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Results for “Fluoroscopy”

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At least 19 recordsLinked to original sources

PubMed1975

Multiple fluoroscopy of the chest: carcinogenicity for the female breast and implications for breast cancer screening programs.

The risk of radiation carcinogenesis has been established for breast tissue from experience with total body irradiation and multiple fluoroscopy of the chest with the patient prone. The doubling dose has been estimated to lie between 20 and 50 rads. Before undertaking radiologic screening programs for breast cancer, therefore, it is necessary to determine whether exposures below this range are safe. Of 792 women who had had tuberculosis and were followed for a minimum of 20 years, 451 had had multiple fluoroscopy while supine; 341 had not had fluoroscopy. The first group received a total radiation dose to the breast averaging 17 rads (141.5 fluoroscopies); the incidence of breast cancer in this group was not increased. Had fluoroscopy been performed with the patient prone the total radiation dose would have averaged 308 rads. The difference is thought to explain the increased incidence of breast cancer attributable to fluoroscopy given with the patient prone. Mid-breast exposure with mammography or xeroradiography varies between 3 and 6 rads. Repetitive screening would, therefore, appear safe provided total exposure did not exceed 20 rads. With this restriction there would appear to be no reason to curtail screening of women for breast cancer.

Breast Neoplasms↗

PubMed1979

Bladder function in children with meningomyelocele: comparison of cine-fluoroscopy and urodynamics.

We have assessed 60 children on an outpatient basis with cine-fluoroscopy combined with urodynamics. Bladder and rectal pressure together with sphincter electromyography were measured during bladder filling under fluoroscopy, which was followed by measurement of rectal pressure and sphincter electromyography during voiding under fluoroscopy. Comparison of the x-ray studies and urodynamics showed that the cystogram alone was not a reliable indicator of ray studies and urodynamics showed that the cystogram along was not a reliable indicator of detrusor function. The sphincter electromyogram during voiding must be interpreted in the face of intra-abdominal pressure changes owing to straining or Credé's maneuver. Residual urine estimations and the appearance of the bladder outflow on fluoroscopy were better parameters of outflow obstruction than sphincter electromyography.

Adolescent↗

PubMed1992

Radiation exposure during gastroenterologic fluoroscopy: risk assessment for pregnant workers.

With more females in childbearing years participating in fluoroscopic examinations, safety guidelines need to be evaluated. Present recommendations suggest limiting fetal irradiation to less than 500 mrem (0.5 rad) during gestation, and to avoid doses above 100 mrem (0.1 rad) from 8 to 15 wk postconception. The average radiation dose delivered per case was monitored during 10 therapeutic biliary procedures with lithium fluoride dosimeters worn at the endoscopist's collar, over the suprapubic region outside a knee-length 0.5-mm leaded equivalent apron, and inside the apron over the mid-pelvis. A short survey of 15 female technicians and physicians was conducted to gather their opinions about working in fluoroscopy during pregnancy. We found that radiation doses beneath the leaded apron were comparable to environmental exposure. The dose measured at the endoscopist's collar was 0.083 mrem/min. The dose over the pelvis was 0.044 mrem/min. The survey revealed that 13 of those interviewed would not feel safe working near fluoroscopy, and 12 wished to be excluded from fluoroscopy if they became pregnant. We conclude that a high level of anxiety regarding fetal safety exists among females participating in fluoroscopic procedures. In this study, with proper use of standard safety equipment, radiation exposure does not exceed those levels currently recommended to avoid during pregnancy.

Adult↗

PubMed1979

Ultrasound fluoroscopy--what is it, and our approach to your requirements.

A discussion on Ultrasound Fluoroscopy and how it relates to the traditional Real Time Instrumentation. This paper covers the various types of Ultrasound Fluoroscopy Instrumentation, a few of the advantages and disadvantages of each and Unirad Corporation's approach to Ultrasound Fluoroscopy. Also detailed discussions on the technical differences between their approach and the traditional Real Time Instrumentation itemizing electronic beam resolution control in some detail as to its advantages, complexity and comparison to Real Time (Non-focused) and the traditional single element Ultrasound Instruments.

Echocardiography↗

PubMed1992

Mitral balloon valvuloplasty with transesophageal echocardiography without using fluoroscopy.

Balloon mitral valvuloplasty with Inoue technique was performed in two group of patients. In group I (n = 40) valvuloplasty was performed under fluoroscopy without using echocardiography, whereas in group II (n = 13) valvuloplasty was performed under the guidance of transesophageal echocardiography alone, without using fluoroscopy. Patients in two groups were comparable with regard to clinical variables and hemodynamic parameters. Two female patients in group II were pregnant. Transmitral pressure gradient decrease did not differ significantly between two groups (pressure gradient: 17 +/- 5 to 4 +/- 1 in group I and 15 +/- 4 to 3 +/- 1 mm Hg in group II). Mitral valvular area increase was also not different in two groups (1.09 +/- 0.2 cm2 to 2.3 +/- 0.5 cm2 in group I and 0.9 +/- 0.2 to 2 +/- 0.3 cm2 in group II). In 14 cases from group 1 and 2 cases from group II mitral regurgitation increased after valvuloplasty (p < .05). Left atrial perforation occurred in one patient from group 1 and 2 patients from group II. In conclusion, mitral balloon valvuloplasty under transesophageal echocardiographic guidance alone is a safe and effective procedure in the treatment of mitral stenosis.

Adult↗

PubMedDate not supplied

Computerized fluoroscopy techniques for intravenous study of cardiac chamber dynamics.

A computerized fluoroscopy system which was recently developed in our laboratories permits image contrast increases of 8-16 relative to conventional image intensifer fluoroscopy and permits study of canine and human ventricular wall motion using peripheral intravenous injections. Two time-dependent image subtraction algorithms are illustrated in connection with observation of artificially infarcted dog hearts. The first algorithm produces a display analogous to direct ventriculography using catheterization. The second displays regions of dyskinetic motion as anomalous image grey shades.

Animals↗

PubMed1978

[X-ray dose reduction in examination of infant's hip with image-intensifier-fluoroscopy-system (author's transl)].

An image intensifier--70mm camera--fluoroscopy system combined with a conventional X-ray tube is used for routine examination of the infant's hip. The high quality of 85% of these 70mm exposures makes immediate diagnostic interpretation possible. An even higher percentage can be achieved by most exact positioning of the patients. Apart from the radiation protection of the gonades, the X-ray skin dose of the primary beam is reduced by 90-95% compared with full size radiography using film screen combinations. This exposure technique can certainly be used not only for the examination of the infant's hip.

Fluoroscopy↗

PubMedDate not supplied

A low-cost system for digital image processing of moving images in real time: application to X-ray fluoroscopy.

A low-cost image processing system and two real-time digital image processing algorithms using parallel processing have been developed to provide automatic equalization of moving images at video frequencies. The algorithms differ in the processing time required and the characteristics of the final image. The system takes an entire image from the video sequence, digitizes it, automatically calculates its histogram and the lowest and highest useful grey levels, equalizes the histogram, and finally converts it to the analogue image. Methods were applied to X-ray fluoroscopy (angiography) images, which are usually saturated or of uniform intensity (low contrast), leading to information loss. An application of these methods is in interventional radiography, which requires images in real time.

Algorithms↗

PubMedDate not supplied

Dynamic radiography. An evaluation of cardiac motion by the analysis of scattered radiation during fluoroscopy.

A non-invasive technique, utilizing scattered radiation, has been developed to monitor and measure the motion of the epicardial surface during fluoroscopy. A number of dogs were studied using a monitoring device which consists of an X-Ray beam collimator, collimated sodium iodide dectetors and their associated electronics. The detector signals are computer processed to obtain frequency fingerprints of epicardial motion that may, in the future, indicate the condition of the myocardium.

Computers↗

PubMedDate not supplied

Real-time digital K-edge subtraction fluoroscopy.

We report in vitro and in vivo trials of K-edge fluoroscopy, by which iodine contrast concentration is displayed live, with tissue and bone images suppressed, free of patient-motion artifacts. Iodine and cerium, 125 and 225 mg/cm2 respectively, filter alternate TV fields of cine-pulsed 50 KVP x-rays. Weighted subtraction of successive TV fields isolates the iodine image and simultaneously minimizes artifacts. Digital techniques are used in real time. At our present x-ray tube limit, 500 mA instantaneous current, the patient exposure is 180 mR/sec and quantum mottle limits the image quality. Integrating four successive difference images provides a compromise between mottle and smoothly moving displays. Cardiovascular images of a 17-kg dog, using 1 ml/kg Renografin-60 injected into a foreleg vein, show that a 15-cm chest thickness is our present practical maximum. This method may be useful in diagnosing cardiovascular anomalies in infants without catheterization or suspension of breathing.

Animals↗

PubMedDate not supplied

Spectral considerations for absorption-edge fluoroscopy.

In our previous reports on absorption-edge fluoroscopy, it was not possible to relate fully the subtleties involved in the selection of spectral parameters. This paper is intended as an overview of this important aspect of the technique. It is shown that, by using the 1-kVp, 2-filter technique, it is possible to image certain elements (e.g., iodine and xenon) in the presence of tissue variations of +/-2 cm about the thickness at which perfect tissue cancellation takes place. Use of logarithmic signal processing extends this range, but bone thickness variations may not be accomodated because only two x-ray energies are involved in the imaging process. Use of a 3-kVp, 3-filter technique with logarithmic signal processing is shown to solve this problem. Computer simulations show that 1-mg/cm2 iodine may be imaged in the presence of 10 cm or more tissue variations and 2000-mg/cm2 bone variations.

Bone and Bones↗

PubMedDate not supplied

Dynamic pulmonary imaging: performance properties of a digital fluoroscopy system.

The physical characteristics of dynamic pulmonary imaging with digital fluoroscopy, which differ from those in DSA equipment, have been determined. The spectral distributions and mean energies were calculated and corresponding exposures with varying high voltage and copper filtration (60-100 kVp, 0-2.83 mm Cu) were measured. The utilization of 90-100 kVp with a filter consisting of 1.39 mm Cu and 3 mm Al minimized disturbing skeletal artifacts and reduced the radiation exposure by a factor of approximately 5 in comparison with imaging at 60 kVp without copper filtration. Simultaneously, the measured signal decreased by about 25%. The mean energy of this spectrum exceeded that of 140 kVp chest imaging. The dynamic pulmonary imaging method produces logarithmically transformed x-ray transmittance values linearly related (r = -0.999) to water thickness between 7-10.5 cm, which is equivalent to the normal range of the chest in pediatric patients. A good linear correlation (r = 0.933,N = 92) was obtained when the change in transmitted radiation was compared with tidal volume measured in a rabbit model using a pneumotachometer. The results indicate that the method is applicable for quantitative measurements of pulmonary ventilation. Changes in tidal ventilation can be measured with this noninvasive x-ray imaging technique.

Animals↗

PubMed1976

Post-lymphographic percutaneous fine needle biopsy of lymph nodes guided by fluoroscopy.

Fine needle, percutaneous aspiration of suspect lymph nodes was carried out in 29 patients during fluoroscopy. The correct positioning of the needle was assured if the node moved with the tip of the needle. In 29 patients, there were 65 successful aspirations and 29 failures. Anesthesia is recommended but care should be taken that the anesthetic does not reach the lymph node itself as this can cause distortion of the cells.

Biopsy, Needle↗

PubMed1979

A hybrid computerized fluoroscopy technique for noninvasive cardiovascular imaging.

The excellent linearity of digital image storage and retrieval permits hybrid analog-digital subtraction to extend the spatial resolution of two previously developed algorithms which employed entirely digital apparatus. A low resolution, time-integrated preinjection digital mask image is reconverted to analog form and subtracted from live analog video images of iodine administered by peripheral intravenous injection to produce a high resolution display of the cardiovascular system with contrast ten times greater than conventional fluoroscopy. Preliminary studies in dogs are compared with images obtained with our digital subtraction algorithms.

Animals↗

PubMed1979

Routine fluoroscopy using minispot cameras.

Routine fluoroscopy was performed using 100- and 105-mm spot film cameras. Radiation dose was reduced to between 30% and 43%, and cameras were acceptably reliable. Cost for film and holders was high.

Fluoroscopy↗

PubMed1979

Percutaneous transperitoneal fluoroscopy-guided fine-needle biopsy of lymph nodes.

After lymphography from the foot, with uncertain findings, fine-needle biopsy during fluoroscopy was performed in 107 patients. In 69 patients with possible metastases, involvement was demonstrated in 46, confirmed in 43 at operation. Lymph node involvement by general lymphatic disease was suggested in 38 patients, with biopsy confirmation in 12. In metastatic disease non-representative material was obtained in only 2 patients, in general lymphatic disease in 10. No significant complications occurred, and the side effects were small.

Biopsy, Needle↗

PubMed1978

Sialography of salivary gland tumors with fluoroscopy and tomography.

Sialography with fluoroscopy and tomography has increased the accuracy of detecting and delineating mass lesions of the parotid gland. Lesions which are small, at the periphery of the gland, or in the deep lobe are often most clearly visualized on tomographic sections. Often differentiation of benign from malignant tumors is not possible.

Adenolymphoma↗

PubMed1992

The usefulness of K-edge filters in automatic brightness controlled fluoroscopy and digital subtraction angiography.

This paper presents the results of a study in which the efficacy of using high atomic number K-edge filters in place of non-selective filters, in Automatic Brightness Controlled fluoroscopy and Digital Subtraction Angiography was examined. Filters investigated in the study were copper, and aluminium [as examples of non-selective filters], gadolinium, erbium and tantalum. The results of this study would suggest, with the possible exception of gadolinium as an added filter in angiography of thin anatomical parts, that the selective K-edge filters offer no particular advantage over the non-selective filters from the viewpoint of either patient dose reduction or image contrast. Further, for imaging of all but the thinnest anatomical parts, their use adds substantially to the problems of x-ray tube loading.

Angiography, Digital Subtraction↗