Safelight Fog does what to contrast and density on film?

Transcription

1 Terri Jurkiewicz

2 Safelight Fog does what to contrast and density on film?

3 ANSWER INCREASES DENSITY DECREASES CONTRAST

4 Explain how you determine if the focal spot size is within appropriate limits. <.8 =50% = 40% > 1.6 = 30%

5 ANSWER YOU MUST HAVE THE MANUFACTURERS FOCAL SPOT SIZES. FOR OUR EQUIPMENT THE FOCAL SPOT SIZES WERE:.6 SMALL FOCAL SPOT 1.5 LARGE FOCAL SPOT ADD X+Y AND DETERMINE THE ENLARGEMENT FACTOR WHICH IS 2 FOR FS LESS THAN 2.5 (THE MAJORITY OF FS WILL BE LESS THAN 2.5) DIVIDE BY THE ENLARGEMENT FACTOR AND COMPARE TO MANUFACTURERS FOCAL SPOT SIZE.

6 When running a test strip for sensitometry, if when it is being plotted it falls above the upper or lower limits, what does that mean you should do?

7 ANSWER RUN TEST STRIP AGAIN. IF IT REMAINS OUT OF LIMITS. CONTACT SERVICE ENGINEER

8 17. What are the densities used to set up a control chart?

9 ANSWER BASE + FOG NEVER MORE THAN.25 SHOULD BE BETWEEN.1-.2 MINIMUM DENSITY IS THE STEP CLOSEST TO.25 MAXIMUM DENSITY IS STEP CLOSEST TO 2.0 ABOVE B+F SPEED INDICATOR IS TH MID DENSITY STEP CLOSEST TO 1. ABOVE THE BASE + FOG. SO IF B+F IS.1 THEN THE STEP CLOSEST TO 1.1 IS THE SPEED INDICATOR. CONTRAST INDICATOR IS THE DIFFERENCE BETWEEN THE MAXIMUM AND MINIMUM VALUES THIS SHOULD NOT VARY BY MORE THAN.15

10 20. WHAT IS RECIPROCITY AND How many exposures should be made to determine reciprocity?

11 ANSWER NO MATTER WHAT THE MA/TIME SETTINGS ARE AS LONG AS THE MAS STAYS THE SAME WITH THE SAME KVP YOUR EXPOSURE SHOULD ALWAYS BE THE SAME WITH MINIMUM OF 3

12 THEN WHAT IS REPRODUCIBILITY?

13 ANSWER IT IS TAKING IMAGES WITH THE SAME TECHNIQUE TO ENSURE THE TECHNIQUE REMAINS THE SAME WITH EACH EXPOSURE WITH NO MORE THAN 5% VARIABILITY

14 WHAT IS MA/TIME LINEARITY?

15 ANSWER SEQUENTIAL INCREASES OR DECREASES IN MAS SHOULD PRODUCE THE SAME SEQUENTIAL INCREASE IN EXPOSURE MEASURED.

16 If 50 radiographs are rejected due to positioning errors and there are 250 radiographs rejected in a month, what percentage is due to positioning errors?

17 ANSWER 50/250=.2 OR 20%

18 When performing safelight fog test, one half of the film must be exposed because??

19 ANSWER LATENSIFICATION FILM IS MUCH MORE SENSITIVE TO LIGHT EXPOSURE AFTER EXPOSURE TO RADIATION.

20 WHAT IS VOLTAGE RIPPLE?

21 ANSWER IT IS A GRAPH OF THE VOLTAGE WAVEFORM GIVEN OFF FROM EACH GENERATOR

22 What is the ripple effect in the waveform of a high frequency generator? What of a 3 phase 12 pulse generator?

23 ANSWER 1-15 % High Frequency generator 3.5% Three phase 12 pulse generator

24 What is the name of this object?

25 ANSWER PENTROMETER

26 Electronic transmission of radiographic images from one location to another is what?

27 ANSWER TELERADIOLOGY

28 Verification of equipment on installation is called?

29 ANSWER ACCEPTANCE TESTING

30 What is veiling glare and what causes it?

31 ANSWER IT IS GLARE OR FLARE CAUSED BY LIGHT REFLECTION FROM THE WINDOW OF THE OUTPUT PHOSPHOR. REDUCING CONTRAST. YOU SEE THIS IN FLUORO. WHEN MOVING THE UNIT FROM AREA OF THE BODY TO ANOTHER.

32 How often and how long should QC of a flat panel display take by QC technologist?

33 ANSWER 1 MINUTE DAILY

34 What might cause and increased base + fog?

35 Repeat rates should have at least patients as a sample for valid results.

36 ANSWER 250 PATIENTS

37 Your repeat rate is 6.4 % what does this mean?

38 ANSWER YOU ARE SLIGHTLY HIGHER THAN THE APPROVED REPEAT RATE. BUT, RATES 10-12% SHOULD BE SERIOUSLY EXAMINED AS THOSE ARE WAY TOO HIGH COSTING DEPARTMENTS MONEY AND EXTRA RADIATION EXPOSURE TO PATIENTS.

39 Why do you want to do a repeat/reject analysis?

40 ANSWER IT ALLOWS THE DEPARTMENT TO ANALYSE WHERE THE FACTORS WHICH CONTRIBUTE TO THE OVERALL REPEAT RATE. IF CORRECTIVE ACTION NEEDS TO BE TAKEN, THEN THE KNOWLEDGE OF WHERE THE ISSUES ARE ARE EVIDENT.

41 WHAT IS THE ACCURACY OF THE COLLIMATION %? PLEASE DISCUSS PERPENDICULATIRY AND COLLIMATION.

42 ANSWER COLLIMATION MUST BE WITHIN 2% OF SID WHICH IS THE WIDTH OF A PENNY AT 40 INCHES. PERPENDICULARITY IS REQUIRED TO LIMIT DISTORTION AND SHOULD BE WITHIN 1 DEGREE.

43 WHAT DOES POOR FILM SCREEN CONTACT PROJECT ON AN IMAGE. WHAT IS THE TEST TOOL THAT IS USED TO DEMONSTRATE POOR CONTACT.

44 ANSWER TOOL: WIRE MESH TEST TOOL IMAGE IS DARKER AND BLURRED.

45 HOW OFTEN SHOULD A FILM SCREEN CASSETTE BE CLEANED?

46 ANSWER WEEKLY

47 Repeat/Reject Analysis What percent of repeats are acceptable in a Radiology Department? At what point should a Radiology department take a serious look at their repeats and make some changes?