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.

Question 15

Bone imaging:
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing?

Answer 15

Tc99m HDP
Oncological: primary tumours/mets, non-onc: neoplasm, inflam, bone infarct…
Encourage patients to drink fluids between injection and scan.
WB scan, LEHR / SPECT/CT
Mask bladder

Dark regions show uptake

Question 16

Myocardial perfusion imaging
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 16

Tc-99m-Tetrofosmin
Suspected Ischemia/obstruction stress/rest
Reviewed by cardiac nurse, 7 days prior
Chemical stress - stress first then rest.
ECG Gated SPECT
Bin images by section of the cardiac cycle
Ischemia shown by dark region

Question 17

Ventilation/Perfusion V/Q Lung scanning
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 17

Perf: Tc-99m MAA Vent: technegas / Krypton
Presentation: Suspected PA, shortness of breath
Preparation: If technegas perf act = vent x 3.
SPECT / STATIC LEGP
Check count ratio

Question 18

DaTSCAN
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 18

I-123 Ioflupane
Differentiate Parkinsons/movement disorders or dementia
Admin thyroid blocker
Im 3-6 hours post admin, Im head above the ears
SPECT LEHR
Can quantify or visually observe, dots/commas.

Question 19

Renography
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 19

Tc-99m MAG3
Susp urinary tract blockage
Diuretic (furosemide) admin 15 mins in to imaging
Dynamic planar LEGP + statics (60s)
60 x 1s, 204 x 10s.
Plot uptake/retention over time

Question 20

Renal Cortex Imaging
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 20

99mTc-DMSA
Assessing for cortical defects and scarring.
Planar LEHR 20s frames or SPECT
Draw roi around kidneys
Can assess relative function

Question 21

Cerebral Perfusion
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 21

Tc99m HMPAO
Assess cerebral disease, where functional impairment often precedes structural changes - sus dementia
The patient should avoid caffeine, alcohol and tobacco for 24-hours prior to the examination
SPECT LEHR

Question 22

Bile Acid retention
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 22

75Se 23-seleno-25-homotaurocholic acid (SeHCAT)
chronic unexplained diarrhoea
halt medications which could delay passage of bile salts
intrinsic day 0 day 7 statics
Sum all counts in both images

Question 23

Thyroid scintigraphy
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing

Answer 23

123I-Iodide
thyroid lesions
halt thyroxine medication / avoid high iodine foods
check calibration with thyroid phantom
Planar/SPECT LEHR Im 3 hours after admin
Planar quantification

Question 24

Renal scintigraphy
Tracer?
Presentation?
Preparation?
Imaging? (type, collimator)
Processing?

Answer 24

Tc-99m DMSA
Suspected kidney failure
Administered IV
LEGP
Draw roi around each kidney, plot function
Sum counts retained in each kidney