Treatment Volumes

Question 1

define treatment volume -

Answer 1

tissue that received the prescribed dose

Question 2

define irradiated volume -

Answer 2

takes into account the healthy tissue in the beam’s path

Question 3

define organs at risk (OARs) -

Answer 3

organs near the PTV that affect the TD (total dose) the tumor will get
-OARs can affect the beam angles too

Question 4

the following is describing which tumor volume?

-ONLY used w/ 4D scans
-incorporates length of the tumor movement related to breathing

Answer 4

ITV -
INTERAL TARGET VOLUME

Question 5

the following is describing which tumor volume?

• CTV + uncertainties
• or ITV + uncertainties

Answer 5

PTV -
PLANNING TARGET VOLUME

Question 6

what does “uncertainties” mean for PTV?

Answer 6

patient movement and set-up

Question 7

the following is describing which tumor volume?

-gross palpable tumor; visible tumor
-smallest tumor volume

Answer 7

GTV -
GROSS TUMOR VOLUME

Question 7

the following is describing which tumor volume?

• GTV + microscopic disease
  -needed for cure; if treating to cure areas with microscopic spread, this volume has to be included

Answer 7

CTV -
CLINICAL TARGET VOLUME

Question 8

T/F: each treatment volume builds upon the last/previous trt volume

Answer 8

TRUE

Question 9

IGRT stands for what?

Answer 9

Image Guided Radiotherapy//Radiation Therapy

Question 10

CTV is GTV + ______________

Answer 10

GTV + microscopic disease

Question 11

IGRT allows for smaller __________

Answer 11

PTV

Question 12

beyond PTV margins there is what 2 volumes?

Answer 12

the 1. Treated Volume (TV) then 2. Irradiated Volume (IV)

Question 13

ideally ___ is the Treated Volume (TV) however that is not always the case

Answer 13

PTV

Question 14

which trt volume is the volume that receives “significant dose”

Answer 14

IV (Irradiated Volume)

Question 15

what is main difference between IV and TV trt volumes?

Answer 15

having to go thru healthy tissue to get to PTV and following path of beam more = IV

whereas TV is –> is focused around PTV more

Question 16

label the following treatment volumes -

–green
–yellow
–blue
–orange
–purple

Answer 16

–green = TV (Treated Volume)
–yellow = GTV
–blue = PTV
–orange = CTV
–purple= IV (Irradiated Volume)

Question 17

remember! to obtain an ITV we need, what?

Answer 17

a 4D scan!

Question 18

a ___ scan captures information as the patient is breathing

Answer 18

4D

Question 19

describe more in depth a 4D scan process -

Answer 19

during a 4D scan, multiple images are taken at the same slice at different phases of breathing.
(ie. breathing in/out)

all this is allowing for the planner to see how the tumor moves as the pat. breathes

Question 20

ITV takes into consideration the entire ___ of motion the tumor will travel to encompass it in it’s treatment volume

Answer 20

length of motion

Question 21

OAR stands for what?

Answer 21

Organs at Risk

Question 22

what is the most RADIOSENSITIVE organ?

Answer 22

lens at 10 Gy // 1000 cGy –TD 5/5

Question 23

what is the most RADIORESISTANT organ?

Answer 23

bladder at 65 Gy // 6500 cGy – TD 5/5

Question 24

what does TMJ stand for?

*hint anatomy

Answer 24

Temporo-mandibular Joint