New Techniques in Radiotherapy
santam
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134 slides
Nov 05, 2007
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About This Presentation
A summary of recent innovations in radiation oncology focussing on the priniciples of different techniques and their application. An overview of clinical results has also been given
Slide Content
New Techniques in
Radiation therapy
Moderator:
Dr S C Sharma
Department of Radiotherapy
PGIMER
Chandigarh
Radiation therapy
Moderator:
Dr S C Sharma
Department of Radiotherapy
PGIMER
Chandigarh
Trends
1990 1995 2000 2005
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Number of Publications in Google Scholar
3 DCRTIMRT IGRT
1990 1995 2000 2005
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Number of Publications in Google Scholar
3 DCRTIMRT IGRT
Overview
3 DCRT
Radiation
Therapy
Teletherapy
Brachytherapy
IMRT
IGRT DART
Electronic Brachytherapy
Tomotherapy
Image Assisted Brachytherpy
Stereotactic radiotherapy
Gamma Knife
LINAC based
Cyberknife
3 DCRT
Radiation
Therapy
Teletherapy
Brachytherapy
IMRT
IGRT DART
Electronic Brachytherapy
Tomotherapy
Image Assisted Brachytherpy
Stereotactic radiotherapy
Gamma Knife
LINAC based
Cyberknife
Solutions ?
Develop technologies to circumvent limitations
Use alternative radiation
modalities
Electrons
Protons
Neutrons
π- Mesons
Heavy Charged Nuclei
Antiprotons
Develop technologies to circumvent limitations
Use alternative radiation
modalities
Electrons
Protons
Neutrons
π- Mesons
Heavy Charged Nuclei
Antiprotons
Development Timeline
1
9
9
0
1
9
6
0
Proimos develops gravity oriented
blocking and conformal field shaping
1
9
8
0
Brahame conceptualized inverse planning
& gives prototype algorithm for (1982-88)
1
st
inverse planning algorithm
developed by Webb (1989)
1
9
7
0Tracking Cobalt unit invented
at Royal Free Hospital
1
9
5
0
Takahashi discusses conformal RT
1
st
MLCs invented (1959)
Boyer and Webb develop
principle of static IMRT (1991)
Carol demonstrates NOMOS MiMIC (1992)
Tomotherapy developed in Wisconsin
(1993)
Stein develops optimal dMLC equations
(1994)
First discussion of Robotic
IMRT (1999)
1
9
9
0
1
9
6
0
Proimos develops gravity oriented
blocking and conformal field shaping
1
9
8
0
Brahame conceptualized inverse planning
& gives prototype algorithm for (1982-88)
1
st
inverse planning algorithm
developed by Webb (1989)
1
9
7
0Tracking Cobalt unit invented
at Royal Free Hospital
1
9
5
0
Takahashi discusses conformal RT
1
st
MLCs invented (1959)
Boyer and Webb develop
principle of static IMRT (1991)
Carol demonstrates NOMOS MiMIC (1992)
Tomotherapy developed in Wisconsin
(1993)
Stein develops optimal dMLC equations
(1994)
First discussion of Robotic
IMRT (1999)
Modulation: Examples
Block:
Binary Modulation
Wedge:
Uniform Modulation
Coarse spatial and
Coarse intensity
Fine spatial
coarse intensity
Fine Spatial and Fine
Intensity modulation
Block:
Binary Modulation
Wedge:
Uniform Modulation
Coarse spatial and
Coarse intensity
Fine spatial
coarse intensity
Fine Spatial and Fine
Intensity modulation
Conformal Radiotherapy
Conformal radiotherapy
(CFRT) is a technique that
aims to exploit the
potential biological
improvements consequent
on better spatial
localization of the high-
dose irradiation volume
- S. Webb
in Intensity Modulated Radiotherapy
IOP
Conformal radiotherapy
(CFRT) is a technique that
aims to exploit the
potential biological
improvements consequent
on better spatial
localization of the high-
dose irradiation volume
- S. Webb
in Intensity Modulated Radiotherapy
IOP
Problems in conformation
Nature of the photon beam
is the biggest impediment
Has an entrance
dose.
Has an exit dose.
Follows the inverse
square law.
Nature of the photon beam
is the biggest impediment
Has an entrance
dose.
Has an exit dose.
Follows the inverse
square law.
Types of CFRT
Two broad subtypes :
Techniques aiming to
employ geometric
fieldshaping alone
Techniques to modulate
the intensity of fluence
across the geometrically-
shaped field (IMRT)
Two broad subtypes :
Techniques aiming to
employ geometric
fieldshaping alone
Techniques to modulate
the intensity of fluence
across the geometrically-
shaped field (IMRT)
Modulation : Intensity or
Fluence ?
Intensity Modulation is a misnomer – The actual term is
Fluence
Fluence referes to the number of “particles” incident on an
unit area (m
-2
)
Fluence ?
Intensity Modulation is a misnomer – The actual term is
Fluence
Fluence referes to the number of “particles” incident on an
unit area (m
-2
)
How to modulate intensity
Cast metal compensator
Jaw defined static fields
Multiple-static MLC-shaped fields
Dynamic MLC techniques (DMLC)
including modulated arc therapy (IMAT)
Binary MLCs - NOMOS MIMiC and in
tomotherapy
Robot delivered IMRT
Scanning attenuating bar
Swept pencils of radiation (Race Track
Microtron - Scanditronix)
Cast metal compensator
Jaw defined static fields
Multiple-static MLC-shaped fields
Dynamic MLC techniques (DMLC)
including modulated arc therapy (IMAT)
Binary MLCs - NOMOS MIMiC and in
tomotherapy
Robot delivered IMRT
Scanning attenuating bar
Swept pencils of radiation (Race Track
Microtron - Scanditronix)
Comparision
MLC based IMRT
√
√
Step & Shoot IMRT
I
n
t
e
s
n
t
i
y
Distance
Since beam is interrupted between
movements leakage radiation is
less.
Easier to deliver and plan.
More time consuming
I
n
t
e
s
n
t
i
y
Distance
Since beam is interrupted between
movements leakage radiation is
less.
Easier to deliver and plan.
More time consuming
Dynamic IMRT
Faster than Static IMRT
Smooth intensity modulation
acheived
Beam remains on throughout –
leakage radiation increased
More susceptible to tumor
motion related errors.
Additional QA required for MLC
motion accuracy.
I
n
t
e
s
n
t
i
y
Distance
Faster than Static IMRT
Smooth intensity modulation
acheived
Beam remains on throughout –
leakage radiation increased
More susceptible to tumor
motion related errors.
Additional QA required for MLC
motion accuracy.
I
n
t
e
s
n
t
i
y
Distance
Caveats: Conformal Therapy
Significantly increased expenditure:
Machine with treatment capability
Imaging equipment: Planning and Verification
Software and Computer hardware
Extensive physics manpower and time required.
Conformal nature – highly susceptible to motion and setup related
errors – Achilles heel of CFRT
Target delineation remains problematic.
Treatment and Planning time both significantly increased
Radiobiological disadvantage:
Decreased “dose-rate” to the tumor
Increased integral dose (Cyberknife > Tomotherapy > IMRT)
Significantly increased expenditure:
Machine with treatment capability
Imaging equipment: Planning and Verification
Software and Computer hardware
Extensive physics manpower and time required.
Conformal nature – highly susceptible to motion and setup related
errors – Achilles heel of CFRT
Target delineation remains problematic.
Treatment and Planning time both significantly increased
Radiobiological disadvantage:
Decreased “dose-rate” to the tumor
Increased integral dose (Cyberknife > Tomotherapy > IMRT)
3D Conformal
Radiation Planning
Radiation Planning
How to Plan CFRT
Patient positioning
and Immobilization
Volumetric Data
acqusition
Image Transfer
to the TPS
Target Volume
Delineation
3D Model
generation
Forward
Planning
Inverse
Planning
Dose distribution
Analysis
Treatment QA Treatment Delivery
Patient positioning
and Immobilization
Volumetric Data
acqusition
Image Transfer
to the TPS
Target Volume
Delineation
3D Model
generation
Forward
Planning
Inverse
Planning
Dose distribution
Analysis
Treatment QA Treatment Delivery
Positioning and Immobilization
Two of the most important aspects of conformal radiation
therapy.
Basis for the precision in conformal RT
Needs to be:
Comfortable
Reproducible
Minimal beam attenuating
Affordable
Holds the Target in place while the beam is turned on
Two of the most important aspects of conformal radiation
therapy.
Basis for the precision in conformal RT
Needs to be:
Comfortable
Reproducible
Minimal beam attenuating
Affordable
Holds the Target in place while the beam is turned on
Types of Immobilization
Immoblization
devices
Frame based
Frameless
Invasive
Noninvasive
➢Usually based on a combination of heat deformable
“casts” of the part to be immobilized attached to a
baseplate that can be reproducibly attached with the
treatment couch.
➢The elegant term is “Indexing”
Immoblization
devices
Frame based
Frameless
Invasive
Noninvasive
➢Usually based on a combination of heat deformable
“casts” of the part to be immobilized attached to a
baseplate that can be reproducibly attached with the
treatment couch.
➢The elegant term is “Indexing”
Cranial Immobilization
BrainLab System
TLC System
Gill Thomas Cosman System
Leksell Frame
BrainLab System
TLC System
Gill Thomas Cosman System
Leksell Frame
Extracranial Immobilization
Elekta Body Frame
Body Fix system
Elekta Body Frame
Body Fix system
Accuracy of systems
System Techniqe Setup Accuracy
Latinen Frame
GTC Frame
X = 5 – 7 mm ,Y = 1 cm Z = 1.0 cm (mean)
Heidelberg frame X = 5 mm,Y = 5 mm, Z = 10 mm (mean)
Body Fix Frame
Noninvasive
Stereotactic frame
Non invasive,
mouthpiece
0.7– 0.8 mm (± 0.5–0.6 mm)
Non invasive,
nasion, earplugs
x = 1.0 mm ± 0.7; y= 0.8 mm ± 0.8; z = 1.7
mm ± 1.0
Non invasive,
mouthpiece
X = 0.35 mm ± 0.06; Y = 0.52 mm ± 0.09;
Z= 0.34 mm ± 0.09
Stereotactic Body
Frame
Non invasive,
vacccum based
Non invasive,
vaccum based
Non invasive,
Vacccum based
with plastic foil
X = 0.4 ± 3.9 mm , Y = 0.1 ± 1.6 mm Z = 0.3
± 3.6 mm. Rotation accuracy of 1.8 ± 1.6
degrees.
With the precision of the body fix frame the
target volume will be underdosed (< 90% of
prescribed dose) 14% of the time!!!
System Techniqe Setup Accuracy
Latinen Frame
GTC Frame
X = 5 – 7 mm ,Y = 1 cm Z = 1.0 cm (mean)
Heidelberg frame X = 5 mm,Y = 5 mm, Z = 10 mm (mean)
Body Fix Frame
Noninvasive
Stereotactic frame
Non invasive,
mouthpiece
0.7– 0.8 mm (± 0.5–0.6 mm)
Non invasive,
nasion, earplugs
x = 1.0 mm ± 0.7; y= 0.8 mm ± 0.8; z = 1.7
mm ± 1.0
Non invasive,
mouthpiece
X = 0.35 mm ± 0.06; Y = 0.52 mm ± 0.09;
Z= 0.34 mm ± 0.09
Stereotactic Body
Frame
Non invasive,
vacccum based
Non invasive,
vaccum based
Non invasive,
Vacccum based
with plastic foil
X = 0.4 ± 3.9 mm , Y = 0.1 ± 1.6 mm Z = 0.3
± 3.6 mm. Rotation accuracy of 1.8 ± 1.6
degrees.
With the precision of the body fix frame the
target volume will be underdosed (< 90% of
prescribed dose) 14% of the time!!!
CT simulator
70 – 85 cm bore
Scanning Field of View (SFOV) 48 cm –
60 cm – Allows wider separation to be
imaged.
Multi slice capacity:
Speed up acquistion times
Reduce motion and breathing artifacts
Allow thinner slices to be taken – better
DRR and CT resolution
Allows gating capabilities
Flat couch top – simulate treatment
table
70 – 85 cm bore
Scanning Field of View (SFOV) 48 cm –
60 cm – Allows wider separation to be
imaged.
Multi slice capacity:
Speed up acquistion times
Reduce motion and breathing artifacts
Allow thinner slices to be taken – better
DRR and CT resolution
Allows gating capabilities
Flat couch top – simulate treatment
table
MRI
Superior soft tissue resolution
Ability to assess neural and marrow infiltration
Ability to obtain images in any plane - coronal/saggital/axial
Imaging of metabolic activity through MR Spectroscopy
Imaging of tumor vasculature and blood supply using a new
technique – dynamic contrast enhanced MRI
No radiation exposure to patient or personnel
Superior soft tissue resolution
Ability to assess neural and marrow infiltration
Ability to obtain images in any plane - coronal/saggital/axial
Imaging of metabolic activity through MR Spectroscopy
Imaging of tumor vasculature and blood supply using a new
technique – dynamic contrast enhanced MRI
No radiation exposure to patient or personnel
PET: Principle
Unlike other imaging can
biologically characterize a leison
Relies on detection of photons
liberated by annhilation reaction
of positron with electron
Photons are liberated at 180° angle
and simultaneously – detection of
this pair and subsequent mapping
of the event of origin allows spatial
localization
The detectors are arranged in an
circular array around the patient
PET- CT scanners integrate both
imaging modalities
Unlike other imaging can
biologically characterize a leison
Relies on detection of photons
liberated by annhilation reaction
of positron with electron
Photons are liberated at 180° angle
and simultaneously – detection of
this pair and subsequent mapping
of the event of origin allows spatial
localization
The detectors are arranged in an
circular array around the patient
PET- CT scanners integrate both
imaging modalities
PET-CT scanner
Flat couch top insert
CT Scanner
PET scanner
60 cm
Allows hardware based registration as the patient is scanned in the
treatment position
CT images can be used to provide attenuation correction factors for the
PET scan image reducing scanning time by upto 40%
Flat couch top insert
CT Scanner
PET scanner
60 cm
Allows hardware based registration as the patient is scanned in the
treatment position
CT images can be used to provide attenuation correction factors for the
PET scan image reducing scanning time by upto 40%
Markers for PET Scans
Metabolic marker
2-
18
Fluoro 2- Deoxy Glucose
Proliferation markers
Radiolabelled thymidine:
18
F
Fluorothymidine
Radiolabelled amino acids:
11
C Methyl
methionine,
11
C Tyrosine
Hypoxia markers
60
Cu-diacetyl-bis(N-4-
methylthiosemicarbazone) (
60
Cu-
ATSM)
Apoptosis markers
99
m
Technicium Annexin V
PET Fiducials
Metabolic marker
2-
18
Fluoro 2- Deoxy Glucose
Proliferation markers
Radiolabelled thymidine:
18
F
Fluorothymidine
Radiolabelled amino acids:
11
C Methyl
methionine,
11
C Tyrosine
Hypoxia markers
60
Cu-diacetyl-bis(N-4-
methylthiosemicarbazone) (
60
Cu-
ATSM)
Apoptosis markers
99
m
Technicium Annexin V
PET Fiducials
Image Registration
Technique by which the coordinates of identical points in
two imaging data sets are determined and a set of
transformations determined to map the coordinates of one
image to another
Uses of Image registration:
Study Organ Motion (4 D CT)
Assess Tumor extent (PET / MRI fusion)
Assess Changes in organ and tumor volumes over time
(Adaptive RT)
Types of Transformations:
Rigid – Translations and Rotations
Deformable – For motion studies
Technique by which the coordinates of identical points in
two imaging data sets are determined and a set of
transformations determined to map the coordinates of one
image to another
Uses of Image registration:
Study Organ Motion (4 D CT)
Assess Tumor extent (PET / MRI fusion)
Assess Changes in organ and tumor volumes over time
(Adaptive RT)
Types of Transformations:
Rigid – Translations and Rotations
Deformable – For motion studies
Concept
Process: Image Registration
The algorithm first measures the degree of mismatch between
identical points in two images (metric).
The algorithm then determines a set of transformations that
minimize this metric.
Optimization of this transformations with multiple iterations take
place
After the transformation the images are “fused” - a display which
contains relevant information from both images.
The algorithm first measures the degree of mismatch between
identical points in two images (metric).
The algorithm then determines a set of transformations that
minimize this metric.
Optimization of this transformations with multiple iterations take
place
After the transformation the images are “fused” - a display which
contains relevant information from both images.
Image Registration
Target Volume delineation
The most important and most error prone step in
radiotherapy.
Also called Image Segmentation
The target volume is of following types:
GTV (Gross Target Volume)
CTV (Clinical Target Volume)
ITV (Internal Target Volume)
PTV (Planning Target Volume)
Other volumes:
Targeted Volume
Irradiated Volume
Biological Volume
The most important and most error prone step in
radiotherapy.
Also called Image Segmentation
The target volume is of following types:
GTV (Gross Target Volume)
CTV (Clinical Target Volume)
ITV (Internal Target Volume)
PTV (Planning Target Volume)
Other volumes:
Targeted Volume
Irradiated Volume
Biological Volume
Target Volumes
GTV: Macroscopic extent of the tumor as defined by
radiological and clinical investigations.
CTV: The GTV together with the surrounding microscopic
extension of the tumor constitutes the CTV. The CTV also
includes the tumor bed of a R0 resection (no residual).
ITV (ICRU 62): The ITV encompasses the GTV/CTV with an
additional margin to account for physiological movement of
the tumor or organs. It is defined with respect to a internal
reference – most commonly rigid bony skeleton.
PTV: A margin given to above to account for uncertainities
in patient setup and beam adjustment.
GTV: Macroscopic extent of the tumor as defined by
radiological and clinical investigations.
CTV: The GTV together with the surrounding microscopic
extension of the tumor constitutes the CTV. The CTV also
includes the tumor bed of a R0 resection (no residual).
ITV (ICRU 62): The ITV encompasses the GTV/CTV with an
additional margin to account for physiological movement of
the tumor or organs. It is defined with respect to a internal
reference – most commonly rigid bony skeleton.
PTV: A margin given to above to account for uncertainities
in patient setup and beam adjustment.
Target Volumes
Definitions: ICRU 50/62
GTV
CTV
ITV
PTV
TV
IV
Treated Volume: Volume of the
tumor and surrounding normal
tissue that is included in the isodose
surface representing the irradiation
dose proposed for the treatment
(V
95
)
Irradiated Volume: Volume
included in an isodose surface with
a possible biological impact on the
normal tissue encompassed in this
volume. Choice of isodose depends
on the biological end point in mind.
GTV
CTV
ITV
PTV
TV
IV
Treated Volume: Volume of the
tumor and surrounding normal
tissue that is included in the isodose
surface representing the irradiation
dose proposed for the treatment
(V
95
)
Irradiated Volume: Volume
included in an isodose surface with
a possible biological impact on the
normal tissue encompassed in this
volume. Choice of isodose depends
on the biological end point in mind.
Example
PTV
CTV
GTV
PTV
CTV
GTV
Organ at Risk (ICRU 62)
Normal critical structures whose
radiation sensitivity may
significantly influence treatment
planning and/or prescribed dose.
A planning organ at risk volume
(PORV) is added to the contoured
organs at risk to account for the
same uncertainities in patient
setup and treatment as well as
organ motion that are used in the
delineation of the PTV.
Each organ is made up of a
functional subunit (FSU)
Normal critical structures whose
radiation sensitivity may
significantly influence treatment
planning and/or prescribed dose.
A planning organ at risk volume
(PORV) is added to the contoured
organs at risk to account for the
same uncertainities in patient
setup and treatment as well as
organ motion that are used in the
delineation of the PTV.
Each organ is made up of a
functional subunit (FSU)
Biological Target Volume
A target volume that
incorporated data from
molecular imaging techniques
Target volume drawn
incorporates information
regarding:
Cellular burden
Cellular metabolism
Tumor hypoxia
Tumor proliferation
Intrinsic Radioresistance or
sensitivity
A target volume that
incorporated data from
molecular imaging techniques
Target volume drawn
incorporates information
regarding:
Cellular burden
Cellular metabolism
Tumor hypoxia
Tumor proliferation
Intrinsic Radioresistance or
sensitivity
Biological Target Volumes
Lung Cancer:
30 -60% of all GTVs and PTVs are changed with PET.
Increase in the volume can be seen in 20 -40%.
Decrease in the volume in 20 – 30%.
Several studies show significant improvement in nodal
delineation.
Head and Neck Cancer:
PET fused images lead to a change in GTV volume in 79%.
Can improve parotid sparing in 70% patients.
Lung Cancer:
30 -60% of all GTVs and PTVs are changed with PET.
Increase in the volume can be seen in 20 -40%.
Decrease in the volume in 20 – 30%.
Several studies show significant improvement in nodal
delineation.
Head and Neck Cancer:
PET fused images lead to a change in GTV volume in 79%.
Can improve parotid sparing in 70% patients.
3 D TPS
Treatment planning systems are complex computer systems
that help design radiation treatments and facilitate the
calculation of patient doses.
Several vendors with varying characteristics
Provide tools for:
Image registration
Image segmentation: Manual and automated
Virtual Simualtion
Dose calculation
Plan Evaluation
Data Storage and transmission to console
Treatment verification
Treatment planning systems are complex computer systems
that help design radiation treatments and facilitate the
calculation of patient doses.
Several vendors with varying characteristics
Provide tools for:
Image registration
Image segmentation: Manual and automated
Virtual Simualtion
Dose calculation
Plan Evaluation
Data Storage and transmission to console
Treatment verification
Planning workflow
Define a dose objective
Total Dose
Total Time of delivery of dose
Total number of fractions
Choose Number of Beams
Choose beam angles and couch angles
Organ at risk dose levels
Choose Planning Technique
Forward Planning Inverse Planning
Define a dose objective
Total Dose
Total Time of delivery of dose
Total number of fractions
Choose Number of Beams
Choose beam angles and couch angles
Organ at risk dose levels
Choose Planning Technique
Forward Planning Inverse Planning
“Forward” Planning
A technique where the planner will try a variety of
combinations of beam angles, couch angles, beam weights
and beam modifying devices (e.g. wedges) to find a
optimum dose distribution.
Iterations are done manually till the optimum solution is
reached.
Choice for some situations:
Small number of fields: 4 or less.
Convex dose distribution required.
Conventional dose distribution desired.
Conformity of high dose region is a less important concern.
A technique where the planner will try a variety of
combinations of beam angles, couch angles, beam weights
and beam modifying devices (e.g. wedges) to find a
optimum dose distribution.
Iterations are done manually till the optimum solution is
reached.
Choice for some situations:
Small number of fields: 4 or less.
Convex dose distribution required.
Conventional dose distribution desired.
Conformity of high dose region is a less important concern.
Planning Beams
Beams Eye View
Display
Room's Eye
View
Digital Composite
Radiograph
Beams Eye View
Display
Room's Eye
View
Digital Composite
Radiograph
“Inverse” Planning
1. Dose distribution specified
Forward Planning
2. Intensity map created
3. Beam Fluence
modulated to recreate
intensity map
Inverse Planning
1. Dose distribution specified
Forward Planning
2. Intensity map created
3. Beam Fluence
modulated to recreate
intensity map
Inverse Planning
Optimization
Refers to the technique of finding the best physical and
technically possible treatment plan to fulfill the specified
physical and clinical criteria.
A mathematical technique that aims to maximize (or
minimize) a score under certain constraints.
It is one of the most commonly used techniques for inverse
planning.
Variables that may be optimized:
Intensity maps
Number of beams
Number of intensity levels
Beam angles
Beam energy
Refers to the technique of finding the best physical and
technically possible treatment plan to fulfill the specified
physical and clinical criteria.
A mathematical technique that aims to maximize (or
minimize) a score under certain constraints.
It is one of the most commonly used techniques for inverse
planning.
Variables that may be optimized:
Intensity maps
Number of beams
Number of intensity levels
Beam angles
Beam energy
Optimization
Optimization Criteria
Refers to the constraints that need to be fulfilled during the
planning process
Types:
Physical Optimization Criteria: Based on physical dose coverage
Biological Optimization Criteria: Based on TCP and NTCP
calculation
A total objective function (score) is then derived from these
criteria.
Priorities are defined to tell the algorithm the relative
importance of the different planning objectives (penalties)
The algorithm attempts to maximize the score based on the
criteria and penalties.
Refers to the constraints that need to be fulfilled during the
planning process
Types:
Physical Optimization Criteria: Based on physical dose coverage
Biological Optimization Criteria: Based on TCP and NTCP
calculation
A total objective function (score) is then derived from these
criteria.
Priorities are defined to tell the algorithm the relative
importance of the different planning objectives (penalties)
The algorithm attempts to maximize the score based on the
criteria and penalties.
Multicriteria Optimization
Sliders for
adjusting EUD
Rectum
Bladder
Intestine
PTV GTV
DVH display
Sliders for
adjusting EUD
Rectum
Bladder
Intestine
PTV GTV
DVH display
Plan Evaluation
Colour Wash Display
Differential DVH
Cumulative DVH
Colour Wash Display
Differential DVH
Cumulative DVH
Image Guided
Radiotherapy and
4D planning
Radiotherapy and
4D planning
Why 4D Planning?
Organ motion types:
Interfraction motion
Intrafraction motion
Even intracranial structures
can move – 1.5 mm shift
when patient goes from
sitting to supine!!
Types of movement:
Translations:
Craniocaudal
Lateral
Vertical
Rotations:
Roll
Pitch
Yaw
Shape:
Flattening
Balloning
Pulsation
Organ motion types:
Interfraction motion
Intrafraction motion
Even intracranial structures
can move – 1.5 mm shift
when patient goes from
sitting to supine!!
Types of movement:
Translations:
Craniocaudal
Lateral
Vertical
Rotations:
Roll
Pitch
Yaw
Shape:
Flattening
Balloning
Pulsation
Interfraction Motion
Prostate:
Motion max in SI and AP
SI 1.7 - 4.5 mm
AP 1.5 – 4.1 mm
Lateral 0.7 – 1.9 mm
SV motion > Prostate
Uterus:
SI: 7 mm
AP : 4 mm
Cervix:
SI: 4 mm
Rectum:
Diameter: 3 – 46 mm
Volumes: 20 – 40%
In many studies decrease
in volume found
Bladder:
Max transverse diameter
mean 15 mm variation
SI displacement 15 mm
Volume variation 20% -
50%
Prostate:
Motion max in SI and AP
SI 1.7 - 4.5 mm
AP 1.5 – 4.1 mm
Lateral 0.7 – 1.9 mm
SV motion > Prostate
Uterus:
SI: 7 mm
AP : 4 mm
Cervix:
SI: 4 mm
Rectum:
Diameter: 3 – 46 mm
Volumes: 20 – 40%
In many studies decrease
in volume found
Bladder:
Max transverse diameter
mean 15 mm variation
SI displacement 15 mm
Volume variation 20% -
50%
Intrafraction Motion
Liver:
Normal Breathing: 10 – 25
mm
Deep breathing: 37 – 55 mm
Kidney:
Normal breathing: 11 -18
mm
Deep Breathing: 14 -40 mm
Pancreas:
Average 10 -30 mm
Lung:
Quiet breathing
AP 2.4 ± 1.3 mm
Lateral 2.4 ± 1.4 mm
SI 3.9 ± 2.6 mm
2° to Cardiac motion: 9 ± 6
mm lateral motion
Tumors located close to the
chest wall and in upper lobe
show reduced interfraction
motion.
Maximum motion is in
tumors close to mediastinum
Liver:
Normal Breathing: 10 – 25
mm
Deep breathing: 37 – 55 mm
Kidney:
Normal breathing: 11 -18
mm
Deep Breathing: 14 -40 mm
Pancreas:
Average 10 -30 mm
Lung:
Quiet breathing
AP 2.4 ± 1.3 mm
Lateral 2.4 ± 1.4 mm
SI 3.9 ± 2.6 mm
2° to Cardiac motion: 9 ± 6
mm lateral motion
Tumors located close to the
chest wall and in upper lobe
show reduced interfraction
motion.
Maximum motion is in
tumors close to mediastinum
IGRT: Solutions
Imaging techniques
USG based Video based Planar X-ray CT MRI
●BAT
●Sonoarray
●I-Beam
●Resitu
●AlignRT
●Photogrammetry
●Real Time Video guided
IMRT
●Video substraction
KV X-ray OBI
MV X-ray Gantry Mounted Room Mounted
●Varian OBI
●Elekta Synergy
●IRIS
●Cyberknife
●RTRT (Mitsubishi)
●BrainLAB (Exectrac)
●EPI
Fan Beam Cone Beam
●Tomotherapy
●In room CT
MV CT KV CT
●Siemens
●Mobile C arm
●Varian OBI
●Elekta
●Siemens Inline
Imaging techniques
USG based Video based Planar X-ray CT MRI
●BAT
●Sonoarray
●I-Beam
●Resitu
●AlignRT
●Photogrammetry
●Real Time Video guided
IMRT
●Video substraction
KV X-ray OBI
MV X-ray Gantry Mounted Room Mounted
●Varian OBI
●Elekta Synergy
●IRIS
●Cyberknife
●RTRT (Mitsubishi)
●BrainLAB (Exectrac)
●EPI
Fan Beam Cone Beam
●Tomotherapy
●In room CT
MV CT KV CT
●Siemens
●Mobile C arm
●Varian OBI
●Elekta
●Siemens Inline
IGRT: Solution Comparision
DOF = degrees of freedom – directions in which motion can be
corrected – 3 translations and 3 rotations
DOF = degrees of freedom – directions in which motion can be
corrected – 3 translations and 3 rotations
EPI
Uses of EPI:
Correction of individual interfraction errors
Estimation of poulation based setup errors
Verification of dose distribution (QA)
Problems with EPI:
Poor image quality (MV xray)
Increased radiation dose to patient
Planar Xray – 3 dimensional body movement is not seen
Tumor is not tracked – surrogates like bony anatomy or
implanted fiducials are tracked.
Uses of EPI:
Correction of individual interfraction errors
Estimation of poulation based setup errors
Verification of dose distribution (QA)
Problems with EPI:
Poor image quality (MV xray)
Increased radiation dose to patient
Planar Xray – 3 dimensional body movement is not seen
Tumor is not tracked – surrogates like bony anatomy or
implanted fiducials are tracked.
Types of EPID
Liquid Matrix Ion Chamber*
Camera based devices
Amorphous silicon flat panel detectors
Amorphous selenium flat panel detectors
Electrode
connected to
high voltage
“Output”
electrode
Liquid 2,2,4 -
trimethylpentane
ionized liquid
High voltage applied
Output read out
by the lower
electrodes
Liquid Matrix Ion Chamber*
Camera based devices
Amorphous silicon flat panel detectors
Amorphous selenium flat panel detectors
Electrode
connected to
high voltage
“Output”
electrode
Liquid 2,2,4 -
trimethylpentane
ionized liquid
High voltage applied
Output read out
by the lower
electrodes
On board imaging
KV Xray
Intensifier
Room Mounted OBI
Gantry mounted OBI
KV Xray
Intensifier
Room Mounted OBI
Gantry mounted OBI
4 D CT acqusition
Axial scans are acquired
with the use of a RPM
camera attached to couch.
The “cine” mode of the scanner is used to
acquire multiple axial scans at
predetermined phases of respiratory cycle
for each couch position
Axial scans are acquired
with the use of a RPM
camera attached to couch.
The “cine” mode of the scanner is used to
acquire multiple axial scans at
predetermined phases of respiratory cycle
for each couch position
RPM System
Patient imaged with the RPM system to
ascertain baseline motion profile
A periodicity filter algorithm
checks the breathing periodicity
Breathing comes to a rythm
Breathing cycle is recorded
Patient imaged with the RPM system to
ascertain baseline motion profile
A periodicity filter algorithm
checks the breathing periodicity
Breathing comes to a rythm
Breathing cycle is recorded
4D CT Data set
Normal
Normal
Problems with 4 D CT
The image quality depends on the reproducibility of the
respiratory motion.
The volume of images produced is increased by a factor of
10.
Specialized software needed to sort and visualize the 4D
data.
Dose delivered during the scans can increase 3-4 times.
Image fusion with other modalities remains an unsolved
problem
The image quality depends on the reproducibility of the
respiratory motion.
The volume of images produced is increased by a factor of
10.
Specialized software needed to sort and visualize the 4D
data.
Dose delivered during the scans can increase 3-4 times.
Image fusion with other modalities remains an unsolved
problem
4D Target delineation
Target delineation can be done on all images acquired.
Methods of contouring:
Manual
Automatic (Deformable Image Registration)
Why automatic contouring?
Logistic Constraints: Time requirement for a single
contouring can be increased by a factor of ~ 10.
Fundamental Constraints:
To calculate the cumulative dose delivered to the tumor during
the treatment.
However the dose for each moving voxel needs to be integrated
together for this to occur.
So an estimate of the individual voxel motion is needed.
Target delineation can be done on all images acquired.
Methods of contouring:
Manual
Automatic (Deformable Image Registration)
Why automatic contouring?
Logistic Constraints: Time requirement for a single
contouring can be increased by a factor of ~ 10.
Fundamental Constraints:
To calculate the cumulative dose delivered to the tumor during
the treatment.
However the dose for each moving voxel needs to be integrated
together for this to occur.
So an estimate of the individual voxel motion is needed.
4D Manual Contouring
The tumor is manually contoured in end expiration and end
inspiration
The two volumes are fused to generate at MIV – Maximum
Intensity Volume
The projection of this to a DRR is called MIP (Maximum
Intensity Projection)
End Expiration
End Inspiration
MIV
The tumor is manually contoured in end expiration and end
inspiration
The two volumes are fused to generate at MIV – Maximum
Intensity Volume
The projection of this to a DRR is called MIP (Maximum
Intensity Projection)
End Expiration
End Inspiration
MIV
Automated Contouring
Technique by which a single moving voxel is matched on CT
slices that are taken in different phases of respiration
The treatment is planned on a reference CT – usually the
end expiration (for Lung)
Matching the voxels allows the dose to be visualized at each
phase of respiration
Several algorithms under evaluation:
Finite element method
Optical flow technique
Large deformation diffeomorphic image registration
Splines thin plate and b
Technique by which a single moving voxel is matched on CT
slices that are taken in different phases of respiration
The treatment is planned on a reference CT – usually the
end expiration (for Lung)
Matching the voxels allows the dose to be visualized at each
phase of respiration
Several algorithms under evaluation:
Finite element method
Optical flow technique
Large deformation diffeomorphic image registration
Splines thin plate and b
Automated Contouring
Movement
vectors
Movement
vectors
Automated Contouring
Day 1 Image Day 2 Image
Individaul
Pixels
Due to the changes in shape
of the object the same pixel
occupies a different
coordinate in the 2
nd
image
+
=
Deformable Image registration circumvents this problems
Day 1 Image Day 2 Image
Individaul
Pixels
Due to the changes in shape
of the object the same pixel
occupies a different
coordinate in the 2
nd
image
+
=
Deformable Image registration circumvents this problems
4D Treatment Planning
A treatment plan is usually
generated for a single phase of
CT.
The automatic planning
software then changes the field
apertures to match for the PTV
at each respiratory phase.
MLCs used should be aligned
parallel to the long axis of the
largest motion.
A treatment plan is usually
generated for a single phase of
CT.
The automatic planning
software then changes the field
apertures to match for the PTV
at each respiratory phase.
MLCs used should be aligned
parallel to the long axis of the
largest motion.
Limitations of 4D Planning
Computing resource intensive – Parallel calculations require
computer clusters at present
No commercial TPS allows 4 D dose calculation
Respiratory motion is unpredictable – calculated dose good
for a certain pattern only
Incorporating respiratory motion in dynamic IMRT means
MLC motion parameters become important constraints
Tumor tracking is needed for delivery if true potential is to
be realized
The time delay for dMLC response to a detected motion
means that even with tracking gating is important
Computing resource intensive – Parallel calculations require
computer clusters at present
No commercial TPS allows 4 D dose calculation
Respiratory motion is unpredictable – calculated dose good
for a certain pattern only
Incorporating respiratory motion in dynamic IMRT means
MLC motion parameters become important constraints
Tumor tracking is needed for delivery if true potential is to
be realized
The time delay for dMLC response to a detected motion
means that even with tracking gating is important
4D Treatment delivery
Options for 4D delivery
Ignore motion Freeze the motion Follow the motion (Tracking)
Patient breaths normally Breathing is controlled
Respiratory Gating Breath holding (DIBH)
Jet Ventilation
Active Breathing control
Options for 4D delivery
Ignore motion Freeze the motion Follow the motion (Tracking)
Patient breaths normally Breathing is controlled
Respiratory Gating Breath holding (DIBH)
Jet Ventilation
Active Breathing control
Minimizing Organ Motion
Abdominal Compression(Hof
et al. 2003 – Lung tumors):
Cranio-caudal movement of
tumor 5.1±2.4 mm.
Lateral movement 2.6±1.4
Anterior-posterior
movement 3.1±1.5 mm
Breath Hold technique:
Patients instructed to hold
breath in one phase
Usually 10 -13 breath holding
sessions tolerated (each 12 -16
sec)
Reduced lung density in
irradiated area – reduced
volume of lung exposed to high
dose
Tumor motion restricted to 2-3
mm (Onishi et al 2003 – Lung
tumors)
Abdominal Compression(Hof
et al. 2003 – Lung tumors):
Cranio-caudal movement of
tumor 5.1±2.4 mm.
Lateral movement 2.6±1.4
Anterior-posterior
movement 3.1±1.5 mm
Breath Hold technique:
Patients instructed to hold
breath in one phase
Usually 10 -13 breath holding
sessions tolerated (each 12 -16
sec)
Reduced lung density in
irradiated area – reduced
volume of lung exposed to high
dose
Tumor motion restricted to 2-3
mm (Onishi et al 2003 – Lung
tumors)
Minimizing Organ Motion
Active Breathing Control
Consists of a spirometer to “actively” suspend the patients
breathing at a predetermined postion in the respiratory cycle
A valve holds the respiratory cycle at a particular phase of
respiration
Breath hold duration : 15 -30 sec
Usually immobilized at moderate DIBH (Deep Inspiration Breath
Hold) – 75% of the max inspiratory capacity
Max experience: Breast
Intrafractional lung motion reduced
Mean reproducibility 1.6 mm
Active Breathing Control
Consists of a spirometer to “actively” suspend the patients
breathing at a predetermined postion in the respiratory cycle
A valve holds the respiratory cycle at a particular phase of
respiration
Breath hold duration : 15 -30 sec
Usually immobilized at moderate DIBH (Deep Inspiration Breath
Hold) – 75% of the max inspiratory capacity
Max experience: Breast
Intrafractional lung motion reduced
Mean reproducibility 1.6 mm
Tracking Target motion
Also known as Real-time Postion Management respiratory
tracking system (RPM)
Various systems:
Video camera based tracking (external)
Radiological tracking:
Implanted fiducials
Direct tracking of tumor mass
Non radiographic tracking:
Implanted radiofrequncy coils (tracked magnetically)
Implanted wireless transponders (tracked using wireless signals)
3-D USG based tracking (earlier BAT system)
Also known as Real-time Postion Management respiratory
tracking system (RPM)
Various systems:
Video camera based tracking (external)
Radiological tracking:
Implanted fiducials
Direct tracking of tumor mass
Non radiographic tracking:
Implanted radiofrequncy coils (tracked magnetically)
Implanted wireless transponders (tracked using wireless signals)
3-D USG based tracking (earlier BAT system)
Results
a = includes setup error
a = includes setup error
Adaptive
Radiotherapy
Planning
Radiotherapy
Planning
Adaptive Radiotherapy (ART)
Adaptive radiotherapy is a technique by which a conformal
radiation dose plan is modified to conform to a mobile and
deformable target.
Two components:
Adapt to tumor motion (IGRT)
Adapt to tumor / organ deformation and volume change.
4 ways to adapt radiation beam to tracked tumor motion:
Move couch electronically to adapt to the moving tumor
Move a charged particle beam electromagnetically
Move a robotic lightweight linear accelerator
Move aperture shaped by a dynamic MLC
Adaptive radiotherapy is a technique by which a conformal
radiation dose plan is modified to conform to a mobile and
deformable target.
Two components:
Adapt to tumor motion (IGRT)
Adapt to tumor / organ deformation and volume change.
4 ways to adapt radiation beam to tracked tumor motion:
Move couch electronically to adapt to the moving tumor
Move a charged particle beam electromagnetically
Move a robotic lightweight linear accelerator
Move aperture shaped by a dynamic MLC
ART: Concept
●Conventional R
x
➢Sample Population based
margins
➢Accomadates variations of
setup for the populations
➢No or infrequent imaging
➢Largest margin
●Offline ART
➢Individual patient based
margins
➢Frequent imaging of
patients
➢Estimated systemic error
corrected based on
repeated measurements
➢A small margin kept for
random error
➢Plans adapted to average
changes
●Online ART
➢Individual patient based
margins
➢Daily imaging of patients
➢Daily error corrected
prior to the treatment
➢Smallest margin required
➢Plans adapted to the
changing anatomy daily!
1. 2. 3.
●Conventional R
x
➢Sample Population based
margins
➢Accomadates variations of
setup for the populations
➢No or infrequent imaging
➢Largest margin
●Offline ART
➢Individual patient based
margins
➢Frequent imaging of
patients
➢Estimated systemic error
corrected based on
repeated measurements
➢A small margin kept for
random error
➢Plans adapted to average
changes
●Online ART
➢Individual patient based
margins
➢Daily imaging of patients
➢Daily error corrected
prior to the treatment
➢Smallest margin required
➢Plans adapted to the
changing anatomy daily!
1. 2. 3.
ART: Why ?
Due to a change in the contours (e.g. Weight Loss) the
actual dose received by the organ can vary significantly
from the planned dose despite accurate setup and lack of
motion.
Due to a change in the contours (e.g. Weight Loss) the
actual dose received by the organ can vary significantly
from the planned dose despite accurate setup and lack of
motion.
ART: Problem
Real time adaptive RT is not possible “today”
Real time adaptive RT is not possible “today”
ART: Steps..
ART: Steps
Helical Tomotherapy
Helical Tomotherapy
Gantry dia 85 cm
Integrated S Band LINAC
6 MV photon beam
No flattening filter – output
increased to 8 Gy/min at
center of bore
Independant Y - Jaws are
provided (95% Tungsten)
Fan beam from the jaws can
have thickness of 1 -5 cm
along the Y axis
Gantry dia 85 cm
Integrated S Band LINAC
6 MV photon beam
No flattening filter – output
increased to 8 Gy/min at
center of bore
Independant Y - Jaws are
provided (95% Tungsten)
Fan beam from the jaws can
have thickness of 1 -5 cm
along the Y axis
Helical Tomotherapy
Binary MLCs are provided – 2
positions – open or closed
Pneumatically driven 64 leaves
Open close time of 20 ms
Width 6.25 mm at isocenter
10 cm thick
Interleaf transmission – 0.5% in
field and 0.25% out field
Maximum FOV = 40 cm
However Targets of 60 cm dia
meter can be treated.
LINAC
Cone Beam
Y jaw
Y jaw
Fan Beam
Binary MLC
Binary MLCs are provided – 2
positions – open or closed
Pneumatically driven 64 leaves
Open close time of 20 ms
Width 6.25 mm at isocenter
10 cm thick
Interleaf transmission – 0.5% in
field and 0.25% out field
Maximum FOV = 40 cm
However Targets of 60 cm dia
meter can be treated.
LINAC
Cone Beam
Y jaw
Y jaw
Fan Beam
Binary MLC
Helical Tomotherapy
Flat Couch provided allows
automatic translations during
treatment
Target Length long as 160 cm
can be treated
“Cobra action” of the couch limits
the length treatable
Manual lateral couch translations
possible
Automatic longitudinal and
vertical motions possible
Flat Couch provided allows
automatic translations during
treatment
Target Length long as 160 cm
can be treated
“Cobra action” of the couch limits
the length treatable
Manual lateral couch translations
possible
Automatic longitudinal and
vertical motions possible
Helical Tomotherapy
Integrated MV CT obtained by an
integrated CT detector array.
MV beam produced with 3.5 MV photons
Allows accurate setup and image guidance
Allows higher image resolution than cone
beam MV CT (3 cm dia with 3% contrast
difference)
Tissue heterogenity calculations can be
done reliably on the CT images as scatter is
less (HU more reliable per pixel)
Not affected by High Z materials (implant)
Dose 0.3 – 3 Gy depending on slice
thickness
Dose verification possible
Integrated MV CT obtained by an
integrated CT detector array.
MV beam produced with 3.5 MV photons
Allows accurate setup and image guidance
Allows higher image resolution than cone
beam MV CT (3 cm dia with 3% contrast
difference)
Tissue heterogenity calculations can be
done reliably on the CT images as scatter is
less (HU more reliable per pixel)
Not affected by High Z materials (implant)
Dose 0.3 – 3 Gy depending on slice
thickness
Dose verification possible
Newer Techniques
in Radiation therapy
Treatment Results (Clinical)
in Radiation therapy
Treatment Results (Clinical)
Prostate Cancer
Late rectal toxicity (Gr 2 or more) is seen in 20 – 30%; ED occurs in 50 -60%!!!
Late rectal toxicity (Gr 2 or more) is seen in 20 – 30%; ED occurs in 50 -60%!!!
Prostate Cancer
Zelefsky et al (2006, J. Urol) –
561 patients (1996 - 2000)
All localized prostate cancer
Risk group according to the
NCCN guidelines
Treated with IMRT ± NAAD
Dose: 81 Gy in 1.8 Gy
PTV dose homogenity ± 10%
Rectal wall constraints:
53% vol = 46 Gy
36% vol = 75.6 Gy
Zelefsky et al (2006, J. Urol) –
561 patients (1996 - 2000)
All localized prostate cancer
Risk group according to the
NCCN guidelines
Treated with IMRT ± NAAD
Dose: 81 Gy in 1.8 Gy
PTV dose homogenity ± 10%
Rectal wall constraints:
53% vol = 46 Gy
36% vol = 75.6 Gy
Prostate Cancer
8 yr biochemical relapse free
survival rates:
85% - Favourable
76% - Intermediate
72% - Unfavourable
CSS (8 yrs):
100% - Favourable
96% - Intermediate
84% - Unfavourable
NAAT: No significant
difference in outcomes
8 yr biochemical relapse free
survival rates:
85% - Favourable
76% - Intermediate
72% - Unfavourable
CSS (8 yrs):
100% - Favourable
96% - Intermediate
84% - Unfavourable
NAAT: No significant
difference in outcomes
Prostate Cancer
Rectal Toxicity:
Grade 2: 7 patients (1.5%); Grade 3: 3 patients (less than
1%)
The 8-year actuarial likelihood of late grade 2 or greater rectal
toxicity 1.6%.
Urinary Toxicity:
Grade 2 chronic urethritis in 50 patients (9%); Urethral
stricture requiring dilation (grade 3) developed in 18 patients
(3%).
The 8-year actuarial likelihood of late grade 2 or greater
urinary toxicities was 15%.
47% patient developed ED (43% IMRT alone; 57% ADT)
No 2
nd
cancers!
Rectal Toxicity:
Grade 2: 7 patients (1.5%); Grade 3: 3 patients (less than
1%)
The 8-year actuarial likelihood of late grade 2 or greater rectal
toxicity 1.6%.
Urinary Toxicity:
Grade 2 chronic urethritis in 50 patients (9%); Urethral
stricture requiring dilation (grade 3) developed in 18 patients
(3%).
The 8-year actuarial likelihood of late grade 2 or greater
urinary toxicities was 15%.
47% patient developed ED (43% IMRT alone; 57% ADT)
No 2
nd
cancers!
Prostate Cancer
Arcangeli et al (2007) WP-IMRT
with Prostate boost
N = 55; All had NAADT, Risk of
nodal mets > 15%
Dose:
55 – 59 Gy (Pelvis)
66 – 80 Gy (Prostate)
33 – 40 fractions
No Gr III toxicity
Late Gr II toxicity:
Rectum: 2 yr actuarial probablity
8%
91%
71%
63%
Arcangeli et al (2007) WP-IMRT
with Prostate boost
N = 55; All had NAADT, Risk of
nodal mets > 15%
Dose:
55 – 59 Gy (Pelvis)
66 – 80 Gy (Prostate)
33 – 40 fractions
No Gr III toxicity
Late Gr II toxicity:
Rectum: 2 yr actuarial probablity
8%
91%
71%
63%
Head and Neck Cancers
AuthorYear NCCT Dose Result
200341 (I)Yes
200639 (I)Yes
Yao (P,NR)200790 (I)Yes
200650 (I)Yes
Huang
(P,NR)
70/60/50 (2.18
Gy per #)
68% Stage IV; 31% Gr III mucositis;
7% Gr IV mucositis; Gr II xerostomia
58.5%; 2 yr Locoregional control
89% ; 2 yr OS 89%
Wendt
(P,NR)
60-70 Gy / 48
-54 Gy (I)
Gr III mucositis 11%; 12% Gr III
xerostomia at 6 months; 2yr Crude
LC 70%; 50 % recurrences outside
high dose region
70/60/54 Gy
(SIB)
All N2/N3 disease; 71% Oropharynx;
3 yr LC 96%; OS 67.5%; PET useful
in patient selection for ND (10)
Arruda
(P,NR)
70 / 59.4 -54 Gy
(76% - SIB)
All oropharynx; 92% ≥ St III; 33%
Gr II xerostomia (1 yr); Gr III
mucositis 38%; 2 yr LRC 88%; OS
98%
Table showing Results of IMRT in H&N Ca
AuthorYear NCCT Dose Result
200341 (I)Yes
200639 (I)Yes
Yao (P,NR)200790 (I)Yes
200650 (I)Yes
Huang
(P,NR)
70/60/50 (2.18
Gy per #)
68% Stage IV; 31% Gr III mucositis;
7% Gr IV mucositis; Gr II xerostomia
58.5%; 2 yr Locoregional control
89% ; 2 yr OS 89%
Wendt
(P,NR)
60-70 Gy / 48
-54 Gy (I)
Gr III mucositis 11%; 12% Gr III
xerostomia at 6 months; 2yr Crude
LC 70%; 50 % recurrences outside
high dose region
70/60/54 Gy
(SIB)
All N2/N3 disease; 71% Oropharynx;
3 yr LC 96%; OS 67.5%; PET useful
in patient selection for ND (10)
Arruda
(P,NR)
70 / 59.4 -54 Gy
(76% - SIB)
All oropharynx; 92% ≥ St III; 33%
Gr II xerostomia (1 yr); Gr III
mucositis 38%; 2 yr LRC 88%; OS
98%
Table showing Results of IMRT in H&N Ca
Head and Neck Cancers
Author NCCT Dose Result
2003
2005
200579 (I)Yes
200769 (I)Yes
200749 (I)Yes
Year
Chao
(P,NR)
126
(I)
Yes
(30%)
72 -68/ 64 -60 Gy
(SIB)
59% Post op IMRT; 67% St IV; 2 yr
LRC 85% ; 89% (Post ND)
Thorstad
(P,NR)
356
(I)
Yes
(40%)
70/56 Gy – Def.;
64/54 Gy –
Postop
63% Post op; 90% ≥ St III; 5 Yr LRC
76%; 14% of the failures were
marginal. All marginal failures in post
op patients.
Wolden
(P,NR)
70 Gy (59 –
Hyperfractionated
; 15 - SIB)
All Npx; 80% ≥ Stage III; 3 yr
actuarial LC 91%; OS 83%; Gr III
hearing loss 15%; 32% Gr II
xerostomia at 1 yr; distant mets
dominant form of therapy
Daly
(P,NR)
66 Gy -Def (2.2
Gy per #); 60.2 –
Post op (2.15 per
#)
33% Post op; 2 yr LC and OS 92% and
74%(Def); 87% and 87% (Post op);
Mean xerstomia significantly improved
than CRT
Schwartz
(P,NR)
60 / 50 Gy (25#)
- SIB
All Stage III/IV; Gr III mucositis 55%,
Gr III dermatitis 8%; 2 yr LC 83% ;
OS 80%
Table showing results of IMRT in H& N Ca
Author NCCT Dose Result
2003
2005
200579 (I)Yes
200769 (I)Yes
200749 (I)Yes
Year
Chao
(P,NR)
126
(I)
Yes
(30%)
72 -68/ 64 -60 Gy
(SIB)
59% Post op IMRT; 67% St IV; 2 yr
LRC 85% ; 89% (Post ND)
Thorstad
(P,NR)
356
(I)
Yes
(40%)
70/56 Gy – Def.;
64/54 Gy –
Postop
63% Post op; 90% ≥ St III; 5 Yr LRC
76%; 14% of the failures were
marginal. All marginal failures in post
op patients.
Wolden
(P,NR)
70 Gy (59 –
Hyperfractionated
; 15 - SIB)
All Npx; 80% ≥ Stage III; 3 yr
actuarial LC 91%; OS 83%; Gr III
hearing loss 15%; 32% Gr II
xerostomia at 1 yr; distant mets
dominant form of therapy
Daly
(P,NR)
66 Gy -Def (2.2
Gy per #); 60.2 –
Post op (2.15 per
#)
33% Post op; 2 yr LC and OS 92% and
74%(Def); 87% and 87% (Post op);
Mean xerstomia significantly improved
than CRT
Schwartz
(P,NR)
60 / 50 Gy (25#)
- SIB
All Stage III/IV; Gr III mucositis 55%,
Gr III dermatitis 8%; 2 yr LC 83% ;
OS 80%
Table showing results of IMRT in H& N Ca
Head and Neck Cancers
Author NCCT Dose Result
200341 (I)Yes
2004 No
Pow (P,R)2006 No
2006 No
Year
Huang
(P,NR)
70/60/50
(2.18 Gy per
#)
68% Stage IV; 31% Gr III mucositis; 7%
Gr IV mucositis; Gr II xerostomia 58.5%;
2 yr Locoregional control 89% ; 2 yr OS
89%
Jabbari
(P,NR)
30 (I),
10 (C)
60-78 Gy (I);
63 -76.8 (C)
At 12 months, median XQ and HNQOL
scores were lower (better) in the IMRT
compared with the standard RT patients
by 19 and 20 points, respectively
24
(I),21
(C)
68-70 / 66-
68(I); 68 / 66
(C)
All Stage II Npx; At 1 yr 83% had
recovered 25% of the pre RT parotid flow
in IMRT (9.5% in Conv RT arm). Subscale
scores for role-physical, bodily pain, and
physical function were significantly higher
in the IMRT group
Braam
(P,NR)
30 (I),
26 (C)
I – 69/66/54
(30#), C – 50
-70/46-50(25
– 35#)
83% in I arm treated definitively (23% in
C arm);mean parotid flow ratio was 18%
(C) and 64% (I); parotid gland
complication rate was 81% (C) and 56%
(I) (p = 0.04).
Table showing Salivary sparing and QOL improvement with IMRT
Author NCCT Dose Result
200341 (I)Yes
2004 No
Pow (P,R)2006 No
2006 No
Year
Huang
(P,NR)
70/60/50
(2.18 Gy per
#)
68% Stage IV; 31% Gr III mucositis; 7%
Gr IV mucositis; Gr II xerostomia 58.5%;
2 yr Locoregional control 89% ; 2 yr OS
89%
Jabbari
(P,NR)
30 (I),
10 (C)
60-78 Gy (I);
63 -76.8 (C)
At 12 months, median XQ and HNQOL
scores were lower (better) in the IMRT
compared with the standard RT patients
by 19 and 20 points, respectively
24
(I),21
(C)
68-70 / 66-
68(I); 68 / 66
(C)
All Stage II Npx; At 1 yr 83% had
recovered 25% of the pre RT parotid flow
in IMRT (9.5% in Conv RT arm). Subscale
scores for role-physical, bodily pain, and
physical function were significantly higher
in the IMRT group
Braam
(P,NR)
30 (I),
26 (C)
I – 69/66/54
(30#), C – 50
-70/46-50(25
– 35#)
83% in I arm treated definitively (23% in
C arm);mean parotid flow ratio was 18%
(C) and 64% (I); parotid gland
complication rate was 81% (C) and 56%
(I) (p = 0.04).
Table showing Salivary sparing and QOL improvement with IMRT
Breast Cancer
Largest randomized trial
Donovan et al (2007)
305 patients – 156(standard)
and 150 (IMRT)
1997 – 2000
Aim:Impact of improved
radiation dosimetry with IMRT in
terms of external assessments
of change in breast appearance
and patient self-assessments of
breast discomfort, breast
hardness and quality of life.
Dose: 50 Gy / 25# with 10 Gy
boost
Largest randomized trial
Donovan et al (2007)
305 patients – 156(standard)
and 150 (IMRT)
1997 – 2000
Aim:Impact of improved
radiation dosimetry with IMRT in
terms of external assessments
of change in breast appearance
and patient self-assessments of
breast discomfort, breast
hardness and quality of life.
Dose: 50 Gy / 25# with 10 Gy
boost
Breast Cancer
➢The control arm had 1.7 times (95% CI 1.2–2.5) more likely to have had some
change than the IMRT arm, p = 0.008.
➢Areas with dose > 105% have 1.9 times higher risk of any change in cosmesis
➢The control arm had 1.7 times (95% CI 1.2–2.5) more likely to have had some
change than the IMRT arm, p = 0.008.
➢Areas with dose > 105% have 1.9 times higher risk of any change in cosmesis
Breat Cancer
Leonard et al 2007 – APBI
55 patients , Non randomized
All patients stage I
Dose: 34 Gy (n=7) / 38.5 (n = 48) BID over 5 days
Median F/U – 1 yr
Good to excellent cosmesis:
Patient assessed: 98% (54)
Physician assessed: 98% (54)
Considered a reasonable option for patients who have large
target volumes and/or target volumes that are in anatomic
locations that are very difficult to cover.
Leonard et al 2007 – APBI
55 patients , Non randomized
All patients stage I
Dose: 34 Gy (n=7) / 38.5 (n = 48) BID over 5 days
Median F/U – 1 yr
Good to excellent cosmesis:
Patient assessed: 98% (54)
Physician assessed: 98% (54)
Considered a reasonable option for patients who have large
target volumes and/or target volumes that are in anatomic
locations that are very difficult to cover.
Lung Cancer
AuthorYear NCCT Dose Result
200537 (I)Yes63 Gy (median)
2005 No
200628 (I)No
200617 (I)Yes
200717 (I) 66 Gy
2007 Yes
Yom et al
(R, NR)
7% incidence of Gr III
pneumonitis
Yorke et al
(P, NR)
78
(3D)
Dose escalation
(50.7 – 90 Gy);
22% incidence of Gr III
pneumonitis above doses of 70
Gy.
Videtec (R,
NR)
50 Gy in 5 fraction
(SBRT)
64% T1; 2.6% Gr II pneumonitis,
no Gr III reactions; LC and OS at
1 yr 96.4% and 93% respectively
Scarbrough
(R, NR)
71.2 Gy (69–73.5
Gy)
Mean age 70; 73% IIIB, FU 1 yr,
No Gr III tox, 2 yr OS 66%
Jensen (P,
NR
Yes
(citux)
Patients no suited for CCRT. 1 Gr
III esophagitis; 79% response (6
mo)
Yom et al
(R, NR)
68 (I),
222
(3D)
63 Gy (median);
Dose > 60 Gy
84% (I), 63%
(3D)
60% stage IIIB, FU = 8 mo
(median); Gr III pneumonitis 8%
(32% for 3D CRT); V
20
35% (I) vs
38%(3D) (p = 0.001)
Table showing results of IMRT in Lung Cancer
AuthorYear NCCT Dose Result
200537 (I)Yes63 Gy (median)
2005 No
200628 (I)No
200617 (I)Yes
200717 (I) 66 Gy
2007 Yes
Yom et al
(R, NR)
7% incidence of Gr III
pneumonitis
Yorke et al
(P, NR)
78
(3D)
Dose escalation
(50.7 – 90 Gy);
22% incidence of Gr III
pneumonitis above doses of 70
Gy.
Videtec (R,
NR)
50 Gy in 5 fraction
(SBRT)
64% T1; 2.6% Gr II pneumonitis,
no Gr III reactions; LC and OS at
1 yr 96.4% and 93% respectively
Scarbrough
(R, NR)
71.2 Gy (69–73.5
Gy)
Mean age 70; 73% IIIB, FU 1 yr,
No Gr III tox, 2 yr OS 66%
Jensen (P,
NR
Yes
(citux)
Patients no suited for CCRT. 1 Gr
III esophagitis; 79% response (6
mo)
Yom et al
(R, NR)
68 (I),
222
(3D)
63 Gy (median);
Dose > 60 Gy
84% (I), 63%
(3D)
60% stage IIIB, FU = 8 mo
(median); Gr III pneumonitis 8%
(32% for 3D CRT); V
20
35% (I) vs
38%(3D) (p = 0.001)
Table showing results of IMRT in Lung Cancer
Brain Tumors
AuthorYearN Dose Result
Sultanem200425
Luchi200625
Narayana200658
60 Gy (GTV); 40
Gy (CTV); 20 #
All GBM,Post op volume < 110 cc;
Majority RPA class 4/5; The 1-year
overall survival rate is 40%, Median
survial 9 mo. No late toxicity.
48 – 68 Gy
(GTV); 40 Gy
(CTV1); 32 Gy
(CTV2); 8 #
2 AA patients; Median KPS 70; 2 yr PFS
53.6%; 2 yr survival 55.6%; Pattern of
death – CSF dissemination most
common cause of death!
60 Gy (PTV);
30#
70% GBM; 1 yr OS 30% (2 yr 0%) for
GBM; No Gr III late toxicity; Pattern of
failure – local
Table showing results of IMRT in brain tumors
AuthorYearN Dose Result
Sultanem200425
Luchi200625
Narayana200658
60 Gy (GTV); 40
Gy (CTV); 20 #
All GBM,Post op volume < 110 cc;
Majority RPA class 4/5; The 1-year
overall survival rate is 40%, Median
survial 9 mo. No late toxicity.
48 – 68 Gy
(GTV); 40 Gy
(CTV1); 32 Gy
(CTV2); 8 #
2 AA patients; Median KPS 70; 2 yr PFS
53.6%; 2 yr survival 55.6%; Pattern of
death – CSF dissemination most
common cause of death!
60 Gy (PTV);
30#
70% GBM; 1 yr OS 30% (2 yr 0%) for
GBM; No Gr III late toxicity; Pattern of
failure – local
Table showing results of IMRT in brain tumors
Cervical Cancer
AuthorYear NCCT Dose Result
200336
200240 Y
200733 Y
200736 Y
Kochanski200562
Mundt
(P,NR)
Y
(53%)
45 Gy (1.8
Gy/#)
80% stage I-II; PTV S3 to L4/5
interspace; Chronic GI toxicity 15% (n=
3; 1 Gr II, 2 Gr I); 50% incidence in
Conventional
Mundt
(P,NR)
45 Gy (1.8
Gy/#)
60% Acute Gr II toxicity (90% Gr II in
Conv.); Less GU toxicity (10% vs 20%);
Patients not requiring antidiarrheal
halved!
Chen
(P,NR)
50.4 Gy /
28#
All Stage I -II; All Post Hysterectomy; 1
yr LRC 93%; Acute GI toxicity 36% (Gr I-
II); Acute Gu toxicity 30% (Gr I-II)
Beriwal
(P,NR)
45 Gy
(EFRT) +
10-15 Gy
boost
2 Yr LC 80%; 2 yr OS 65%; 11 had
recurrences – 9 distant; Gr III toxicity –
10%
Y
(64%)
45 Gy (1.8
Gy /#)
29% Post op; 20 Stage IIB-IIIB; 3 yr DFS
72.7%; 3 yr pelvic control 87.5%; 5% Gr
II or higher late toxicity
AuthorYear NCCT Dose Result
200336
200240 Y
200733 Y
200736 Y
Kochanski200562
Mundt
(P,NR)
Y
(53%)
45 Gy (1.8
Gy/#)
80% stage I-II; PTV S3 to L4/5
interspace; Chronic GI toxicity 15% (n=
3; 1 Gr II, 2 Gr I); 50% incidence in
Conventional
Mundt
(P,NR)
45 Gy (1.8
Gy/#)
60% Acute Gr II toxicity (90% Gr II in
Conv.); Less GU toxicity (10% vs 20%);
Patients not requiring antidiarrheal
halved!
Chen
(P,NR)
50.4 Gy /
28#
All Stage I -II; All Post Hysterectomy; 1
yr LRC 93%; Acute GI toxicity 36% (Gr I-
II); Acute Gu toxicity 30% (Gr I-II)
Beriwal
(P,NR)
45 Gy
(EFRT) +
10-15 Gy
boost
2 Yr LC 80%; 2 yr OS 65%; 11 had
recurrences – 9 distant; Gr III toxicity –
10%
Y
(64%)
45 Gy (1.8
Gy /#)
29% Post op; 20 Stage IIB-IIIB; 3 yr DFS
72.7%; 3 yr pelvic control 87.5%; 5% Gr
II or higher late toxicity
Anal Canal
AuthorYear NCCT Dose Result
200640 (I)Yes
200517 (I)Yes
200634 (I)Yes
200612 (I)Yes
Salama et
al (R, NR)
45 Gy WP + 9 Gy
boost
12.5% Gr III GI toxicity, 0 Gr III
skin toxicity, 2 year colostomy-
free, disease free, and overall
survival 81%, 73%, and 86%
Milano et al
(P, NR)
45 Gy WP + 9 Gy
boost
53% Gr II GI toxicity, No Gr III
acute or late complications. 82%
CR rate, the 2-year CFS, PFS,
and overall survial are: 82%,
65%, and 91%
Devisetty
(P,NR)
45 Gy WP + 9 Gy
boost
17% Acute GI toxicity; volume of
bowel receiving 22 Gy (V22) was
correlated with toxicity (31.8%
acute GI toxicity for V22 > 563 cc
vs. 0% for V22 ≤ 563 cc)
Hwang
(P,NR)
30.6 Gy WP +
14.4 Gy Low
Pelvic + 9 Gy
boost
42% Gr III dermal toxicity, 8% Gr
III GI toxicity, 83% CR rate
AuthorYear NCCT Dose Result
200640 (I)Yes
200517 (I)Yes
200634 (I)Yes
200612 (I)Yes
Salama et
al (R, NR)
45 Gy WP + 9 Gy
boost
12.5% Gr III GI toxicity, 0 Gr III
skin toxicity, 2 year colostomy-
free, disease free, and overall
survival 81%, 73%, and 86%
Milano et al
(P, NR)
45 Gy WP + 9 Gy
boost
53% Gr II GI toxicity, No Gr III
acute or late complications. 82%
CR rate, the 2-year CFS, PFS,
and overall survial are: 82%,
65%, and 91%
Devisetty
(P,NR)
45 Gy WP + 9 Gy
boost
17% Acute GI toxicity; volume of
bowel receiving 22 Gy (V22) was
correlated with toxicity (31.8%
acute GI toxicity for V22 > 563 cc
vs. 0% for V22 ≤ 563 cc)
Hwang
(P,NR)
30.6 Gy WP +
14.4 Gy Low
Pelvic + 9 Gy
boost
42% Gr III dermal toxicity, 8% Gr
III GI toxicity, 83% CR rate
New Techniques in
Stereotactic
Radiation therapy
Stereotactic
Radiation therapy
Stereotaxy
Derived from the greek words Stereo = 3 dimensional space
and Taxis = to arrange.
A method which defines a point in the patient’s body by
using an external three-dimensional coordinate system which
is rigidly attached to the patient.
Stereotactic radiotherapy uses this technique to position a
target reference point, defined in the tumor, in the isocenter
of the radiation machine (LINAC, gamma knife, etc.).
Units used:
Gamma Knife
LINAC with special collimators or mico MLC
Cyberknife
Neutron beams
Derived from the greek words Stereo = 3 dimensional space
and Taxis = to arrange.
A method which defines a point in the patient’s body by
using an external three-dimensional coordinate system which
is rigidly attached to the patient.
Stereotactic radiotherapy uses this technique to position a
target reference point, defined in the tumor, in the isocenter
of the radiation machine (LINAC, gamma knife, etc.).
Units used:
Gamma Knife
LINAC with special collimators or mico MLC
Cyberknife
Neutron beams
Stereotactic Radiation
Two braod groups:
Radiosurgery: Single
treatment fraction
Radiotherapy: Multiple
fractions
Frameless stereotactic
radiation is possible in one
system – cyberknife
Sites used:
Cranial
Extracranial
Rigid application of a stereotactic
frame to the patient
3 D Volumetric imaging with the
frame attached
Target delineation and Treatment
planning
Postioning of patinet with the
frame after verification
QA of treatment and delivery of
therapy
Two braod groups:
Radiosurgery: Single
treatment fraction
Radiotherapy: Multiple
fractions
Frameless stereotactic
radiation is possible in one
system – cyberknife
Sites used:
Cranial
Extracranial
Rigid application of a stereotactic
frame to the patient
3 D Volumetric imaging with the
frame attached
Target delineation and Treatment
planning
Postioning of patinet with the
frame after verification
QA of treatment and delivery of
therapy
Sterotactic Radiation
The first machine used by Leksell in 1951 was a 250 KV Xray
tube.
In 1968 the Gamma knife was available
LINAC based stereotactic radiation appeared in 1980
Other machines using protons (1958) and heavy ions – He
(1978) were also used for stereotactic postioning of the
Bragg's Peak
The first machine used by Leksell in 1951 was a 250 KV Xray
tube.
In 1968 the Gamma knife was available
LINAC based stereotactic radiation appeared in 1980
Other machines using protons (1958) and heavy ions – He
(1978) were also used for stereotactic postioning of the
Bragg's Peak
Gamma Knife
Designed to provide an
overall treatment accuracy
of 0.3 mm
3 basic components
Spherical source housing
4 types of collimator
helmets
Couch with electronic
controls
201 Co
60
sources (30 Ci)
Unit Center Point 40 cm
Dose Rate 300 cGy/min
Designed to provide an
overall treatment accuracy
of 0.3 mm
3 basic components
Spherical source housing
4 types of collimator
helmets
Couch with electronic
controls
201 Co
60
sources (30 Ci)
Unit Center Point 40 cm
Dose Rate 300 cGy/min
LINAC Radiosurgery
Conventional LINAC aperture modified
by a tertiary collimator.
Two commercial machines
Varian Trilogy
Novalis
Conventional LINAC aperture modified
by a tertiary collimator.
Two commercial machines
Varian Trilogy
Novalis
Cyberknife
Floor mounted Amorphous
silicon detectors
6 MV LINAC
Roof mounted KV X-ray
Frameless patient
immobilization couch
Robotic arm with 6
degrees of freedon
Circular Collimator
attached to head
Floor mounted Amorphous
silicon detectors
6 MV LINAC
Roof mounted KV X-ray
Frameless patient
immobilization couch
Robotic arm with 6
degrees of freedon
Circular Collimator
attached to head
Advantages of Cyberknife
An image-guided, frameless radiosurgery system.
Non-isocentric treatment allows for simultaneous irradiation
of multiple lesions.
The lack of a requirement for the use of a head-frame allows
for staged treatment.
Real time organ position and movement correction facility
Potentially superior inverse optimization solutions
available.
An image-guided, frameless radiosurgery system.
Non-isocentric treatment allows for simultaneous irradiation
of multiple lesions.
The lack of a requirement for the use of a head-frame allows
for staged treatment.
Real time organ position and movement correction facility
Potentially superior inverse optimization solutions
available.
Cyberknife
185 published articles till date; 5000 patients treated.
73 worldwide installations
Areas where clinically evaluated:
Intracranial tumors
Trigeminal neuralgia and AVMs
Paraspinal tumors – 1° and 2°
Juvenile Nasopharyngeal Angiofibroma
Perioptic tumors
Localized prostate cancer
However till date maximum expirence with Intracranial or
Peri-spinal Stereotactic RT
185 published articles till date; 5000 patients treated.
73 worldwide installations
Areas where clinically evaluated:
Intracranial tumors
Trigeminal neuralgia and AVMs
Paraspinal tumors – 1° and 2°
Juvenile Nasopharyngeal Angiofibroma
Perioptic tumors
Localized prostate cancer
However till date maximum expirence with Intracranial or
Peri-spinal Stereotactic RT
Results
Tumor Year N Result
2004
2003 285
UP 203
2002 203
Brain mets
(Andrews et al)
333 (164
SRT / 164
C)
Survival advantage for patients with single
brain mets (Median survival 6.5 – 4.9 mo);
Better functional status at follow up – SRT with
WBRT Rx in single brain mets (RTOG 9508)
Benign brain
tumors
( Kondziolka et al)
95% tumor control (media F/U 10 yr); actuarial
tumor control rate at 15 years was 93.7%.
Normal facial nerve function was maintained in
95% with aucostic neuromas
Malignant Glioma
(Souhami et al)
SRT + EBRT + BCNU did not result in significant
survial advantage – 13.6 vs 13.5 mo (RTOG
9305)
Malignant Glioma
(Souhami et al)
SRT + EBRT + BCNU did not result in significant
improvement in Quality adjusted survival
(RTOG 9305)
The only randomized trial comparing stereotactic radiation therapy boost has
failed to reveal a significant survival benefit for patients with malignant
gliomas. (RTOG 9305). However 18% of the patients in the stereotactic
radiotherapy arm had significant protocol deviations.
Tumor Year N Result
2004
2003 285
UP 203
2002 203
Brain mets
(Andrews et al)
333 (164
SRT / 164
C)
Survival advantage for patients with single
brain mets (Median survival 6.5 – 4.9 mo);
Better functional status at follow up – SRT with
WBRT Rx in single brain mets (RTOG 9508)
Benign brain
tumors
( Kondziolka et al)
95% tumor control (media F/U 10 yr); actuarial
tumor control rate at 15 years was 93.7%.
Normal facial nerve function was maintained in
95% with aucostic neuromas
Malignant Glioma
(Souhami et al)
SRT + EBRT + BCNU did not result in significant
survial advantage – 13.6 vs 13.5 mo (RTOG
9305)
Malignant Glioma
(Souhami et al)
SRT + EBRT + BCNU did not result in significant
improvement in Quality adjusted survival
(RTOG 9305)
The only randomized trial comparing stereotactic radiation therapy boost has
failed to reveal a significant survival benefit for patients with malignant
gliomas. (RTOG 9305). However 18% of the patients in the stereotactic
radiotherapy arm had significant protocol deviations.
New Techniques in
Brachytherapy
Brachytherapy
Brachytherpy
An inherently conformal
method of radiation delivery
Relies on the inverse square
law for the conformity
Unlike traditional EBRT
brachytherapy is both :
Physically conformal
Biologically conformal
Recent advances have
focused on better method of
target identification and
radio-isotope placement.
D
o
s
e
Distance
Rapid dose fall off from
the radio-isotope
An inherently conformal
method of radiation delivery
Relies on the inverse square
law for the conformity
Unlike traditional EBRT
brachytherapy is both :
Physically conformal
Biologically conformal
Recent advances have
focused on better method of
target identification and
radio-isotope placement.
D
o
s
e
Distance
Rapid dose fall off from
the radio-isotope
Brachytherapy: What's New
Image Based Brachytherapy
Image Guided Brachytherapy
Robotic Brachytherapy
‡
Electronic Brachytherapy*
Image Based Brachytherapy: Technique where advanced
imaging modalites are used to gain information about the
volumetric dose delivery by brachytherapy
Image Guided Brachytherapy: Technique where imaging
is used to guide brachytherapy source placement as well
give information regarding the volumetric dose distribution
Image Assisted
Brachytherapy
Image Based Brachytherapy
Image Guided Brachytherapy
Robotic Brachytherapy
‡
Electronic Brachytherapy*
Image Based Brachytherapy: Technique where advanced
imaging modalites are used to gain information about the
volumetric dose delivery by brachytherapy
Image Guided Brachytherapy: Technique where imaging
is used to guide brachytherapy source placement as well
give information regarding the volumetric dose distribution
Image Assisted
Brachytherapy
Image Assisted Brachytherapy
Principle: Cross sectional imaging utilized to plan and
analyze a brachytherapy procedure
Steps:
Image assisted provisional treatment planning
Image guided application
Image assisted definitive treatment planning
Image assisted quality control of dose delivery
Provisional planning refers to the planning of the implant
prior to the placement of the applicator in situ – important to
realize the significant anatomical distrortions 2° to the
applicator placement.
Definitive planning refers to the definitve treatment
planning with the applicator in situ.
Principle: Cross sectional imaging utilized to plan and
analyze a brachytherapy procedure
Steps:
Image assisted provisional treatment planning
Image guided application
Image assisted definitive treatment planning
Image assisted quality control of dose delivery
Provisional planning refers to the planning of the implant
prior to the placement of the applicator in situ – important to
realize the significant anatomical distrortions 2° to the
applicator placement.
Definitive planning refers to the definitve treatment
planning with the applicator in situ.
Equipment: Overview
Equipment: Imaging
Site
Mobile Tongue MRI CT
Floor of mouth MRI CT, US
Oropharynx MRI, ES CT
Nasopharynx ES, MRI CT
Cervix MRI CT, US (Endo)
Endometrium MRI, ES CT, US (Endo)
Vagina US (endo), MRI CT
Breast Mammography, MRI CT, US
Bladder ES, MRI, CT US
Prostate MRI US (endo), CT
Anorectal ES, MRI, US (endo) CT
Oesophagus ES, Oesophagogram (Barium) CT, MRI, US (endo)
Bile duct Cholangiogram, ES CT, US, MRI
Soft tissue sarcoma MRI CT
Bronchus ES, CT, Chest X Ray MRI
Brain MRI CT
1
st
Choice 2
nd
Choice
Table showing Imaging modality of choice in different anatomical areas
Site
Mobile Tongue MRI CT
Floor of mouth MRI CT, US
Oropharynx MRI, ES CT
Nasopharynx ES, MRI CT
Cervix MRI CT, US (Endo)
Endometrium MRI, ES CT, US (Endo)
Vagina US (endo), MRI CT
Breast Mammography, MRI CT, US
Bladder ES, MRI, CT US
Prostate MRI US (endo), CT
Anorectal ES, MRI, US (endo) CT
Oesophagus ES, Oesophagogram (Barium) CT, MRI, US (endo)
Bile duct Cholangiogram, ES CT, US, MRI
Soft tissue sarcoma MRI CT
Bronchus ES, CT, Chest X Ray MRI
Brain MRI CT
1
st
Choice 2
nd
Choice
Table showing Imaging modality of choice in different anatomical areas
Equipment: Applicators
Image Acqusition
Images should be acquired in 3 dimensions parallel and
perpendicular to the axis of the applicator
This minimizes reconstruction related artifacts
The best modality in this respect is the MRI
CE MRI can provide excellent soft tissue contrast too
Para Sagittal Para Coronal Para Axial
Images should be acquired in 3 dimensions parallel and
perpendicular to the axis of the applicator
This minimizes reconstruction related artifacts
The best modality in this respect is the MRI
CE MRI can provide excellent soft tissue contrast too
Para Sagittal Para Coronal Para Axial
Tumor Delineation
Tumor delineation requires a good
clinical examination in
brachytherapy:
Mucosal infiltration is usually
picked up on visual inspection only.
The ideal imaging modality for soft
tissue resolution : MRI
Tumors are usually contoured in
the T2 weighted image
T1 images are better for detection
of lymphadenopathy
Tumor delineation requires a good
clinical examination in
brachytherapy:
Mucosal infiltration is usually
picked up on visual inspection only.
The ideal imaging modality for soft
tissue resolution : MRI
Tumors are usually contoured in
the T2 weighted image
T1 images are better for detection
of lymphadenopathy
Target Volumes
The target volumes as defined by ICRU 58 are similiar to the
ICRU 62 recommendations
Modifications specific to brachytherapy:
PTV generally “approximates” CTV as applicators are
considered to maintain positional accuracy.
If the patient is treated with EBRT / Sx prior to brachy the CTV
is the initial tumor volume (GTV) prior to treatment.
The GTV for brachytherapy should be recorded seperately in
such cases.
Due to high dose gradient organ delineation is meaningful if
done in the vicinity of the applicator
For luminal structures wall delineation can give a better idea
about the dose received as compared to the whole volume
The target volumes as defined by ICRU 58 are similiar to the
ICRU 62 recommendations
Modifications specific to brachytherapy:
PTV generally “approximates” CTV as applicators are
considered to maintain positional accuracy.
If the patient is treated with EBRT / Sx prior to brachy the CTV
is the initial tumor volume (GTV) prior to treatment.
The GTV for brachytherapy should be recorded seperately in
such cases.
Due to high dose gradient organ delineation is meaningful if
done in the vicinity of the applicator
For luminal structures wall delineation can give a better idea
about the dose received as compared to the whole volume
Image based brachytherapy
Dose Distribution at level of
ovoids and tandem
3 D view of the
applicator geometry
3 D Dose
distribution
Rectum
Bladder
Dose Distribution at level of
ovoids and tandem
3 D view of the
applicator geometry
3 D Dose
distribution
Rectum
Bladder
Provisional Planning
B Mode USG with stepper
Template
Acquired sagittal image
demonstrating bladder prostate
interface
Saggital Image with template overlay
Pubic
arch
Prostate
Urethra
Rectum
B Mode USG with stepper
Template
Acquired sagittal image
demonstrating bladder prostate
interface
Saggital Image with template overlay
Pubic
arch
Prostate
Urethra
Rectum
Provisional Planning
Beaulieu et al reported on 35 cases (IJROBP 2002)
Prostate contours were created in a preplan setting as well
as in the operating room (OR).
In 63% of patients the volume of the prostate drawn had
changed.
These changes in volume and shape resulted in a mean dose
coverage loss of 5.7%.
In extreme cases, the V
100
coverage loss was 20.9%.
At present applied clinically for prostate cancer only.
For both intraluminal and intracavitary significant changes of
the anatomy on application preclude provisional planning.
Beaulieu et al reported on 35 cases (IJROBP 2002)
Prostate contours were created in a preplan setting as well
as in the operating room (OR).
In 63% of patients the volume of the prostate drawn had
changed.
These changes in volume and shape resulted in a mean dose
coverage loss of 5.7%.
In extreme cases, the V
100
coverage loss was 20.9%.
At present applied clinically for prostate cancer only.
For both intraluminal and intracavitary significant changes of
the anatomy on application preclude provisional planning.
Image Guided Brachytherapy
Radiation Oncologist
acquiring sectional
USG images
Contouring and dose
planning being done on
the TPS
The finalized plan with
the superimposed grid on
the template indicated
the point of placement of
each needle
Radiation Oncologist
acquiring sectional
USG images
Contouring and dose
planning being done on
the TPS
The finalized plan with
the superimposed grid on
the template indicated
the point of placement of
each needle
Image Guided Brachytherapy
A machine called the
seed loader can receive
instructions from the
TPS directly
“Seed afterloader” with
the needle containing
the in postion.
Needles being
inserted into the
prostate under
direct USG
guidance
A machine called the
seed loader can receive
instructions from the
TPS directly
“Seed afterloader” with
the needle containing
the in postion.
Needles being
inserted into the
prostate under
direct USG
guidance
Image Guide Brachytherapy
View of the B Mode Stepped USG device
with the template for insertion of the
needles. Some needles have been
placed already
Final Seed placement
View of the B Mode Stepped USG device
with the template for insertion of the
needles. Some needles have been
placed already
Final Seed placement
Real Time dynamic IGBRT
Results
Keasten et al (IJROBP 2006)
564 patients of prostate CA – IGRT or IGBRT (5 yr FU)
5-year BC rates were similar in both groups (78–82% for IGRT vs
80–84% for IGBRT)
IGRT higher chronic grade≥2 GI toxicity (22% vs 12% for
EBRT+HDR)
EBRT+HDR higher chronic grade≥2 GU toxicity (30% vs 17% for
IGRT)
Nandalur et al (IJROBP 2006)
479 Prostate cancer patients IGRT vs IGBT
5 yr biochemical control rates > 90% (GR III toxicity ~ 4-6%!!)
C-IGBT patients experienced significantly less chronic grade 2 GI
toxicity and sexual dysfunction.
Keasten et al (IJROBP 2006)
564 patients of prostate CA – IGRT or IGBRT (5 yr FU)
5-year BC rates were similar in both groups (78–82% for IGRT vs
80–84% for IGBRT)
IGRT higher chronic grade≥2 GI toxicity (22% vs 12% for
EBRT+HDR)
EBRT+HDR higher chronic grade≥2 GU toxicity (30% vs 17% for
IGRT)
Nandalur et al (IJROBP 2006)
479 Prostate cancer patients IGRT vs IGBT
5 yr biochemical control rates > 90% (GR III toxicity ~ 4-6%!!)
C-IGBT patients experienced significantly less chronic grade 2 GI
toxicity and sexual dysfunction.
Electronic Brachytherapy
Customized Ballon
Applicator
KV Xray Tube
AXXENT
X ray Source Assembly
Customized Ballon
Applicator
KV Xray Tube
AXXENT
X ray Source Assembly
Conclusions
Conformal radiation therapy requires a good imaging guidance and
better machines for delivery – development expensive and time
consuming
Dosimetric results invariably show superiorty of conformal
avoidance
IMRT the best conformal EBRT technique can allow new methods
of radiotherapy – bringing hypofractionation back into fashion
Several unresolved questions – sparse but emerging clinical data
Cancers of developing nations – stand maximum to gain from
Conformal radiation therapy
Approach – Cautious Embrace?
Conformal radiation therapy requires a good imaging guidance and
better machines for delivery – development expensive and time
consuming
Dosimetric results invariably show superiorty of conformal
avoidance
IMRT the best conformal EBRT technique can allow new methods
of radiotherapy – bringing hypofractionation back into fashion
Several unresolved questions – sparse but emerging clinical data
Cancers of developing nations – stand maximum to gain from
Conformal radiation therapy
Approach – Cautious Embrace?
Thank You
Radiotherapy can treat 30% cancers while Chemo/Biotherapy 2% -
But considered as the “sticking plaster” of oncology”
S. Webb
Radiotherapy can treat 30% cancers while Chemo/Biotherapy 2% -
But considered as the “sticking plaster” of oncology”
S. Webb
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