A bone scan is a sensitive imaging test that uses radiopharmaceuticals like Tc-99m MDP to detect areas of bone activity, indicating possible injury or disease. While it's valuable for diagnosing various conditions such as tumors, fractures, and infections, it has limitations including low specificity and high costs. The procedure typically includes whole-body planar imaging, with multiple phases to assess vascular, soft tissue, and bone activity.

3. Definition
• A bone scan is a test that detects areas of
increased or decreased bone activity by
injecting a certain radiopharmaceutical i.e.
Tc-99m MDP. This may indicate bone
injury or disease.

4. SenSitivity anD
Specificity
• Bone scan is very sensitive study but it is not
specific.
• Although findings on bone scan are non-specific,
its monostotic or polyostotic status and
anatomical distribution can provide important
clues to the differential diagnosis.

5. aDvantageS vS DiSaDvantageS
Advantages Disadvantages
 Needs radiopharmaceuticals
& gamma camera not widely
available.
 Low specificity.
 Cost is high.
 Whole-body evaluation in one
test/ same rad exposure.
 Low radiation exposure.
 Sensitive evaluation

6. anatomy

7. RadiophaRmaceuticals
 Bone-seeking agents are analogs of calcium,
phosphates.
Tc-99m Methylene diphosphonate
(Tc-99m MDP)
Tc-99m MDP
The most widely used
Radiopharmaceuticals is
Tc-99m labeled
diphosphonates

8. tc-99m mdp
• Used within 4 hrs after preparation.
• High target/bcg ratio within 2-3 hrs. with
• Rapid renal clearance
• Renal Impairment: increased soft tissue
activity, poor image quality, delayed excretion,
higher radiation exposure due to retained high
activity

9. technique
• Preparation: None
• Injection of Tc-99m 20-25
mCi IV, (250 uCi/Kg) for
children, good hydration
afterwards & frequent
voiding
• Wait for about 2-3 hrs to
start imaging, avoid
contamination
• Empty bladder prior to
scanning
• Change the cloth and remove
things likely cause artifact.

10. pooR image quality
• Renal impairment
• Decreased cardiac output
• Dehydration
• Extravasation of the radiopharamceutical
• Aging.
• Underdosage of the radiopharmacetical.
• Obesity.

11. imaging acquisition

12. Routine Bone scan imaging
• Whole-body planar
imaging in anterior and
posterior projection.
• Additional static images if
required eg. Oblique or
additional spot
views(squat view)

13. • This is the bony phase of bone scan.
• Inject radiopharmaceutical and image in 2-
4 hours.
• When we say bone scan, we usually mean
whole body bone scan.

15. 3-phase bone scan imaging
• Phase 1; Vascular phase: 60 s
dynamic immediately post
injection
• Phase 2; Soft-tissue (blood-
pool) phase: 5 min post
injection.
• Phase 3; Delayed (bone)
phase: 2-3 hr post injection.
Soft-tissue delayed 2-3hr
Vascular phase

16. First phase
• 30-60 dynamic images are usually obtained
over 1 minute immediately after injection.
• This is radionuclide angiography and gives an
idea about the local vasculature. During the
first minute after injection, injected dose is
still intravascular.

17. second phase
• Static image is obtained in 5 minutes after
dose injection.
• Within 5 minutes post injection,
radiopharmaceutical moves from
intravascular space to extravascular space
(soft tissue). It gives idea about soft tissue
edema.

18. blood pool

19. Hyperemia
• If there is focal increased activity in
the first and second phases,
hyperemia or acute inflammatory
process is present.

20. THird pHase
• It is the bony phase image obtained in
2-4 hours post injection.
• It is the same as whole body bone
scan.

21. indicaTions
 Neoplastic disease: Primary bone tumors & Bone metastasis
– Staging for malignancies that have high incidence of bone
metastasis eg. cancers of prostate, breast, lung,
neuroblastoma.
– Unexplained bone pain in a patient with known malignancy (neg X-ray)
– Unexplained bone pain in a patient with no history of
malignancy.
 Trauma: Fracture/ Stress injuries (eg, stress fracture, shin splints).
 Infection:(osteomyelitis)
 Avascular necrosis
 Arthritis:Degenerative changes
 Metabolic & Endocrine disorders: (eg, Paget’s Disease,
Hyperparathyroidism)
 Bone marrow diseases: Sickle cell disease

22. clinical applicaTions
• Malignancy
1- Primary bone cancer
2- Secondary metastatic bone disease
• Osteomyelitis
• Stress fractures

23. THANK YOU