Biomedical subjects

S L Fritz

Publications and source records attributed to S L Fritz.

24 records · Page 2Linked to original sources

PubMed1978

Computed tomographic evaluation of the breast.

Experience with a dedicated breast CT scanner (General Electric CT/M) using a contrast medium enhancement technique indicates that CT is superior to mammography, thermography, or physical examination for diagnosing both benign and malignant mammary disease especially in dense, thick, or fibrocystic breasts. CT is capable of diagnosing totally unsuspected early miniature carcinomas. It can identify and differentiate potential precancerous lesions from benign fibrocystic disease, and is the diagnostic tool of choice for evaluating and following severe fibrocystic disease. CT evaluation also affords definitive diagnostic help in instances where the mammographic, thermographic, and/or physical examinations are inconclusive. It can influence immediate surgical intervention or mitigate against an unnecessary biopsy. The study not only demonstrates morphologic changes in the breast but also accurately depicts an altered iodine pool in mammary tissues.

Adult↗

PubMedDate not supplied

A comparison of computed and measured heel effect for various target angles.

Two models for thick target emission spectra, one using constant depth of Bremsstrahlung and one using continuous slowing-down of electrons and multiple thin targets, were used to predict filtered emission spectra at various angles with respect to the central axis. Integration of these spectra and comparison against measured heel effect gave excellent agreement for tungsten targets with take-off angles of 7 degrees and 10 degrees at 60 and 100 kVp when the angular anisotropy of Bremsstrahlung was taken into account. Results for a 17.5 degrees target at 60 kVp were poor, possibly indicating a need for a better model of Bremsstrahlung angular dependence.

Radiography↗

PubMedDate not supplied

Scatter/primary ratios for x-ray spectra modified to enhance iodine contrast in screen-film mammography.

Contrast mammography to detect the uptake of iodine-containing contrast material may be enhanced by spectral modification of the x-ray beam. Luminance scatter-to-primary ratios were measured for three candidate x-ray tube anode/filter combinations (Mo/Mo, W/Ce, and Ce/Ce). Results show that scattered radiation is significant for all tubes, is lowest for the Mo/Mo system and is essentially the same for the tungsten and cerium anode systems.

Cerium↗

PubMedDate not supplied

The effect of anode curvature on radiographic heel effect.

Previous computer modeling of radiographic heel effect has shown that a simple model can give an accurate representation of heel effect for flat anode surfaces. This paper details the extension of this model to allow curved anode surfaces. A fixed-anode x-ray tube with a demountable anode was constructed and used to test the predictions of the computational model at 25 kVp using stainless-steel anodes. The computer model was also used to estimate the magnitude of the heel effect for a tungsten anode at 60 kVp. This work allows determination of the effect of anode curvature, which is an inherent feature of certain recently proposed tube designs for scanning slit radiography.

Computers↗

PubMedDate not supplied

High-resolution digital x-ray detector utilizing a discrete array of CdWO4 scintillators and a self-scanned photodiode array.

A high-resolution x-ray detector array for x-ray imaging is described. It consists of a discrete array of CdWO4 scintillators and a Reticon 1024S photodiode array with a fiber-optic faceplate. The scintillator elements measure 0.099 X 3 X 4 mm and are bonded together with aluminum foil separators to minimize light crossover. Detective quantum efficiency (DQE) of individual detector channels was 0.38. Systematic variations between channels were substantial. With only a simple correction for between channel variations, DQE for the entire array was 0.04. Evaluation of the edge response function of the array showed that resolution is similar to a detector whose line spread function is Gaussian with a standard deviation of 0.172 mm.

Cadmium↗

PubMedDate not supplied

Phantom evaluation of angiographer performance using low frame rate acquisition fluoroscopy.

The authors have investigated the effect of 5 frames/s television fluoroscopy on the time required to selectively catheterize five test arteries in an angiographic phantom. Here, 5 frames/s acquisition was accomplished by sampling frames from a 30 frames/s video signal. Sampled frames were stored in a video memory which provided continuous display to the fluoroscopist between samples. The test phantom was a plastic model of an aorta with branching vessels immersed in an isodense suspension of barium in water. For four of the five vessels there was no significant difference in time required for catheter placement between 30 frames/s and 5 frames/s.

Catheterization↗