Which conditions are likely to require a decrease in exposure?

• A. Congestive heart failure and ascites
• B. Emphysema and bowel obstruction
• C. Pleural effusion and edema
• D. Multiple myeloma and hydrocephalus

Answer: (B)

The correct answer pertains to the conditions known to affect tissue density and overall radiographic exposure settings. Emphysema is characterized by the destruction of lung tissue, leading to increased air spaces which reduces the overall density of the lung. This results in a need for decreased exposure during radiographic imaging to avoid saturation and ensure clear imaging.

Bowel obstruction, particularly when it leads to increased gas production, can also lead to a decrease in tissue density. As gas is less dense than soft tissue and fluid, the radiographic exposure may need to be adjusted downward to accurately depict the anatomy without overexposing the image.

Both emphysema and bowel obstruction significantly reduce the effective density that is encountered by the X-ray beam, so radiographers typically decrease the exposure parameters, including milliampere-seconds (mAs) or kilovoltage peak (kVp), to prevent overexposure and optimize image quality.

In summary, both conditions listed in the correct answer decrease tissue density, making it essential to adjust exposure settings accordingly to maintain optimal imaging results.