Image Guided Radiotherapy

IGRT CLINICAL DEMONSTRATION IN
HEAD AND NECK & CNS TUMORS
Dr Sheetal R Kashid

CONTENT
IGRT- What, Why, When, How
Set Up Errors and correction protocols
IGRT equipments inTMH
IGRT approach for Head & Neck Oncology in TMH
IGRT approach for Neuro-Oncology in TMH

What is IGRT ?
“Delivery of therapeutic radiation by applying image-based target re-
localization to allow proper patient repositioning for the purpose of
ensuring accurate treatment and minimizing the volume of normal
tissue exposed to ionizing radiation.”
-ACR-ASTRO
Reference :ACR-ASTRO practice parameter for image-guided radiation therapy
(IGRT) revised in 2019

Brief history of IGRT
• 1958- Mouting an x ray tube to Co60 machine
• 1958- Stanford medical linear accelerator- collimating device
• 1978- Logistically impossible to acquire daily localisation films
• 1985- Leong et al. first online verification system -fluoroscopic technique combined with digital
imaging processing
• 1992- Ezz et al. first video based portal imaging system
• 2004: KV cone beam CT was released by Elekta and Varian
Cobalt Therapy, 1951, Note the illustration of a
positioning device mounted to the head of the machine
that most likely refers to the X-ray systems reported in
the literature by Johns, Cunningham and Holloway at
that time
– A (short) history of image-guided radiotherapy: Dirk Verellen*, Mark De
Ridder, Guy Storme

Target
OAR
Why Do We Need IGRT?
•To ensure accurate & precise delivery of radiation as planned
•The main aim of image guidance is to prevent ,identify and correct error in planning
and delivery.
Target
OAR
Prescription
isodose
Prescription
isodose shifted
OAR
overdose
Target
missed
PLANNING TREATMENT

Advantages of IGRT?
 Accurate delivery of radiation
 Improved definition, localization and monitoring of tumour position, size and shape before
and during treatment
 Possibility of higher, targeted radiation dosage to improve tumour control- short course or
hypofractionated regimens
 Record for quality assurance and education about safe treatment practices
 Adaptive radiotherapy
•Reference: https://www.mayoclinic.org/tests-procedures/image-guided-radiation-therapy/about/pac-20385267

Prior to Implementing IGRT in Clinical Practice
• What is the optimal imaging modality: Ultrasound, video, planar, or volumetric?
• What has to be imaged: part of target, full target, or surrogate?
• Which type of X-ray imaging should be used: Kilovoltage (kV) or megavoltage (MV)?
• What should be the frequency of imaging: Daily, alternate days, or weekly?
• What should be the registration based on: Bone, soft tissues, or both?
• How should the registration be performed: Automatic or manually?
• Who should perform the registration: Therapist or oncologist?
• What should be the action level: No action level, 3 mm, or 5 mm?
• What if registration is unsatisfactory: re-position, re-image, still treat, or call RO?
• Who is involved at every step in this implementation process?
What, Which, How, Who of IGRT?
Gupta, T., & Narayan, C. A. (2012). Image-guided radiation therapy: Physician’s perspectives.
Journal of Medical Physics / Association of Medical Physicists of India, 37(4), 174–182.

HOW TO DO IGRT
1. ACQUIRE AN IMAGE
2. OBTAIN TARGET REGISTRATION ERROR
3. PERFORM AN INTERVENTION
Process map and workflow of IGRT showing a series of inter-connected steps of
treatment planning, delivery, and verification with a feedback loop
Gupta, T., & Narayan, C. A. (2012). Image-guided radiation therapy:
Physician’s perspectives. Journal of Medical Physics / Association of Medical
Physicists of India, 37(4), 174–182.

Set Up Errors and image guidance
•Discrepancy between intended and actual treatment position with respect to radiation delivery.
Ref- On Target: Ensuring geometric accuracy in radiotherapy (RCR) 2008
TYPES:
By pattern
Gross error
Systematic error
Random error
By direction of shifts
Translational error
Rotational error

Types of Errors
•An Error that potentially
causes an under dose of the
CTV or an unacceptably large
dose to be delivered to
surrounding healthy tissues
outside of the PTV .
01
•Any error that occur in the
same direction and magnitude
for each fraction throughout the
treatment course.
•Estimated from the mean
displacement from the planned
isocentre over the number
fractions
02
•A random error is a deviation that
differs in direction and magnitude
for each treatment fraction.
•Daily variation around the mean
displacement
03
03
Gross Error Systematic Error Random Error
Ref- On Target: Ensuring geometric
accuracy in radiotherapy (RCR) 2008

Ven Herk (2000)
PTV= 2.5 ∑ + 0.7 σ
To ensure minimum cumulative dose of 95% to 90% of the
CTV
What do we do with the error patterns?
When analysing setup errors for an individual or a population,
we derive the systematic and random component of errors
Using these components we derive the PTV margins necessary
to cover the target with some certainty
Systematic error are more dangerous- a greater component
of systematic error requires a bigger margin.
We also aim to identify Systematic errors and correct them
early on in the course of Radiotherapy

Translational & Rotational Errors
Translational Shifts
Vertical Y Translation around anterior–posterior axis
Longitudinal Z Translation around superior–inferior axis
Lateral X Translation around right–left axis
Rotational shifts
Roll Rotation about the superior–inferior axis
Yaw Rotation about the anterior–posterior axis
Pitch Rotation about the right–left axis

Corrections strategies
Use setup errors from first
few treatments for future
Match after treatment
Image for first few
fractions
Offline Verification
Image daily
Match before treatment
Use match for correction
before each day’s treatment
Online Verification
Corrects Systematic error
Conventional fractionation
Corrects sytematic & random error
Hypofractionated Schedule

How an offline protocol works?
Without correction ,PTV does
not cover the target every time.
The mean of the errors of the
first few fractions gives an
estimate of the systemic
error.
setup isocentre is adjusted by this
mean value. PTV now covers the
target for the remaining fractions.
Daily random verifications around the
mean are not corrected individually

Correction protocols
Shrinking Action Level (SAL)
1993
No Action Level (NAL)
2001
Extended No Action Level
(eNAL) 2007
Extended No Action Level++
(eNAL++) 2015
Setup error is averaged over
the measured treatment
fractions  compared to a
threshold  decide if a
correction is necessary
Mean setup error calculated
over a fixed number of
fractions.
Same as NAL but additional
weekly measurements are
performed, setup correction
updated after each followup
measurement
Same as eNAL but online
verification is done for setup
correction
Threshold shrinks with increase
in number of measurements
Correction always applied for
the mean.
Time-dependent systematic
changes are tracked and
corrected.
Time consuming
Less need for setup
corrections. Prevents the
unnecessary small setup
corrections in the early part of
treatment
Easier to understand and use
Less imaging is required
Need expertise

Ref- On Target: Ensuring geometric
accuracy in radiotherapy (RCR) 2008

Types of image guidance
VOLUMETRIC
3D
CBCT/MVCT
PLANAR
2D-Orthogonal
EPID
KV Fluro/ X-Ray
MV Fluro/ X-Ray
OTHERS
Electromagnetic Tracking
Optical Surface Tracking
Ultrasound Tracking
MRI based Tracking
Video based Tracking

MACHINE TRUEBEAM UNIQUE I UNIQUE II NOVALIS TRILOGY TOMO
EPID
(2D
Imaging)
Amorphous
silicon
AS1000
Amorphous
silicon
AS1000
Amorphous
silicon
AS1000
Amorphous
silicon
AS1000
Amorphous
silicon
AS1000
NA
CBCT /
MVCT
(3D
Imaging)
CBCT NA NA CBCT CBCT MVCT
IGRT EQUIPMENTS IN TMH

If You Can`t See, You Cant Hit
If You Can`t Hit, You Can`t Cure !

X RAY BASED ANATOMY (LATERAL VIEW)
Skull
Orbit
Base of skull
Maxilla
Mandible
Cervical vertebrae
C1
C2
C3
C4
C5
C6
C7
Pituitary fossa

X RAY BASED ANATOMY (ANTERIOR
VIEW)
Orbit
Maxilla
Mandible
Vertebrae
Clavicle

CT SCAN – SAGITAL VIEW
Skull
Cervical vertebrae
Soft palate
Hard palate
Mandible
Hyoid bone
Thoracic vertebrae

AXIAL
CORONAL
SAGITTAL
Eye
Pituitary gland
Brainstem
IMPORTANT STUCTURES AND OARS IN 3 VIEWS

SAGITTAL
CORONAL
AXIAL
Nasal
cavity
Maxillary sinus
Nasopharynx

Oral cavity
Parotid gland
Spinal cord
Oropharyngeal
airway
AXIAL
SAGITTAL
CORONAL

SAGITTAL
CORONAL
AXIAL
Larynx
Posterior
pharyngeal wall

LEVEL- Ib
LEVEL - II
LYMPH NODE LEVEL
SAGITTAL
AXIAL

LEVEL -III
LEVEL- V
CORONAL
LEVEL II
LEVEL IV
AXIAL

• Uses a detector that produce high quality digital images rapidly
Advantages:
• Provides matching based on bony surrogates or fiducials
• Can take treatment portals
• Less mechanical calibration required
• Easy to use & less time consuming
Disadvantages:
• Poor contrast 2D images
• Lack of soft tissue details
• Does not provide rotational shifts
• Need orthogonal images
EPID (Electronic Portal Imaging Device)

How to do Electronic Portal Imaging (MV)?

Change of imaging
window
Zooming
Split view/
Checkerboard views
Alternating view
Compare with
refernce
Image reference : Varian Eclipse offline review interface

PARAMETERS FOR HEAD AND NECK EPID
Features
FOV at Iso 27cm*20cm (adjustable)
Pixel 1024*786
Pixel resolution 0.39 mm
Detector area 40cm*30 cm
Detector to source distance 95-180 cms
Capturing 14 bit images at 30 fps(frames per second)
Detector to Iso distance- 50 cms(P2 level)

Cone Beam Computed Tomography
 Photon beam made up of kV x rays are projected as a cone
shaped beam on a flat panel imager
 Beam diverge in 2 direction (Width-x , length-z) and the
imager is positioned to catch the entire beam
 Different from a diagnostic CT where the beam is projected
as a fan shaped beam which only diverge in one direction
(width x) on to a arc shaped detectors
 Kv source is mounted perpendicular to MV beam with
imager opposite to it on robotic arms of gantry

CBCT
• Rapid Image acquisition 32–100s
• Submm geometric accuracy and precision in
three dimensions
• Higher contrast & spatial resolution radiographs
as compared with MV portal imaging.
• Better soft tissue visibility
• Basis for adaptive treatment
• Image quality poor compare to conventional CT
• Large volume of tissue irradiated during imaging
• Workload generated by CBCT scan, reconstruction
and 3-D registration adds about 5-10 minutes to
treatment time slot
• Need expertise
Disadvantages
Advantages

Megavoltage CT in Helical Tomo therapy
 Fusion of MV Linac with a helical CT scanner
 3.5 MV for imaging & 6MV for treatment
 Arc shaped xenon detector
 Allows daily patient set-up verification and repositioning
 Provides less soft tissue contrast
 Less artefacts induced by highly attenuating high-Z
materials
 Dose 10–30 mGy per scan.

Bow Tie filters
• Angling of X rays gives non uniform photons in detector. Bow tie filters produces uniform
fluence in detector by differential attenuation
Full bow tie filter Half bow tie filter
1. Imaged target <24cm in diameter 1. Imaged target >24cm in diameter
2. Field-of-view = 26.6 cm 2. Field-of-view = 48 cm
3. Minimum rotation = 180 deg 3. Minimum rotation = 360 deg
4. Used for Head scanning 4. Used for Pelvis or Thoracic scanning
a-Si X-rayImage
Detector
Focus
Physical aperture:
~ 90 cm
TreatmentCouch
Full-Fan Geometry Half-Fan Geometry
Field of View:
26.6 cm 50 cm

Varian OBI CBCT work flow
Treat
Retract imaging gear
Adjust patient position/shift
Align CBCT with reference
Reconstruct CBCT
Fire kV while moving gantry
Select imaging parameters
Extend imaging gear
Bring gantry in start position
Position patient
Select/load patient

PARAMETERS OF HEAD AND NECK CBCT
CBCT mode High-quality head
Low- quality head (Pediatric
patients)
Patient orientation Head First-Supine
Diameter [cm] PA axis 25 cm; LR axis 25cm
Acquisition mode Full fan – Manually put in Trilogy/Novalis. Automatic in
Truebeam
Reconstruction volume 512 x 512
Gantry rotation 22˚to 178˚
FOV 26.6 cm
Extent 16cm
Reconstruction slice thickness Same slice thickness as planning CT – 2.5mm (1mm to
10mm)
ROI Large ROI including PTV Primary and Neck
Dose of CBCT 1-3 cGY

STEPS OF ONLINE CBCT MATCHING
STEP 2: Zoom the scan for adequate view.
STEP 3: Unselect all structures from structure set.
Select PTV, PTV nodes, adjacent OAR from the structure set.
STEP5: Adjust window of simulation and CBCT scan by selecting
auto window/ Level. If required one can also change window
manually to best possible view.
STEP 1: Acquire CBCT scan

AUTO MATCH
STEP 6: Select Auto match option
Adjust ROI to include the bony structures including base
of skull and frontal sinus etc.
Select vertical, lateral and longitudinal shifts.
Unselect rotation
Start Auto match after selecting intensity range to bones
and structure VOI as PTV. While selecting structure VOI
select as “last step only” and “unselect margin or set
margin to 0”.

RESULT AFTER AUTOMATCH
STEP 7: After auto match, scroll and check the entire
CBCT and make manual adjustments where required

MANUAL MATCH
Manual match: Sagittal f/b Coronal f/b Axial view
Sagittal view: Match vertebral column, hard palate, mandible for vertical and
longitudinal shift correction
Coronal view: Lateral shift correction
Axial view: Final verification in all sections
•Additional checks: Body contour match
•Verification of soft tissue location important for Oropharynx, Larynx,
Hypopharynx
•Critical OAR location in relation to PTV
STEP 8: CBCT to be taken on the 1st 3 fractions, and to be matched by the
physician. Thereafter, weekly CBCT to be taken(may be matched by
physician / RTT with off-line review by physician)

CLINICAL DEMONSTATION OF IGRT IN HEAD
AND NECK CANCER
IMRT is now a standard of care in HNSCC
Sharp Dose gradients between target and normal tissue
Positioning errors can lead to either marginal misses or excess dose to OARs
Need of IGRT :
1. To ensure accuracy of treatment
2. To check the need for adaptive planning.
3. Surface irregularities in Head and neck region
4. Daily reproducibility is a challenge : eg. Flexion or extension of neck
5. Contour mismatch due to weight loss, shrinkage/progression of tumor
6. Proximity to Critical structures e.g. Brainstem, optic nerve, eye, spinal cord
7. Difference in Upper v/s Lower Neck matching

Registration Issues: Example With EPID
52/F diagnosed case of Ca Tongue post op pT4aN0 SCC
Planned for adjuvant EBRT to post op bed to a dose of 60Gy/30# & bilateral neck nodes level I-IV to a dose of 54Gy/30#
using IMRT technique on Unique.
Simulation: Head first Supine, Arms by side
LDBP, NNR-3, FLAT-1
4 clamp HN thermoplastic mould
Fiducials kept at the level of glabella
2.5 mm CECT cuts taken from vertex to carina

Acquisition Image: Shifts in 3 directions:
vert = -0.1, long = +0.1, lat = 0

• First 3 days: Shifts in cm
X Y Z
Day 1 -0.1 0.1 0
Day 2 -0.1 0 -0.1
Day 3 0 0 -0.2
Is any corrective strategy required??
Solution: No corrective strategies required.

51/M diagnosed case of Ca Epiglottis pT1N3bM0 PDSCC
Planned for definitive EBRT to a dose of 66Gy/30# to the primary disease & involved nodes and elective nodal
irradiation to bilateral neck nodes to a dose of 54Gy/30# using IMRT technique
LDBP, 4 clamp HN thermoplastic mould
NNR-3, FLAT-1

• CBCT first 3 days: Shifts
X Y Z
Day 1 0.5 0.6 0.4
Day 2 0.4 0.6 0.5
Day 3 0.5 0.7 0.5
• Corrective Strategies:
 Treat if the match is good
 Inform to physicain about the error
 Reset up if match is not good
 Find the mean error & apply the shifts on D4
 If repeat CBCT shows shifts are within PTV margin, then can be acquired for the subsequent treatment fractions.
 If not find the cause and rectify it. And do repeat imaging.

Registration Issues: Adaptive RT After
Tumor Shrinkage
59/M diagnosed case of cancer of hypopharynx cT3N0M0
Planned for definitive CTRT to a dose of 66 Gy/30# to the primary disease and 54Gy/30# to bilateral uninvolved neck
nodes level II-IV on truebeam .
Simulation: Head first Supine, Arms by side
LDBP, NNR3, 4 clamp HN Orfit

PFS ADAPTIVE Tm shrinkage
Date: 28.04.20

Date: 28.04.20
compare with
12#

Date:29.05.20 12#
Intermediate CBCT: Despite small shifts and good bony match, soft tissue not matching well

Date: 28.05.20 Adaptive
Planning CT

Date: 16.06.20 22# Post
Second Adaptive

Registration Issues: Adaptive RT due to
Tumor Shrinkage
61/F diagnosed case of small cell ca of nasopharynx cT2N0M0
LDBP, NNR3, 4 clamp HN thermoplastic mould

Example 2 of Adaptive RT- Tm shrinkage
Date: 20.05.20

Planning CT
Date: 10.07.20 22#

Adaptive RT Example: Nodal shrinkage &
Weight loss
44/F diagnosed case of cancer of base of tongue cT4a cN3 PDSCC P16 neg
Planned for CTRT to a dose of 66Gy/30# to the primary disease & involved nodes and 54Gy/30# to uninvolved
bilateral neck nodes using IMRT technique on truebeam.

ADAPTIVE RT DUE TO weight loss
61/F diagnosed case of small cell ca of nasopharynx cT2N0M0
LDBP, NNR3, 4 clamp HN Orfit

Registration Issues: Example Of Systematic
Error
55/F diagnosed case of Ca Nasal cavity cT4bN0M0
Unreserctable i/v/o dura invovlement and proximity to orbital apex hence planned for definitive CTRT
Planned for definitive CTRT to a dose of 70Gy/35# to primary disease and elective nodal irradiation to a dose of
54Gy/30# using IMRT technique.

X Y Z
Day 1 0.2 -0.5 0
Day 2 0.1 -0.4 0.1
Day 3 0.2 -0.5 0.1
Registration Issues: Example Of Systematic
Error
Apply the shifts and treat everyday for first 3days.
Systematic error: Hence acquire the shifts.
Review CBCT again next day:
• If within tolerance limits, continue treatment and weekly CBCT

Registration Issues: Good Bony Match But
Poor Soft Tissue Match
55/F diagnosed case of Ca Nasal cavity cT4bN0M0
Unreserctable i/v/o planum dura invovlement and proximity to orbital apex hence planned for definitive CTRT
Planned for definitive CTRT to a dose of 70Gy/35# to primary disease and elective nodal irradiation to a dose of
54Gy/30# using IMRT technique.

Balance out the shifts
Know priority structures

• Aim: Evaluate three dimensional (3D) set-up errors and propose optimum margins
for target volume coverage in head and neck radiotherapy with use of EPID
Radiat Oncol. 2007; 2: 44. Published online 2007 Dec 14. doi: 10.1186/1748-717X-2-44

• The absence of direct evidence regarding the clinical benefit of IGRT has been a
criticism since long
• No direct impact of more intense IGRT but upto 50% reduction PTV margins has been
obtained when using daily CBCT in head and neck cancer patients.
• Also ability of volumetric imaging to detect soft tissue and tumor changes brings us to
adaptive RT which has the potential to improve outcomes.
• Need of more prospective studies for demonstrating benefits of IGRT
Semin Radiat Oncol . 2012 Jan;22(1):50-61. doi: 10.1016/j.semradonc.2011.09.001.

CLINICAL DEMONSTRATION OF IGRT IN
NEURO-ONCOLOGY
Given the location of tumor near critical structures IGRT plays important role in treatment of CNS tumors.
Pediatric Tumors like Medulloblastoma and Benign tumors like Pitutary adenoma, AVM, Meningioma has very
good outcome with radiotherapy but often associated with long term treatment related morbidity
Treatment like SRS needs to be accurate and very precise
Narrow Therapeutic index during cases of Re-RT

IGRT Protocol in Neurooncology
• D1-D5 daily imaging
• Apply the shifts on D5
• Once weekly imaging
• If any day shifts >5mm repeat imaging D1-D5
• For CSI & Re-irradiation daily CBCT

Ref- On Target: Ensuring geometric accuracy in radiotherapy (RCR) 2008

Registration Issues: EPID MATCH
56/M diagnosed case of GBM WHO Grade IV, IDH Negative, ATRX retained post surgical debulking.
Planned for adjuvant RT and temozolamide to a dose of 59.4Gy/33# using 3DCRT technique
Simulation: Patient supine arm by side
LDBP, NNR1, 4clamp HN orfit
Fiducials at the level of glabella
2.5mm NCCT cuts taken

X Y Z
Day 1 0 0.1 0
Day 2 -0.2 0.1 -0.5
Day 3 -0.1 0.3 -0.1
Registration Issues: EPID MATCH
Random error.
However within 5mm, hence to continue treatment and weekly EPID.

Registration Issues: Gross Error
9 year old female child diagnosed case of high grade astroblastoma operated outside on 11.12.2019
Planned for adjuvant EBRT partial brain to a dose of 59.4 Gy/ 33# with VMAT technique on truebeam.
Simulation: Patient supine arm by side
OAR dose: brainstem Dmax- 55.8 Gy & Dmax of optic chiasm 54.4Gy
Daily IGRT

X Y Z
Day 1 -0.3 0.1 -0.2
Day 2 -0.2 0.1 -0.8
Day 3 -0.2 0.4 -0.1
Registration Issues: Gross Error
Gross error.
Find the Cause of gross error
Always Re-setup

CSI ON TOMOTHERAPY
Gupta, T., Upasani, M., Master, Z., Patil, A., Phurailatpam, R., Nojin, S., … Jalali, R. (2015). Assessment of
Three-dimensional Set-up Errors using Megavoltage Computed Tomography (MVCT) during Image-guided
Intensity-modulated Radiation Therapy (IMRT) for Craniospinal Irradiation (CSI) on Helical Tomotherapy
(HT). Technology in Cancer Research & Treatment, 29–36. https://doi.org/10.7785/tcrt.2012.500391

 N=34, underwent supine CSI on HT from December 2007 till June 2012
 Methods:MVCT scans were acquired and co-registered with planning scan
separately at three different levels (brain, upper, and lower spine) at every
fraction
 Only translational displacements were analysed
 Mean displacements, systematic, and random errors of the study population
were calculated at all three levels separately
 Residual uncertainty of the spinal column was lesser after daily co-
registration referenced to the skull, suggesting that smaller set-up margins
maybe appropriate while using daily IGRT with an online correction protocol
 Distinct systematic trend towards increasing inaccuracy from the brain
towards the lower spine. Gupta, T., Upasani, M., Master, Z., Patil, A., Phurailatpam, R., Nojin, S., … Jalali, R. (2015).
Assessment of Three-dimensional Set-up Errors using Megavoltage Computed Tomography
(MVCT) during Image-guided Intensity-modulated Radiation Therapy (IMRT) for Craniospinal
Irradiation (CSI) on Helical Tomotherapy (HT). Technology in Cancer Research & Treatment, 29–
36. https://doi.org/10.7785/tcrt.2012.500391

Registration Issues: CSI
13yrs/ female diagnosed case of pineoblastoma, grade IV, GFAP-negative, Post surgery-8/1/20.
Planned for CSI to a dose of 35Gy/21# on tomotherapy by IMRT technique along with concurrent carboplatin
Simualtion: Supine, arms by side, All in one baseplate
NNR3 neutral neck
4 clamp HN thermoplastic mould and 4 clamp pelvic thermoplastic mould
Hands outside
Pelvic orfit upper clamps- inner
Lower clamps- outer
Fiducials at glabella and xiphi
5mm NCCT cuts taken
Tattoo done at xiphi

BRAIN THORACIC SPINE LOWER SPINE
Appl
ied
Lat
cm
Long
cm
Vert
cm
Lat
cm
Long
cm
Vert
cm
Lat
cm
Long
cm
Vert
cm
Shift
+0.2 -0.1 +0.1 -0.7 -0.1 +0.1 -0.5 -0.1 +0.1
0 0 +0.1 -0.9 0 0 -0.7 0 0 +0.2
+0.1 0 0 -0.8 0 0 -0.6 0 0 +0.1
CSI How to apply shifts? Example 1

Here in this case it is impossible to correct this error by applying average
of shifts and Re-setup is highly recommended in such cases
Appl
ied
Lat
cm
Long
cm
Vert
cm
Lat
cm
Long
cm
Vert
cm
Lat
cm
Long
cm
Vert
cm
Shift
+0.4 -0.1 +0.1 -1 -0.1 +0.1 -0.4 -0.1 +0.1
0 0 +0.1 -1.4 0 0 -0.8 0 0 +0.4
+0.6 0 0 -0.8 0 0 -0.2 0 0 -0.2

Appl
ied
Lat
cm
Long
cm
Vert
cm
Lat
cm
Long
cm
Vert
cm
Lat
cm
Long
cm
Vert
cm
Shift
+0.4 -0.1 +0.1 +0.8 -0.1 +0.1 +0.2 -0.1 +0.1
0 0 +0.1 +0.4 0 0 -0.2 0 0 +0.4
-0.1 0 0 0.3 0 0 -0.3 0 0 +0.5

REGISTRATION IN PITUTARY ADENOMA
53/F diagnosed case of ACTH secretory pitutary adenoma, post op 24/10/2018
Planned EBRT to post op bed and residual disease to a dose of 45Gy/25# using IMRT technique on truebeam.
IGRT Protocol: CBCT D1-D5 Apply mean shifts on D6Weekly IGRT
If shifts more than 5mm repeat imaging for 5 days
Simulation:Patient supine arm by side

IGRT in cases of Re irradiation
8year girl, d/c/o Rt frontoparietal Anaplastic Ependymoma Gr III at the age of 2 yr  Post op Post adjuvant chemo
Post RT EBRT to a dose of 59.4Gy/33# with 6 MV photons, using IMRT from 23.04.15 to 12.06.15
Progressed in Sept 15 Post salvage chemo f/b COMBAT
Progressed in feb 2020Post surgery diagnosed to have high grade glioma now planned for Re-irradiation to
partial brain to a dose of 50.4Gy/28#
Simulation:Patient supine arm by side

SUMMARY
Effective immobilization: for reducing setup and systematic errors.
Establishment of departmental PTV margins based on calculation of the
systematic and random center-specific uncertainties.
Univocal definition of volume(s) or the region of interest for volumetric imaging, to
allow reliable automated matching.
Continuous update of IGRT procedures.
Regular audits of IGRT & Training

HAPPINESS ISHOW YOU
SEE YOURSELF….
THANK YOU

Image Guided Radiotherapy

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