Fluoroscopy Exam with correct answers 100%

What is the maximum mA used when operating fluoroscopy? - Correct Answer The maximum mA used during fluoroscopy is 5mA or less. Fluoroscopy Exam with correct answers 100% Despite lower mA, the patient dose is higher during fluoroscopy than it is in radiographic exams because the x-ray beam exposes the patient for a considerably longer period of time. What structure of the eye is responsible for scotopic vision? - Correct Answer Rods cell (almost entirely responsible for night vision) more sensitive than cone cells. Personnel wearing protective lead aprons during a procedure where the minimum exposure rate is 5mR/hr must contain the equivalent of what thickness in lead? - Correct Answer .25mm lead equivalent (according to NCRP) Total Brightness Gain is determined by which 2 factors? - Correct Answer It is determined by minification gain & flux gain. Total brightness gain is a measurement of the increase in image intensity achieved by an image intensification tube. Cones are used primarily for daylight vision. This type of vision is referred to as? - Correct Answer Photopic vision What is the minimum filtration required for fluoroscopy machines? - Correct Answer 2.5mm Aluminum or Aluminum equivalent In DF, spatial resolution is determined by what 2 components? - Correct Answer In DF, spatial resolution is determined both by image matrix and by the size of the image intensifier. Spatial resolution is limited by pixel size. What is the formula used to determine brightness gain? - Correct Answer Minification Gain X Flux Gain What is the Input Phosphor is made up of? - Correct Answer Cesium Iodide (CsI) What does the Image Intensifier of a fluoroscopic machine do? - Correct Answer The Image Intensifier raises the intensity of available light into the cone-vision region, where visual acuity is the greatest. What is NOT a non-stochastic effect? - Correct Answer They do not cause genetic effects (cancer) Non-stochastic effects are biologic somatic effects that exhibit a threshold dose below which the effect does not occur. Stochastic Effects are? - Correct Answer Stochastic effects are effects that occur by chance and which may occur without a threshold level of dose. The probability is proportional to the dose and the severity is independent of the dose. In the context of radiation protection, the main stochastic effect is cancer. Radiographs and image intensified fluoroscopic images are best visualized under what illumination levels? - Correct Answer under illumination levels of 10 to 1000ml (milliamberts) Which part of the eye behaves like a diaphragm of a photographic camera to control the amount of light emitted to the eye? - Correct Answer The Iris The iris is located between the cornea & the lens of the eye. During low light conditions, the iris dilates & allows for more light to enter. What is vignetting? - Correct Answer Vignetting is the loss of brightness at the edge of the image. The following factors influence dose rate at a table top fluoroscopic machine: - Correct Answer mA kVp Collimation Filtration Exposure time Target panel distance Fovea Centralis is? - Correct Answer Fovea Centralis are cones concentrated at the center of the retina. What is the magnification for an image viewed with a 9" image intensifier tube that has used a 5" diameter area during magnification? - Correct Answer Magnification= input screen / diameter of input screen used during magnification. 9/5 magnification = 1.8 The Fluoroscopic Automatic Brightness Control (ABC) should be evaluated for quality control when? - Correct Answer Anually To ensure the component is properly working. Federal Law requires an audible _______ minute timer in Fluoroscopy? - Correct Answer 5 Minute Timer Fluoroscopy is interrupted when the 5 minutes has elapsed and the radiographer must reset the timer to continue the procedure. Which 2 structures of the eye are responsible for sensation of vision? - Correct Answer Rods and Cones What is Teratogenesis? - Correct Answer Birth defect due to irradiation of the fetus. Size Distortion is primarily caused by what factor? - Correct Answer OID (Object to Image Distance) It is the factor that affect plain radiography magnification. Who invented the fluoroscope? - Correct Answer Thomas A Edison invented the fluoroscope in 1896. Clarence Dally was Mr. Edison's assistant. In Fluoroscopy, video monitoring uses a rate of _________ frames per second? - Correct Answer 30 frames per second Flux gain is the ratio of? - Correct Answer The # of light photons at the output phosphor to the # of x-rays at the input phosphor. What is the brightness gain for a 17cm Image intensifier table having a flux gain of 120 & 5cm output phosphor? - Correct Answer Brightness Gain = 17(squared)/5(squared) = 289/25=11.56 = (12) X 120= 1440 The vidicon camera target assembly consists of? - Correct Answer Glass face plate, signal plate & target At what 2 angles from the table does the most scatter occur? - Correct Answer 135 & 120 degrees. Minimum Scatter occurs at 45, 60 & 90 degrees A nurse worker is exposed to 230mR/hr from a radiation source. If the nurse remains at that position for 37 minutes, what will be the total occupational exposure? - Correct Answer 230mR/hr divided by 60 minutes = 3.83mR X 37 minutes = 141.83 = 142mR What does the remnant radiation first strike in the Image Intensifier? - Correct Answer The x-rays exit the patient's body & strike the Image Intensifier input phosphor. What % of the population has a fluoroscopic exam each year? - Correct Answer 5% Which type of table top material greatly reduces patient exposure? - Correct Answer Carbon Fiber The photocathode responds to stimulation of the input phosphor light by? - Correct Answer Emission of electrons. The photocathode emits electrons when illuminated by the input phosphor. X-ray interacts with the input phosphor; its energy is converted what? - Correct Answer Visible light. When x-ray interacts with the input phosphor, its energy is converted into visible light. What is the formula for Flux Gain? - Correct Answer # of output light photons / divided by # of input x-ray photons. Which of the following factors directly influences patient exposure? - Correct Answer mA kVp collimation SID all directly influence patient exposure What cell type is the most radiosensitive? - Correct Answer Lymphocytes. Amongst the body cells, the most sensitive are oocytes, lymphocytes, spermatogonia, erythroblasts, epidermal stem cells and gastrointestinal stem cells. Due to high mitotic activity, these cells are most sensitive to radiation. The least sensitive are nerve cells and muscle fibers Who was the first American fatality from radiation exposure? - Correct Answer Clarence Dally, Thomas Edison's assistant Scans of the target are completed in even odd passes. Each pass of the beam is referred to as? - Correct Answer Field. Each pass of the beam over the video target is called a field. This is called interlaced horizontal scanning How many times per second does the electron beam scan the stored image? - Correct Answer 30 times/second.