29/03/2020 Medical 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 order of imaging methods (from worst to best) with respect to visibility of detail (resolution) isRadiography, fluoroscopy, MRI.Ultrasound, fluoroscopy, radiography.Gamma camera, fluoroscopy, CT.Gamma camera, fluoroscopy, MRI.2. A substantial increase in conventional fluoroscopic brightness levels is accomplished in most modern systems using a(an)Image intensifierTelevision systemVideo tape unitMagnification technique3. The major factors effecting the amount of brightness gain in an image intensifier areAdaptation and vignestting gainsFocal and scoptic vision gainsDispersion and retinal gainsMinification ratio and flux gains4. In order to accommodate human eye integration time, each frame of a television image must be presented in less than1/30 second1 second1/2 second1/10 second5. The principle advantage of image intensified fluoroscopic technique compared to routine radiographic imaging is that it allows for:1. an increase in the degree of spatial resolution in the images2. a reduction in the amount of exposure the patient will receive 3. the ability to visualize dynamic motion of the tissue2 only3 only1, 2, and 31 only6. ____releases electrons when struck by light photons and _____releases electrons when struck by x-ray photons Amorphous silicon, amorphous seleniumSilverbromide, zinc lead sulfideAmorphous selenium, amorphous siliconGadolinium oxysulfide, cesium iodide7. The anode's target Reaches temperatures in excess of 1000 degrees C during x-ray production.Usually has a copper base.Is composed of tungsten.All of the above8. The reduction of brightness at the periphery of image display of an image intensified fluoroscpoe is termedModulation transferVignettingDimunitionLateral dispersion9. Attenuation coefficient of bone is 600 m-¹ for x-rays of energy 20 keV and intensity of beam of x-rays is 20 Wm-², then intensity of beam after passing through a bone of 4mm is2.5 Wm-²2.0 Wm-²3 Wm-²1.8 Wm-²10. Which of the following phases of renal contrast enhancement best demonstrates transitional cell carcinoma (TCC) of the bladder?CorticomedullaryNephrographicEarly arterialExcretory11. Diffuse fatty inflitration of the hepatic parenchyma may be referred to asLipomatosisCirrhosisSteatosisChromatosis12. The release of trapped energy in a meta-stable F center (Europium electron holes) of a BaFBr (Barium fluorobromide)crystal in the photostimulable phosphor imaging plate (PSP) of a CR imaging system are triggered by the exposure to teh visible (laser) light in theUltraviolet spectrumBlue-violet spectrumRed spectrumGreen spectrum13. Which of the follwoing sets of section width and spacing would be most suitable for a general survey CT oe neck?0.75 mm thick every 0.75 mm10 mm thick every 10 mm3 mm thick every 3 mm3 mm thick every 5 mm14. For protons, the gyromagnetic ratio has the value5e8 rads-¹ T-¹3e8 rads-¹ T-¹4e8 rads-¹ T-¹2.68e8 rads-¹ T-¹15. Which of the following CT studies of the head is typically performed without a contrast agent?Ct of brain to r/o metastatic diseaseCoronal scan to r/o pituitary tumorCt angiogram for circle of WillisCT of brain to r/o subdural hematoma16. Air trapping within the trachea and bronchial tree may be optimally demonstrated with multiplanar volume reconstruction (MPVRs) of the thorax known asShaded-surface displays (SSDs)3D volume renderingsMinimum intensity projections (min-IPs)Maximum intensity projections (MIPs)17. In the radiology literature the relationship between the sensitivity and specificity of a diagnostic procedure is generally shown using aTrue-negative/false-negative ratioROC curve.MTF curve.True-positive/false-positive ratio.18. The image on a photostrimulable phosphor plate (PSP) of a CR imaging system is not permanent and will fade at a rate of about25% per hour after the initial exposure25 % within 8 hours of the exposure10 % within 8 hours of the exposure10% per hour after the initial exposure19.  Which of the following modalities does not use a form of ionizing radiation:Computed tomography.Radiography.Magnetic resonance imaging.Sonography.20. During a spiral or helical CT examination, the scanner acquires dataIn the form of a complete volumetric data setContinuously as the patient travels through the gantryA & COne section at a time21. The most common material used in the formation of the input phosphor of a modern image intensifier isZinc cadmium sulfideBarium lead sulfateCalcium tungstateCesium iodide22. Filaments located in an x-ray tubeMust have a low melting point and low atomic number.Are made of molybdenum.Emit electrons when heated.Are found in the anode.23. With either an amorphous selenium or cesium iodide amorphous silicon digital radiographic imaging, the latent image is formed by an electronic signal that is stored byA vidicon television camera tubeAn array of photodiodesAn array of thin-film transtors (TFT's)A series of quantum detectors24. A focused, thin section axial CT acquisition through just the regionof the vocal cords should extendFrom hard palate inferiorly to the hyoid boneFrom above the hyoid bone inferiorly through the cricoid cartilageFrom external auditory to the mandibleFrom the cricoid cartilage inferiorly through sternoclavicular joint25. The section thickness that would demonstrate the greatest detail of the paranasal sinuses is9 mm5 mm7 mm3 mm26 out of 25Time is Up!
