Patient Factors & Technique Selection
What three factors are considered patient factors when selecting radiographic technique?
Anatomical thickness/body habitus, body composition, pathology
Which tissue type is considered radiolucent?
Fat
Which image quality factor describes sharpness of detail?
Spatial resolution
Which exposure factor primarily controls x-ray quantity?
mAs
APR primarily improves what aspect of imaging?
Workflow efficiency
Radiographic technique charts are primarily based on which body habitus?
Sthenic
A lytic bone lesion is classified as what type of pathology?
Destructive
Scatter radiation primarily degrades which image quality factor?
Contrast resolution
Increasing SID without changing exposure factors causes what effect?
Decreased beam intensity
Automatic Exposure Control (AEC) terminates the exposure when which of the following conditions is met?
A sufficient amount of radiation has been detected at the image receptor
Why should patient thickness not be estimated visually?
Accurate measurement ensures consistent technique selection
How does destructive pathology affect technique selection?
Requires decreased exposure
Elongation is most often caused by what error?
Improper alignment of tube or IR
Which technique chart method keeps kVp constant and adjusts mAs?
Fixed kVp - Variable mAs
A noisy digital image is most likely caused by what?
Insufficient mAs
When imaging a thicker body part using fixed or variable technique charts, what is the correct adjustment?
Increase kVp or mAs, but not both
Which technique is most appropriate for a routine PA chest radiograph?
High kVp, low mAs
Foreshortening occurs when the anatomy is in what position?
Not parallel to the IR
Which technique chart is best suited for extremities?
Variable kVp - Fixed mAs
Increasing kVp by 15% while maintaining exposure requires what change in mAs?
Halving mAs
Two patients have the same thickness, but one requires more exposure due to ascites. Why?
Mass density differences thanks to fluid buildup in one of the patients
To reduce patient dose in a thin patient, what should primarily be decreased?
mAs
A radiographic image appears uniformly gray with minimal visible differences between anatomical structures. Which exposure factor error is most likely responsible for this appearance?
Excessive kVp
High-kVp techniques are most commonly used for which exams?
Chest and barium studies
Which adjustment reduces patient dose while maintaining image quality?
Decrease mAs