The document discusses the evolution of radiation therapy techniques for treating prostate cancer. 3D-CRT from 1995 used 4 fixed beams but exposure of nearby organs limited safe dose. IMRT from 2000 used up to 8 beam directions for better targeting but still some rectal/bladder exposure. VMAT since 2009 uses continuous 360-degree arcs for highly conformal dose distribution in only 2 minutes of treatment time, minimizing nearby organ exposure.

1. From 3D - CRT (appeared in 1995-not anymore
“modern” )
•
PROSTATE EXAMPLE
•
Prostate
Overdose
Rectum
3D - CRT
3D - CRT = 3D Conformal Radiation Therapy
Source: Amethyst management
4 beams: 2 AP/PA +2 lateral
beams
Overdosage in bladder /
rectum limits dose which can
be delivered to tumor volume

2. From 3D - CRT to IMRT
•
PROSTATE EXAMPLE
•
With IMRT up to 6-8 beam
directions
Still risk of overdosage in
bladder/ rectum
Target conformity
“Control” of dose
deposition still coarse
3D - CRT
3D - CRT = 3D Conformal Radiation Therapy
IMRT
= Intensity Modulated Radiation Therapy
Source: Amethyst management
IMRT

3. IMRT technology (2000)
PROSTATE EXAMPLE
Target
conformity
•
•
•
IMRT Prostate showing five
beams
Dose distribution better than
the 3D-CRT method but still
high dose in bladder/ rectum
Treatment time of about 10
minutes
“Control” of dose
deposition still
coarse
IMRT
IMRT
= Intensity Modulated Radiation Therapy
Source: Amethyst management

4. VMAT technology (used since 2009*)
•
PROSTATE EXAMPLE
•
Target
conformity
VMAT
VMAT
= Volumetrically Modulated Arc Therapy
Source: Amethyst management
•
Beams, coming from 360
directions
Highly conformal dose
distribtution
Only 2 minutes treatment
time

5. From 3D - CRT to IMRT to VMAT
VMAT demo
Source: Amethyst management