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 ?
13.6 Gy/min, P < 0.001) in PA projection, 87.3% (2.5 Gy/min vs.
Whether the default or optimized group, there was a significant difference in the radiation dose rates among the three projection positions (all P < 0.001).The PA projection provided the least radiation dose rate, and the LAO 45[degrees] projection provides the most.
The transseptal sheath/dilator was placed in the superior vena cava and then the dilator, sheath and needle combination was withdrawn inferiorly in the PA projection until the tip of the dilator "popped" into the fossa ovalis.
Dose surveys conducted in two Brazilian cities (Curitiba (20) and Sao Paulo (21)) reported mean ESD values to adult patients undergoing chest examinations similar to the ones obtained here: 0.33 and 0.22 mGy (PA projection) and 1.01 and 0.98 mGy (LAT projection).
The PA projection is preferred for pediatric patients, but some pediatric patients are difficult to image this way because they are frightened.
Although left lower lobe pneumonias may be obscured by the heart on the PA projection, they are often visible on the lateral view.[8,9] On the normal lateral chest view, the apparent density of the vertebral bodies gradually decreases from superior to inferior (Figure 1).[9] Any interruption in this progression, making the lower vertebrae appear more dense, may indicate a pathologic process in the lungs, even if the process is not seen on the PA view (Figure 2).[2,8-10] This finding on the lateral view is known as the "spine sign" or "vertebral fade off sign,"[8] and is often present in patients with left lower lobe pneumonia.[8,10]
(2) This will elevate the patient enough to demonstrate a curve correction by comparing this image with the PA projection.
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 example, a PA projection should be used for a scoliosis series of young female patients because their breast tissue is extremely sensitive to the development of radiation-induced breast cancer.
1.) 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.