NM clinical imaging

Question 1

Bone scan protocol

Answer 1

Tc99m MDP

Localises osteoblastic activity, stable,
Quick clearance
Excreted via kidneys
Image at 2-4 hrs

Question 2

Bone indications

Answer 2

Assessment of bone metastases, Paget’s and primary bone tumours.
Prosthesis loosening/infection

Question 3

Osseous mets detection

Answer 3

Good for Breast, Neuroblastoma and Prostate.

Reduced sensitivity for other tumours.

Question 4

Benign lesions detection

Answer 4

Increased uptake in acute fractures and degenerative change

Low uptake can be seen in bone cysts

Question 5

Phases of joint loosening

Answer 5

• Arterial • Blood pool • Delayed

• Infection demonstrates increased uptake on all phases.
• Loosening should only be increased on delayed

Question 6

Process for liver scans

Answer 6

Tc99m HIDA • Hepatocyte uptake, transport and excretion. Activity seen after 60 mins

• Acute cholecystitis • Biliary obstruction • Sphincter of Oddi dysfunction • Gallbladder emptying studies • Biliary leak

Question 7

Types of Renal imaging

Answer 7

MAG3
DTPA
DMSA

Question 8

Describe the MAG3 protocol

Answer 8

To assess drainage and reflux
Tubular secretion

Hydrate patient to improve excretion rate
Early im assess perfusion
30-40 min assess drainage

Question 9

Describe DMSA protocol

Answer 9

To assess relative function and cortical scarring - Cortical binding
Imaging at 2-3hrs – better target to background.
Carried out 3-6 months after stones/infection

Question 10

Describe the Thyroid imaging protocol

Answer 10

Tc99m iv: Trapped by the follicular cells of the thyroid gland, but not organified and therefore not retained – peak imaging 20-30mins.

I123 oral - Retained therefore peak imaging 24hrs hence imaging between 4 and 24hrs - Normal range depends on time of imaging.

Question 11

Describe parathyroid imaging

Answer 11

For the investigation of primary hyperparathyroidism:

• Tc-99m Sestamibi • Rapid uptake and slow release by parathyroid adenomas • Washout vs subtraction

Question 12

Specialist tumour imaging

Answer 12

I123 MIBG (metaiodobenzylguanidine) • Norepinephrine analogue – Uses • Phaeochromocytomas • Neuroblastoma

In 111 Octreotide • Binds to Somatostatin receptors – Uses • Neuroendocrine tumour imaging

Question 13

Describe lung perfusion protocol

Answer 13

• Tc99 MAA (macro aggregated albumin) • Can be used with Ventilation scintigraphy • Trapped in capillary bed at first pass • MAA particle half life 4-6hrs • Blocks approx <1% capillaries

Used to look for pulmonary embolism or emphysema pre-op

Question 14

Describe white cell scanning

Answer 14

For Inflammatory Bowel Disease - labelling process

• Image before 1hr 15mins. Before this bowel activity is less likely to be physiological. • 1hr and 4hr imaging • For infection image at 4hrs with 20hr imaging if needed eg vascular grafts.