Nuclear

Question 1

basic steps of nuclear

Answer 1

a suitable radiopharmaceutical is introduced to the patient
the radiopharmaceutical is allowed to concentrate in a a specific organ
rhe organ is scanned using an appropriate scanner

Question 2

functions of NM

Answer 2

• Physiological measurement
• Lung, heart, kidney, bone
• Diagnosis of primary tumours
• Diagnosis of secondary tumours (metastases)
• Radionuclide therapy

2D- planar imaging technique

3D- SPECT and PET

Question 3

overview of spect

Answer 3

Single photon emission computed tomography
Uses similar / same radiopharmaceuticals as 2D imaging
e.g. technetium based
Mode of acquisition changes
i.e. how the data is acquired and processed
Cross-sectional imaging

Question 4

radioisotope

Answer 4

any isotope which is radioactive

Question 5

isotope

Answer 5

any nucleus which contains the same atomic number as the given nucleus but different mass number

Question 6

unstable nucleus

Answer 6

the strong nuclear forces do not generate enough NBE to hold the nucleus together permanently
unstable nucleus tend to attain stability by emitting extra energy in the form of radiation and convert into stable nucleus to lower energy - process called radioactive decay

Question 7

what is alpha decay

Answer 7

spontaneous emission of an alpha particle
the nucleus should have an A>150 and must have too few neutrons for the number of protons
they have a short-range in tissues so have little pratical applications

Question 8

what is beta decay

Answer 8

nucleus should contain too many neurons
conversion of neutrons to protons and vice versa
a particle having a mass equal to that of an electron is ejected from nucleus
the particle can have either a positive (positron) or negative charge (negatron)

Question 9

what is gamma decay

Answer 9

gamma ray emission

Question 10

What is the difference between Gamma ray emission and alpha or beta decay

Answer 10

Gamma ray emission (not particulate like alpha or beta decay

Question 11

The physical half-life of Technetium-99 metastable is 6 h. How much activity is needed at 9 am if 80 MBq is needed at 9 am next day?

A.2000 MBq

B.1280 MBq

C.320 MBq

D.160MBq

Answer 11

B.1280 MBq

Question 12

Which of the following radiopharmaceuticals is useful in positron emission tomography (PET) scan for detecting malignant tumours?

A.Technetium 99m DTPA

B.18-Fluorodeoxyglucose

C.Technetium 99m Pertechnetate

D.Technetium 99m HIDA

Answer 12

B.18-Fluorodeoxyglucose

Question 13

What is technetium

Answer 13

•Technetium is an radioisotope (gamma ray emitter) and DTPA is excreted by kidneys and hence allows the measurement of renal function (DTPA scan or renogram)

Question 14

Describe the detector from a gamma camera

Answer 14

• Scintillation crystal
• Usually sodium iodide crystal doped with thallium
• Converts gamma radiation into visible light
• Inefficient process

About 10% of incident gamma radiation converted to light

Question 15

Define Effective half-life

Answer 15

is the time taken for the activity of a certain radionuclide in a certain organ to be reduced to half of its original activity.

•1/t1/2(eff)=1/t1/2(phys)+ 1/t1/2(bio)

Question 16

Define Biological half-life

Answer 16

•is the time taken for the concentration of a certain chemical in an organ to be reduced to half its original concentration.

Question 17

ideal isotopes should have

Answer 17

a short half life
emit gamma-rays of relatively low energy
emit no particles
be added to the pharmaceutical without altering its chemical energy
be readily excreted
be easily generated

Question 18

what gamma rays are only deteced

Answer 18

only ones perpendicular to the detector as best quality

Question 19

high sensitvity

Answer 19

photomultipliers further apart

get as many rays as possibe

Question 20

high resolution

Answer 20

photomultipliers closer together

only get good quality rays

Question 21

what is the gamma ray detector made up of

Answer 21

scinillation crystals
usually sodium iodide crystal with thallium
converts gamma radiation into visible light
inefficient process - about 10% of incident gamma radiaition converted to light

Question 22

the photomultiplier tube

Answer 22

makes the detector more efficient
mulitplier small light beam into lots of electrons
light beam hits cathode, generating electron, electron hits dynode which produces more electrons
electrons get to anode

Question 23

overview of PET

Answer 23

PET (Positron emission tomography)
Different pharmaceutical to planar and SPECT imaging
FDG (Flurodeoxygluocose) (18
Radiopharmaceuticals decay by the emission of positrons
Annihilation – positron travels a few mm then interacts with an electron
Two gamma photons are emitted (511 keV)
1800 opposed to each other
The camera detects gamma rays to produce the image

Question 24

overview of SPECT

Answer 24

Single photon emission computed tomography
Uses similar / same radiopharmaceuticals as 2D imaging
e.g. technetium based
Mode of acquisition changes
i.e. how the data is acquired and processed
Cross-sectional imaging

Question 25

role of nucelar

Answer 25

physioloical measurements
lung, heart, kindeys and bones
diagnosis of primary tumors
diagnosis of secondary tumors

Question 26

use on bones

Answer 26

cancer staging
inject radionucleotide which is taken up by osteoclasts
send them away for 2-3 hours, ask them to drink lots
scan

Question 27

use in lungs

Answer 27

perfusion and ventilation imaging

pulmonary embolism

Question 28

use in GI

Answer 28

Gi bleeds 
gastric emptying 
gastric reflux 
gall bladder 
bile

Question 29

use in heart

Answer 29

disease

• MI
• ischemia
• at exercsie and rest
  
  • planes and SPECT images

Question 30

use in neurology

Answer 30

cerebral perfusion imaging
dopmaine receptor imaging
tumors
lympathetic system and lymph nodes