1. Properties of a good chest X-ray and all views
John-Henry Corbett
02/2012

2. PA chest Technical Central ray Exposure at full inspiration
kV, 3 mAs
Hand on hips, palms out
Shoulder rotated forward against IR (scapula out of lung fields)
Shoulder pressed downward to remove clavicles from apices
Central ray
Central ray perpendicular to IR in midsagittal plane at level of T7
18-20cm below vertebral prominence or inferior angle of scapula
Source image distance of 180cm
Exposure at full inspiration
10-11 posterior ribs visible
Alternative if patient cannot stand
Sit with feet over edgde of bed / trolley
– ‘hugging’ IR

3. AP Chest Technical Central ray
Supine or semi-erect (if patient cannot stand/sit)
Raise head of trolley/bed where possible
Roll shoulder forward by rotating arms medially or internally
IR behind patient
Central ray
Central ray angled caudally (± 5˚) to be perpendicular to long axis of sternum
3 posterior ribs should be seen above clavilces
Central ray to T7 : 8-10cm below jugular notch
Source image distance of 100cm (vs 180cm)
The heart will appear larger because of decreases source-image distance and increase object image distance
Pleural effusion will obscure vascular markings
Inspiration will not be as full – 8-9 posterior ribs
Lungs will appear more dense because of decreased aeration

4. Lateral chest (left)
Left side against IR with arms crossed above head or holding arm support
Technical
kV , 6mAs
Central ray
Perdendicular on level of T7
Source image distance of 180cm
If patient cannot stand, he/she can sit on trolley/wheelchair against IR

5. AP lordotic projection
Lateral decubitus
Demonstrates small pleural fluid or air collections
For air the affected side most be up
For fluid the affected side must be down
AP lordotic projection
Performed primarily to rule out masses and calcifications beneath the clavivles
Patient stands 30cm away from IR, leaning back, with shoulders, back and neck against IR
Central ray perpendicular to IR 9cm below jugular notch
If patient is too weak/ unable to take this position
AP semi-axial projection
Patient supine AP with central ray angled degrees cephelad
Clavicles appear nearly horizontal with medial ends superimposed over 1st ribs

6. Anterior oblique positions (RAO/ LAO)
Ribs, pathology in lung fields or mediastinum
Left or right shoulder against IR with angle of 45 degrees
Arm nearest IR flexed on hip with palm out
Other arm above head
Rest as normal chest XR
For anterior obliques, the side furthest from the IR is usually the side of interest
RAO will best show the left lung
Inspiratory and expiratory CXR
Easier detection of pneomothorax
Doubles cost and radiation dose ; not routinely recommended
Children with suspected foreign body inhilation

7. Properties of a good chest x-ray
Structures shown
Both lung fields included from lung apices to costophrenic angles
Hilum region markings, heart, great vessels
Bony thorax
Postion
Chin sufficiently elevated to prevent superimposition over lung apices
Sufficient forward shoulder rotation to prevent scapulae superimposition over lung fields
Large breast shadows, primarily lateral to lung fields
No rotation
Sternoclavicular joints same distance from centre line of spine
Distance from lateral rib margins to vertebral comlumn the same on each side for upper and lower rib cage
Scoliosis and kyphosis may lead to differences without rotation

8. Properties of a good chest x-ray
Collimation and central ray
Collimation margins near equal on bottom and top
Center of collimation field (CR) at T7
Full inspiration with no motion
10-11 posterior ribs above diaphragm
No motion evident by
Sharp outlines of rib margins, diaphragm and heart borders
Sharp lung markings in hilar regions and throughout lungs
Exposure criteria
Outline of at least upper and mid thoracic vertebra through the cardiac shadow and mediastinal structures
Visualization of fine vascular markings in the lungs

9. Reference list
Bontrager, KL. Textbook of radiographic positioning and related anatomy, 7th Edition. Mosby Elsevier; Chapter 3 : Chest.