Fluoroscopy final exam California Question and Answers 2024

Fluoroscopy final exam California Question and Answers 2024 Linear, non threshold Most cancers Linear, threshold Deterministic effects, cataracts and skin Nonlinear, non threshold Small radiation to see large damage Nonlinear, threshold High dose response, cataracts Short term effects Acute injury, 25 rads or less, minutes days weeks Long term effects Years after exposure, long latent period. Acute high dose or chronic low dose over years. Deterministic effects Radiation response increases in severity with increasing radiation dose. Occurs within days after radiation exposure. Cataracts, skin damage, threshold dose Stochastic effects Cancer. Incidence of radiation response increases with increasing radiation dose. Is not observed for months or years. Non-threshold, randomly occurring. Radiation induced congenital abnormalities Occurs within 10 days to 12 weeks after conception. Skeletal abnormalities 3 to 20 weeks Spontaneous abortion Absorbed dose of 50 rads to fetus Doubling dose for humans 1.56 SV Compton effect scatter of x-ray photons from the atoms of the body, incoming x-ray photon knocks outer shell electron out of shell Photoelectric absorption X-ray photon interacts with inner shell electrons. Occurs in Adams with higher atomic number and higher tissue density. 97 to 99 percent of incident x-rays are absorbed by the patient. Only half of remnant beam interacts with IR. Photo electron is absorbed within 1 to 2 mm of soft tissue Coherent ( classical ) scatter Interaction which occurs between low energy x-ray photons and matter. Below 10 KEV Thomson Type of scatter. Single outershell electrons of an atom is involved in the interaction. Rayleigh scattering All electrons of atom are involved in interaction tungsten filament 2 mm diameter, one or 2 cm long. Addition of 1 to 2 percent thorium to tungsten filament Enhances the efficiency of thermionic emission and prolongs tube life Space charge effect Cloud of electrons that make it difficult for subsequent electrons to be emitted by the filament because of electrostatic repulsion Saturation current Further increase in KVP does not result in higher ma because all of the available electrons have been used Line focus principle The size of the effective focal spot influences image sharpness. Effective focal spot size is much less than actual focal spot size Bremsstrahlung radiation Most photons are produced by these target interactions. Occur only when the incident electron interacts with the force field of the nucleus. Incident electron must have enough energy to pass through the orbital shells and approach the nucleus. Characteristic radiation Formed within the target atoms as a result of interactions with the K-shell electrons. Characteristic cascade is created when higher energy outer adjoining shell electron drops into the hole and then the next and the next Frequency the number of complete wavelengths that pass a point in a given time, measured in Hz or cycle per second Amount of primary beam x-rays absorbed by the patient 97-99% speed of light (c) 3.00 x 10^8 m/s ABC Automatic brightness control. Maintain the brightness of image by automatically adjusting the exposure factors as necessary according to subject density and contrast AEC Automatic exposure control. Illuminates need for radiographer to set exposure time, x-ray exposure termination device AERC Automatic exposure rate control. He maintains the radiation dose per frame at a predetermined level, adapting to the attenuation characteristics of the patient's anatomy and maintaining a consistent level of image quality throughout the examination. Percent reduction for females with gonadal shielding 50% Percent reduction for males with gonadal shieldin