeric film ratio, the most appropriate enhancer and its optimum concentration to be used to achieve the maximum release of the drug. The results show that prazosin release from polymeric films containing Carboset 525:Eudragit RL 100 in a 1:1 ratio was significantly (p < 0.05) higher than from films in a 1:0.25 ratio and non-significantly (p > 0.05) higher than from those containing 1:0.5, 1:3 polymer ratios and non-significantly lower from those containing 1:4 polymer ratios. The addition of various enhancers, n-decyl alcohol (7, 9 and 11% w/w), Azone (4, 6 and 8% w/w) and Cineole (7, 9, 11 and 14% w/w) significantly (p < 0.05) enhanced the prazosin release from these polymeric films containing the two polymers in a 1:1 ratio. The best concentrations of these enhancers were 11% n-decyl alcohol, 9% Cineole and 8% Azone. The formulations containing these concentrations of the enhancers are being further studied for drug release through rabbits skin. It was found that using either of these enhancers in these concentrations resulted in a significant (p < 0.05) increase in the amount of prazosin transported across the skin. On the other hand these enhancers did not show any significant (p > 0.05) difference between them. The mechanism of drug release from the polymeric films was further studied using water vapor permeability (W.V.P.), the permeability constant (P) and differential scanning calorimetry. The enhancers were found to increase the W.V.P. and the permeability constant (P) and the results were in very good agreement with the effect of enhancers on the in-vitro drug release. The DSC thermograms showed that the enhancers physically interacted with either or both of the polymeric film materials and prazosin which could be one of the reasons for the improvement in the release of the drug from these polymeric films.

Acrylic Resins↗
PubMed1998

Molecular basis of film formation from a soybean protein: comparison between the conformation of glycinin in aqueous solution and in films.

Fourier transform infrared spectroscopy has been used to investigate the conformational changes of glycinin. a major storage protein of soybean seeds, upon film-forming. The results show that the secondary structure of glycinin is mainly composed of a beta-sheet (48%) and unordered (49%) structures. The amide I band of glycinin in film-forming conditions, i.e. in alkaline media and in the presence of plasticizing agent, reveals the conversion of 18% of the secondary structure of the protein from the beta-sheet (6%) and random coil (12%) to the alpha-helical conformation due to the helicogenic effect of the ethylene glycol used as the plasticizing agent. Conformational changes also occur upon the film-forming process leading to the formation of intermolecular hydrogen-bonded beta-sheet structures. Results obtained from other plant families indicate that, whatever the origin and conformation of protein, formation of films leads to the appearance of intermolecular hydrogen-bonded beta-sheet structures, suggesting that this type of structure might be essential for the network formation in films. Thus, it is hypothesized that, in the film state, intermolecular hydrogen bonding between segments of beta-sheet may act as junction zones in the film network. This study reveals for the first time that there is a close relationship between the conformation of proteins and the mechanical properties of films.

Globulins↗
PubMed2002

Plasma-induced graft polymerization of acrylic acid onto poly(ethylene terephthalate) films: characterization and human smooth muscle cell growth on grafted films.

Graft polymerization of acrylic acid onto plasma treated poly(ethylene terephthalate) (PET) films was carried out to develop surfaces for protein immobilization and smooth muscle cell seeding. Films with various graft densities were characterized by contact angle measurements, attenuated total reflectance infrared spectroscopy, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The contact angle was observed to decrease from 72.9 degrees for the virgin PET films to between 26 degrees and 33 degrees depending on the graft density. Storage of grafted films led to an increase in the contact angle, suggesting molecular rearrangement at the surface. However, films with the lowest graft levels showed maximum enhancement in the contact angle up on storage. XPS confirmed the presence of the polyacrylic acid grafts at the film surface and AFM showed a marked increase in the wavelength of the surface roughness as the graft density increased. The amount of collagen immobilized at the surface of the grafted films also increased as the graft density increased. The collagen immobilized films provided an excellent substrate for the growth of human smooth muscle cells.

Acrylates↗
PubMed2002

Finite element analysis of slow drug release through deformed coating film: effects of morphology and average thickness of coating film.

This paper, a continuation of our previous work, is a presentation of the effect of the morphology and the average thickness of the deformed coating films on the slow diffusional release characteristics analyzed numerically under the constraints of the constant volume of the drug matrices and the coating films, if the films have the same average thickness. Increasing the average thickness of the coating films slows down the fractional release and the average release rate of the drug and smoothen the initial burst of the drug, as well as increase the initial lag time. The effect due to deformation of the coating films on these diffusional release characteristics are found to be less significant with the increasing average thickness of the coating films. Interestingly initial lag times are found to be the same for the coated particles having the same smallest thickness but different average thickness of coating films. The effect due to the change in the average thickness of the coating films on the characteristics of the slow controlled-release is discussed to shed light on the design of a better controlled-release device.

Algorithms↗
PubMed1998

Selectively Swollen Films of Triblock/Diblock Copolymer Blends: Dependence of Swollen Film Structure on Blend Composition.

Compositional variation in blends of triblock and diblock copolymer films can be used to adjust the film response to a selective solvent. We investigated the relationship between blend composition and film structure in ordered films containing poly(styrene-b-2-vinylpyridine) (PS-P2VP) diblocks and PS-P2VP-PS triblocks. The study focuses on films possessing a lamellar morphology. Methanol, a strongly selective solvent for P2VP, is used to swell the films. Since methanol solvates P2VP but not PS, periodic multilayer structures result in which solvent-rich P2VP domains are separated by undissolved PS domains. The film structure is characterized in the dry and swollen states with neutron reflectivity. Although the dry state morphology dimensions are practically identical for all samples, in the swollen state films richer in triblock swell less due to higher density of bridges interconnecting the PS domains. Furthermore, in swollen triblock-containing samples, polymer concentration variations in P2VP domains are suppressed and the PS domains are better aligned with respect to the substrate.

Journal Article↗