PA projection

PA pro·jec·tion

the standard frontal chest film projection; radiographic skull projection with the petrous ridge superimposed on the orbits.

PA pro·jec·tion

(prŏ-jek'shŭn)
A radiographic study in which x-rays travel from posterior to anterior.
Synonym(s): posteroanterior projection.
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References in periodicals archive ?
The PA projection provided the least radiation dose rate, and the LAO 45[degrees] projection provides the most.
Table 2: Population by size as projected for 2056 and 2101 TFR NOM pa Projection series June 2006 June 2056 June 2101 1.
The PA projection is preferred for pediatric patients, but some pediatric patients are difficult to image this way because they are frightened.
1,3,7] These studies may have lacked sensitivity because the lateral view is likely to be most helpful in patients whose pathologic processes are hidden by the heart or diaphragms on the PA projection.
Although left lower lobe pneumonias may be obscured by the heart on the PA projection, they are often visible on the lateral view.
In normal patients with helpful lateral views, the PA projection was often difficult to interpret because the radiograph was underpenetrated, the patient was obese, or there was cardiomegaly.
However, obtaining an AP or PA projection of the patella completely free of bony obscuration from the relatively dense condylar and epicondylar portions of the distal femur sometimes is difficult because of the position of the patella in relation to the femur.
This means that the AP standing radiograph of the knee often misses joint space narrowing, while an erect, semiflexed PA projection will show the narrowing.
For this PA projection, the beam runs through the SST joint eliminating almost all the bone overlap.
The PA projection revealed no irregularities in contrast, detail or unusual artifacts aside from metallic surgical clips from a previous breast surgery.