Part V

Question 1

fissionable material usually in the core of NR:

Answer 1

Natural Uranium 235; U-238

Question 2

NF of U235

Answer 2

spontaneous NF (7x10^8), splitting into two0 lighter nuclear fragments and emit 2 or 3 neutrons in the process

Question 3

3 components of NR

Answer 3

fuel cells
moderator
control rods

Question 4

contain fissionable material are surrounded by a moderator material

Answer 4

Fuel Cells

Question 5

purpose is to slow down rather energetic fission neutrons

Answer 5

moderator

Question 6

more efficient initiators of additional fission events

Answer 6

slow neutrons (aka thermal neutrons)

Question 7

commonly used moderator

Answer 7

“heavy water”, (containing deuterium) and Graphite

Question 8

positioned to either expose or shield the fuel cells from one another - ABSORB EXCESS NEUTRONS

Answer 8

control rods

Question 9

composition of control rods and reason

Answer 9

Cadmium or Boron - strong neutron absorbers but do not undergo nuclear fission themselves

Question 10

“Runaway” Reaction & possible meltdown of reactor core

Answer 10

if control rods were removed, each fission event would stimulate more that one additional nuclear fission

Question 11

NR produced RN charac:

Answer 11

-neutrons are + = beta emission
-(n, g) reaction - not carrier free
-small target of nuclei activated = v. low specific a.

Question 12

used to accelerate electrically charged subnuclear particles such as PROTONS, DEUTRONS, TRITONS and ALPHA p. to v. high energies

Answer 12

charged particle accelerators

Question 13

Some NR RNs:

Answer 13

N14 (n,p) C14
Na23 (n,g) Na24
P31 (n,g) P32

Question 14

Cyclotron Process

Answer 14

1. has semi-circular Dees
2. Ion source - middle (p) accelerated to v. high energy
3. electric shield on ends of middle to contain ef
4. circular motion bc of mf
5. p gain energy every time it cross the gap
   6.accelerated p hits target creating neutron and desired daughter RN

Question 15

Cylotron produced RN charac:

Answer 15

• • charge added to nucleus = EC & beta + emission
• added + charge change Z = carrier free products
• smaller quantities
  -expensive

Question 16

consists of p-d rn contained in an apparatus that permits separation or extraction of d from p

Answer 16

RN Generator

Question 17

most important generator

Answer 17

Mo-99 -Tc 99m

Question 18

y rad emitted by Tc 99 favorable by anger camera

Answer 18

140 keV

Question 19

Mo 99 column, eluant

Answer 19

alumina column, 5-25 ml normal saline

Question 20

available Tc99m extracted in a single elution

Answer 20

75-85%

Question 21

causes radioactivity

Answer 21

imbalance no. of N and Z - Natural RN
excitation due to bombardment of particles - Artificial RN

Question 22

R. material experience an exponential decay
-DR is the no. of disintegrations occurring each sec

Answer 22

Activity

Question 23

typical Act values in NM

Answer 23

0.1-30 mCi = dx
up to 300 mCI = therapy

Question 24

total no. or nuclear transformations in an organ or tissue
-values are often diff. for healthy and pts with disease

Answer 24

cumulative activity

Question 25

cumulative activity of Tc99m

Answer 25

5.2 x 10 ^6 Ci/g

Question 26

time taken for no. of radioactive atoms to decay by half

Answer 26

half life

Question 27

most important h

Answer 27

effective half life

Question 28

EFH depends on the:

Answer 28

RP Organ Involved Patient Variations Health State of Organ

Question 29

Preferred rn gamma energy released

Answer 29

50-300 keV

Question 30

reason for 50-300 keV

Answer 30

high enuf to exit the pt but low enuf to be collimated and measured

Question 31

reason for mono-energetic y rays

Answer 31

range of PHA is based on energy emitted by RN

Question 32

produce y rad via EC

Answer 32

it will happen if nucleus is still unstable even if it has already captured e

Question 33

cyclotron rns are [..] and thus, decay by [..] or [..]

Answer 33

neutron poor b+ EC

Question 34

neutrons bombard unstable target nuclei

Answer 34

NF

Question 35

neutrons bombard stable target nuclei

Answer 35

NA

Question 36

production of Tc99m

Answer 36

1. NF - 235 U -> Mo 2. Mo in compound (ammonium molybdenate) loaded to column = inorganic alumina resin 3. Adsorption -Mo attaches to alumina molec ;Mo bond with alumina, Tc does not 4. Elution - 99 Mo decays to 99m Tc; eluant -isotonic saline (flush generator - separate d) 5. Mo 99 not soluble to saline, Tc99m soluble-extracted 6. Eluted once daily for 1 wk then replaced; Mo -66 hrs

Question 37

technique mainly used for separation of p-d rn

Answer 37

chemical technique - Column Chromatography

Question 38

types of generators

Answer 38

dry types wet type

Question 39

other name for dry type

Answer 39

manufacturer's method/type

Question 40

separate container of saline solution that is changed every time a new elution will be made. manual inject saline solution

Answer 40

dry type

Question 41

it has a built-in container with enough volume of saline solution for all elutions

Answer 41

wet type

Question 42

activity of d at elution depends on the:

Answer 42

1. act of parent 2. rate of formation of d = to rate of decay of p 3. time since last elution 4. elution efficiency (80 to 90%)

Question 43

Ibritumomab tiuxetan (zevalin) / (bexxar) therapy

Answer 43

non-hodgkin's lymphoma