Radiographic positions and procedures

Radiographic positions and procedures

By

Mr.souheil Barakat, Radiographic2011Contents

Basic terms,

Chest , lungs,

Trachea,

Bronchography,

Nasophrayngography (for adenoid).

Pharyngography.

Positive contrast pharyngography.

Radiographic positions and procedures

Basic terms

1) Body positions: Body positions are the manner in which the patient is placed in relation to the surrounding space.

a) Decubitus : position assumed in lying down; the position assumed is described according to dependent body surface:

Dorsal decubitus: supine or lying on back.

Ventral decubitus: prone or lying face down

Right lateral decubitus: lying on right side Left lateral decubitus: lying on left side.

b) Standing position

c) Seated position

2) Positioning terms:

a) Projection:

Projection usually describes the path of radiation as it goes from the x-ray tube through the patient to the image receptor.

b) View:

View describes the representation of an image as seen from the vantage of the image receptor.

c) Method:Some radiologic procedures are named after individuals (for example, chassard-lapine or Towne) in recognition of their having developed a method to demonstrate a specific anatomic part.

3) Projection terminology:

a) Frontal projections (AP or PA):

AP (anteroposterior) projection :the x-ray beam is shown entering the front (anterior ) body surface and exiting the back (posterior) surface.

PA (posteroanterior) projection:The central ray entering from the posterior body surface .

b) Lateral projections: Lateral projections are always named by the side of the patient that is placed closest to the film (Right or left lateral projection).

c) Oblique projections: The term oblique refers to a position in which the body part is rotated so that it does not produce a frontal ( AP or PA) or a lateral projection. Oblique projections could be :RAO or LAO in prone position and RPO/ LPO in supine .

-In supine position : - LPO ( left anteroposterior oblique) : the patient is rotatd, So that the left side

of the body is closest to the film .

- RPO (right anteroposterior oblique) : the patient is rotated, So that the right

side of the body is closest to the film.

-In prone position:

- RAO (right posteroanterior oblique) : the right side of the patient is closest to

the film.

- LAO (left posteroanterior oblique) : the left side of the patient is closest to the

film.

d) Decubitus projections:

Decubitus projections are so named to indicate that the patient is lying down.

Similar to lateral and oblique position, decubitus positions are named by the body surface on which the patient is lying.

Dorsal decubitus : patient is lying on his back.

Ventral decubitus : patient is in prone position.

Right lateral decubitus : patient is lying on the right side of the body laterally.

Left lateral decubitus : patient is lying on the left side of the body laterally.

e) Tangential projection: A tangential projection is one in which the central ray skims between body parts to profile a bony structure and project it free of superimposition.

f) Axial projections: In an axial projection there is longitudinal angulation of the central ray with the long axis of the body part.

4) Body movement: The following terms are used to describe movement related to the extremities:

a) Abduction and adduction

Abduction :movement of a part away from central axis of body. Adduction : movement of a part toward central axis of body

b) Flexion and extension

Extension :straightening of a joint; stretching of a part; also, a backward bending movement; opposite of flexion.

Flexion : a bending movement of a joint whereby angle between contiguous bones is diminished; also , a forward bending movement; opposite of extension.

c) Inversion and eversion

Evert or eversion: movement of the foot when turned outward at the ankle joint.

Invert or inversion :movement of the foot when turned inward at the ankle joint. d) Pronate and supinate

Pronate: to turn arm so that palm of hand faces backward. Supinate: to turn arm so that palm of hand faces forward.5) Central ray : refers to the direction of the X-ray beam arising from tube toward patient (area of interest):

a) Straight central ray: perpendicular , vertical or horizontal.

b) Angled central ray could be:

Cephalad : the central ray is oriented superiorly /proximally.

Caudad: the central ray is oriented inferiorly/distally or caudally.

Medially: inside.

Laterally: outside

Anteriorly or posteriorly.

Chest - Lungs

1) PA Chest Projection :

a) Position: place the patient in the standing or sitting position, with arms hanging at sides.

Place the hands low on the hips, with their palmars facing upward to rotate the scapulae laterally.

Adjust the hight of cassette so that the upper border of the film is about 2 cm above the shoulders.

The patient must keep the shoulders in contact with the grid device.

b) Central ray :

Direct the central ray in the midsagittal plane to the central of the film at the level of the sixh thoracic vertebra.

c) Breating instructions:

The radiography must be made at the end of full inhalation

d) Structures shown :

The air-filled trachea.

The lungs.

The diaphragmatic domes.

The heart and aortic knob.

The bronchial tree is shown from an oblique angle.

e) Evaluation criteria :

The sternal ends of the calvicles should be equidistant from the vertebral column.

The trachea should be seen in the midline.

The scapulae should be projected outside the lung fields .

One to two inches of lung apex should show above the clavicles.

Ten posterior ribs should be seen above the diaphragm .

The distance from the vertebral column to the lateral border of the ribs should be equidistant on each side.

A small amount of the heart should be seen on the right side of the vertebral column.

The costophrenic angles must be included.

The heart and diaphragm shoud show sharp outlines.

A faint shadow of the ribs and superior thoracic vertebrae should be seen through the heart shadow.

The exposure should clearly demonstrate the lungs fields.

2) Lateral chest projection :a) Position :

The left lateral (left side against the film):when the left lung is of primary interest. The right lateral : when the right lung is of primary interest.

The upper border of the film must be 1 inches above the shoulders.

Have the patient sit or stand straight, extend the arms directly upward, flex the elbows, and , with the forearm resting on his head.

b) Central ray :

Direct the central ray horizontally to the sixth thoracic vertebra.

c) Structures shown :

The left lateral projection : is used to show the heart and aorta and left-sided pulmonary lesions :

The right lateral projection : is used to show the right-sided pulmonary lesions :

The lateral positions : are employed extensively to demonstrate the interlobar fissures, to differentiate the lobes, and to localise pulmonary lesions .d) Evaluation criteria :

The ribs posterior to the vertebral column should be superimposed .

No shadow of the arm on its soft tissues overlapping the upper lung field.

The long axis of the lung fields should be vertical , without forward-backward leaning.

The sternum should be lateral and not rotated.

The costo-phrenic angles and the apices of the lungs must be included.

The exposure should penetrate the lung fields and heart,

The thoracic intervertebral spaces should be open except for patients with scoliosis.

The heart and diaphragm should show sharp outlines.

The hilum should be in the approximate center of the radiography.

3) Chest: AP Projection :

a)Position :

- Patient is placed in the AP position, either erect or lying.

- If possible, flex the elbows, pronate the hands, and place the

hands on the hips to draw the scapulae laterally .

- Adjust the shoulders to lie in the same transverse plane.

- The exposure is made at the end of full inhalation.

a) Central ray :

Direct the central ray perpendicularly to the long axis of the sternum at the level of T7.

b) Structures shown :

- This position is used when the patient is too ill to be turned to

the prone position.

- Being farther from the film, the heart and great vessels cast

magnified shadows, and the lung fields appear shorter

because of the magnification of the shadow of the diaphragm .

- The shadows of the clavicles are projected higher, and the

ribs assume a more horizontal appearance.

c) Evaluation criteria :

- The medial portion of the clavicles should be equidistant from

the vertebral column.

- The trachea should be seen in the midline.

- The clavicles will lie more horizontal and obscure more the

apices than in PA projection .

- The distance from the vertebral column to the lateral border of

the ribs should be equidistant on each side.

- A small amount of the right ventricle should be seen on the

right side of the vertebral column.

- The costophrenic angles should be included.

- The exposure should demonstrate the lung fields clearly .

4) Chest : pulmonary apices :

A) PA axial pulmonary apices projection :

a) Position :

Place the patient in the PA position, either standing or seated.

-Rest the chin on top of the grid device.

-Flex the elbows and place the hands, palms out, on the hips.

-Depress the shoulders, rotate the forward, and adjust hem to lie in the same transverse plane.

-Have the patient keep the shoulders in contact with the grid device.

-Make the exposure at the end of full inhalation or full exhalation.

b) Central ray :

If the exposure is made on inhalation: Direct the central ray through the third thoracic vertebra at an angle of 10 or 15 degrees cephalad.

If the exposure is made on exhalation: Direct the central ray perpendicularly to the third thoracic vertebra.

c) Structures shown : -The apices project above the shadows of the clavicles.

d) Evaluation cirteria :

-The apices should be well demonstrated and included in their entirety.

-Along with the apices, only the adjacent upper lung region is shown. -The calvicles should lie below the apices.

-The medial portion of the clavicles should be equidistant from the vertebral column

B) AP axial pulmonary apices projection :

a) Position :

Place the patient in the AP projection , in the erect or the

supine position.

Flex the elbows and place the hands on the hips with the

palms out, or pronate the hands beside the hips.

Rotate the shoulders forward, and adjust them to lie in

the same transverse plane.

Make the exposure at the end of full inhalation.

b) Central ray : Direct the central ray to the second thoracic vertebra at

an angle of 15 or 20 degrees cephalad.

c) Structures shown :

This projection shows the apices lying below the

shadows of the clavicles.d) Evaluation criteria :

The calvicles should be lie superior to the apices.

The sternal ends of the clavicles should be equidistant from the vertebral column. The apices should be included in their entirety.

Only the apices and adjacent upper lung region need to be included on the radiography.

The clavicles should be lying horizontally with their medial ends overlapping only the first or second ribs.

The ribs should appear distorted with their anterior and posterior portions somewhat superimposed.

5) Chest : AP lordotic projections : LINDBLOM method:

a)Position:

I) AP lordotic projection :

Place the patient in the AP position standing.

Flex the elbows and place the hands , palms out, on the hips..

Have the patient lean backward in a position of extreme lordosis and rest his shoulders against the vertical grid device . Make the exposure at the end of full inhalation.II) Oblique lordotic projection : a)position: Rotate the body approximately 30 degrees away from the AP position, with the affected side toward and centred to the grid.

b)Central ray : Direct the central ray horizontally to the midsternum . c)Structures shown :-These both projections are used to demonstrate the apices and such conditions as interlobar effusion .d) Evaluation criteria : 1-AP axial lordotic :

The clavicles should lie superior to the apices.

The sternal ends of the clavicles should be equidistant from the vertebral column.

The apices and lungs should be included in their entirety. 2- Oblique lordotic :

The dependent apex and lung of the affected side should be demonstrated in its entirety.

6) PA pulmonary apices lordotic projection : FLEISCHNER method: a)Position : Place the patent in the PA position before a vertical grid device.

Have the patient grasp the grid device, brace his abdomen against it, and then lean backward in a position of extreme lordosis.

The thorax should be inclined posteriorly approximately 45 degrees .

Make the exposure at the end of full inhalation.

b)Central ray :Direct the central ray horizontally to the fourth thoracic vertebra.

c)Structures shown:

The magnified interlobar effusions should be demonstrated. The apices and lung should be shown.

d)Evaluation criteria :The same as for AP lordotic projection.

7) Lungs and pleura

I) Frontal projections ( AP or PA ) in lateral decubitus position :For fluid levels and small pneumothoraces :

a)Position :

- Patient placed in a lateral decubitus position, lying on either the right or the left, as indicated by the existing condition.

- Extend the arms well above the head.

-Place the anterior or posterior surface of the chest against a vertical

grid device.

-Make the exposure at the end of full inhalation.

a) Central ray : directed horizontally through the fourth or seventh vertebra.

b) Structures shown : The frontal projection ( AP or PA ) in lateral decubitus position reveals :

-The change in position of the fluid and reveals pulmonary areas

that are obscured by the fluid in standard projections. -The presence of any free air in the case of a suspected pneumothorax.c) Evaluation criteria :

The patient should not be rotated from a true frontal projection.

The affected side should be included in its entirety.

The apices should be shown.

The patient arms should be removed from the field of interest.

II) Lateral projections for fluid level :( ventral or dorsal decubitus position) :

a) Position :

Place the patient in a prone or a supine position, with the affected side against a vertical grid device. Extend the arms well above the head. Make the exposure at the end of full inhalation.

b) Central ray :

directed horizontally to the midaxillary line at the level of the sixth thoracic vertebra.c) Structures shown :

The change in position of the fluid and reveals pulmonary areas that area obscured by the fluid in standard projections.

d) Evaluation criteria :

The anterior and posterior surfaces of the lung fields should be demonstrated.

The arms should not obscure the upper lung field.

8) Chest in expiration ( exhalation ) :

a) Position and central ray :

The same position and central ray as for PA projection

standing, but the exposure must be made at the end of full

exhalation.

- Sometimes, this may be made also in a lateral projection

standing at the end of full exhalation.

b) Interest :

-Study of diaphragmatic mobility, emphysema and localised pneumothorax, compared to that made in a full inhalation.

9) PA oblique projections ( RAO and LAO ) :

a)Position :

1)Left PA oblique projection (LAO):

- Rotate the patient to place the left shoulder and breast in contact with grid device, either standing or seated erect position. - Oblique x-ry :

- 45 degrees for routine examinations of the chest and for separating the shadows of the aorta and the spine .

- 55 to 60 degrees :for studies of the heart and great vessels.

2) Right PA oblique projection (RAO) : Reverse the above position. b)Central ray : directed hoirzontally to the sixth thoracic vertebra.

c)Evaluation criteria :

Approximately twice as much distance should exist between the vertebral column and the outer margin of the ribs on the

remote side of the film compared to the dependent side.

Both lungs should be included. Identification markers should be visible.d) Interest : - Investigation of specific lesions .

- Study of some structures of the thorax ( lungs, hili or mediastinum ) .

10) AP obliques projections ( RPO and LPO ) :

Used when the patient is too ill to be turned to the prone position and sometimes as supplementary projections in the investigation of specific lesions.

The right AP oblique projection ( RPO ) corresponds to the left PA oblique projection .

The left AP oblique projection ( LPO ) corresponds to the right PA oblique projection .

For AP projections, the side closest to the film is usually the side of primary interest .

1) AP trachea projection a)Position :

- Examine the patient in either the supine or the erect position.

- When the trachea is examined in the AP position, use a grid technique to minimize secondary radiation.

- Adjust the shoulders to lie in the same transverse plane.

- Extend the head slightly.

- Instruct the patient to inhale slowly during the exposure to ensure filling the trachea with air.

b)Central ray : directed perpendicularly to the manubrium . c) Structures shown : The outline of the air-filled trachea.

2) Trachea Lateral projection : trachea and superior mediastinum :

a)Position :

- Place the patient in a lateral position, either seated or standing.

- Instruct the patient ot clasp his hands behind his body.

- Rotate the shoulders posteriorly as far as possible.

- Extend the head slightly.

- Make the exposure during deep inhalation.

b) Central ray : Direct the central ray horizontally through a point midway between the manubrial notch and the anterior border of the head of the humerus for the superior mediastinal structures, and from 4 to 5 inches, lower

for thdemonstration of the entire chest. c) Structures shown :

- The air-filled trachea .

- Retrosternal extensions of the thyroid gland, thymic enlargement in infants. d) Evaluation criteria :

- The area from the mid-cervical to mid-thoracic region should be included.

- The shoulder should not be superimposed over the trachea or superior mediastinum.

- The tracheal should be filled with air.

- The patient should not be rotated.

Bronchography is applied to the specialized radiologic examination of lungs and bronchial tree by means of introducing an opaque contrast medium into the bronchi.

Numerous iodinated media, both aqueous and oily, are available for bronchography . However, the oily media are more generally used.

In bronchography, the lung can be imaged down the level of the fifth division.

Bronchography is rarely used at the present time, that due in part ot ct-scan and the development of the fiberoptic bronchoscope.

a) Methods of contrast instillation :

The supraglottic and infraglottic methods of instillation are identical except for the placment of the laryngeal cannula, through which the medium is introduced.

Immediately after completion of the instillation, while an adequate amount of the medium is still in the trachea, the patient is placed in the supine position. He is then rotated and the table is angled as required to distribute the medium through the upper-lobe segments of the bronchi.. this procedure may be done under fluoroscopic observation with spot films exposed as indicated.

b) Bronchography filming:

Bronchography filming may include :

1- A supine AP projection.

2- An erect PA projection.

3- Right and left oblique projections.

4- A lateral projection : when only one side is injected or, in the case of bilateral examination, of the first side injected.

Postinjections exposures should be increased to penetrate the contrast media.

Larynx and pharyx : anatomy

Lateral projection. Head in extension. Central ray : directed to nasopharynx ( 2 cm directly anterior to the external auditory meatus ).

The film must be exposed during the intake of a deep breath through the nose.. The mouth must be closed.

- Fluoroscopic equipment is available to spot film in rapid sequence the patient during the act of swallowing or to record the fluoroscopic image on vidiotape or cinefilm during deglutition . Opaque studies of the pharynx are made with an ingestible contrast medium, usually a thick, creamy mixture of water and barium sulfate.

The images may then be studied to identify any abnormalities during the active progress of deglutition.

Projections : AP and lateral projections :

Interest : Study of the pharynx and upper oesophagus during the act of

swallowing.

For examination of the larynx and hypopharynx.

The examination is carried out under fluoroscopy with the use of spot

films and/or cineradiographic recordings.

- Projection : AP and lateral projections :

Rarely used.

TRACHEA

BRONCHOGRAPHY

Lateral nasopharynx x-ray : for adenoids

PHARYNGOGRAPHY

Positive contrast laryngopharyngography

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