Clover Learning Radiography Image Production Practice Test

If an exposure is made using 100 mA and 0.05 seconds, how will the patient dose change if one repeats the exposure using 200 mA and 0.025 seconds?

Patient dose increases

Patient dose decreases

Patient dose remains the same

In this scenario, it's important to consider how radiation dose is calculated in relation to the exposure settings in radiography. The patient dose is primarily determined by the product of the milliamperage (mA) and the exposure time (seconds). This relationship can be represented by the formula:

Dose = mA × time

For the initial exposure:

- mA = 100

- Time = 0.05 seconds

- Total Dose = 100 mA × 0.05 s = 5 mAs (milliampere-seconds)

For the repeated exposure:

- mA = 200

- Time = 0.025 seconds

- Total Dose = 200 mA × 0.025 s = 5 mAs

In both cases, the total dose delivered to the patient is the same, at 5 mAs. This illustrates that although the mA and exposure time have changed, their product (and therefore the patient dose) remains constant.

This consistency in dose under different exposure parameters is a fundamental principle in radiography, which helps maintain patient safety and optimize image quality. Thus, when the total dose remains the same, it indicates that the patient dose has not changed, leading to the conclusion

Patient dose doubles