FREE RADIOLOGY AND STUDY GAMES ABOUT

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FREE RADIOLOGY AND STUDY GAMES ABOUT

FLUOROSCOPY WEEK 2 EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -35 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: What is Total Brightness Gain? What is the formula?

Answer:

The measurement of the increase in Image Intensity achieved by the Image Intensification tube?BG=MGxFG Question 2: Why does the C-Arm allow the IR to be raised and lowered? Why should the Image Intensifier be as close to the patient as possible?

Answer:

To vary beam geometry for maximum resolution. TO reduce exposure to the operator from scatter by the patient.

Question 3: What does brightness control regulate?

Answer:

Regulates the x-ray tube mA?Question 4: What is the potential difference from the photocathode to anode & output screen?

Answer:

25,000 V or 25 kV.

Question 5: How much do modern Image Intensifier's increase image brightness?When does Photopic (Cone) vision become active?

Answer:

500-8000x. Photopic vision becomes active at about 1000x.Question 6: How many light photons are converted from 1 x-ray photon at the Input phosphor?

Answer:

1000 light photons from 1 x-ray phton.

Question 7: How much does Brightness Gain decrease per year? Why is this?

Answer:

As much as 10% per year. Input & Output phosphors age.Question 8: What does minification gain occur as a result of? What is the formula for minification gain?

Answer:

The same # of electrons that were produced at the input phosphor being compressed into the area of the output screen? MG=Distance 1 squared/Distance 2 squared.Question 9: Is the # of electrons emitted by the photocathode directly proportional to the intensity of light reaching it?

Answer:

Yes Question 10: What do federal regulations prohibit in regards to fluroscopy x-ray tube and primary beam? What is done to avoid this from happening?

Answer:

Federal regulations prohibit the use of fluoroscopy x-ray tube when entire primary beam is not resulting in exposure. An exposure cannot be made until carriage is returned to full beam intercept position & locked in place.

Question 11: What are the typical input screen sizes?

Answer:

6", 9" & 12"

Question 12: What year was the Image Intensifier developed?

Answer:

1948 Question 13: Why is there a loss of detail with video system fluoroscopy in comparison optical mirror viewing systems?

Answer:

Image noise from transferring the image resulting in loss of detail.

Question 14: Where are the emitted electrons from the photocathode directed to?

Answer:

Towards the anode end of the Image Intensification tube?

Question 15: What is the Conversion Factor? What is the formula?

Answer:

The ratio of intensity of the output phosphor to the input exposure rate to the input phosphor?Conversion Factor = FG/mrads per sec from input phosphor Question 16: What is the arm that's suspended over the table that supports the image intensifier called?

Answer:

The Carriage Question 17: What happens at Electronic Lenses of the Image Intensification tube? How does the lens accelerate the electrons?

Answer:

The Elecctronic Lenses focus & accelerate the elctrons from the photocathode. The Electronic Lens is negatively charged which repels the electrons accelerating & focusing them towards the much smaller output screen.Question 18: What does the primary x-ray beam strike after it exits the patient on a fluroscopy x-ray tube?

Answer:

Primary x-ray beam strikes the input phosphor after exiting the patient?

Question 19: What does the output screen do with the incoming electrons and where do the electrons come from?

Answer:

The output screen absorbs the electrons from the photocathode that went through the electronic lenses through the hole in the Anode. The output screen converts the electrons into light photons.Question 20: What happens at the input phosphor? How much of the incident beam is absorbed by the CsI?

Answer:

The x-ray photon from the primary beam is absorbed by CsI and converted into a light photon. 66% of the incident beam is absorbed by CsI.

Question 21: What fluorescent material is the Input phosphor made of?

Answer:

Cesium Iodide (CsI)

Question 22: What is Flux Gain?

Answer:

A measurement in the increase of light photons due to conversion efficiency of the output screen. In simple terms "How many light photons are produced at the output phosphor for each electron that strikes it?" Question 23: What is Anode usually charged? What voltage is it usually supplied from and from where?

Answer:

The Anode is usually positively charged. It's usually supplied with 25 kV from the negatively charged photocathode.Question 24: How many light photons are emitted at the output phosphor? How many times brighter is the output phosphor than the input phosphor?

Answer:

3000 light photons. 1000x brighter.

Question 25: What is the Magnification Factor?

Answer:

MF = Diamter 1/Diamter 2