Dr. Malhar Patel DNB (Radiation Oncology) 4D-CBCT (Symmetry) – a useful tool to verify and treat traditional ITV without 4D-CT simulation in treatment of lung cancer. Dr. Malhar Patel DNB (Radiation Oncology) 4D-CBCT (Symmetry) – a useful tool to verify & treat traditional ITV without 4D-CT simulation in a treatment of lung cancer.

Introduction Image guidance EPID 4D-CBCT (Symmetry) Challenges in modern radiotherapy. What to do about it??? Image guidance EPID 4D-CBCT (Symmetry) Introduction

6D Definition Ling et al defined IGRT more broadly as ―the use of imaging for detection and Diagnosis, Delineation of target and organs at risk (OARs), Determining biological attributes, Dose distribution design, Dose delivery assurance, and Deciphering treatment response,‖ a so-called six-dimensional definition.

Lung Tumour Motion While Free Breathing Artifact PTV??

The Management of Respiratory Motion in Radiation Oncology AAPM TG‐76 (Report 91) SUPERIOR - INFERIOR ANTERIOR – POSTERIOR LEFT - RIGHT 0 – 18.5 mm 0 – 9.5 mm 0 – 10 mm • Accounting for Respiratory Motion • Motion‐encompassing methods (Free Breathing) • Respiratory Gating Techniques • Breath‐hold Techniques • Forced shallow breathing ‐ abdominal compression • Real‐time tumor‐tracking The Management of Respiratory Motion in Radiation Oncology AAMP: American Association of Physicists in Medicine

CONCLUSIONS: Systematic and random baseline variations constitute a substantial portion of the geometric variability present in the treatment of patients with lung cancer and require generous safety margins when relying on accurate setup/immobilization or bony anatomy-driven correction strategies. The 4D-CBCT has the ability to accurately monitor tumor trajectory shape and baseline variations and drive image-guided correction strategies that allows safe margin reduction. Int J Radiat Oncol Biol Phys. 2008 Feb 1;70(2):590-8. Epub 2007 Nov 26

Combination of Thermoplastic Mask and Vac Lock For Thorax Region. Immobilization Immobilization Device. Combination of Thermoplastic Mask and Vac Lock For Thorax Region.

Patient preparation Instruct patient to breathe in 3 phase You Have 4D CT SCAN?? Instruct patient to breathe in 3 phase Normal Breathing Deep Inspiration Deep Expiration Patient preparation.

CT Simulation Whole Thorax region 3 phase respiration CT Slice thickness 3mm Patient aligned to the fiducials & laser marks IV contrast to enhance target & critical organs DICOM images transferred through networking Fiducial CT Imaging

GTV: Gross Tumour Volume CTV: Clinical Target Volume ITV: Internal Target Volume PTV: Planning Target Volume ITV = CTV + IM (Internal Margin) PTV = ITV + SM (Setup Margin)

Contouring GTV Contouring

XVI Imaging and 4D Symmetry Pre-RT evaluation. Daily XVI Imaging was done. 4D CBCT (Symmetry) First Day and repeated weekly. XVI Imaging and 4D Symmetry

4D (Symmetry) Pre RT Evaluation

4D (Symmetry) After 20 # 4D (Symmetry) After 15 #

(Anterior-Posterior) Results The defined ITV margin is adequate to cover the moving target in free respiratory cycle. 30 4D-CBCT 130 XVI (CBCT) Organ Motion Longitudinal (Superior-Inferior) Vertical (Anterior-Posterior) Lateral (Left Right) 4.9 mm 2.56 mm 1.89 mm Results SUPERIOR - INFERIOR ANTERIOR – POSTERIOR LEFT - RIGHT 0 – 18.5 mm 0 – 9.5 mm 0 – 10 mm AAMP

Transitional Setup Error Setup Errors Transitional Setup Error Lateral Longitudinal Vertical Mean (cm) 0.1165 -0.1055 -0.187 standard deviation (SD) 0.066447 0.324877 0.093529 Setup Errors for Transitional

Conclusion Accuracy Precision Verification Conclusion FUTURE???

12 February 2018 Thank you