Which exposure technique system uses the rule of doubling or halving mAs for every 5 cm of subject thickness?

The correct answer is the fixed kilovoltage peak (kVp) system. This technique relies on maintaining a consistent kVp while adjusting the milliampere-seconds (mAs) based on the thickness of the subject being imaged. The rule of doubling or halving the mAs for every 5 cm change in subject thickness is a fundamental principle of this system, as it helps to compensate for variations in tissue density and thickness, ensuring optimal image quality.

In the fixed kVp system, the chosen kVp is kept constant to improve image contrast and maintain patient safety by minimizing radiation exposure. Adjustments to mAs allow for adequate penetration and exposure based on specific patient conditions. This systematic approach is particularly useful because it leads to consistent results across various patient sizes.

By contrast, the variable kVp system adjusts both the kVp and mAs in response to the subject’s thickness, which does not follow the straightforward doubling or halving rule for mAs. The automatic exposure control (AEC) system utilizes sensors to automatically adjust the exposure factors in real-time based on the detected radiation, which is not reliant on manual thickness adjustments. The constant mAs system aims to maintain a consistent mAs regardless of thickness changes, rather than employing the rule of