clinical practice

Question 1

what is preplanning

Answer 1

consent

Question 2

localisation

Answer 2

scan and tattoos

Question 3

why verify ?

Answer 3

to ensure … patient is in same position

treat what you planned

Question 4

plan is based on

Answer 4

CT scan

Question 5

Set up error … types

Answer 5

systematic error

random error

Question 6

what is systematic error

Answer 6

error is reproducable and consistent.

occurs in same direction

Question 7

what is random error

Answer 7

varies in direction and magnitude for each delivered treatment fraction

Question 8

GTV

Answer 8

Gross target volume … the tumour

Question 9

CTV

Answer 9

clinical target volume .. to account for the microscopic diseases you cant see

Question 10

PTV

Answer 10

planning target volume … to account for set up error

this size depends on what critical structures are near

Question 11

what is a gross error

Answer 11

error of more than 1cm

Question 12

what should the space be inbetween CTV and PTV

Answer 12

0. 5cm

0. 3cm for head and neck

Question 13

what is interfraction motion

Answer 13

target and/or patient move between each fraction

Question 14

what is introfraction motion

Answer 14

target and/or patient move during treatment daily

Question 15

why do we have set up error

Answer 15

poor immobolisation
poor patient positioning
internal organ motion

Question 16

how to reduce errors

Answer 16

vertification

take care in p&im

Question 17

choice of modality depends on…

pt1

Answer 17

technology avail.
treatment site
target positions and dose

Question 18

choice of modality depends on…

pt2

Answer 18

-patient co-morbities
-imm
treatment intent (rad or pal)

Question 19

IGRT

Answer 19

image guided radiation therapy

Question 20

IGRT 2D imaging … used for

what

Answer 20

breast and whole brain

2 pics taken 2gether aka ORTHOGONAL IMAGES

Question 21

IGRT 2D imaging uses

Answer 21

mv image…. can only see soft tissue no bone

Question 22

IGRT volumetric 3D imaging uses

Answer 22

KV or MV image

Question 23

limitation of IGRT 3D

Answer 23

accumlated dose bit higher

takes longer to get (adquire)

Question 24

MV images can be

Answer 24

single or double

Question 25

KV images can image

Answer 25

area close to isocentre

Question 26

properties of kv imaging

Answer 26

mainly seen in RT. department
requires additional software
gives less dose 
improves image clarity
has fluroscopic mode

Question 27

emerging IGRT modalities…Surface guided radiation therapy

no radiation involved

Answer 27

surface tracks

Question 28

what does surface tracking do

Answer 28

• align RT or Vision RT
• Track patient 3D surface in real time
• calculate patients movemnet in all 6 degrees of freedom
• monitor respiratory movement

Question 29

what does seriotactic mean

Answer 29

delivering v high dose

Question 30

CBCT means

Answer 30

cone beam ct

Question 31

what is set up error

Answer 31

inconsistency between planned patient position and patient position on that treatment day

Question 32

less common on treatment

IGRT modalities

Answer 32

high frequency imaging
implated transponders
integrated MR/linac

Question 33

high frequency imaging

example and properties

Answer 33

cyberknife

non-invasive
use tracking software to track tumour position
0.01-20 cGy

Question 34

implanted transponders example

Answer 34

calypso