29/03/2020 Medical Imaging(Senior Class Physics Study by Topics) 29/03/2020 0Comments by Gate Academy Welcome to your Medical Imaging(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. In order to maintain image clarity, the path of electron flow from photocathode to output phosphor in the image intensification tube is controlled by The input phosphor The accelerating anode The vacuum glass envelope Electrostatic lenses 2. After initiation of rapid bolus administration of an iodinated contrast agent, the arterial phase of hepatic contrast enhancement occurs at aproximately: 120-180 secs 25-35 secs 60-70 secs 15-20 secs 3. The most common material used in the formation of the input phosphor of a modern image intensifier is Zinc cadmium sulfide Barium lead sulfate Cesium iodide Calcium tungstate 4. Diffuse fatty inflitration of the hepatic parenchyma may be referred to as Chromatosis Steatosis Lipomatosis Cirrhosis 5. The visible light image that impinges upon the target of a television camera tube is converted into a(an) X-ray image Electronic image Audible signal Latent image 6. The presence of noise in a medical image will generally Produce image distortion. Reduce visibility of low contrast objects. Produce blurring. Produce artifacts. 7. The third ventricle of the brain communicates with the fourth ventricle through the Cerebral aqueduct Septum pellucidum Fornix Anterior commissure 8. X-ray electromagnetic radiation travels in a straight line, the direction of which can be altered False True 9. 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 unsharpness. Image noise. Image blurring Visibility of anatomical detail. 10. The usual range of milliamperage required for an image intensified fluoroscopy is about 1-5 mA 6-10 mA 100-600 mA 25-100 mA 11. A substantial increase in conventional fluoroscopic brightness levels is accomplished in most modern systems using a(an) Image intensifier Video tape unit Television system Magnification technique 12. A radiograph is synonymous with an x-ray False True 13. The section thickness that would demonstrate the greatest detail of the paranasal sinuses is 3 mm 5 mm 7 mm 9 mm 14. An electronic signal that carries the information generated in the television camera to the cathode-ray tube (TV monitor) is termed the Analog signal Procession signal Video signal Synchronization pulse 15. Digital imaging in radiography is the general term used to describe a number of techniques that can be used to enable the digital acquisition of the information contained in the radiation beam after it exits the patient. All of the following terms are used to describe these processes EXCEPT? Computed radiography (CR) Indirect electronic radiography (IER) Digital fluoroscopy (DF) Direct-to-digital radiography (DDR) 16. The vidicon and plumbicon are the most commonly employed ______for a modern radiography department Image intensifier tubes Cinefluoroscopic tubes Television camera tubes Fluoroscopic xray tubes 17. Which of the following statements is true? Gamma rays are required for the production of a radiograph X-rays with shorter wavelengths penetrate farther than x-rays with longer wavelengths. X-rays with longer wavelengths penetrate farther than x-rays with shorter wavelengths. Electromagnetic radiation with lower frequency has more penetrating power through space and matter. 18. The anode's target Is composed of tungsten. Reaches temperatures in excess of 1000 degrees C during x-ray production. All of the above Usually has a copper base. 19. The major factors effecting the amount of brightness gain in an image intensifier are Adaptation and vignestting gains Minification ratio and flux gains Focal and scoptic vision gains Dispersion and retinal gains 20. The electronic image formed on the surface of the photocathode will be converted into____by the output phosphor of the image intensifier Laser image Video signal Visible light image Digital matrix 21. For protons, the gyromagnetic ratio has the value 2.68e8 rads-¹ T-¹ 3e8 rads-¹ T-¹ 4e8 rads-¹ T-¹ 5e8 rads-¹ T-¹ 22. Most modern image intensifiers utilize an input fluorescent screen layer which is composed of Zinc cadmium sulfied Cesium iodide Barium lead sulfate Calcium tungstate 23. Which of the following CT studies of the head is typically performed without a contrast agent? Ct of brain to r/o metastatic disease Ct angiogram for circle of Willis Coronal scan to r/o pituitary tumor CT of brain to r/o subdural hematoma 24. The image on a photostrimulable phosphor plate (PSP) of a CR imaging system is not permanent and will fade at a rate of about 10% per hour after the initial exposure 25 % within 8 hours of the exposure 10 % within 8 hours of the exposure 25% per hour after the initial exposure 25. Electrons travel Within the nucleus of an atom. Toward the anode in an x-ray tube. Away from the anode in an x-ray tube Toward the cathode in an x-ray tube. 1 out of 25 Time is Up! Time's up