2. Overview of Skeletal
Imaging
Review of Skeletal
System
Clinical Indications
Radiopharmaceutical
used
Dosage &
Administration
Technique
The Normal Scan
Artifacts & Pitfalls
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3. What do they all have in common…?
• A 65 year old lady, after total hip
replacement, now with persistent hip pain
and doubtful x-rays
• An 18 year old basketball player with
burning pain in the foot despite negative
foot x-rays
• A 45 year old breast cancer patient with
recent unexplained back and hip pain.
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4. ….a visit to the Nuclear Medicine
department for a:
Bone Scintigraphy
(Bone scan)
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5. The Skeletal System
• Axial skeleton
• Skull
• Vertebral column
• Thorax
• Appendicular skeleton
• Shoulder girdle
• Arms
• Pelvic girdle
• Legs
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Review of Skeletal System
14. • Detect/stage metastatic disease & follow-up
• Evaluate primary bone neoplasms
• Evaluate inflammatory vs. infectious diseases
• Evaluate bone pain in pt with normal radiographs
• Investigate unexplained, increased alkaline
phosphatase levels (enzyme used by osteoblasts to
lay down bone matrix)
• Assess bone graft viability, infarction or aseptic
necrosis
• Assess prosthetic joints for infection or loosening
• Evaluation of roentgenologically difficult fractures
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Clinical Indications
15. Radiopharmaceutical used
Generic name Chemical name
• Tc-99m medronate Methylene
(technetium) Di Phosphonate
(MDP)
• Tc-99m oxidronate HydroxyMethylene
DiphosPhonate
(HDP or HMDP)
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Mechanism of uptake - Chemisorption
16. • Pediatrics by weight : Recommended
• 0.25 mCi/kg (pediatric dose)
Young’s rule or Webster’s rule for pediatric dosage
calculation:
Age in years + 1
Age in years + 7
Dosage
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Dosage & Administration
X Adult dose
20 – 30 mCi (adult dose) ( MBq)740 –1110
19. Patient preparations (after arrival)
• Identify the patient; verify the
physician’s order; review the clinical
indication for the exam
• Explain exam to patient; obtain
relevant medical history
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Technique
20. Relevant Medical History
• Bone pain
• Trauma/fracture
• Arthritis
• Medications/dietary
supplements
• Surgery
• Malignancies
• Biopsy/pathology
• Radiation/chemotherapy
• Kidney/bladder problems
• Recent dental work
• Chronic health problems
• Other medical imaging
results
• Pregnancy status
• Lab results
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Technique
21. Patient Preparation
• Radiopharmaceutical
clearance depends on
several factors, including:
• Age
• Renal status
• Ideal wait time:
• 2 to 3 hours post inj
• Immediately before
imaging:
- remove attenuating
materials
- patient should void
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Technique
22. Imaging the patient
Use one of the following imaging
techniques:
- Static studies
- Dynamic studies
- Multiphase studies (with 3-phase/
4-phase)
- Tomographic studies (SPECT)
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Technique
23. Static studies
• Time delay post tracer injection
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• Preset total counts or time
• Whole body vs limited (“spot” view)
- Imaging localized concentration of
radiopharmaceutical in the body
Technique
24. Dynamic Studies (Flow)
- Multiple sequential Imaging of
nonlocalized radioactivity in the body
usually yielding functional data
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Technique
(as in imaging blood flow, gastric emptying, kidney filtration, etc)
25. Multiphase Studies
• 3-Phase Study
Imaging in the following sequence:
1) Immediate flow dynamic images
2) Early (5-15min) static image(s)
3) Delayed (3-4hr) static image(s)
• 4-Phase Study: 3-phase study plus a 24 hour
delayed image
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Technique
27. Bone SPECT
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Technique
(single photon emission computed tomography)
• Multiple planar images taken around
the body (projections)
Planar vs. Tomographic
Mathematically reconstructs 3-D volume from
projection data using a computer
28. Bone SPECT (continued..)
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Transverse Slices (Top -> Bottom)
Sagittal Slices (Right -> Left)
Coronal Slices (Front -> Back)
Technique
The projection images are used
to reconstruct slices in 3
different planes using computer
29. Bone SPECT Continued…
Advantages & Disadvantages
• Improves lesion detection
• Better localizes abnormality suspected in
planar images
• Most valuable in complex bony structures
• Time consuming
• Patient discomfort
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Technique
30. Normal Adult
• Symmetry
• Increased tracer
concentration in the
following areas:
• nasopharynx
• sternum
• shoulder joints
• anterior iliac crests
• Posterior S.I. Joints
• Visualization of
kidneys/bladder
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The Normal Scan
31. “Super Scan”
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There is minimal soft-tissue
activity and virtually no renal
or bladder activity. This
pattern is indicative of
diffuse bone metastases
and is often referred to as a
superscan.
Also associated with:
-certain metabolic bone
diseases
- abnormally extended delay
before imaging
Radiographics. 2003;23:341-358
32. Normal Child
• Tracer distribution is
age dependent
• In addition to areas listed
for adults, increased activity
also noted in areas of bone
growth:
– epiphyseal plates
– costochondral
junctions
The Normal Scan
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33. Bone Scintigraphy – Sensitivity vs.
Specificity
Nuclear medicine bone imaging is very sensitive to
pathologic changes in bone physiology (eg., bone
destruction, changes in perfusion), but it is not
specific for a particular disease.
Greater specificity is achieved by gathering more data
about the patient such as clinical symptoms or the
results of other diagnostic tests.
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The Abnormal Scan
34. Bone uptake principles
• Recall that the skeleton undergoes constant
remodeling
• Radiopharmaceutical uptake in the bone is
proportional to blood flow, bone mass, and
metabolic activity
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The Abnormal Scan
Pathology: - Increased tracer uptake (“hot spots”)
- Decreased tracer uptake (“cold spots”
or photopenia)
35. Pathology Manifestations
Pathological conditions
causing Increased Uptake
Neoplastic disease
Trauma sites
Metabolic bone disease
Degenerative bone
disease
Inflammatory bone
disease
Pathological conditions
causing Decreased Uptake
Radiation injury
Avascular necrosis
Cyst
Multiple myeloma
Fluid collections
The Abnormal Scan
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36. Extraosseous Activity
• Renal anatomy & abnormalities
• Acute myocardial infarction
• Soft tissue inflammation
• Neoplastic soft tissue tumors
• Normal female breasts
• Amyloidosis
SPECT image shows pedicle uptake to
be more superficial in overlying soft
tissue (arrow). Patient had received
injections of antiinflammatory drugs at
this site a few weeks before scan.
Artifacts & Pitfalls
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38. Evaluate images for technical quality
Urine contamination
Attenuation artifacts
Patient positioning
Tracer extravasation (infiltration)
Other artifacts (radiopharmaceutical, equipment, patient)
Artifacts & Pitfalls
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Was image acquired at correct time
following tracer administration?
• Check radiopharmaceutical distribution
• Look for soft tissue/blood clearance
Is the radiopharmaceutical distribution
as expected?
• Normal biodistribution
• Pathology
• Patient preparation
Does the image include all relevant
anatomy?
• Patient/camera positioning
Was the patient positioned correctly?
• Relevant anatomy
• Correct positioning
Were the correct acquisition parameters
used?
• Collimator
• Static vs dynamic
• Total counts, time or framing rate
• Acquisition matrix (spatial resolution)
Are the images displayed and labeled
correctly?
• Format
• Media (film, laser paper, workstation monitor)
Are there any artifacts that need to be explained
or removed (require image to be repeated)?
