Nuc Medicine

Question 1

what is so different about nuclear medicine than other imaging modalities?

Answer 1

focus is on physiological function rather than anatomy

Functional MRI
CT/MR enterography
Doppler ultrasound
also have functional components

Question 2

T-F nuclear imaging the body is imaged from the outside in?

Answer 2

false- inside out

Question 3

T-F- side effects are very common in nuclear medicine?

Answer 3

false- extremely rare

radiation effects are so small they can not be measured

Question 4

what is the most commonly used compound in nuclear medicine? what is its half life? what is special about it.

Answer 4

technetium 99m

6 hours

readily combines with various compounds

Question 5

What iodine isotope is used for imaging? treatment?

Answer 5

123 imaging or uptake studies for thyroid

131- high energy, destroys tissue

Question 6

The following is a list of common studies for nuclear medicine

Answer 6

Ventilation/Perfusion (V/Q)
Myocardial Perfusion Imaging
Renal scan
Hepatobiliary and spleen imaging
GI bleeding 
Meckel’s diverticulum scan
GI motility study
Infection imaging 
Thyroid/parathyroid imaging
Skeletal imaging
Imaging of neuroendocrine tumors
Lymphoscintigraphy
FDG-PET

Question 7

T-F- skeletal seeking radiotracers depict osteoclastic activity and regional blood flow to bone? Is it specific?

Answer 7

false- osteoblastic

Non-specific: any cause of increased osteoblastic activity will lead to abnormal tracer uptake. However, it is highly sensitive.

Question 8

What are common bone scan indications?

Answer 8

malignancy (not multiple myeloma)
fractures
osteomyelitis (three phase scan)
benign bone tumors
Paget's

Question 9

Is a dexa scan a bone scan?

Answer 9

no- it uses x-rays to determine bone density

Question 10

If a child has knee pain and it lights up on bone scan, what should we be thinking?

Answer 10

osteomyelitis

Question 11

what should we think on a bone scan of vertical hot spots along the ribs?

Answer 11

multiple fractures likely trauma and very unusual for metastatic disease

Question 12

on bone scan what should we think with a hot spot then a thickened hot streak going up the shin line

Answer 12

shin splints

Question 13

on bone scan what should we think if there is a ton of bone looking material and mishaping an entire limb?

Answer 13

paget’s

Question 14

Indium111 tagged WBC is used when?>

Answer 14

May be performed when infectious source cannot be determined

Then get more specific imaging

if uptake in LLQ think diverticulosis

Question 15

Defects on VQ scan can be caused by pneumonia- so what else do we need to get

Answer 15

x-ray

Question 16

myocardial perfusion imaging uses what predominantly?

Answer 16

Tc-99m tetrofosmin

Question 17

review indications for myocardial perfusion imaging-

Answer 17

• Diagnosis of CAD (patient who might benefit from revascularization therapy)
• Diagnosis of acute MI
• Risk stratification after infarction
• Assessment of viable myocardium vs. scar in patients with chronic CAD
• Preoperative cardiac risk assessment

Question 18

On cardiac perfusion what side is septal on?

Answer 18

left and lateral is on right

base is away from apex

Question 19

in myocardial perfusion reversible defect- what is bright and what is dark?

Answer 19

stress= dark
rest= light

Question 20

What methodology gives the most info about esophageal gastric and intestinal motility

Answer 20

radionuclide scans

Question 21

Hepatobiliary imaging uses what chemical?

Answer 21

Tc-99 iinodiacetic acid

dame uptake and transport as bilirubin- dependent on hepatic function

Question 22

on nuclear imaging of hepatobiliary system what are signs of acute cholecystitis?

Answer 22

no gallbladder filling
dilated intrahepatic ducts
dilated CBD
normal bowel excretion

Question 23

What are the two major diagnostic imaging modalities for acute cholecystitis/

Answer 23

US and cholescintigraphy

US sens and spec.> 90%

Question 24

Review the TC-99m HIDA scan

Answer 24

Non-visualization (non-filling) of the GB by 60 minutes = cholecystitis

Then extend study for up to 4 hours

Non-visualization at 4 hours = ACUTE cholecystitis

If the gallbladder fills between 1 and 4 hours = possible CHRONIC cholecystitis

Can’t wait 4 hours? Use morphine

Question 25

What is the point of morphine augmentationcholescintigraphy?

Answer 25

If patient is acutely ill you can’t always wait for a full 3-4 hrs.

Morphine is an alternative to delayed imaging, given at 60 mins

Morphine causes increased intraluminal pressure by constricting sphincter of Oddi  10-fold increase in resting CBD pressure

The goal is to preferentially get bile flow to and through cystic duct, if patent

Question 26

PETs measurement of decay is based on the annihilation reaction between what? what then happens

Answer 26

positron and a tissue electron–> 2 photons created in the reaction travel away from each other and simultaneously sensed by detectors. detection reveals their line of origin–> 3D