radiation safety and parts of accelerator

Question 1

suoerficial xrays kv

Answer 1

40-100

Question 2

superficial xrays can treat to what depth

Answer 2

.5cm

Question 3

dose orthovoltage

Answer 3

100-300kv

Question 4

superficial xrays use HVL of?

orthovoltage uses HVL of ?

Answer 4

superficiAL- AL

orthovoltage- Cu`

Question 5

ssd of orthovoltage

Answer 5

50cm

Question 6

what depth can orthovoltage be treated to

Answer 6

2-3cm

Question 7

whats the accelerating waveguide

Answer 7

a hollow tube that allows ekectrons to be accelerated after the cathode until they leave the waveguide

Question 8

what components are in the drive stand

Answer 8

klysteon, cooling system, waveguie and circulator

Question 9

i provide microwave power to accelerate electrons

Answer 9

klystron

Question 10

what does klystron do

Answer 10

provides microwave power to accelerate elctrons

Question 11

i stop microwaves from returning to the klystron

Answer 11

circulator

Question 12

circulator is between ____ and _____

Answer 12

klystron and waveguide

Question 13

what does circulator do

Answer 13

it acts like a valve and directs microwave from klystron to the waveguide and prevents microwaves from returning to the klystron

Question 14

components of the gantry

Answer 14

electron gun, accelerator structure and treatment heasd

Question 15

______ produces electrons and injecs them into th accelerator structure

Answer 15

electron gun

Question 16

shape and material of linac cathode

Answer 16

tungdten that is sphere shape

Question 17

2 types of accelerator waveguides

Answer 17

can be vertical or horizontal

Question 18

when is vertical vs horizontal waveguides

Answer 18

vertical, are shorter distance and poduces lower energy in treament machine
horizontal is longer and produces higher energies and longer distance

Question 19

whta is in the treatment head for photons

Answer 19

bending magnet, x ray target, primary collimator, beam flattening filter, ion chamber and secondary collimator

Question 20

what part of the LINAC limits th3e FS

Answer 20

primary collimator

Question 21

benading magnet

Answer 21

may bend electrons through eledctrons 90-270 degrees onto x ray target

Question 22

after electrons leave bending magnet where do electrons go

Answer 22

go to primary collimator

Question 23

what is in the tx machine for photons thats not used for eledctrons

Answer 23

the target and beam flattening filter are in field when treating photons

Question 24

what is in the treatment head for electrons but not photons

Answer 24

eledctrons use 1-2 scattering foils and remove target

Question 25

what is located on the carousel

Answer 25

beam flattening filter (for photons) | and scattering foils for electrons

Question 26

what does beam flattning filter do in terms of treating a photon field

Answer 26

imorives dose uniformity | more photons absorbed from central axis than from the periphery of the beam

Question 27

1st vs second scattering foil

Answer 27

used for eldctrons the first fol is used to mak pencil beam into usable beam the second foil is used to beam more uniform

Question 28

how much bremstralung contamination is in elctron beam

Answer 28

<5% of thed beam

Question 29

how many leaves are in MLCs in LINAC

Answer 29

52-160

Question 30

percentaged of leakage

Answer 30

2.5-4%

Question 31

what is used in arm of an EPID

Answer 31

amophorus silicon

Question 32

where does the electron go after the bending magnet

Answer 32

goes to the target (in photons) and to the scattering foil in electrons

Question 33

creation of photons

Answer 33

1- klystron creates electrons 2-wave guide brings electrons from klystron to electron gun 3-electron gun injects electrons to accelerator guide 4-accelerator guide makes electrons in straight line 5-electrons acclerated to speed of light 6-hits bending magnet to 270 degrees 7-e beams hits target in photons or scattering foil in electron 8- collimator shapre xray beam 9-tx pt

Question 34

what is typically used for shielding

Answer 34

Pb

Question 35

what materials are used ot shield when compton is primary interaction

Answer 35

concrete or steel

Question 36

what is traditional personel monitoring system

Answer 36

film monitor

Question 37

how do film monotors measure dose

Answer 37

they havea film pack which once developed are cmopared to non exposed areas by someone with light densimoter

Question 38

what is cons of film monitors

Answer 38

not super accurate, is an estimated dose | artifacts occur when exposed to heat and humidity

Question 39

pros of film monitors

Answer 39

cheap

Question 40

what is used in TLD

Answer 40

Crystaline sustance | LiF

Question 41

How are TLD measured

Answer 41

composed of crystalin substance when crystak is heated electrons return to initial state and dose received is proportional to damage of the crystal substqance

Question 42

what is the cons of TLD

Answer 42

Can only have reading done once

Question 43

what dosimeter is best for personel monitoring now

Answer 43

osl

Question 44

what dosimeters use crystals

Answer 44

TLD and OSL

Question 45

What devices measure PERSONEL monitoring

Answer 45

TLD, OSL and film monitor

Question 46

what dosimiter is best at finding contamination XRT or low level XRT

Answer 46

geiger muller counter

Question 47

what is the clicking detector

Answer 47

geiger muller

Question 48

whatXRT detector can directly and immediately give quantitative dose info

Answer 48

ion chamber

Question 49

what is con of GM counter

Answer 49

does not give specific quantitative dose

Question 50

GM counter uses what to detect XRT

Answer 50

gas filled tube

Question 51

what XRT detector is used for brachytherapy

Answer 51

GM is used in HDR tx room to find lost sources asnd confirm no contamination

Question 52

what detector is used in nuc med imaging

Answer 52

scintilation detectors

Question 53

what detectors are event or pulse detectors

Answer 53

GM detectors and scintilation detectors

Question 54

what crystals ae used in scintilation detectors

Answer 54

NaI

Question 55

when the scintilation detector stops working what does this indicate

Answer 55

a v large xrt field

Question 56

what detector uses crystals for radiation measurement

Answer 56

scintilation detectors for XRT expsoure, and TLD and OSL for personel monitoring

Question 57

occupational exposure of the lens oF the eye anually

Answer 57

150mSv

Question 58

occupational exposure of b.m, breast, lung, gonad, skin, extremity

Answer 58

500mSv

Question 59

ft of shielding primary and secondary barrier for 6mv

Answer 59

primary 6 f secondary 3-4ft

Question 60

ft of shielding primary and secondary barrier for 15Mv

Answer 60

pimary 7-9 ft | secondary 4-5ft

Question 61

activity is defined as

Answer 61

radiactiv disintegrations/ time

Question 62

xposure is defined as

Answer 62

``` only for photons # ionization / photons unit mass of air ```

Question 63

asorbed dose is defined as

Answer 63

energy absorbed / mass of any material

Question 64

largest contribution of internal radiation

Answer 64

potassium

Question 65

what is alpha beta ratio for arly responding tissus

Answer 65

10

Question 66

what is alpha beta ratio for late responding tissues

Answer 66

3.5

Question 67

what test is required t=packages with >1mci and half life of 30 days

Answer 67

wipe test

Question 68

what dose and half life requires wipe tests

Answer 68

>1mCi | 30 days 1/2 life

Question 69

how to dispose of rdioactive waste

Answer 69

sewer system included flushing draining or put it into emptying tank incineration rquires licensing transfer to recipient burial requires special license

Question 70

what methods of radioactive waste disposal requires license

Answer 70

incineration and burial

Question 71

how long should records be maintained about disposal of radioactive waste

Answer 71

3 years

Question 72

shielding around stored radioisotopes should reduce XRT to ?

Answer 72

<2mrem/hr at 1m

Question 73

caution radiation area dose

Answer 73

>5mrem/hr

Question 74

caution high radiation area dose

Answer 74

>100mrem/hr

Question 75

caution grave danger very high XRT area dose

Answer 75

>500cGy/hr

Question 76

whats considered to be the cathode of the linac

Answer 76

electron gun

Question 77

how to find the avg energy of an MV photon beam

Answer 77

its 1/ 3 of the energy of the electron beam

Question 78

_____ sets the maximum FS

Answer 78

primary collimator

Question 79

what part of th LINAC signals for the machine to shut off after the dose has been delivered

Answer 79

ionization chamber

Question 80

the LINAC is presurized with ___ to -risk for electrical breakdown

Answer 80

sf6