CT registry- image production Exam Questions and Answers 100% Pass

CT registry- image production Exam Questions and Answers 100% Pass Fundamental principle of ct may be summarized as - Correct Answer ️️ -An image of an object may be reconstructed on the basis of the attenuation that occurs as x radiation is transmitted through it Detectors measure - Correct Answer ️️ -The radiation that is transmitted through the pt. An image is reconstructed in the basis of the magnitude of X-ray attenuation that occurs at spatially distributed points within the pt General process of ct imaging imaging may be divided into several steps- - Correct Answer ️️ -Data acquisition- measurement of the attenuation that occurs along each path through the pt from X-ray tube to detector Data reconstruction- computerized processing of the transmission measurements into the ct image Multidimensional image display- display of the reconstructed grayscale image in two dimensional and or 3D format. A representation of the attenuation that occurred across the scanned volume of tissue Image archival and communication- display as well as storage, both short term and long term (archival) of images on computer workstations Most basic scan mode by ct - Correct Answer ️️ -Scout image acquisition. This survey scan is a digital radiograph obtained by keeping the X-ray tube and detector array in a fixed position while the pt bed is translated through the gantry Scout aka - Correct Answer ️️ -Scanogram or localizer. Scout may be AP, PA, lateral, or oblique Azimuth - Correct Answer ️️ -The angle of the tube and detectors in relationship to the pt position during scout acquisition Ct system consists of - Correct Answer ️️ -Powerful computer, display system, bed, gantry components The gantry houses the - Correct Answer ️️ -Majority of mechanical components of ct system operation including the generator, X-ray tube, assorted collimators, data acquisition system, slip rings, detectors Slip ring technology - Correct Answer ️️ -Eliminates the need for cables by utilizing a system of contact brushes that supply electricity to power the system and enable the passage of transmission data to the computer systems. Eliminates need of cords and wires. Also allows for the continuous helical acquisition technical components of helical ct acquisition includes - Correct Answer ️️ -Continuous rotation of the gantry components Powerful X-ray tube Continuous movement of pt bed Specialized mathematical reconstruction techniques The reconstruction of ct sections at any point along the scanned volume is possible. However, the - Correct Answer ️️ -Section width must be the same, however, is controlled by the collimation (slice thickness) chosen before data acquisition X-ray tube. Metal enclosed X-ray tube consisting of a - Correct Answer ️️ -Cathode, anode, and a rotating anode disc Dual filaments allow for a - Correct Answer ️️ -Choice of two focal spot sizes ranging from .5-1.2 mm in diameter. The choice of foci may be controlled by the user through the selection of MA setting, SFOV, and so on. Smaller focal spots improve the - Correct Answer ️️ -Geometric efficiency of the X-ray beam, leading to greater spatial resolution Flying focal spot technology - Correct Answer ️️ -Electromagnetic steering of the electron beam emitted from the cathode. The beam of electrons is directed toward two separate locations on the rotating anode resulting in two sources of xradiation As the tube rotates around the pt, the number of data samples is essentially doubled bc - Correct Answer ️️ -Of the electronic switching between the two focal spots. This oversampling technology can be used to improve the systems temporal and spatial resolution Cooling of the tube - Correct Answer ️️ -Oil and air cooling, increased anode diameter, and conduction by tube rotation Modern ct X-ray tube specific characteristics demanded by state of the art MDCT - Correct Answer ️️ -High heat rating- must have ability to absorb at while dissipating quickly Small size, lightweight- must be capable of rotating within the ct gantry at a high rate of speed Stable and long lasting- must be capable of withstanding huge centrifugal forces with an extended useful life Ma setting - Correct Answer ️️ -Vary from 30 mA to 800 mA. Depends on study, pt size, SNR. Automatic tube current modulation programs adjust the mA throughout an acquisition to reduce pt radiation dose to a min according to a predetermined noise index that is acceptable for appropriate image quality Exposure time - Correct Answer ️️ -Varies and is determined by anatomic extent, detector configuration, table speed, and so reach up to 30-60 sec in length with total scan scan times equal to the sum of all acquisitions occurring during the study The mas value directly controls the - Correct Answer ️️ -Quantity of xradiation, or photon influence directed toward pt Photon flux - Correct Answer ️️ -Rate at which the photon fluency passes through a unit of area Mas value for a given acquisition is ____ proportional to pt dose and _____ proportional to image noise - Correct Answer ️️ -Directly Indirectly Effective mAs can be described as: - Correct Answer ️️ -Calculated mas value per acquired slice. Main controlling factor of effective mas is table speed. The pitch selected for a given acquisition determines the spee