proton

Question 1

what is the name for heavy particles

Answer 1

hadrons

Question 2

what is the hadron made up off

Answer 2

3 quarks

Question 3

give 2 examples of a hadron

Answer 3

proton and neutron

Question 4

what is an e- and why

Answer 4

lepton, light particle that cannot be broken down further

Question 5

what can quarks be broken down into

Answer 5

(+)2/3 up-quarks and (-) 1/3 down-quarks

Question 6

what is the quark configuration for neutrons

Answer 6

1 UP quarks and 2 DOWN quarks - therefore neutral charge

Question 7

what is the quark configuration for proton

Answer 7

2 UP quarks and 1 down - therefore positive charge

Question 8

why do protons attracted e- in the body as they pass through

Answer 8

because protons have a + charge and e- are -

Question 9

how fast does a proton travel

Answer 9

2/3 the speed of light

Question 10

why is little dose given out by the proton as it travels through the body

Answer 10

due to its fast speed, e- care not stripped as they are too slow, therefore as dose is given out when an e- is stripped, if few are stripped then little dose is emitted but he proton

Question 11

why does the proton eventually slow/stop

Answer 11

due to the proton slowing down each time it interacts with an e-, meaning as more interactions occur, the proton slows down proportionally until it is stationary

Question 12

what occurs when the proton is stationary

Answer 12

Bragg peak - lots of interactions occur with the proton, meaning nearly all its dose is deposited at this point.

Question 13

how do you ensure the proton reaches the required depth

Answer 13

the initial energy given to the proton will justify the Bragg peak position

Question 14

is there exit dose from proton

Answer 14

yes, however, minimal compared to photon

Question 15

how do you achieve a uniform dose distribution when using protons

Answer 15

By varying the intensity of the protons used during treatment, you can manipulate the depth at which the dose is delivered and therefore, ensure an even dose list. is achieved throughout the tumour

Question 16

name two main areas that protons are used

Answer 16

brain
paediatrics

Question 17

what is the name of the proton particle accelerator

Answer 17

cyclotron

Question 18

brief concept of a cyclotron (4 main points)

Answer 18

accelerating charged particles
guided in circular orbits
created by a magnetic field
with incremental increases in energy

Question 19

what is an ion source

Answer 19

provides a source of charged particles by ionising hydrogen gas within cyclotron

Question 20

what does RF power source do

Answer 20

provides alternating potential different to Dee electrodes

Question 21

what does the magnet do in cyclotron

Answer 21

provides magnetic field

Question 22

what is the purpose of the 2 Dee electrodes

Answer 22

provide an acceleration gap between the 2

Question 23

what is a vaccum tank in a cyclotron

Answer 23

the vaccum all components sit within

Question 24

what is an electrostatic deflector in cyclotron

Answer 24

A channel of negative energy so positive protons follow this path when at sufficient energy and can leave the cyclotron

Question 25

what is the water cooling system of a cyclotron

Answer 25

to dissipate heat of machine

Question 26

Describe the process of a proton within a cyclotron

Answer 26

2 hollow Dees within cyclotron have alternating voltage A proton is accelerated towards the negative Dee due to opposite charge and repled by the positive Dee due to same charge Once the proton enters the negative Dee the magnetic field that has been created by the magnets above and below, causes the proton to move in a cyclical motion, Turing the proton back around to face the gap The potential difference between the Dees is then alternated Meaning the proton is accelerated across the gap towards the negative Dee due to attraction and is repelled from the positive Dee. Magnetic field created causes proton to continue in a cyclical motion and repeat the process until it is accelerating at a high speed. Once the required speed is reached the proton can exit the cyclotron via a negatively charged channel - Electrostatic deflector.

Question 27

give 4 practical challenges of proton therapy

Answer 27

1. 1 cyclotron sources 3 gantrys - requires lots of planning and management and 1 delayed machine may affect them all 2. extremely expensive 3.postcode lottery 4. staff training - not taught to students at university ( can be a positive however, as encourages career progression)