Simulator Design and Operation

Question 1

Primary purpose of simulator

Answer 1

levels target volume

collect anatomic info

Question 2

Basoc elements of simulator

Answer 2

• gantry: rotates 360
• PSA (patient support Assembly): couch where pt lays
• x ray tube
• collimater device
• imaging system of fluoro unit
• optical devices: lasers, light field

Question 3

3 parts of treatment palnning

Answer 3

• tumor localization
• computation of dose distributions
• fabrication of treatment aids

Question 4

What is DRR?

Answer 4

digital reconstructed radiograph

Question 5

Set up functions of simulation

Answer 5

• tumor localization

- treatment verification

Question 6

Who determines the extent and localization of tumor

Answer 6

the physician

Question 7

Who sets the isocenter and field margins

Answer 7

dosimetrist

Question 8

designed to simulate the mechanical, geometrical,a dn optical conditions of various treatment untis

Answer 8

conventional sim

Question 9

What is is the tolerance for the gantry angle?

Answer 9

1 degree

Question 10

Mechanical components:

gantry

Answer 10

arm
head
image intensifying/ film holder system

Question 11

360 degrees
rotates along isocenter @ 100 cm
divergent edge
central axis is nondivergent

Answer 11

Gantry

Question 12

patient’s right is always __ degrees

patient’s left is always ___ degrees

Answer 12

270

90

Question 13

Varian machine, top is __ degrees

IEC machine, top is ___ degrees

Answer 13

180

0

Question 14

Gantry head components:

collimator assembly

Answer 14

comprises gantry head and rotates

Question 15

Gantry head components:

ODI

Answer 15

optical distance indicator
number readout
corresponds to SSD/ who deep we are going

Question 16

Gantry head components:

field defining wires

Answer 16

represent diaphragms on machine

Question 17

Gantry head components:

beam restricting diaphragms

Answer 17

determine size of x-ray beam

Question 18

Gantry head components:

fudicial plate

Answer 18

plate with hashmarks, measurement

can also measure magnification

Question 19

Gantry head components:

accessory holder

Answer 19

holds blocks and whatever needed for treatment

distance should be the same

Question 20

OFD

Answer 20

object to field distance

Question 21

SFD

Answer 21

source to film distance

Question 22

TFD

Answer 22

target to film distance

Question 23

SSD

Answer 23

source to skin distance

Question 24

IFD

Answer 24

intrafield distance

Question 25

IT

Answer 25

isocenter to table top

Question 26

Positioning lasers

Answer 26

red or green
for positioning external landmarks (tattoos)
QA lasers

Question 27

Types of Sim:

Answer 27

1. conventional- old method
2. conventional& CT- old method
3. virtual- current method

Question 28

Two main functions of CT sim:

Answer 28

1. target localization and localization of clerical structures
2. have DRR printed out

Question 29

+ of CT sim

Answer 29

• mark patient

- able to transfer data from one system to another

Question 30

multiple sources to get anatomical data for patient

Answer 30

fusion

Question 31

when scan done in diagnostic position& one in treatment position

Answer 31

deformable fusion

Question 32

attenuation rates or tissue density differences displayed as pixels of different shades of gray
range from +1,000 to -1,000
also called CT numbers

Answer 32

Hounsfield Units

Question 33

examples of HU

Answer 33

-1,000: air
0: water
15: CSF
20: blood
40: gray matter
50: muscle
650: bone
+1,000: enamal