This fact is from Radiographic Techniques in Oral Medicine & Radiology. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
OPG = orthopantomogram most common extraoral radiograph
Bisecting angle technique causes foreshortening or elongation
Paralleling technique = more accurate positioning = XCP holder
kVp controls quality and contrast
mA controls quantity and density
ALARA principle = as low as reasonably achievable.