PET

Question 1

What is PET?

Answer 1

• position emission tomography

- used for oncology, cardiology, infection and neurology

Question 2

How does PET work?

Answer 2

• hydrogen ions are accelerated in a cyclotron and is ejected and hits different targets such as carbon but most commonly fluorine
• unstable fluorine emits positron
• positron and electron meet and gama ray is made (only rays at 180 to each other are detected)
• 1H+ to 1 target molecule to 1 electron to 2 gama rays to ring of detection

Question 3

Why does patient blood sugar level effect scan?

Answer 3

• too much sugar = body will discrete
• too little sugar = all body will uptake
• normal 4-10milimol is good for showing cancer uptake (fasting for 6hrs prior)

Question 4

Why do you have to wait for PET after RT?

Answer 4

• 6 weeks is not okay as the good cells are still dead/repairing

Question 5

What is the normal bio distribution of fluorine?

Answer 5

• brain
• kidneys and bladder
• liver and spleen
• heart
• skeletal muscle
• bone marrow
• thyroid

Question 6

What are the steps for performing a PET?

Answer 6

• prepare radiopharmaceutical
• prepare the patient
• inject the patient
• scan the patient
• discharge the patient

Question 7

What is brown fat?

Answer 7

• uptake of muscle due to shivering when cold

Question 8

What is the importance of CT in PET?

Answer 8

• ct provides attenuation correction

- precisely localise pathology

Question 9

What is the Ga68 Donate Study?

Answer 9

• new diagnosis, treatment response and relapse for neuroendocrine tumours
• use agent that binds to somatostatin receptor
• fasting not required as not metabolic response

Question 10

What is the Ga68 PSMA study?

Answer 10

• used for prostate and renal cell carcinoma

- hydrate to dilate urin to visualise metastasis

Question 11

What are consideration to imaging?

Answer 11

• patient size and age
• contraindications
• presence of metal
• claustrophobia
• patient compliance
• pregnancy
• radiation exposure
• room set up

Question 12

What is theranostics?

Answer 12

• radionuclide agent to assess disease and then use closely related agent to treat
• radio iodine used to diagnose and treat thyroid cancer
• if all cells uptake then a positive outcome is achieved