Procedures · Head, spine and pelvis3 min read5-question check
Scoliosis series and skeletal survey
Scoliosis: erect and PA to spare breasts and thyroid. Skeletal survey: many collimated images, never one babygram.
Scoliosis series
Scoliosis is a lateral curve of the spine, often in adolescent girls who will have many follow-up exams. It is taken erect to show the curve under body weight. A PA is preferred over an AP. The breasts and thyroid are anterior, so on a PA they sit on the exit side of the beam and get much less dose. Use a long IR or stitched images at a long SID, often 60 to 72 inches. Include the whole thoracic and lumbar spine, with the bottom of the IR 1 to 2 inches below the iliac crests. An erect lateral completes the routine.
Ferguson and bending
The Ferguson method takes two PA images. The first is a standard erect PA. For the second, a block 3 to 4 inches high goes under the foot on the convex side of the curve, and the patient stands without help or rotation. It separates the primary, or structural, curve from the compensatory curve. Lateral bending images are PA or AP views with the patient bending as far as possible to the right, then to the left, with the pelvis still. They show how flexible the curve is, which guides surgical planning.
Skeletal survey
A skeletal survey images the whole skeleton in separate, collimated views. Indications include suspected non-accidental trauma in children, especially under 2, multiple myeloma, and some metastatic disease. For suspected abuse the set is about 20 images: AP and lateral skull, lateral cervical spine, AP and lateral thorax, both rib obliques, AP pelvis, lateral lumbar spine, and frontal views of each humerus, forearm, hand, femur, tibia and foot. A follow-up survey about 2 weeks later shows healing fractures.
Doing it well
One whole-body babygram is never acceptable, because divergence and poor detail hide small fractures. Each part gets its own collimated, marked image. Myeloma lesions are lytic and often do not show on a bone scan, which is why a survey or low-dose CT is used. Move these patients gently, since their bones may break easily. With a child, stay neutral, document carefully, and leave conclusions to the physician.
Clinical Example
A 14-year-old girl comes for a scoliosis follow-up. You take an erect PA instead of an AP to cut breast and thyroid dose, then a second PA with a 3-inch block under the foot on the convex side, as the Ferguson protocol orders.
Common Mistakes
- Taking scoliosis images AP, which puts the breasts and thyroid on the entrance side.
- Placing the Ferguson block on the concave side of the curve.
- Imaging a suspected abuse case with one or two whole-body images.
- Thinking a negative bone scan rules out multiple myeloma.
Why It Matters
The 2027 projection list names the AP or PA and lateral scoliosis views and the bone survey. Expect questions on why scoliosis is shot PA and when a survey is ordered. Ferguson and bending views still appear in many protocols.
Key Relationships
- PA scoliosis → breasts and thyroid on the exit side → lower dose
- Ferguson block on the convex side → primary vs compensatory curve
- Lateral bending → curve flexibility
- Lytic myeloma → may be missed on bone scan → skeletal survey