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The Commission adopts a Second Report and Order releasing reserved radio spectrum in the 806-821/851-866 MHz bands for Private Land Mobile Radio Service use. The rules adopted provide enhanced flexibility in radio system design and user options. The action is necessary to satisfy land mobile spectrum needs across the country.
The author discusses the rise of "interactive radio" and its potential as a form of social support. Ranging from music request shows to on-air counselling, interactive radio reduces isolation, allows listeners to participate in various kinds of networking and dialogue, and conveys information and advice that may be helpful in promoting mental health. Based in part on his own experience with a weekly program, the author identifies characteristics of interactive radio that will be to interest or professionals who want to use the medium for community mental health promotion.
This report is a description of the development and organisation of an area radio paging service in Cambridge and its application to doctors and para-medical staff working in various hospitals and in the community. It reviews the first five years of operation.Personal selective radio paging has some fundamental advantages over the car radio-telephone as a means of communication. Currently, the service operates only in the Cambridge area, but it is planned to extend this to cover the new county of Cambridgeshire by February 1975, and, at the same time, to introduce speech.
This study examined the potential risk of hearing loss by commercial radio announcers. This risk is developed through the regular use of headphones. These headphones are used to monitor broadcast transmission and communication information from program producers. To our knowledge there are no published studies of the noise exposure of radio announcers. The experimental method utilised a headphone parallel to the one in use mounted on a wideband, artificial ear. A Sound Level Meter was then used to measure the sound level and then calculate the exposure level. Depending on the feedback level applied to their headphones radio announcers are exposed to potentially damaging levels of noise. Levels measured correlate with results from other studies of long-term average speech spectrum and voice level measurements.
The affects of noise on the human inner ear have been well known for a long time, and measures to prevent occupational noise-induced hearing loss show a clear reduction in the statistics of morbidity. Nevertheless, there are working environments in which the use of ear protection seems to be inapplicable, because communication by speech is indispensable, for example in the cockpit of aircraft. Noise exposure measurements were performed on pilots of helicopters and propeller-machines of the German Federal Navy during realistic flight situations. The ambient noise levels during regular flight service were maintained at levels between 89 dB and 120 dB. Sound protection by flight-helmets and headphones is not only neutralised while using radio and intercom, but the noise during radio-communication is even louder than the noise of the engines. The use of ear protection to avoid excessive noise exposure is only of limited effectiveness. While pilots with normal hearing show only little impairment of speech intelligibility, those with noise-induced hearing loss show substantial impairment that varies in proportion to their hearing loss. Communication abilities may be drastically reduced which may compromise the reliability of radio-communication. The problem may be possibly solved in future by an electronic compensation system for noise.
Effects of radio-frequency lesions or injections of 6-hydroxydopamine (6-OHDA) into far-lateral hypothalamus (FLH) and substantia nigra (SN) on feeding behavior and motor activity were studied in four groups of cats. Hypoactivity, aphagia and adipsia followed by gradual recovery of alimentary behavior were observed only after radio- frequency lesions of FLH (group I). 6-OHDA injections into FLH evoked only slight and transient disturbances in regulation of fluid intake (group II). Radio-frequency destructions of SN produced long-lasting drop in drinking (group III) while 6-OHDA injections into SN caused long- lasting fall in food consumption (group IV). In both groups with SN damages different pattern of alimentary behavior was accompanied by motor hyperactivity.
Anesthetized random source dogs were cooled by ice water immersion to a stable core temperature of 25 degrees C and subsequently rewarmed with warm humidified inhalation (43 degrees C, 450 cc of min ventilation X kg-1) or radio-frequency induction hyperthermia (4-6 watts X kg-1). The mean time required for core rewarming to 30 degrees C was 280 +/- 114 min for ventilation and 58 +/- 13 min for radio wave therapy (p less than 0.001). There was no evidence of tissue damage with either modality. These data suggest radio wave heating is superior to warm humidified inhalation therapy for core rewarming of rapidly induced immersion hypothermia.
In Poland, 28 AM radio stations operate at frequencies from 738 kHz to 1602 kHz with output powers ranging from 1 kW to 750 kW. Altogether 384 workers are employed at those radio stations. Levels of exposure to electromagnetic fields (EMF) were identified at 5 of those radio stations, separately for 3 groups of workers, i.e. operation, maintenance, and administration. Electric and magnetic field intensities: E (in V/m) and H (in A/m), and the effective time of individual worker's exposure to EMF were assessed. The assessments were carried out independently by the conventional (MEH-1 plus stop-watch) and computer-aided (Holaday Programmable Recorder) methods. The study provided reliable data on the actual time of worker's exposure to EMF of exactly determined intensities. The study indicated a wide range of different exposure levels between individual groups of workers, which depended rather on a particular AM broadcast station and the type of job performed by individual groups of workers' than on the transmitter power or the type of protective zones in the vicinity of transmitters.
A recent study reported the results of an exploratory study of alterations of the quantitative sleep profile due to the effects of a digital mobile radio telephone. Rapid eye movement (REM) was suppressed, and the spectral power density in the 8-13 Hz frequency range during REM sleep was altered. The aim of the present study was to illuminate the influence of digital mobile radio telephone on the awake electroencephalogram (EEG) of healthy subjects. For this purpose, we investigated 34 male subjects in a single-blind cross-over design experiment by measuring spontaneous EEGs under closed-eyes condition from scalp positions C3 and C4 and comparing the effects of an active (0.05 mW/cm2) and an inactive digital mobile radio telephone (GSM) system. During exposure of nearly 3.5 min to the 900 MHz electromagnetic field pulsed at a frequency of 217 Hz and with a pulse width of 580 microseconds, we could not detect any difference in the awake EEGs in terms of spectral power density measures.
The goal of our studies was to determine whether administration of IL-1/GM-CSF to mice could reduce radio-antibody-induced myelosuppression and allow either dose escalation of radio-antibody using 131I, 90Y or 188Re conjugated to either intact antibody or bivalent fragments or more frequent dosing with 131I-IgG. Survival, peripheral blood counts, hematopoietic tissue weight and number of marrow CFCs were used to determine the ability to dose-intensify with a single dose or to reduce the spacing between doses. In this report, we show that in the absence of cytokines, 2 cycles of 131I-IgG spaced at 28, 35, 42 and 49 days resulted in 100%, 100%, 40% and 0% lethality, respectively. In contrast, cytokine intervention reduced lethality to 45%, 20%, 0% and 0% at the same time intervals between doses. Thus, the use of cytokines permits at least a 1 week earlier redosing of 131I-IgG. Cytokine intervention also has reduced the magnitude of myelosuppression, as measured by neutropenia and thrombocytopenia, thus permitting intensification of single doses of radio-iodinated intact antibodies, bivalent fragments and 90Y-IgG by at least 30%, 50% and 25%, respectively. However, cytokines were not effective at permitting dose escalation of either 90Y-F(ab')2 or 188Re-IgG. Further optimization of the dose schedule of cytokine administration needs to be explored for these 2 nuclide-antibody forms.
In 1994, Giuffré et al. reported two unrelated families in which some of the members had microcephaly and radio-ulnar synostosis, suggesting a new condition. Since this first report, Tsukahara et al. and Udler et al. described two distinct patients with a different condition characterized by radio-ulnar synostosis, short stature, microcephaly, scoliosis, and mental retardation. Here we report on a new case of microcephaly and radio-ulnar synostosis and discuss the possible relationship between Tsukahara's syndrome and the phenotype described by Giuffré et al.
Liver tumours frequently present at a late stage and only a minority of patients are likely to benefit from resection or transplantation. Inoperable tumours carry a grave prognosis. External beam irradiation of the liver is dose-limited by the radiosensitivity of hepatocytes, particularly in the presence of cirrhosis, but internal radiation using radio-isotope sources can achieve more selective irradiation of the chosen field. Sealed sources are dose-limited by their effects on surrounding tissues, whereas with unsealed sources the dose of radio-isotope administered is limited by bone marrow suppression. Iridium-192 wires are most frequently employed as a sealed intracavitary source. They may be inserted surgically, transhepatically or endoscopically. Doses of up to 60 Gy can be delivered to a malignant biliary stricture without damage to the surrounding parenchyma. The incidence of cholangitis is low if treatment is administered after insertion of an endoprosthesis. Unsealed radio-isotope sources may be injected directly into the tumour, administered embolically via the hepatic artery in the form of microspheres or lipid droplets, or given via parenteral infusion attached to tumour-specific antibodies. Of these vehicles, the lipid agent Lipiodol appears to be the most effective and can deliver a potentially lethal dose of radiation to small tumours. Host reaction to the injected antibody remains a major drawback to the use of monoclonal antibodies as targeting agents. Iodine-131 is a beta- and gamma-emitter, producing a local tumoricidal effect and allowing accurate dosimetry by means of external scintigraphy. Yttrium-90 is a pure beta-emitter with a greater maximum beta energy and cytotoxic range; however, it is retained in bony tissues, resulting in a dose-related risk of marrow suppression. Bone absorption cannot be measured by external imaging owing to the absence of gamma emission. This lack of accurate dosimetry, coupled with the toxic side-effects of yttrium treatment, make iodine-131 the current isotope of choice.
BACKGROUND: The management of regional lymph nodes in patients with clinical Stage I testicular carcinoma is a controversial problem. The authors investigated the feasibility and accuracy of radio-guided mapping of sentinel lymph nodes (SLNs) for men with clinical Stage I testicular tumors. METHODS: Twenty-two patients with clinical Stage I testicular carcinoma were enrolled in the study. One day before surgery, (99m)Technetium-labeled phytate was injected around the testicular tumor. After undergoing radical orchiectomy, patients underwent laparoscopic retroperitoneal lymph node dissection (L-RPLND). All radioactive lymph nodes were marked in the L-RPLND procedure, and three-dimensional SLN maps were made. All resected lymph nodes were evaluated by routine histopathologic examination, and the clinical significance of intraoperative SLN mapping was evaluated. RESULTS: SLNs were detected in 21 of 22 patients (95%). Nearly all SLNs were detected at the ventral or lateral side of the vena cava or at the aorta between the levels of the aortic bifurcation. All SLNs were detected easily in a surgical procedure. Only 1 radio-positive area per patient was identified in 15 patients, and approximately 2-4 positive areas were detected in 6 patients. Two patients had micrometastasis only in SLNs. In 2 patients who had seminoma, lymph node recurrences (at the level of the renal vein and in the obturator lymph node area) occurred at 10 months and 20 months after surgery. CONCLUSIONS: Radio-guided mapping of SLNs with laparoscopy was feasible, and nearly all SLNs were detected accurately by the procedure. In the near future, the standard retroperitoneal lymph node dissection may be avoided in most patients with clinical Stage I testicular carcinoma by utilizing focused examination of SLNs.
Radio-telemetry is an excellent tool for gathering data on the biology of animals and their interactions with the environment they inhabit. Many methods have been developed for analyses of spatial information, on home range size and utilization density. Activity patterns are often described using radio-tracking data, but no generally accepted method is currently available specifically for determining the temporal independence of this type of data for statistical inference. Activity rhythms have generally been analysed by ecologists with the assumption that data are temporally independent, or by subjectively fixing an independence interval, based on attributes of their ranging behaviour. Although some good approximations of activity patterns can be obtained in these ways, we underline the need for a functionally correct method of estimating independence interval. Here we use semi-variograms to estimate the minimum interval required for the readings to be sequentially independent. This geostatistical tool is applied to the analysis of data on activity of Chilean foxes (Pseudalopex culpaeus) and Chacoan peccaries (Catagonus wagneri). Data were collected in the field by radio-tracking over 24-hr periods, with readings on activity state taken every 15 min. The spatial dimension in which the theory of geostatistics lies has been transferred into the time dimension, so that the correlation interval is expressed in time units (min). Time of independence as estimated by the variogram was 110 min for foxes, while data on peccaries indicated that they have long periods of activity, more suitable for time-series analysis. Copyright 1999 Academic Press.
The minimally invasive treatment of liver tumors represents an alternative to the open surgery approach. Radio-frequency ablation destroys a tumor by delivering radio-frequency energy through a needle probe. Traditionally, the probe is placed manually using imaging feedback. New approaches use robotic devices to accurately place the instrument at the target. The authors developed an image-guided robotic system for percutaneous interventions using computed tomography. The paper presents a randomized patient study comparing the manual versus robotic needle placement for radio-frequency ablation procedures of liver tumors. The results of this study show that in our case robotic interventions were a very viable solution. Several treatment parameters such as radiation exposures and procedure-times were found to be significantly improved in the robotic case.
A computed radiograph system (Toshiba, model TCR-201) was used to investigate the digital image analysis of radio-opacity of the paranasal sinuses. The results of the preliminary phantom examination for evaluating the exposure technique indicated that the tube voltage should be kept constant. By using conventional radiographic images and tomographic images of normals and cases of sinusitis, the quantum values (Q-values), Q-value profiles, and Q-value histograms of radio-opacities in the paranasal sinuses were assessed statistically. Findings demonstrated that radio-opacities in the paranasal sinuses could be evaluated quantitatively by these digital image analyses.
Experimental investigations on the dimethyl-amino-stilbous carcino-sarcoma of the rat have led to a modified interstitial post-operative Curie-therapy of gliomas in the brain hemispheres following treatment with radio sensitizers. After treatment with the thymine-analogous radio-sensitizers 5-brom-2-desoxyuridine (BUDR) and 5-brom-2-desoxycytidine (BCDR) and desoxyguanosine as well as the anti-metabolites 5-fluor-uracile (FU) and methotrexate (Mtx), there is greater incorporation of the thymine analogues in the DNS of the tumour cells. More than any other combination, BUDR and Mtx effectively sensibilizes the tumour cells. Syncavit and actinomycine-D are also effective. After radio-sensitizing the post-iridium-192 contact irradiation apparatus on 133 patients with gliomas. This treatment lengthened postoperative survival times.
Microwave radiometry is a spectral measurement technique for resolving the electromagnetic radiation of matter when its temperature is above absolute zero. The radio-thermometer utilises this technique and consequently can provide temperature distributions in subcutaneous biological tissues. A new phantom was proposed that imitates a mammary gland tumour, and the brightness temperature was observed using radio-thermometers operated at different frequencies, 1.75GHz and 3GHz. The proposed phantom, simulating heat diffusion propagated by tissues around real tumours, revealed that the thermal characteristics of the tumour imitator were well matched to the heat transfer properties of a real tumour and a proportional linear relationship between the location of the tumour imitator and the brightness temperature in a homogenous medium was established. From experiments using the proposed mammary gland tumour phantom and a clinical trial on patients with breast cancer, it could be concluded that a radio-thermometer with a short wavelength (lambda = 10cm, i.e. f= 3GHz) is useful to resolve a thermal anomaly at a shallow depth in an homogenous medium such as a breast.