Download NMTCB-CT Exam Questions With 100% Correct Answers 2024 and more Exams Advanced Education in PDF only on Docsity! NMTCB-CT Exam Questions With 100% Correct Answers 2024 Where are x-rays made? - Correct Answer-in the electron shell structure of an atom What is Bremsstrahlung radiation? - Correct Answer-energetic electrons pass very near the nucleus of an atom. The strong forces of th positive charged atom causes the negatively charged electron to decelerate; the path of the electron is changed, and some of the kinetic energy of the electron is lost, and converted into x-rays what is characteristic x-ray radiation? - Correct Answer- following the ionization of an atom that leaves an inner shell, outer shell electrons drop down to refill the inner shell. As these electrons drop down, they lose energy, which is released as x-rays. What does pre-collimation do? - Correct Answer-(used before x-rays enter the patient) defines the beam shape and width (which is usually fan or cone shaped) and protects the patient from excess radiation What does post-collimation do? - Correct Answer-(used to reduce scatter after leaving the patient) is used before the radiation strikes the detectors What are advantages of thinner collimation? - Correct Answer-A: less volume averaging B: increased spatial resolution C: decreased spatial resolution D: fewer artifacts E: all of the above F: a,b,d ** True or false: in CT, the gantry rotates continuously in one direction on a slip ring system - Correct Answer-true What is a scout imaged used for? - Correct Answer-Positioning /localization Pitch - Correct Answer-the ratio of patient's movements through the gantry during one 360 degree beam rotation relative to the beam collimation (in single slice CT) E: before every scan What is the purpose of the daily tube warm up? - Correct Answer-to prevent damage to the anode as energy is created How often should the cylindrical water phantom QC be performed? - Correct Answer-daily (or before use) What is the purpose of the water phantom in QC? - Correct Answer-to test CT number values, noise levels, and resolution What is the HU for air? - Correct Answer-A: -100 B: 0 C: -1000 ** D: none of the above Attenuation - Correct Answer-the reduction of the number of X-ray photons as the pass though the tissues of the patient's body. Which method of scanning allows for the gathering of cross- sectional data while the patient moves through the center of the gantry in increments? - Correct Answer-conventional/step and shoot what is the most common method of scanning? - Correct Answer-helical What anatomy is most easily visualized using sharp reconstruction filters? - Correct Answer-muscular skeletal detail What anatomy is most easily visualized using smooth reconstruction filters? - Correct Answer-soft tissue In imaging, what is the importance of gray scale? - Correct Answer-grayscale is a continuous spectrum of shades of gray that represent the tissue on an image as determined by the amount of attenuation properties of that tissue. What is the HU for water? - Correct Answer-A: 10 B: -10 C: >2000 D: 0 ** What is the HU for fat? - Correct Answer--50 to -100 Window width - Correct Answer-the total number of CT numbers that would be available in an image window; width can be either wide or narrow, with a narrow window showing fewer shades of gray window level - Correct Answer-represents the midpoint of the range for example if your range was 0 to 50 25 would be your window level 0 to 50 would be your window width How is beam hardening artifact caused? - Correct Answer- when the density of the oral or intravenous contrast is great
