Diagnostic Imaging Exam 2 Module 5

What do the directional terms stand for?

L (left), R (right), D (dorsal), V (ventral), M (medial), L (lateral), Cr (cranial), Cd (caudal), Pa (palmar), Pl (plantar), O (oblique)

How is beam direction named?

First letter = beam entry; second letter = beam exit

What are the primary considerations for radiographic positioning?

Patient welfare, proper restraint, minimal trauma, minimal staff exposure

Why are two views required?

Radiographs are 2D; need at least two views to evaluate a 3D structure

What is collimation and why is it important?

Use smallest field size possible; reduces scatter and improves contrast

Where do you measure with calipers?

Over the thicket part of the area being radiographed

Where is the area of interest placed relative to the film?

As close to the film as possible to reduce distortion and magnification

What does the central beam align with?

Directly over area of interest

What must be removed before radiography?

Collars, tags, debris, metal objects

Why fast for abdominal radiographs?

GI contents can obscure structures

Why consider bandages/splints?

May require increased exposure factors

Where should R/L markers be placed?

On correct side of patient, never over anatomy

On lateral views, what does the marker indicate?

The side DOWN son the table

What contrast scale do soft tissues require?

Long scale of contrast (many grays)

Thorax respiration phase?

Full inspiration

Abdomen respiration phase?

Full expiration

When to use a grid?

For body parts >10 cm thick

Lateral Thorax Measure

Caudal border of scapula

Lateral Thorax Beam Center

Caudal border of scapula

Lateral Thorax Positioning

Right lateral by default; forelimbs extended cranially; full inspiration

Lateral Thorax FOV

Entire thorax including all ribs

VD Thorax Measure

Caudal border of scapula

VD Beam Center

Caudal border of scapula

VD Thorax Positioning

Supine; forelimbs cranial; sternum superimposed on spine

VD Thorax FOV

Entire thorax

VD Thorax Caution

Contraindicated in respiratory distress

DV Thorax Purpose

Best for evaluating heart

DV Thorax Positioning

Sternal recumbency

When checking for metastasis

Both lateral thorax views

Lateral Abdomen Measure

Caudal aspect fo 13th rib

Lateral Abdomen Beam Center

Caudal aspect of 13th rib

Lateral Abdomen Positioning

Right lateral; hind limbs caudal; full expiration

Lateral Abdomen FOV

Diaphragm → femoral heads

VD Abdomen Measure

Caudal aspect of 13th rib

VD Abdomen Center

Caudal aspect of 13th rib

VD Abdomen Positioning

Symmetrical dorsal recumbency with positioning aids

VD Abdomen FOV

Diaphragm → femoral heads

Abdomen Patient Prep

Fasted; enema if needed

Lateral Skull Measure

Highest point of cranium

Lateral Skull Beam Center

Lateral cantos of eye

Lateral Skull Positioning

True lateral using aids; entire head included

Lateral Skull FOV

Tip of nose → base of skull

VD Skull Measure

Highest point of cranium

VD Beam Center

Lateral canthus of eye

VD Skull Positioning

Maxilla parallel to table

VD Skull FOV

Entire head

VD Open Mouth Measure

Level of 3rd upper premolar

VD Open Mouth Beam Center

Level of 3rd upper premolar

VD Open Mouth Positioning

Open mouth with non-metal aids

VD Open Mouth

Entire maxilla

Rostrocaudal (Frontal) Measure

Over frontal sinuses

Rostrocaudal (Frontal) Beam Center

Between eyes

Tympanic Bullae Common Projections

Lateral oblique and rostrocaudal open mouth

TMJ Standard View

VD oblique

TMJ Beam Center

center of TMJ

TMJ Measure

Over lateral canthus of eye

Cervical Spine Lateral + VD Beam Center

C4-C5 space

Cervical Spine Lateral + VD Measure

Thoracic inlet

Cervical Spine Lateral + VD FOV

Base of skull → few thoracic vertebrae

Cervical Spine Lateral + VD Precaution

Don’t hyperflex neck

Thoracic Spine Lateral Beam Center

7th thoracic vertebra

Thoracic spine Lateral Measure

7th rib

Thoracic spine Lateral FOV

C7 → L1

Thoracic Spine VD Beam Center

Caudal border of scapula

Thoracic Spine VD Measure

Highest point of sternum

Thoracic Spine VD FOV

C7 → L1

Thoracolumbar Beam Center

TL junction

Thoracolumbar Measure

TL junction

Thoracolumbar FOV

TV area

Lumbar Beam Center

L4

Lumbar Measure

L1

Lumbar FOV

T13 → S1

Long Bones Beam Center

Middle of bone

Long Bones Measure

Thickest part of bone

Long Bones FOV

Joint above + joint below

Joints Beam Center

Over joint

Joints Measure

Thickest part of joint

Joints FOV

Portions of bones above and below

Scapula Beam center

Middle of scapula

Scapula Measure

Thickest region

Shoulder Joint Beam Center

Point of shoulder

Shoulder Joint Measure

Thickest area of shoulder

Humerus beam Center

Middle of humerus

Humerus Measure

Thickest area

Humerus FOV

Shoulder → elbow

Elbow Projections

Mediolateral + craniocaudal

Elow Flexed lateral

Carpus pulled toward neck

Elbow Beam Center

Middle of elbow

Elbow Measure

Distal humerus

Radius/Ulna Beam Center

middle of bones

Radius/Ulna Measure

Over elbow

Radius/Ulna FOV

Include proximal + distal joints

Carpus Beam Center

Middle of joint

Carpus Measure

Middle of Joint

Carpus FOV

Include bits of bones above and below

Metacarpus/Phalanges Beam Center

Over area

Metacarpus/Phalanges Measure

Thickest portion

Metacarpus/Phalanges FOV

Include joints

Pelvis + Hips Lateral Pelvis Positioning

Down limb cranial, up limb caudal

Pelvis + Hips Lateral Pelvis FOV

Entire pelvis, lumbar spine, femurs