Question

a radiograph acquired on a non - compliant patient demonstrates appropriate exposure but significant motion blur. if the original technique was 100 milliamperes (ma) and 0.5 seconds (s), what new technique will decrease motion artifact while maintaining the same total exposure? 50 ma and 1.0 s 250 ma and 0.5 s 500 ma and 0.1 s 500 ma and 0.5 s

Explanation:

Step1: Calculate original total exposure

The total - exposure is given by the product of milliamperes (mA) and seconds (s). The original technique has $mA_1 = 100$ mA and $s_1=0.5$ s. So the original total exposure $E_1=mA_1\times s_1 = 100\times0.5=50$ mAs.

Step2: Check each option for equal exposure

• Option 1: $mA = 50$ mA and $s = 1.0$ s. Then $E=50\times1.0 = 50$ mAs.
• Option 2: $mA = 250$ mA and $s = 0.5$ s. Then $E=250\times0.5=125$ mAs.
• Option 3: $mA = 500$ mA and $s = 0.1$ s. Then $E=500\times0.1 = 50$ mAs.
• Option 4: $mA = 500$ mA and $s = 0.5$ s. Then $E=500\times0.5=250$ mAs.

To decrease motion artifact, we need to decrease the exposure time (shorter exposure time reduces the time during which the patient can move). Among the options with the same total exposure (50 mAs), the option with the shortest exposure - time is $500$ mA and $0.1$ s.

Answer:

500 mA and 0.1 s