29/03/2020Medical Imaging(Senior Class Physics Study by Topics) 0Comments by Gate Academy Welcome to your Medical Imaging(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. The section thickness that would demonstrate the greatest detail of the paranasal sinuses is 3 mm 7 mm 5 mm 9 mm2. Most modern image intensifiers utilize an input fluorescent screen layer which is composed of Zinc cadmium sulfied Cesium iodide Barium lead sulfate Calcium tungstate3. Which of the following modalities does not use a form of ionizing radiation: Computed tomography. Magnetic resonance imaging. Sonography. Radiography.4. Filaments located in an x-ray tube Emit electrons when heated. Are found in the anode. Are made of molybdenum. Must have a low melting point and low atomic number.5. After initiation of rapid bolus administration of an iodinated contrast agent, the arterial phase of hepatic contrast enhancement occurs at aproximately: 120-180 secs 15-20 secs 60-70 secs 25-35 secs6. Which of the following are possible effects of excessive heat within an x-ray tube? Roughened target surface. Bearing failure and decreased anode speed. All of the above Arcing.7. The usual range of milliamperage required for an image intensified fluoroscopy is about 25-100 mA 1-5 mA 100-600 mA 6-10 mA8. Which of the following is recommended to reduce unnecessary radiation of the patient or persons restraining the patient and to decrease scatter radiation? Placement of a lead apron over the area of interest on the patient. Adjustment of the collimator so that the smallest field size possible is used. Opening the collimator as wide as possible. Selection of full-wave rectification as opposed to half-wave rectification.9. In order to accommodate human eye integration time, each frame of a television image must be presented in less than 1/30 second 1 second 1/10 second 1/2 second10. Imaging systems are often evaluated by measuring their resolution (line pairs/mm). Resolution is a characteristic which is directly related to the following except Image noise. Image unsharpness. Image blurring Visibility of anatomical detail.11. The condition of intermittent cramping pain in the legs due to poor circulation is called Stenosis Varices Claudication Thrombosis12. Genetic damage is not detectable until future generations are produced False True13. Which system is capable of the highest resolution Intensifying screen Radiographic film Human eye Fluoroscopic screen14. The major factors effecting the amount of brightness gain in an image intensifier are Focal and scoptic vision gains Minification ratio and flux gains Adaptation and vignestting gains Dispersion and retinal gains15. The total brightness gain for a modern image intensifier fluoroscopic image is about ____greater than a conventional fluoroscopic screen image 20-40 times 5-20 times 5000-30000 times 50-100 times16. At what percentage of overlap should CT sections be reconstructed to improve the quality of multiplannar reformation (MPR) images? 50% 100% 10% 25%17. Gradual decrease in X-ray beam intensity as it passes through material is called attenuation radioactivity decay imaging18. Which of the following is a type of somatic damage caused by radiation? Sterility Cataracts Gene mutation None of the above19. Diffuse fatty inflitration of the hepatic parenchyma may be referred to as Cirrhosis Lipomatosis Chromatosis Steatosis20. An incident x-ray photon of 37 keV strikes an electron with 40 keV binding energy. A scattered photon results with 37 keV energy. This describes Compton event Brems event Coherent event Photoelectric event21. The presence of noise in a medical image will generally Produce image distortion. Produce artifacts. Produce blurring. Reduce visibility of low contrast objects.22. The time it takes for the human eye to adjust to adjust to the low light levels of conventional fluoroscopy is called Integration time Interlace time Adaption time Flicker timer23. The most frequently used device for the production of a hard copy image in radiology is a Laser printer Floppy disk Display terminal Photo-spot camera24. The recommended scan field of view (SFOV) for a CT examination of the cervical spine is 50.0 cm 15.0 cm 25.0 cm 9.6 cm25. The two principle advantages that digital fluoroscopy (DF) has over image intensified fluoroscopy (IIF) are A higher speed of spot image acquisition and the ability to post process the image An improved ability to eliminate patient motion and reduce patient exposures Images with long scale contrast and higher spatial resolution A lower contrast detectability and a reduced noise level26 out of 25Time is Up!