Question

the default technique for the lateral projection of the thoracic spine is 400 milliamperes (ma), 0.1 seconds (s), 80 kilovoltage peak (kvp), and 40 inches source-to-image distance (sid). how should the technologist modify this technique to blur the ribs and increase the visibility of the spine while maintaining the same receptor exposure?

increase ma and decrease exposure time
decrease ma and increase exposure time
increase ma and decrease kvp
decrease ma and increase kvp

Explanation:

To blur ribs (motion blur) and maintain receptor exposure, we use the reciprocity law (\( \text{mAs} = \text{mA} \times \text{s} \), so equal mAs keeps exposure). Decreasing mA and increasing time (same mAs) causes motion (blurs moving ribs) while keeping exposure. Other options: A doesn't cause motion, C/D change exposure or don't blur.

Answer:

B. Decrease mA and increase exposure time