Which technical factor should the technologist use to control the receptor exposure?

Which technical factor should the technologist use to control the receptor exposure?

• A. Kilovoltage potential (kVp)
• B. Source-to-image distance (SID)
• C. Protective shielding
• D. Milliamperage-seconds (mAs)

Answer: (D)

The main lever for receptor exposure is milliampere-seconds (mAs). This is the product of tube current and exposure time and directly sets how many x-ray photons are produced and reach the image receptor. Increasing mAs increases photon flux and receptor exposure; lowering mAs reduces it, with a roughly proportional change. Kilovoltage (kVp) changes beam quality and penetration and can modestly affect receptor exposure indirectly, but the dominant factor controlling exposure quantity is mAs. Source-to-image distance alters exposure via the inverse-square law—moving the tube-receptor distance changes exposure at the receptor, but it’s not the primary manual control clinicians use to adjust exposure for a given patient and exam. Protective shielding reduces dose to tissues but does not adjust the amount of radiation reaching the receptor in the imaging field.

The main lever for receptor exposure is milliampere-seconds (mAs). This is the product of tube current and exposure time and directly sets how many x-ray photons are produced and reach the image receptor. Increasing mAs increases photon flux and receptor exposure; lowering mAs reduces it, with a roughly proportional change. Kilovoltage (kVp) changes beam quality and penetration and can modestly affect receptor exposure indirectly, but the dominant factor controlling exposure quantity is mAs. Source-to-image distance alters exposure via the inverse-square law—moving the tube-receptor distance changes exposure at the receptor, but it’s not the primary manual control clinicians use to adjust exposure for a given patient and exam. Protective shielding reduces dose to tissues but does not adjust the amount of radiation reaching the receptor in the imaging field.