Distortion Flashcards
what are the 2 factors of size distortion
SID & OID
what is the relationship between SID and magnification
inverse relationship
as SID increases MAGNIFICATION decreases (beam diverges less)
what is the relationship between OID and MAGNIFICATION
direct relationship
as OID increases MAGNIFICATION increases (beam diverges more)
which size SID is used to minimize size distortion
larger SID
which OID is used to minimize size distortion
smaller OID
what are the 2 types of shape distortion
Elongation
Foreshortening
define elongation
image size is longer than object length
stretching the image in 2 directions
define foreshortening
image size is shorter than object length
compressing the anatomy in 2 directions
off-centering the CR or the part will result in what type of shape distortion
elongates the anatomy
what will happen if you off-center the IR
you will clip anatomy not distort the image
angling the CR will result in what type of shape distortion
elongates the anatomy
Angling the IR results in what shape distortion
elongates the anatomy
angling the body part will result in what type of shape distortion
foreshortening the anatomy (AP lordotic chest)
is rotating the body part the same as part angling
yes, but its complicated
some anatomy is foreshorten
some anatomy is elongated
in most obliques is anatomy elongated or foreshortened
mostly its foreshortened
which obliques show no discernible shape distortion
round anatomy structures (knee)
define displacement
moving 2 or more anatomical structures away from each other
what is the purpose of aligning the CR or rotating/angling the part
to displace anatomical structures
what are the 2 ways to create displacement
angling the CR or angling the PART
How do you minimize size distortion
Increase SID or Decrease OID
how do you minimize shape distortion
part should remain perpendicular to CR and parallel to IR and be properly aligned
why must you take separate images on the hip, knee, and ankle
to make sure CR is aligned precisely and to avoid any elongation
in a caldwell skull, angling the CR will result in what
elongation and displacement
In a caldwell skull, angling the part will result in what
foreshortening and displacement
in a caldwell skull, angling the IR will result in what
elongation and no displacement
Angling the part and the IR will result in what
elongation and displacement
