Radiographic Distortion

When an object lies off to one side of the central axis of the x-ray beam

The MF will be unchanged

Shape (true) distortion can cause

elongation and foreshortening

Size (Magnification) Distortion

affects the size of the structure, NOT the shape

To achieve a 2x mag of a structure place the structure:

halfway between the tube and the IR

Shape (true) distortion

isn't ALWAYS bad

When shape distortion is undesirable you need to do 2 things

keep the part parallel to IR and keep the CR perp to part and IR

The image will always be _______ than the actual object

larger

Macroradiography

magnification radiography

The weakest link in an imaging chain is the

monitor

Radiographic Distortion

Any misrepresentation of a structure's true shape or size

Size distortion is not always undesirable! Some procedures require magnification techniques: (4)

Cerebral arteriography/angiography, Temporomandibular Joints (TMJ), Sternum, Carpal navicular

Teleroentgenography

X-rays at 72" SID

Radiographic Distortion occurs when

the object is not positioned in a plane that is parallel to the plane of the IR

The most critical and significant factor affecting image magnification is:

OID

Cieszynski Rule (Law of Isometry)

Minimizes shape distortion of an object that cannot be placed parallel to the film

Size distortion is influenced by only two factors:

1. OID 2. SID 3. SOD

2 Types of Radiographic Distortion

1. Shape (true) distortion 2. Size (magnification) distortion

Advantageous distortion is used for:

Stecher/Navicular

Shape (true) distortion results from misalignment of what three things?

part, tube, IR