Treatment Volumes Flashcards
define treatment volume -
tissue that received the prescribed dose
define irradiated volume -
takes into account the healthy tissue in the beam’s path
define organs at risk (OARs) -
organs near the PTV that affect the TD (total dose) the tumor will get
-OARs can affect the beam angles too
the following is describing which tumor volume?
-ONLY used w/ 4D scans
-incorporates length of the tumor movement related to breathing
ITV -
INTERAL TARGET VOLUME
the following is describing which tumor volume?
- CTV + uncertainties
- or ITV + uncertainties
PTV -
PLANNING TARGET VOLUME
what does “uncertainties” mean for PTV?
patient movement and set-up
the following is describing which tumor volume?
-gross palpable tumor; visible tumor
-smallest tumor volume
GTV -
GROSS TUMOR VOLUME
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
CTV -
CLINICAL TARGET VOLUME
T/F: each treatment volume builds upon the last/previous trt volume
TRUE
IGRT stands for what?
Image Guided Radiotherapy//Radiation Therapy
CTV is GTV + ______________
GTV + microscopic disease
IGRT allows for smaller __________
PTV
beyond PTV margins there is what 2 volumes?
the 1. Treated Volume (TV) then 2. Irradiated Volume (IV)
ideally ___ is the Treated Volume (TV) however that is not always the case
PTV
which trt volume is the volume that receives “significant dose”
IV (Irradiated Volume)
what is main difference between IV and TV trt volumes?
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
label the following treatment volumes -
–green
–yellow
–blue
–orange
–purple
–green = TV (Treated Volume)
–yellow = GTV
–blue = PTV
–orange = CTV
–purple= IV (Irradiated Volume)
remember! to obtain an ITV we need, what?
a 4D scan!
a ___ scan captures information as the patient is breathing
4D
describe more in depth a 4D scan process -
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
ITV takes into consideration the entire ___ of motion the tumor will travel to encompass it in it’s treatment volume
length of motion
OAR stands for what?
Organs at Risk
what is the most RADIOSENSITIVE organ?
lens at 10 Gy // 1000 cGy –TD 5/5
what is the most RADIORESISTANT organ?
bladder at 65 Gy // 6500 cGy – TD 5/5
what does TMJ stand for?
*hint anatomy
Temporo-mandibular Joint
