What is the HU value for 70 kVp, 25 mA, exposure time of 1 second, with W assumed equal to 1?

What is the HU value for 70 kVp, 25 mA, exposure time of 1 second, with W assumed equal to 1?

• A. 1,250 HU
• B. 1,500 HU
• C. 1,750 HU
• D. 2,000 HU

Answer: (C)

Heat units reflect the thermal energy the x-ray tube must endure during exposure. They are estimated by multiplying the tube voltage (kVp) by the tube current (mA) and the exposure time, with a waveform factor W that accounts for generator type. Since W is given as 1, the calculation is straightforward: HU = kVp × mA × time × W = 70 × 25 × 1 × 1 = 1,750 HU. If the waveform had a multiplier, the result would be higher, but with W = 1 it’s simply 1,750 HU.

Heat units reflect the thermal energy the x-ray tube must endure during exposure. They are estimated by multiplying the tube voltage (kVp) by the tube current (mA) and the exposure time, with a waveform factor W that accounts for generator type. Since W is given as 1, the calculation is straightforward: HU = kVp × mA × time × W = 70 × 25 × 1 × 1 = 1,750 HU. If the waveform had a multiplier, the result would be higher, but with W = 1 it’s simply 1,750 HU.