± º * G JX Ü ¼ 'Qº ¼ -Á p - 大阪大学大学院医学系研究科放射線 ... · PDF file · 2014-02-03| varian oncology systems...

1 | VARIAN ONCOLOGY SYSTEMS

| VARIAN ONCOLOGY SYSTEMS
VarianIMRTIMRT
MLC LMC

VarianIMRT
IAEA
Changes Over Time: ICRU 50 to 62
PRV: Includes margin around the OAR to compensate for changes in shape and internal motion and for set-up variation.
GTV CTV ITV
PTV
TREATED VOLUME
IRRADIATED VOLUME
OAR
PRV
ICRU50/62

| VARIAN ONCOLOGY SYSTEMS | VARIAN ONCOLOGY SYSTEMS
IMRT
Contouring
Field Setup
(Optional) BAO Optimization
Fluence Optimization
Optimal Fluence
Objectives

Leaf Motion CalculationLMC Parameters MLC Parameters
Actual Fluence Leaf Motions
3D dose calculation
AAA, PBC, Acuros XB algorithm
Delivery
Optimal Fluence
IMRT

Only b5mm
IMRT

IMRTRapidArc
NTO
IMRT
Relative number
(0 1000) Defines importance
of the objective
IMRT

Upper Objective
Lower Objective
Objectives on a Line
IMRT

Objective - Function
IMRT
i= d=! p=! CF=
CF = u Dmin di( )2
+ o di Dmax( )2( )
i=1
N
N= u=!Dmin= o= Dmax=

k=! i=! p=! N=! d=! Dmax=!
CF = pk di,k Dmax,k( )2
i=1
Nk
)
!10
Objective - Function
IMRT

Normal Tissue Objective
IMRT

Where r = Distance from target border rstart = start of fall off f0 = start dose (%) f = end dose (%) k = Fall off
Normal Tissue Objective (NTO)
IMRT
f (r) = f0ek(rrstart ) + f(1 e
k(rrstart ) ), r rstartf0 , r < rstart
$%&
'&

Smoothing Objectives
IMRT
XY
XVarian MLCMUYMUTongue & Groove

Minimize Dose Objective
IMRT
Normal Tissue Objective

Beamlet (IMRT) !
Base dose plan Maximum number of iterations Maximum optimization time
Optimization Parameters
IMRT

IMRT
Point SamplingCalculation Grid
IMRT

Point SamplingCalculation Grid
IMRT

EIPOptimization - Volume Representation
IMRT

Ray trace !!!!
Size of the beamlet Leaf width x 2.5 mm
row = leaf pair
Optimization - Field Representation
IMRT

0.5cm
0.5cm Y
Optimization - Target Masking
IMRT

Beamlet - xj
Dose at point - di
Optimization - Dose Computation
IMRT
EclipseTarget Masking
PointBeamlet
, Beamlet

BA
C1
2
p1 > 40 w1 = 100
p2 < 20 w2 = 50
BA
C1
2
A B C 1 2
d 37 41 38 22 23
(d 9 1 4 4 9
violate? 1 0 1 1 1
penalty 900 0 400 200 450
1300 650
Nextiteration
A B C 1 2
d 38 40 39 21 22
(d 4 0 1 1 4
violate? 1 0 1 1 1
penalty 400 0 100 50 200
500 250
Gain 800 400
Penalty Calculation
IMRT

() !!!
()
Fobj = FPTVallPTVs + FCritical
allCS + FNTO + FSmoothXY
Fields + FMin.Dose
Fields
Objective function
IMRT

MRDC
Intermediate Dose Calculation

optimal fluenceactual fluence LMC
Sliding Window Multiple Static Segments None
Field size definition
Leaf Motion Calculator
Segment

Paul Keall et. al. Virginia Commonwealth University Medical College of Virginia Hospital
()
Large Field IMRT
Segment

LargeIMRT
Large Field IMRT
Segment

RapidArc
Contouring
Field Setup
OptimizationMachine ParametersObjectives
MRDC
Leaf Motions MU per deg
Auto adjust

Leaf Motions MU per deg
AAA or Acuros XB 3D dose
calculation
Delivery
RapidArc

VMAT
Couch structures may be added to account for attenuation of the treatment couch.
Numerous Varian couches are available
Rails can be positioned in or out, for both left and right
Couch position may be adjusted
Create Couch Structure

RT Administration
Dose rate
/ 0.1 MU/deg
VMATConstraints - Varian Delivery Platforms

30
Avoidance sectors VMAT
Field size Collimator, Couch rotation Isocenter
Arc geometry tool
VMATGeometry

2 0
15
VMATAvoidance Sectors

Progressive Resolution Optimization (PRO)
Starts with few directions (control points)
Optimizes the MLC motion, Dose Rate, Gantry Speed for each control point
Respects MLC, Gantry Speed Constraints
VMATRapidArc - Arc Optimization ()

resolution
multi-resolution
Control Points
Calculation direction
for arc segment
VMATProgressive resolution ()

PRO3
resolution level
VMATSteps

f(x,v,t)x,vf(x,v,t)dxdvdxdv
!"!" + !
!"!" +
!!
!"!" = !
!!!! !!! !"!!!
vv
(AcurosXB)
Monte Calo

(Stochastic) (Monte Carlo) -
(Deterministic) -
(Analytic) -
AcursoXBLBTE
(AcurosXB)
Monte Calo

CT3.0
(AcurosXB)
Monte Calo

Initial Phase Space
Modified Phase Space
qprim= qsec = qecont =
qunc = qeunc = qeeunc =
(AcurosXB)
Monte Calo

CutOff
TERMA Kernel
Superposition AcurosXB MonteCarlo
(AcurosXB)
Monte Calo

2cm
8cm
4cm
5cm
11cm
Monte Carlo
(AcurosXB)
5cm(Water)2cm(Titanium)
8cm(Lung)4cm(Bone)
11cm(Water)
6MV, 5x5cm
Monte Calo

IMRT

3
270
MLC
COPYRIGHT 2010 VARIAN MEDICAL SYSTEMS

6
2704
Stand Gantry
Clinac Beam

Clinac Beam
Stand Gantry
4

z
x
y
E
H
Ex = E0 sin { (z / c t)}Hy = H0 sin { (z / c t)}E0 / H0 = / ( 376.7c = 1 /
E H
S = E H
zEx = E0 sin { (z / c + t)}By = B0 sin { (z / c + t)}

TM010
Ez z r = b 0d
2b z
Ez
d
V = E0 cos t dz
= E0 cos z / v + t0 dz
= V0 T cos t0
d/2
d/2
d/2
d/2
t = t0 z = 0
V0 = E0 dT = sin < 1T
d2v
d2v
2b EzE0
r

± º * G JX Ü ¼ 'Qº ¼ -Á p - 大阪大学大学院医学系研究科 放射線 ... · PDF file · 2014-02-03| varian oncology systems...

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± º * G JX Ü ¼ 'Qº ¼ -Á p - 大阪大学大学院医学系研究科放射線 ... · PDF file · 2014-02-03| varian oncology systems...