Nuclear medicine 1

Question 1

what is tomography

Answer 1

slices that can be obtained

Question 2

what kind of rays are used

Answer 2

gamma rays

Question 3

what does PET stand for

Answer 3

positron-emission tomography

Question 4

why do we use gamma rays

Answer 4

• not absorbed in patient
• high energy

Question 5

how much KeV does technetium 99m produce

Answer 5

140 KeV

Question 6

how much KeV dos PET use

Answer 6

511 KeV

Question 7

where does radiation come from

Answer 7

radioactive tracers that have been injected into the patient (radioactive isotopes)

Question 8

what happens when tracer is injected

Answer 8

• radiation is emitted continuously
• gradually decreases depending on half life

Question 9

functional applications of radionuclide imaging

Answer 9

• shoes metabolic process and disease changes
• nuclear med can identify changes in disease/ recurrence of disease after treatment

Question 10

practical applications of radionuclide imaging

Answer 10

• brain (stroke/ alzheimer’s)
• oncology (metastasis/ cancers)
• renal function
• cardiac heart muscle function/ infarction
• pulmonary embolism

Question 11

what makes a radioisotope

Answer 11

increased number of neutrons will make nucleus unstable

Question 12

how does a nucleus regain stability

Answer 12

emits gamma rays

Question 13

what is ejected during alpha decay

Answer 13

• 2 neutrons
• 2 protons
  (helium)

Question 14

what is isomeric transition

Answer 14

can occur through internal conversion
- nucleus is an excited state and undergoes transition to a lower-energy isomeric state by emitting gamma ray protons

Question 15

what is electron capture

Answer 15

orbital electron captured by nucleus and combines with proton to form a neutron

Question 16

what is a neutron called after an electron combines with a proton

Answer 16

neutrino

Question 17

what happens when electron combines with proton

Answer 17

neutrino emitted from nucleus and carries away some energy
- remaining energy appears in form of x-rays

Question 18

advantages of radionuclide imaging

Answer 18

• tracers give functional information about physiology molecular transport
• relatively easy to give in small volumes
• can merge functional images with anatomical ones

Question 19

hybrid imaging

Answer 19

functional images merged with anatomical ones

Question 20

3 broad classes of scanner

Answer 20

• planar RNI - 2D images using single gamma camera
• SPECT - sectional 3D RNI
• PET

Question 21

what does SPECT stand for

Answer 21

single photon emission imaging

Question 22

problems associated with gamma rays

Answer 22

• tend to pass through things
• cant focus
• also emitted in nature
• ionising radiation cause radiation dose

Question 23

what are modern gamma cameras

Answer 23

detect gamma rays emitted by radioactive tracers within body allowing for visualisation of organ function and identification of abnormalitiesw

Question 24

what do modern gamma cameras use

Answer 24

cadmium zinc telluride (CZT)
- solid state detectors offer improved energy resolution and sensitivity compared to traditional scintillation crystals

Question 25

what kind of tracer does bone scan use and why

Answer 25

Tc-99m has a strong affinity for bone tissue
- phosphate

Question 26

process of bone scanning

Answer 26

• inject phosphate based tracer
• 2-4 hours wait
• image
• table moves between camera heads
• software removes blurring
• 20 minutes