A technologist is preparing to image a patient's lumbar spine. To minimize patient exposure while maintaining image quality, which combination of exposure factors should be used?

A technologist is preparing to image a patient's lumbar spine. To minimize patient exposure while maintaining image quality, which combination of exposure factors should be used?

• A. Low kVp and high mAs.
• B. High kVp and low mAs.
• C. High kVp and high mAs.
• D. Low kVp and low mAs.

Answer: (B)

To minimize patient exposure while preserving diagnostic quality, use exposure factors that maximize beam penetration with the least amount of radiation delivered. Increasing the kVp raises the energy of the x-ray beam, allowing photons to pass through the thicker lumbar region more effectively, so you can reduce the mA (or exposure time) and still achieve adequate receptor exposure. Lowering the mAs directly lowers the amount of radiation the patient receives. While higher kVp does reduce image contrast, the lumbar spine has sufficient inherent contrast between bone and surrounding tissues, and with proper positioning and technique (plus scatter control), the resulting image remains clinically acceptable. Therefore, a high kVp with a low mAs best achieves the goal of reducing dose while maintaining image quality.

To minimize patient exposure while preserving diagnostic quality, use exposure factors that maximize beam penetration with the least amount of radiation delivered. Increasing the kVp raises the energy of the x-ray beam, allowing photons to pass through the thicker lumbar region more effectively, so you can reduce the mA (or exposure time) and still achieve adequate receptor exposure. Lowering the mAs directly lowers the amount of radiation the patient receives. While higher kVp does reduce image contrast, the lumbar spine has sufficient inherent contrast between bone and surrounding tissues, and with proper positioning and technique (plus scatter control), the resulting image remains clinically acceptable. Therefore, a high kVp with a low mAs best achieves the goal of reducing dose while maintaining image quality.