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A light source for testing radiological television cameras.

A light source for testing and setting up radiological television systems has been designed and built using green light emitting diodes and an optical integrating sphere. It is shown to have an optical spectrum similar to the green output phosphors used in x-ray image intensifiers (XRII's). It can be made uniform in intensity across the output port and does not show the small scale granularity characteristic of phosphors. It has a Lambertian angular distribution which, by the addition of neutral density filters, can be made to mimic the angular distribution at the output of an XRII. It can easily and accurately be modulated or switched and a luminance comparable to that of an XRII output phosphor can be achieved.

Lighting↗

Wiener noise power spectra of radiological television systems using a digital oscilloscope.

Measurement of spatial noise power spectra from television based radiographic and fluoroscopic systems is essential to the understanding of their operation and optimization. However, conventional methods require acquisition and processing of large numbers of complete images, thus confining such measurements to special applications where accessible frame buffers already exist or elaborately equipped laboratories. We have developed a method which only requires storage of single TV lines or point scans. A digital oscilloscope captures these point scans and a laboratory microcomputer facilitates manipulation of the data to separate out different components of the noise power spectra. The x-ray dependent component of the noise power spectrum so produced is not the ordinary Wiener spectrum. However, it is shown that reconstruction of the full Wiener spectrum from this is possible subject only to the requirement that the x-ray noise spectrum at the output of the imaging system is circularly symmetric.

Fluoroscopy↗

Television slit-lamp biomicroscopy.

The basic requirements for performing television slit-lamp biomicroscopy are outlined, and the methods of demonstrating particular features of ocular anatomy and ocular disease are discussed. The technique has a particular role in teaching in the clinical setting.

Eye↗

Television epilepsy and pattern sensitivity.

Properly functioning domestic television sets may induce seizures in epileptic patients (TV epilepsy). We investigated the effects of different types of visual stimuli on paroxysmal electroencephalographic (EEG) activity in 32 patients known to be sensitive to intermittent photic stimulation (stroboscopic light). We monitored sensitivity to patterns of horizontal and vertical lines, both stationary and vibrated (pattern sensitivity), and to normal broadcasts on a domestic, black and white (405- or 625-line) TV receiver (TV sensitivity). Twenty-three of the 32 patients were sensitive to pattern. Twenty-two were sensitive to vibrated patterns, and 11 to static patterns (P less than 0-01), All patients sensitive to pattern were also sensitive to TV; The association between sensitivity to pattern and to TV was significant. Clinical history of TV epilepsy (16 out of 32 patients) and laboratory evidence of pattern or TV sensitivity were not significantly associated. The high incidence of pattern sensitivity among flicker-sensitive patients and its association with TV sensitivity suggests that linear patterns produced by the raster of a black and white set as it scans, or "line-jitter" produced by the raster in areas of low TV-signal strength may contribute to the epileptogenic effect of TV.

Adolescent↗

Un-health promotion: results of a survey of alcohol promotion on television.

To estimate how widely and to whom alcoholic drinks are promoted 1258 television advertisements were studied over a 10 week period that included the Christmas and New Year holidays in 1986-7. A total of 156 advertisements (12%) promoted alcohol, and this percentage increased significantly over the holiday period to 17%. These advertisements were longer than those advertising other products, and just over half (56%) occupied the first position in commercial breaks. During sports programmes and between the hours of 1800 and 1900 there was an increase in the number of advertisements for alcohol, but there was no difference before and after 2100. It was found that the extent and influence of the promotion of alcohol were great and that such advertising is seen by many children and adolescents.

Advertising↗

Effect of closed circuit television on urban violence.

OBJECTIVE: To evaluate the effect of city and town centre closed circuit television (CCTV) surveillance on violence in terms of accident and emergency (A&E) department and police assault data. METHODS: A&E department and local police assault data in three centres in Wales (Cardiff, Swansea, and Rhyl) two years before and two years after the installation of CCTV were studied. British Crime Survey and police crime statistics were used as control data. RESULTS: A&E records of 24,442 assault patients and 3228 violent offences recorded by the police were studied. Data from two A&E departments (Swansea (+3%) and Rhyl (+45%)) showed increases in recorded assaults after CCTV installation but a decrease (12%) in the largest centre, Cardiff. There was an overall reduction in town/city centre violence from the A&E department perspective of 1% in the two years after CCTV installation. In contrast, police data demonstrated changes in the opposite direction (-44%, -24%, and +20% respectively) contributing to an overall decrease of 9%. British Crime Survey and police statistics for England and Wales demonstrated no overall change and a 16% increase respectively. CONCLUSIONS: City centre CCTV installation had no obvious influence on levels of assaults recorded in A&E departments. There was a negative relationship between police and A&E recording in all three centres. A&E departments are important and unique sources of information about community violence.

Crime Victims↗

Effect of urban closed circuit television on assault injury and violence detection.

OBJECTIVE: To evaluate the effect of closed circuit television (CCTV) surveillance on levels of assault injury and violence detection. DESIGN: Intervention versus control study design. SETTING: Five town/cities with CCTV surveillance and five, matched control centres without CCTV surveillance in England. INTERVENTION: CCTV installation and surveillance. METHODS: Assault related emergency department attendances and violent offences recorded by the police in CCTV and control centres in the four years, 1995-99, two years before and two years after CCTV installation, were compared. RESULTS: Assault related emergency department attendances decreased in intervention centres (3% decrease, ratio 0.96; 95% confidence interval (CI) 0.93 to 0.99) and increased in control centres (11% increase, ratio 1.11; 95% CI 1.08 to 1.14). Overall, changes in emergency department assault attendance in CCTV and control centres were significantly different (t test, p<0.05). Police recorded violence increased in CCTV (11% increase, ratio 1.16; 95% CI 1.08 to 1.24) and control centres (5% increase, ratio 1.06; 95% CI 0.99 to 1.13). Overall, changes in police recording in CCTV and control centres were not significantly different (t test, p>0.05). In CCTV centres, decreases in assault related emergency department attendances and increases in police violence detection were not uniform. CONCLUSION: CCTV surveillance was associated with increased police detection of violence and reductions in injury or severity of injury. CCTV centre variation deserves further study.

Crime Victims↗

Consulting patterns after a television programme on sexually transmitted diseases.

The effect on the work load in one of two clinics featured in a television programme devoted to the sexually transmitted diseases was monitored. The patients' source of referral was recorded before and after the programme and the number of telephone inquiries noted during the same periods. For the two weeks after the programme 18% of the male patients and 13% of the female patients attending the clinic came as a result of watching it. A sexually transmitted disease was diagnosed in 30% and 22% of those men and women respectively. This proportion of positive diagnoses was lower than for other sources of referral. The mean number of telephone inquiries rose by 56% after the programme.

England↗

Young adults' opinions of Philip Morris and its television advertising.

OBJECTIVE: To determine what young people think about the tobacco company Philip Morris and how it affects their evaluations of the company's new television advertising. DESIGN: Data were gathered in the context of a controlled experiment in which participants saw four Philip Morris ads about youth smoking prevention, four Philip Morris ads about charitable works, or four Anheuser-Busch ads about preventing underage drinking (the control group). Knowledge and opinion of Philip Morris were measured before ad exposure. SETTING: A California state university in the San Francisco Bay area. SUBJECTS: A convenience sample of undergraduates (n = 218) aged 18-25 years. MAIN OUTCOME MEASURES: Advertising evaluation measured by 12 semantic differential scales. RESULTS: A little more than half of the students knew that Philip Morris is a tobacco company. Neither this knowledge nor students' smoking status was related to their opinion of the company. Philip Morris ads were rated less favourably by students who were aware that the sponsor is a tobacco company than by students who were unaware. CONCLUSIONS: Advertisements designed to discredit the tobacco industry typically avoid references to specific companies. This study suggests that such counter-advertising would benefit from teaching audiences about the industry's corporate identities.

Adolescent↗

Tobacco imagery on New Zealand television 2002-2004.

Considerable emphasis has been placed on the importance of tobacco imagery in the movies as one of the "drivers" of smoking among young people. Findings are presented from a content analysis of 98 hours of prime-time programming on New Zealand television 2004, identifying 152 scenes with tobacco imagery, and selected characteristics of those scenes. About one in four programmes contained tobacco imagery, most of which might be regarded as "neutral or positive". This amounted to about two scenes containing such imagery for every hour of programming. A comparison with our earlier content analysis of programming in 2002 indicated little change in the level of tobacco imagery. The effect of this imagery in contributing to young viewers taking up smoking, and sustaining the addiction among those already smoking, deserves more research attention.

Adolescent↗

Can anti-smoking television advertising affect smoking behaviour? controlled trial of the Health Education Authority for England's anti-smoking TV campaign.

OBJECTIVES: To evaluate the effectiveness of the Health Education Authority for England's anti-smoking television advertising campaign in motivating smokers to give up and preventing relapse in those who had already given up. DESIGN: A prospective, controlled trial was conducted in four TV regions in central and northern England. One region received no intervention (controls), two regions received TV anti-smoking advertising (TV media), and one region received TV anti-smoking advertising plus locally organised anti-tobacco campaigning (TV media + LTCN). The TV advertisements were screened in two phases over 18 months; during the first phase the intensity of the advertising was varied between TV regions. 5468 men and women (2997 smokers, 2471 ex-smokers) were selected by two stage random sampling and interviewed before the intervention, of whom 3610 were re-interviewed six months later, after the first phase of the campaign. Only those interviewed at six months were followed to the main end point at 18 months when 2381 subjects were re-interviewed. MAIN OUTCOME MEASURES: Self reports of cigarette smoking at the 18 month follow up were compared between the three levels of intervention. Odds ratios for intervention effects were adjusted for pre-intervention predictors of outcome and pooled for smokers and ex-smokers using meta-analytic methods. RESULTS: After 18 months, 9. 8% of successfully re-interviewed smokers had stopped and 4.3% of ex-smokers had relapsed. The pooled adjusted odds ratio for not smoking in the TV media only condition compared to controls was 1.53 (95% confidence intervals (CI) 1.02 to 2.29, p = 0.04), and for TV media + LTCN versus controls, 1.67 (95% CI 1.0 to 2.8, p = 0.05). There was no evidence of an extra effect of the local tobacco control network when combined with TV media (odds ratio 1.15, 95% CI 0.74 to 1.78, p = 0.55). The was also no evidence of any intervention effects after the first phase of the TV media campaign, including no effect of varying the intensity of the advertising during this initial phase. Applying these results to a typical population where 28% smoke and 28% are ex-smokers, and where there would be an equal number of quitters and relapsers over an 18 month period without the campaign, suggests that the campaign would reduce smoking prevalence by about 1.2%. CONCLUSIONS: The Health Education Authority for England's anti-smoking TV campaign was effective in reducing smoking prevalence through encouraging smokers to stop and helping prevent relapse in those who had already stopped. The lack of an effect after the first phase of the campaign indicates that if advertising at this intensity is to have an impact, a prolonged campaign is necessary. These results support the UK governments' recent decision to fund similar campaigns, and suggests that anti-smoking TV advertising should be undertaken routinely as an essential component of any population smoking reduction strategy. Reducing smoking prevalence would make a substantial contribution to achieving the UK government's target of preventing 300 000 cancer and heart disease deaths over the next 10 years.

Advertising↗

Single monitor stereoradiological television system using PLZT electrooptic shutters.

A new family of materials consisting of lead lanthanium zirconate titanate (PLZT) has evolved from recent advances in ferroelectric ceramics. PLZT electrooptic ceramics may be used as electronically triggered high-contrast optical shutters in lightweight stereoscopic viewing devices. A PLZT electrooptic shutter stereoradiology system in which dual x-ray tubes are used to generate stereo pairs of fluoroscopic images is presented. This system requires only a single television monitor for stereoscopic viewing by one or more observers. The viewer which contains the optical shutters is compact, light-weight, and can be attached easily to normal eyeglasses.

Humans↗

Radiographic, photofluorographic, and television imaging systems: an evaluation.

A feasibility study for the photographic recording of fluoroscopic images from a high resolution system is described. Resolution on the television monitor was 2 line pairs/mm, making clinically acceptable recordings possible. Significant reductions in radiation dose to the patient and potential financial savings are indicated if a multiformat camera is developed to photograph the monitor.

Fluoroscopy↗

A television system for the teaching of radiologic diagnosis.

The authors describe a television system for use in teaching radiographic interpretation to a large class. The system consists only of a camera, receiver, and communications link, and it can be used equally well for transparent and opaque materials. With magnification, fine detail is clearly visualized.

Radiography↗

The effect of a television digital noise reduction device on fluoroscopic image quality and dose rate.

In conventional fluoroscopy, the current, and therefore the dose rate, is usually determined by the level at which the radiologist visualizes a just tolerable amount of photon "mottle" on the video monitor. In this study, digital processing of the analogue video image reduced noise and generated a television image at half the usual exposure rate. The technique uses frame delay to compare an incoming frame with the preceding output frame. A first-order recursive filter implemented under a motion-detection scheme operates on the image of a point-by-point basis. This effective motion detection algorithm permits noise suppression without creating noticeable lag in moving structures. Eight radiologists evaluated images of vesicoureteral reflux in the pig for noise, contrast, resolution, and general image quality on a five-point preferential scale. They rated the digitally processed fluoroscopy images equivalent in diagnostic value to unprocessed images.

Animals↗

A microscope-television system for studying flow velocity in human skin capillaries.

A noninvasive technique for studying blood flow dynamics in human skin capillaries is described. A light microscope combined with a closed-circuit TV system was used to monitor and record capillary blood flow velocity on video tape. Arterial pulsations were recorded plethysmographically and converted into video signals by modulating the position of a square, white area in the televised scene. Twelve healthy subjects were studied. The mean (+/- SD) resting capillary blood flow velocity was 0.65 +/- 0.3 mm/s at an average skin temperature of 30.4 +/- 2.3 degrees C. Spontaneous fluctuations at a frequency of 6-10 cycles/min were observed in most subjects. A well-pronounced flow pulsatile component could be demonstrated in all capillaries studied. The technique can be used in clinical practice for studying the physiology and pathophysiology of cutaneous microcirculation in man. It can be expected that the method may become an important diagnostic tool in diseases that involve disturbances of the microcirculation, such as diabetes, hypertension, and atherosclerosis.

Capillaries↗

Influence of television on photosensitive epileptics.

We examined 32 epileptics (20 female; 12 male; aged 6-73 years) who had displayed photoconvulsive reactions to flickering light in the EEG; they were examined with regard to their risks of getting epileptic seizures upon watching television (TV) under certain conditions. On a colour TV set each patient was shown a 3-min videofilm with slow- and fast-moving parts under 16 different conditions. The conditions had the following variables: (1) colour - monochrome; (2) dark room - light room, and (3) four different distances from the screen. In addition, each patient was subjected for 3 min to manipulated image interferences, including the vertical rolling of the picture. The results of this TV stimulation were always negative, i.e. in no patient did TV provoke a reproducible paroxysmal discharge in the EEG, nor was there any epileptic seizure. Our findings are discussed in connection with the corresponding literature.

Adolescent↗