TECH 99m

Question 1

tech 99m half life?

Answer 1

6 hours

caution in pediatric patients

more cancellous greater than cortical uptake

greater in the axillary

Question 2

When the tracer is complexed with polyphosphates, it creates a great attraction to?

Answer 2

hydroxyapatite crystals

Question 3

Tc99 has no inherent bone affinity, T/F?

Answer 3

T

Question 4

best time to view bone?

Answer 4

2-4 hours post injection

Question 5

What causes a “Hot spot”? What causes a “cold spot”?

Answer 5

Hot = anything that causes bone to remodel. (Sepsis, OM, Fractures, tumors, MBD, HPOA
-“double-strip sign”)

Cold = Loss of blood supply to area. (Avascular necrosis – “Perthe’s Disease, infarction)

Question 6

In a bone scan, you see the “string of lights” sign. What is it? Describe the sensitivity vs. specificity in this case?

Answer 6

Indicates RSD. This is one of the few times in Bone Scanning where specificity > sensitivity.