Tube Rating Charts and Cooling Curves

What are the three types of rating charts?

• tube rating charts

• anode cooling charts

• housing cooling charts

What determines the maximum technical factors (mA, time, kVp) that can be used without overloading the tube?

tube rating charts

(T/F) Each filament for each tube has a separate rating chart.

true

Where does an intersection of the time and kVp indicate a safe exposure?

under the mA line

Is an exposure of 80 kVp, 0.1 second, and 200 mA within the limits of the 1 phase, 0.6 mm focal spot tube?

it is safe

Is an exposure of 90 kVp, 0.08 second and 600 mA within the limits of the 3 phase, 1.2 mm focal spot tube?

not safe

What chart demonstrates the time it takes for the anode to cool?

anode cooling chart (curve)

What can an anode cooling chart (curve) determine?

What is it calculated in terms of?

the time necessary for the anode to cool enough for additional exposures

heat units

What is the formula for the anode cooling chart (HU)?

kVp x mA x time x rectification constant

What is the rectification constant of 1 phase, 2 pulse?

1.00

What is the rectification constant of 3 phase, 6 pulse?

1.35

What is the rectification constant of 3 phase, 12 pulse?

1.41

What is the rectification constant of high frequency?

1.45

How many heat units are generated by an exposure of 80 kVp, 200 mA, and 0.2 second on a single phase, full-wave rectified unit?

3,200 HU

How many heat units are generated by an exposure of 70 kVp, 300 mA, and 0.15 second on a 3 phase, 6 pulse unit?

4,253 HU

How many heat units are generaetd by two exposures of 65 kVp, 400 mA, and 0.05 sec on a three phase, 12 pulse unit?

3,666 HU

Three exposures of 85 kVp, 500 mA, and 0.3 seconds are produced with a 3 phase, 6 pulse x-ray machine.  How long will it take for the tube to cool completely?​

9 minutes

On a three phase, 12 pulse unit, how many exposures using 90 kVp, 600 mA, and 0.5 second can be taken without exceeding the tube limit?​

9 exposures

Using the anode cooling curve, calculate the length of time necessary for the anode to cool to 50,000 HU after 5 exposures of 80 kVp, 500 mA, and0.5 sec are taken on a 1 phase unit.​

2.5 minutes

What does a housing cooling chart calculate?

the time necessary for the tube housing to cool before additional exposures can be made

What works the same as the anode cooling chart?

housing cooling chart

(T/F) Usually, the anode does not reach its maximum before the tube housing.

False, it does