SK
Uploaded bySheetal R Kashid
1,873 views

Image Guided Radiotherapy

1. Dr. Sheetal R Kashid presented on the use of IGRT for head and neck cancers and central nervous system tumors at TMH. 2. IGRT uses image guidance to precisely position patients and correct for setup errors, allowing for accurate radiation delivery while minimizing dose to surrounding healthy tissues. 3. At TMH, IGRT is performed using CBCT, EPID, and offline protocols to correct for systematic and random errors in head and neck and neuro-oncology patients.

1 / 109
2 / 109
3 / 109
4 / 109
5 / 109
Most read
6 / 109
7 / 109
8 / 109
9 / 109
10 / 109
11 / 109
12 / 109
13 / 109
14 / 109
15 / 109
16 / 109
17 / 109
18 / 109
19 / 109
20 / 109
21 / 109
22 / 109
23 / 109
24 / 109
25 / 109
26 / 109
27 / 109
28 / 109
29 / 109
30 / 109
31 / 109
32 / 109
33 / 109
34 / 109
35 / 109
36 / 109
37 / 109
38 / 109
39 / 109
40 / 109
41 / 109
42 / 109
43 / 109
44 / 109
Most read
45 / 109
46 / 109
47 / 109
48 / 109
49 / 109
50 / 109
51 / 109
52 / 109
53 / 109
54 / 109
55 / 109
56 / 109
57 / 109
58 / 109
59 / 109
60 / 109
61 / 109
62 / 109
63 / 109
64 / 109
65 / 109
66 / 109
67 / 109
68 / 109
69 / 109
70 / 109
71 / 109
72 / 109
73 / 109
74 / 109
75 / 109
76 / 109
77 / 109
78 / 109
79 / 109
80 / 109
Most read
81 / 109
82 / 109
83 / 109
84 / 109
85 / 109
86 / 109
87 / 109
88 / 109
89 / 109
90 / 109
91 / 109
92 / 109
93 / 109
94 / 109
95 / 109
96 / 109
97 / 109
98 / 109
99 / 109
100 / 109
101 / 109
102 / 109
103 / 109
104 / 109
105 / 109
106 / 109
107 / 109
108 / 109
109 / 109
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
IGRT Benefits Cost
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 online protocol works?
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)?
PORTAL IMAGING MV
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. Registration Issues: Example With EPID
Registration Issues: Example With EPID 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 Simulation: Head first Supine, Arms by side LDBP, 4 clamp HN thermoplastic mould NNR-3, FLAT-1 Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
• 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 Registration Issues: Example With EPID • 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 Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
PFS ADAPTIVE Tm shrinkage Date: 28.04.20
Date: 14.05.20 1#
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: 15.06.20 21# CBCT
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 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 thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
Example 2 of Adaptive RT- Tm shrinkage Date: 20.05.20
Planning CT Date: 10.07.20 22#
CBCT 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. Simulation: Head first Supine, Arms by side LDBP, NNR3, 4 clamp HN thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
Date: 30.11.17 #
Date: 30.11.17 #
ADAPTIVE RT DUE TO weight loss 61/F diagnosed case of small cell ca of nasopharynx cT2N0M0 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 Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
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. Simulation: Head first Supine, Arms by side LDBP, NNR3, 4 clamp HN thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
• CBCT first 3 days: Shifts 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. Simulation: Head first Supine, Arms by side LDBP, NNR3, 4 clamp HN thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
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
• CBCT first 3 days: Shifts 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 LDBP, NNR1, 4clamp HN orfit Fiducials at the level of glabella 2.5mm NCCT cuts taken OAR dose: brainstem Dmax- 55.8 Gy & Dmax of optic chiasm 54.4Gy Daily IGRT
• CBCT first 3 days: Shifts 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
CSI ON TOMOTHERAPY
CSI ON TOMOTHERAPY
CSI ON TOMOTHERAPY
CASE CAPSULE: CSI Matching
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
CSI How to apply shifts? Example 2 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 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 +0.4 -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
CSI How to apply shifts? Example 3 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 +0.4 -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 LDBP, NNR1, 4clamp HN orfit Fiducials at the level of glabella 2.5mm NCCT cuts taken
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 LDBP, NNR1, 4clamp HN orfit Fiducials at the level of glabella 2.5mm NCCT cuts taken
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

More Related Content

PPTX
Role of Image Guidance in Radiotherapy
bySusan Rochelle
 
PDF
Image Guided Radiotherapy
byNamrata Das
 
PPTX
Intensity modulated radiation therapy and Image guided radiation therapy
byRavindra Shende
 
PPT
Inverse Planning
byfondas vakalis
 
PDF
Intensity Modulated Radiation Therapy (IMRT)
byDilshad Kottuparamban
 
PPTX
Advanced Radiotherapy in Cancer Care in Central India- ALEXIS NAGPUR 2017
byPuneet Seth
 
PPTX
Elekta presentation
bySunilMaurya82
 
PPTX
3DCRT and IMRT
byKiron G
 
Role of Image Guidance in Radiotherapy
bySusan Rochelle
 
Image Guided Radiotherapy
byNamrata Das
 
Intensity modulated radiation therapy and Image guided radiation therapy
byRavindra Shende
 
Inverse Planning
byfondas vakalis
 
Intensity Modulated Radiation Therapy (IMRT)
byDilshad Kottuparamban
 
Advanced Radiotherapy in Cancer Care in Central India- ALEXIS NAGPUR 2017
byPuneet Seth
 
Elekta presentation
bySunilMaurya82
 
3DCRT and IMRT
byKiron G
 

What's hot

PPTX
IGRT - Image Guided Radiotherapy Technique.pptx
bySubrata Das
 
PDF
Image guided adaptive radiotherapy
byapollo seminar group
 
PPT
Image Guided Radiotherapy
byGemelli Advanced Radiation Therapy
 
PDF
Image Guided Radiation Therapy (IGRT)
byTeekendra Singh Faujdar
 
PPT
Respiration motion management
byKiran Ramakrishna
 
PPTX
Radiotheray transition from 2D to 3D Conformal radiotherapy(3D-CRT)
byGebrekirstos Hagos Gebrekirstos, MD
 
PDF
SRS, SRT CNS Tumours
byNamrata Das
 
PPTX
Adaptive radiotherapy in head and neck cancer
byDr. Rituparna Biswas
 
PPTX
LUNG SBRT A LITERATURE REVIEW
byKanhu Charan
 
PPTX
Stereotactic radiosurgery and radiotherapy
byumesh V
 
PPTX
Role of SBRT in lung cancer
byDrAyush Garg
 
PPT
IMRT in Prostate Cancer
byDr.Ram Madhavan
 
PPT
Radiotherapy plan evaluation in brain tumours
byAshutosh Mukherji
 
PPTX
Plan evaluation in RADIOTHERAPY
byKanhu Charan
 
PPTX
Stereotactic body radiotherapy
byNanditha Nukala
 
PPTX
Dose Distribution Measurement (part 1)
byNik Noor Ashikin Nik Ab Razak
 
PPTX
Concept of bed in radiobiology
byRANJITH C P
 
PPTX
Proton beam therapy
byNanditha Nukala
 
PPT
PARTICLE BEAM RADIOTHERAPY
byKanhu Charan
 
PPTX
Particle beam – proton,neutron & heavy ion therapy
byAswathi c p
 
IGRT - Image Guided Radiotherapy Technique.pptx
bySubrata Das
 
Image guided adaptive radiotherapy
byapollo seminar group
 
Image Guided Radiotherapy
byGemelli Advanced Radiation Therapy
 
Image Guided Radiation Therapy (IGRT)
byTeekendra Singh Faujdar
 
Respiration motion management
byKiran Ramakrishna
 
Radiotheray transition from 2D to 3D Conformal radiotherapy(3D-CRT)
byGebrekirstos Hagos Gebrekirstos, MD
 
SRS, SRT CNS Tumours
byNamrata Das
 
Adaptive radiotherapy in head and neck cancer
byDr. Rituparna Biswas
 
LUNG SBRT A LITERATURE REVIEW
byKanhu Charan
 
Stereotactic radiosurgery and radiotherapy
byumesh V
 
Role of SBRT in lung cancer
byDrAyush Garg
 
IMRT in Prostate Cancer
byDr.Ram Madhavan
 
Radiotherapy plan evaluation in brain tumours
byAshutosh Mukherji
 
Plan evaluation in RADIOTHERAPY
byKanhu Charan
 
Stereotactic body radiotherapy
byNanditha Nukala
 
Dose Distribution Measurement (part 1)
byNik Noor Ashikin Nik Ab Razak
 
Concept of bed in radiobiology
byRANJITH C P
 
Proton beam therapy
byNanditha Nukala
 
PARTICLE BEAM RADIOTHERAPY
byKanhu Charan
 
Particle beam – proton,neutron & heavy ion therapy
byAswathi c p
 

Similar to Image Guided Radiotherapy

PPT
IMRT by Musaib Mushtaq.ppt
byMusaibMushtaq
 
PDF
Intensity Modulated Radiation Therapy (IMRT)
byDilshad KP
 
PPT
3 d crt
byKiran Ramakrishna
 
PPTX
3 dcrt
byLAKSHMI DEEPTHI GEDELA
 
PPTX
IGRT in lung cancer
bySantam Chakraborty
 
PPTX
Arc therapy [autosaved] [autosaved]
byradiation oncology
 
PDF
4 D Igrt
byfondas vakalis
 
PPT
Beam Directed Radiotherapy - methods and principles
bySantam Chakraborty
 
PPT
Thastro08 igrt1
byKarthik Periasamy
 
DOCX
THE RATIONALE AND BENEFITS OF IGRT
byMelissa McClement
 
PDF
Medical uses of ionising radiation
byAmin Amin
 
PDF
Radiation Oncology in 21st Century - Changing the Paradigms
byApollo Hospitals
 
PDF
IMAGE GUDIED RADIOTHERAPY IN OUR COUNTRY INDIA
byNISARGPATKAR
 
PDF
Session 8 - IGRT_ Guidelines for Matching _ Alignment, Methods & Workflows.pdf
byJalalEltabib1
 
PPT
genreal principal of 3D_crt_imrt,3dcrt,igrt
byGunjannMiddha
 
PPT
study and evaluate setup uncertainty in radiotherapy
byMajoVJJose
 
PPTX
How Centers Can​ Thrive in the Modern Era
bySGRT Community
 
PPTX
How Centers Can​ Thrive in the Modern Era
byRachaelSmith830794
 
PPS
Hst motion inradiotherapy
bySrinivasan Annamalai
 
PDF
Prostate IGRT With Setup Intelligence 4sharing
bycjhampton
 
IMRT by Musaib Mushtaq.ppt
byMusaibMushtaq
 
Intensity Modulated Radiation Therapy (IMRT)
byDilshad KP
 
3 d crt
byKiran Ramakrishna
 
3 dcrt
byLAKSHMI DEEPTHI GEDELA
 
IGRT in lung cancer
bySantam Chakraborty
 
Arc therapy [autosaved] [autosaved]
byradiation oncology
 
4 D Igrt
byfondas vakalis
 
Beam Directed Radiotherapy - methods and principles
bySantam Chakraborty
 
Thastro08 igrt1
byKarthik Periasamy
 
THE RATIONALE AND BENEFITS OF IGRT
byMelissa McClement
 
Medical uses of ionising radiation
byAmin Amin
 
Radiation Oncology in 21st Century - Changing the Paradigms
byApollo Hospitals
 
IMAGE GUDIED RADIOTHERAPY IN OUR COUNTRY INDIA
byNISARGPATKAR
 
Session 8 - IGRT_ Guidelines for Matching _ Alignment, Methods & Workflows.pdf
byJalalEltabib1
 
genreal principal of 3D_crt_imrt,3dcrt,igrt
byGunjannMiddha
 
study and evaluate setup uncertainty in radiotherapy
byMajoVJJose
 
How Centers Can​ Thrive in the Modern Era
bySGRT Community
 
How Centers Can​ Thrive in the Modern Era
byRachaelSmith830794
 
Hst motion inradiotherapy
bySrinivasan Annamalai
 
Prostate IGRT With Setup Intelligence 4sharing
bycjhampton
 

Recently uploaded

PPTX
“Optimizing Chemoradiation Sequencing in Cervical Cancer”
byKanhu Charan
 
PPTX
AI in veterinary medicine: for students to learn current state
byAndrzej Jarynowski
 
PPTX
Simplifying Complex Cancer Data into Actionable Knowledge with Golden Helix C...
byGolden Helix
 
PDF
Bariatric-Anaesthesia-Navigating-the-Challenges-of-Obesity-in-Surgery.pdf
byAssist. Prof. Radhwan Hazem Alkhashab
 
PDF
Bloodstream_Infections_CME_Presentation_ Oct 2025.pdf
byTahseen Siddiqui
 
PPTX
CARDIOGENIC SHOCK-Approach to Nontraumatic Shock .pptx
byDr PANKAJ PARMAR
 
PPTX
DELIVERY IN THE EMERGENCY DEPARTMENT (Essential Skills for the Emergency Phys...
byuseriphone
 
PPTX
FORCE SYSTEMS AND TISSUE RESPONSE TO FORCES IN ORTHODONTICS.pptx
byThomas Philip
 
PPTX
Case taking in Psychiatry (History and Mental Status Examination).pptx
byAlaka Acharya
 
PPTX
manegement of lower GIT bleeding in children.pptx
bymhalihamed580
 
PDF
HPM HEERA-44 ( 2,4-D Ethyl Ester 38% EC )
byHpm India
 
PPT
Quiet Progression, Loud Impact in MS: Expert Insights on the Role of BTK Inhi...
byPVI, PeerView Institute for Medical Education
 
PPTX
Cancer screening in females and pap smear test
bybswetha049
 
PDF
HPM HEERA-77 ( 2-4-D AMINE SALT 58% SL )
byHpm India
 
PPTX
Approach to subcutaneous and soft tissue tumours .pptx.pptx
byAmrAleasyi1
 
PDF
free Park’s Textbook of Preventive and Social Medicine (27th Edition) Author:...
bymadan Bhandari Academy of Health sciences
 
PDF
Internal medicine ward survival guide .pdf
byAbdulghani Nasser Jaafar
 
DOCX
How Boosting Nitric Oxide Can Help You Feel Younger
byusmanahmadhse67
 
PPTX
Organ Transplantation - THE SCIENCE OF TRANSPLANTATION GENERAL SURGERY.pptx
byArchitPathak7
 
PPTX
Trauma in Dance - Effects of Life Trauma on Dancers
byNicoletta P. Lekka
 
“Optimizing Chemoradiation Sequencing in Cervical Cancer”
byKanhu Charan
 
AI in veterinary medicine: for students to learn current state
byAndrzej Jarynowski
 
Simplifying Complex Cancer Data into Actionable Knowledge with Golden Helix C...
byGolden Helix
 
Bariatric-Anaesthesia-Navigating-the-Challenges-of-Obesity-in-Surgery.pdf
byAssist. Prof. Radhwan Hazem Alkhashab
 
Bloodstream_Infections_CME_Presentation_ Oct 2025.pdf
byTahseen Siddiqui
 
CARDIOGENIC SHOCK-Approach to Nontraumatic Shock .pptx
byDr PANKAJ PARMAR
 
DELIVERY IN THE EMERGENCY DEPARTMENT (Essential Skills for the Emergency Phys...
byuseriphone
 
FORCE SYSTEMS AND TISSUE RESPONSE TO FORCES IN ORTHODONTICS.pptx
byThomas Philip
 
Case taking in Psychiatry (History and Mental Status Examination).pptx
byAlaka Acharya
 
manegement of lower GIT bleeding in children.pptx
bymhalihamed580
 
HPM HEERA-44 ( 2,4-D Ethyl Ester 38% EC )
byHpm India
 
Quiet Progression, Loud Impact in MS: Expert Insights on the Role of BTK Inhi...
byPVI, PeerView Institute for Medical Education
 
Cancer screening in females and pap smear test
bybswetha049
 
HPM HEERA-77 ( 2-4-D AMINE SALT 58% SL )
byHpm India
 
Approach to subcutaneous and soft tissue tumours .pptx.pptx
byAmrAleasyi1
 
free Park’s Textbook of Preventive and Social Medicine (27th Edition) Author:...
bymadan Bhandari Academy of Health sciences
 
Internal medicine ward survival guide .pdf
byAbdulghani Nasser Jaafar
 
How Boosting Nitric Oxide Can Help You Feel Younger
byusmanahmadhse67
 
Organ Transplantation - THE SCIENCE OF TRANSPLANTATION GENERAL SURGERY.pptx
byArchitPathak7
 
Trauma in Dance - Effects of Life Trauma on Dancers
byNicoletta P. Lekka
 
In this document
Powered by AI

Introduction to IGRT in Head and Neck & CNS tumors, including objectives and equipment used at TMH.

Definition of IGRT, benefits for accurate radiation delivery, and historical context highlighting its evolution.

Benefits, considerations before implementing IGRT, including optimal imaging modalities and registration approaches.

Steps required for conducting IGRT, types of setup errors, and correction strategies for accurate treatment delivery.

Details on systematic, random, gross errors, and correction protocols in IGRT for effective patient care.

Overview of imaging types for IGRT, equipment used in TMH, and the significance of imaging quality in treatment.

X-ray based anatomy views relevant for IGRT, emphasizing areas crucial for planning in head and neck cancers.

Detailed imaging parameters for the head and neck using EPID and Cone Beam CT, highlighting advantages and workflows.

Application of IGRT for precise treatment planning in head and neck cancers and case studies demonstrating its necessity.

Challenges of registration in treatment planning and adjustment strategies based on clinical examples.

Examples of adaptive radiotherapy addressing tumor shrinkage, weight loss, and techniques for maintaining treatment accuracy.

Role of IGRT in neuro-oncology, especially for pediatric tumors, focusing on precision in treatment protocols.

Clinical examples and outcomes of craniospinal irradiation using IGRT, detailing specific case studies and their registrations.

Summary of IGRT efficacy, importance of continuous updating procedures, audits, and patient safety.

Image Guided Radiotherapy

  • 1.
    IGRT CLINICAL DEMONSTRATIONIN HEAD AND NECK & CNS TUMORS Dr Sheetal R Kashid
  • 2.
    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
  • 3.
    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
  • 4.
    Brief history ofIGRT • 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
  • 5.
    Target OAR Why Do WeNeed 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
  • 6.
  • 7.
    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
  • 8.
    Prior to ImplementingIGRT 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.
  • 9.
    HOW TO DOIGRT 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.
  • 10.
    Set Up Errorsand 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
  • 11.
    Types of Errors •AnError 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
  • 12.
    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
  • 13.
    Translational & RotationalErrors 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
  • 14.
    Corrections strategies Use setuperrors 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
  • 15.
  • 16.
    How an offlineprotocol 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
  • 17.
    Correction protocols Shrinking ActionLevel (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
  • 18.
    Ref- On Target:Ensuring geometric accuracy in radiotherapy (RCR) 2008
  • 19.
    Types of imageguidance 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
  • 20.
    MACHINE TRUEBEAM UNIQUEI 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
  • 21.
    If You Can`tSee, You Cant Hit If You Can`t Hit, You Can`t Cure !
  • 22.
    X RAY BASEDANATOMY (LATERAL VIEW) Skull Orbit Base of skull Maxilla Mandible Cervical vertebrae C1 C2 C3 C4 C5 C6 C7 Pituitary fossa
  • 23.
    X RAY BASEDANATOMY (ANTERIOR VIEW) Orbit Maxilla Mandible Vertebrae Clavicle
  • 24.
    CT SCAN –SAGITAL VIEW Skull Cervical vertebrae Soft palate Hard palate Mandible Hyoid bone Thoracic vertebrae
  • 25.
  • 26.
  • 27.
    Oral cavity Parotid gland Spinalcord Oropharyngeal airway AXIAL SAGITTAL CORONAL
  • 28.
  • 29.
    LEVEL- Ib LEVEL -II LYMPH NODE LEVEL SAGITTAL AXIAL
  • 30.
  • 31.
    • Uses adetector 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)
  • 32.
    How to doElectronic Portal Imaging (MV)?
  • 33.
  • 34.
  • 35.
    Change of imaging window Zooming Splitview/ Checkerboard views Alternating view Compare with refernce Image reference : Varian Eclipse offline review interface
  • 36.
    PARAMETERS FOR HEADAND 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)
  • 37.
    Cone Beam ComputedTomography  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
  • 38.
    CBCT • Rapid Imageacquisition 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
  • 39.
    Megavoltage CT inHelical 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.
  • 40.
    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
  • 41.
    Varian OBI CBCTwork 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
  • 42.
    PARAMETERS OF HEADAND 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
  • 43.
    STEPS OF ONLINECBCT 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
  • 44.
    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”.
  • 45.
    RESULT AFTER AUTOMATCH STEP7: After auto match, scroll and check the entire CBCT and make manual adjustments where required
  • 46.
    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)
  • 47.
    CLINICAL DEMONSTATION OFIGRT 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
  • 49.
    Registration Issues: ExampleWith 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
  • 50.
    Acquisition Image: Shiftsin 3 directions: vert = -0.1, long = +0.1, lat = 0
  • 51.
    • First 3days: 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. Registration Issues: Example With EPID
  • 52.
    Registration Issues: ExampleWith EPID 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 Simulation: Head first Supine, Arms by side LDBP, 4 clamp HN thermoplastic mould NNR-3, FLAT-1 Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 54.
    • CBCT first3 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 Registration Issues: Example With EPID • 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.
  • 55.
    Registration Issues: AdaptiveRT 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 Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 56.
    PFS ADAPTIVE Tmshrinkage Date: 28.04.20
  • 57.
  • 58.
  • 59.
    Date:29.05.20 12# Intermediate CBCT:Despite small shifts and good bony match, soft tissue not matching well
  • 60.
  • 61.
  • 62.
    Date: 16.06.20 22#Post Second Adaptive
  • 63.
    Registration Issues: AdaptiveRT due to Tumor Shrinkage 61/F diagnosed case of small cell ca of nasopharynx cT2N0M0 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 thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 64.
    Example 2 ofAdaptive RT- Tm shrinkage Date: 20.05.20
  • 65.
  • 66.
  • 67.
    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. Simulation: Head first Supine, Arms by side LDBP, NNR3, 4 clamp HN thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 68.
  • 69.
  • 70.
    ADAPTIVE RT DUETO weight loss 61/F diagnosed case of small cell ca of nasopharynx cT2N0M0 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 Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 73.
    Registration Issues: ExampleOf 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. Simulation: Head first Supine, Arms by side LDBP, NNR3, 4 clamp HN thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 75.
    • CBCT first3 days: Shifts 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
  • 76.
    Registration Issues: GoodBony 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. Simulation: Head first Supine, Arms by side LDBP, NNR3, 4 clamp HN thermoplastic mould Fiducials kept at the level of glabella 2.5 mm CECT cuts taken from vertex to carina
  • 79.
    Balance out theshifts Know priority structures
  • 80.
    • Aim: Evaluatethree 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
  • 81.
    • The absenceof 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.
  • 82.
    CLINICAL DEMONSTRATION OFIGRT 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
  • 83.
    IGRT Protocol inNeurooncology • 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
  • 84.
    Ref- On Target:Ensuring geometric accuracy in radiotherapy (RCR) 2008
  • 85.
    Registration Issues: EPIDMATCH 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
  • 87.
    • CBCT first3 days: Shifts 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.
  • 88.
    Registration Issues: GrossError 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 LDBP, NNR1, 4clamp HN orfit Fiducials at the level of glabella 2.5mm NCCT cuts taken OAR dose: brainstem Dmax- 55.8 Gy & Dmax of optic chiasm 54.4Gy Daily IGRT
  • 90.
    • CBCT first3 days: Shifts 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
  • 91.
    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
  • 92.
     N=34, underwentsupine 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
  • 93.
    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
  • 94.
  • 95.
  • 96.
  • 99.
  • 100.
    BRAIN THORACIC SPINELOWER 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
  • 101.
    CSI How toapply shifts? Example 2 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 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 +0.4 -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
  • 102.
    CSI How toapply shifts? Example 3 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 +0.4 -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
  • 104.
    REGISTRATION IN PITUTARYADENOMA 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 LDBP, NNR1, 4clamp HN orfit Fiducials at the level of glabella 2.5mm NCCT cuts taken
  • 106.
    IGRT in casesof 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 LDBP, NNR1, 4clamp HN orfit Fiducials at the level of glabella 2.5mm NCCT cuts taken
  • 108.
    SUMMARY Effective immobilization: forreducing 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
  • 109.
    HAPPINESS ISHOW YOU SEEYOURSELF…. THANK YOU

Editor's Notes