DI - Positioning for Different Radiograph Views

Lateral Thorax — Positioning

Lateral recumbent; forelegs extended CRANIALLY (before centering); foam wedge under sternum so thoracic spine and sternum are parallel and equidistant from tabletop; head in NEUTRAL position; take on INSPIRATION.

Lateral Thorax — Measurement Point

Caudal edge of the scapula (highest point of the ribs), with front legs extended cranially.

Lateral Thorax — Collimation/Radiation Field

Shoulder joint (legs extended cranially) to the 11th rib; sternum to dorsal spinous processes of thoracic vertebrae. If animal is too deep for the plate, omit the dorsal spinous processes.

Lateral Thorax — Marker Placement

Ventral to the sternum (within collimated field but NOT in anatomy, NOT dorsal).

Lateral Thorax — Correct Positioning on Film

INSPIRATORY pause (air space between diaphragm and apex of heart); front legs not over chest; costochondral junctions at same level; rib heads superimposed in center of radiograph.

Lateral Thorax — Positioning Pitfall

Do NOT use ilial wings or caudal ribs to evaluate positioning — they are at the film edges where the beam passes at an angle, so they will seldom be superimposed.

VD Thorax — Positioning

Dorsal recumbent; legs extended forward; head down on tabletop; sternum and spine SUPERIMPOSED; take on INSPIRATION.

VD Thorax — Sedated Positioning

V trough under thoracic area OR long square foamies snug against chest walls with sandbags on outside; for large dogs tie front legs DIAGONALLY; if still tipping, stretch adhesive tape across chest from table edge to table edge.

VD Thorax — Awake Positioning

Extend each front leg and place on either side of neck/head ("trapping" the head); legs down to table or as close as possible; grasp neck skin or ears for a better hold.

VD Thorax — Measurement Point

Caudal edge of the scapula (highest point of ribs).

VD Thorax — Collimation/Radiation Field

Shoulder joint to the 11th rib; sternum to dorsal spinous processes of thoracic vertebrae.

VD Thorax — Marker Placement

Right side, lateral to the body within the collimated field (not in anatomy).

VD Thorax — Correct Positioning on Film

INSPIRATORY pause (air space between diaphragm and heart apex); front legs not over chest; sternum superimposed over vertebrae; ribs equal length on both sides; dorsal spinous processes centered in vertebral body; equal abdomen/ribs on either side of spine.

DV Thorax — When to Use

Taken INSTEAD OF a VD when the patient is in respiratory distress — dorsal recumbency could further compromise the patient's ability to breathe.

DV Thorax — Positioning

Sternal recumbent; legs extended forward; head down on tabletop; sternum and spine superimposed; take on INSPIRATION.

DV Thorax — Measurement Point

Caudal edge of the scapula.

DV Thorax — Collimation/Radiation Field

Shoulder joint to the 11th rib; sternum to dorsal spinous processes of thoracic vertebrae.

DV Thorax — Correct Positioning on Film

Same as VD — sternum/spine superimposed, equal rib lengths, INSPIRATORY pause, front legs not over chest.

Heart — Views

DV and right lateral (left lateral may also be requested).

Heart — Measurement Point

Caudal edge of the scapula (when front legs are extended cranially).

Heart — Collimation/Radiation Field

Shoulder joint to the 11th rib; sternum to dorsal spinous processes. If too deep for plate, dorsal spinous processes can be omitted.

Heart — Marker Placement

VD and DV — right side; Lateral — ventral to sternum.

Heart — Lateral Recumbency Rule

For ALL lateral recumbencies, the sternum must be on the same level as the thoracic vertebrae (may need a small foam wedge to raise the sternum).

Lateral Abdomen — Positioning

Lateral recumbent; forelegs extended cranially; hind legs slightly extended caudally — do NOT OVEREXTEND (tightens abdominal wall and compresses viscera); sternal wedge plus abdominal wedge for true lateral; take on EXPIRATION.

Lateral Abdomen — Measurement Point

Caudal rib cage where abdomen is widest — the 10th or 11th rib (highest point of ribs laterally).

Lateral Abdomen — Collimation/Radiation Field

Curve of the 7th rib to the greater trochanter of the femur.

Lateral Abdomen — Marker Placement

Ventral to the abdomen.

Lateral Abdomen — Correct Positioning on Film

EXPIRATORY pause (no air space between diaphragm and heart apex); front legs not over chest; costochondral junctions at same level; rib heads superimposed in center; lumbar transverse processes superimposed; hind legs caudal but not overextended.

Flexed Leg Lateral Abdomen — Positioning

Lateral recumbent; forelegs cranially; hind legs neutral; sternal wedge for true lateral; hind legs HYPEREXTENDED CRANIALLY toward the abdomen to visualize the urethra; EXPIRATION.

Flexed Leg Lateral Abdomen — Collimation

Caudal abdomen.

VD Abdomen — Positioning

Dorsal recumbent; legs extended forward; sternum and spine superimposed; take on EXPIRATION.

VD Abdomen — Sedated Positioning

Trough under abdominal area OR long foamies snug against chest walls with sandbags outside; VD — tie front legs DIAGONALLY to table (especially big dogs); DV — extend front legs equally on either side of neck; if tipping, tape across chest; hind legs may be extended OR frog-legged.

VD Abdomen — Awake Positioning

Same head-trapping technique — each front leg on either side of neck/head, legs to table, grasp neck skin or ears.

VD Abdomen — Measurement Point

1 inch CAUDAL to the tip of the xiphoid of the sternum.

VD Abdomen — Collimation/Radiation Field

1 inch CRANIAL to the tip of the xiphoid of the sternum to the greater trochanter.

VD Abdomen — Marker Placement

Right side, lateral to the body.

VD Abdomen — Correct Positioning on Film

Front legs not over chest; sternum superimposed over vertebrae; ribs equal length both sides; dorsal spinous processes centered. NOTE: criteria sheet lists "inspiratory pause" for VD/DV abdomen — flag this discrepancy; the Abdomen views section says expiration.

Lateral Soft Tissue Neck — Positioning

Lateral recumbent; head extended; wedge beneath the nose; flat foam if mid-cervical sags to keep spine parallel to tabletop; forelimbs extended CAUDALLY toward abdomen; higher kVp/low mA for long scale of contrast; NO sedation.

Lateral Soft Tissue Neck — Measurement Point

Shoulder area.

Lateral Soft Tissue Neck — Collimation/Radiation Field

Temporomandibular joints (TMJs) to the thoracic inlet.

Forepaw — Positioning

DPa: sternal recumbent, forelimb fully extended, head elevated/turned away, thorax upright, tape foot flat if needed. Lateral: lateral recumbent, affected side down, flex elbow, pull radius/ulna cranially, unaffected leg caudally. Digit isolation: separate and tape toes apart in slightly oblique lateral.

Forepaw — Measurement Point

Mid-metacarpals (DPa and lateral).

Forepaw — Collimation/Radiation Field

Claws to the distal 1/3 of the radius/ulna.

Forepaw — Marker Placement

DPa — lateral to limb; Lateral — DORSAL to limb.

Forepaw — Correct Positioning on Film

DPa — all digits visible; dewclaw may slightly overlap other digits.

Carpus — Positioning

DPa: sternal recumbent, forelimb fully extended, head elevated/turned away, thorax upright, tape flat if needed. Lateral: lateral recumbent, affected side down, flex elbow, pull R/U cranially, unaffected leg caudally. Specials: 45° dorsolateral-palmarmedial oblique, 45° dorsomedial-palmarlateral oblique, flexed lateral, stress views.

Carpus — Measurement Point

Over the thickest part of the carpus (DPa, lateral, or special views).

Carpus — Collimation/Radiation Field

Distal 1/3 of radius/ulna to proximal 1/3 of metacarpals.

Carpus — Marker Placement

DPa — lateral to limb; Lateral — DORSAL to limb; Obliques — indicate which oblique on film, placed lateral to limb.

Radius & Ulna — Positioning

Cr/Ca: sternal recumbent, forelimb fully extended, head elevated/turned away, thorax upright, humerus-elbow-R/U aligned. Lateral: lateral recumbent, affected side down, slight elbow flex, R/U pulled cranially, unaffected leg caudally. Sedated: tie foot to table end to extend.

Radius & Ulna — Measurement Point

Proximal end of the bones (Cr/Ca and lateral).

Radius & Ulna — Collimation/Radiation Field

Distal 1/3 of humerus to proximal 1/3 of metacarpals.

Radius & Ulna — Marker Placement

Cr/Ca — lateral to limb; Lateral — CRANIAL to limb.

Radius & Ulna — Correct Positioning on Film

Cr/Ca — both medial and lateral humeral epicondyles visible; olecranon process approximately equidistant between them. Lateral — humeral condyles superimposed.

Humerus — Positioning

Ca/Cr: dorsal recumbent, forelegs cranial, affected leg parallel to tabletop, include elbow and shoulder. Cr/Ca (less stress): affected limb extended CAUDALLY, humerus parallel to tabletop, abduct slightly to avoid ribs. Lateral: lateral recumbent, affected side down, affected limb cranial/ventral, unaffected leg caudal, head/neck slightly dorsal to move trachea.

Humerus — Measurement Point

Lateral — proximal end of the bone; Ca/Cr — across T1 (armpit) with leg extended cranially.

Humerus — Collimation/Radiation Field

Distal 1/3 of scapula to proximal 1/3 of radius/ulna.

Humerus — Marker Placement

Cr/Ca and Ca/Cr — lateral to limb; Lateral — cranial to limb.

Humerus — Correct Positioning on Film

Ca/Cr — parallel, epicondyles visible on both sides of olecranon process, olecranon equidistant between epicondyles. Lateral — no neck structures across proximal humerus; humeral condyles superimposed.

Scapula — Positioning

Lateral body: lateral recumbent, affected side down, grasp down leg below elbow, extend elbow, push dorsally so scapular body bulges above spinous processes; pull up leg ventral/caudal to rotate thorax. Lateral neck: affected limb cranial/ventral, unaffected leg caudal. Ca/Cr: dorsal recumbent, forelegs cranial, rotate sternum ~10° away from affected side, let body fall away from affected scapula.

Scapula — Measurement Point

Lateral — across both scapulas; Ca/Cr — across T1 (armpit) with leg extended cranially.

Scapula — Collimation/Radiation Field

Shoulder joint to the caudal/dorsal borders of the scapula.

Scapula — Marker Placement

Ca/Cr — lateral to limb; Lateral — cranial to limb.

Scapula — Correct Positioning on Film

Ca/Cr — body of scapula is a straight heavy white line with scapular spine extending laterally. Lateral — upper scapula should NOT be superimposed over affected scapula except at the dorsal border.

Shoulder — Routine Positioning

Ca/Cr: dorsal recumbent, forelegs cranial, DO NOT rotate the humerus (avoid oblique). Lateral: lateral recumbent, affected side down, affected limb cranial/ventral, unaffected leg caudal, head/neck slightly dorsal.

Shoulder — OCD Positioning ("T" technique)

Head/neck extended dorsally; unaffected limb extended caudally = top of T; affected limb drawn more ventrally, pull humeral head down = bottom of T; ROTATE LIMB CRANIALLY, elbow toward ceiling (humeral head closer to beam = more detail); radiograph BOTH shoulders; if no lesion, third view rotating limb CAUDALLY.

Shoulder — Measurement Point

Lateral — across the joint; Ca/Cr — across armpit with leg extended cranially.

Shoulder — Collimation/Radiation Field

Distal 1/3 of scapula to proximal 1/3 of humerus.

Shoulder — Marker Placement

Lateral — cranial to limb; Ca/Cr — lateral to limb.

Shoulder — Correct Positioning on Film

Routine Ca/Cr — humerus/scapula parallel, no medial opening of joint space. Routine lateral — fully isolated, no structures across joint. OCD lateral — joint isolated with evidence of rotation (narrowed greater tubercle).

Elbow — Routine Positioning

Lateral: lateral recumbent, affected side down, affected limb cranial/ventral, unaffected leg caudal, 45° or 90° flexion (clinician preference), pad to level joint. Cr/Ca: sternal recumbent, forelimb fully extended, head elevated/turned away, thorax upright; if cannot fully extend, angle beam 10–20°.

Elbow — UAP Positioning

Lateral recumbent, affected side down; sandbag against caudal distal R/U to FULLY flex the joint (cranial surfaces of humerus and R/U should touch); pad to level; keeping carpus in true lateral, move carpus toward neck to hyperflex; radiograph BOTH elbows; OFA only requires hyperflexed lateral; NOT recommended on conscious patient.

Elbow — Measurement Point

Routine — Cr/Ca and lateral across the joint; UAP — over the flexed elbow.

Elbow — Collimation/Radiation Field

Distal 1/3 of humerus to proximal 1/3 of radius/ulna.

Elbow — Marker Placement

Lateral — cranial to limb; Cr/Ca — lateral to limb; UAP flexed lateral — CAUDAL to limb.

Elbow — Correct Positioning on Film

Routine Cr/Ca — both epicondyles visible, olecranon equidistant. Routine lateral — humeral condyles superimposed. UAP — anconeal process visible and isolated from the distal humerus.

Bicipital Groove — Positioning

Sternal recumbent; head turned slightly away without rotating thorax (thorax stays upright); flex elbow so shoulder projects over proximal 1/3 of R/U; cassette in crook of elbow (or DR panel with R/U moved slightly lateral); palpate humeral head, center over bicipital groove; collimate tightly.

Bicipital Groove — Measurement/Center Point

Head of the humerus.

Bicipital Groove — Marker Placement

Lateral to the limb.

Positioning Aids — 3 Reasons to Use

Minimize radiation exposure; attain quality imaging; minimize the number of people needed in the room (aids range from tape/rope to thoracic positioner or chemical restraint; foam blocks, wedges, sandbags can be easily made).

Radiographic Terminology — Rule

The 1st letter/word indicates the direction the x-ray beam ENTERS the patient; the 2nd indicates the direction it EXITS.

Two-View Rule

Nearly always required to take 2 views at right angles to one another. Exemptions: areas where a second view would be non-diagnostic due to anatomy, or life-threatening conditions (e.g., respiratory distress).

Heel Effect

Greater intensity of the x-ray beam toward the CATHODE side of the tube. Place the denser/thicker portion of the body toward the cathode side.

Viewing Radiographs — VD/DV

Patient's RIGHT side is on your LEFT; cranial portion at the TOP of the viewer/screen.

Viewing Radiographs — Lateral

Patient's HEAD faces toward your LEFT; dorsal portion at the TOP of the viewer/screen.

Marker Rule — Lateral Spine/Pelvis

Marker placed DORSAL to the spine/pelvis, within the collimated area but NOT in the anatomy and NOT ventrally.

Marker Rule — Lateral Thorax/Abdomen

Marker placed VENTRALLY within the collimated field, NOT in the anatomy and NOT dorsally (e.g., left marker in axillary region for lateral thorax).

Marker Rule — VD/DV

Left or right marker placed LATERAL to the body within the collimated field, NOT in the anatomy.

Marker Rule — Extremity Lateral/Oblique

Marker placed CRANIALLY within the collimated field but NOT in the anatomic region being imaged.

SID (Source-Image Distance)

Minimally 40 inches for a 300 mA generator; can increase to 44 inches for 400–600 mA if recommended by manufacturer. Consistency is important — heart size differs at 40 vs. 44 inches.

Small Focal Spot

Use for extremity and headwork on anatomic parts measuring 10 cm or LESS to improve image quality.

Patient Preparation

Coat dry and debris-free (wet hair/debris create artifacts); remove iodine-based skin meds (radiopaque), bandages, splints, collars, harnesses as appropriate; enemas/fasting may be called for abdomen.

Measurement Timing

Measure the patient AFTER placement in the recumbent position — NOT standing on the table.

Dosimeter Wearing Rule

Worn UNDER the lead protective apron at WAIST or CHEST level.

PPE Required in Room During Exposure

Lead apron, gloves, thyroid shield, safety glasses, and personal dosimeter — MANDATORY if remaining in the room during exposure.

Primary Beam Rule

NO human body part, whether covered in protective clothing or not, should be in the primary radiation beam. Placing lead gloves over hands is NOT acceptable.

Collimation Requirement

Every radiograph must show restriction of the primary beam (collimation) to an area SMALLER than the size of the cassette.

Cassette Holding Rule

For table-top radiography, the film cassette must NEVER be held by hand — a radiographic cassette holder must ALWAYS be used.

Radiation Dose Action Level (WorkSafeBC)

1 mSv/year — employer must establish an exposure control plan and provide dosimeters if workers exceed or may exceed this level. Worker exposure limit is 20 mSv/year.

Lead Apron Lead Equivalency — Ambulatory Practice

0.5 mm lead apron with thyroid shield to keep whole body dose below 1 mSv/year.