Image Image- -Guided and Adaptive Guided and Adaptive - PowerPoint PPT Presentation

Image Image- -Guided and Adaptive Guided and Adaptive Radiotherapy Radiotherapy Radiotherapy Radiotherapy th Conference PMH 50 th PMH 50 Conference A. A. Fyles Fyles y Dept. of Radiation Oncology Dept. of Radiation Oncology Princess Margaret Hospital Princess Margaret Hospital

IMRT for IMRT for Cervix Cancer Cervix Cancer Four-field IMRT M. Milosevic, PMH-RMP IGRT, 25/1/2008

Challenges in IMRT for Cervix Cancer Challenges in IMRT for Cervix Cancer g Target Identification • MR vs CT MR CT • Nodal targets • Online image quality Online image quality Organ motion • Influence of – Bladder filling – Rectal filling g – Normal uterus position Workload Workload

PMH CTV Definition PMH CTV Definition GT GTV Cervix Cervix Uterus Vagina g Parametria CTV • CTV = GTV (+0.7cm margin) + Cervix + parametria + lower 2cm uterus + upper 2cm vagina • Nodal CTV as per Taylor et al Nodal CTV as per Taylor et al • Normal Organs at Risk • rectum, bladder, sigmoid, bowel, bone etc.

Point of Interest Analysis in 16 Patients Point of Interest Analysis in 16 Patients Point of Interest Analysis in 16 Patients Point of Interest Analysis in 16 Patients – Mean Values Mean Values Mean Values Mean Values 14.0 mm 3.8 mm 1.7 mm 6.2 mm 5.6 mm 1.4 mm 1.6 mm 9.6 mm INTERFRACTION INTRAFRACTION Internal Uterine Fundus Internal Uterine Fundus Cervical Os Cervical Os + y + z

Point of Interest Analysis in 16 Patients Point of Interest Analysis in 16 Patients – – Mean Values Mean Values Cranio Cranio- -Caudal Caudal Ant Ant- -Post Post UB = UB = 14.0 mm 3.8 mm Uncertainty Uncertainty (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) Bounds Bounds B B d d 1.7 mm 6.2 mm (confidence (confidence 5.6 mm 1.4 mm limits) limits) 1.6 mm 9.6 mm Total Total Intra Intra Total Total Intra Intra INTERFRACTION INTRAFRACTION Fundus UB Fundus UB Fundus UB Fundus UB 36.9 36.9 36.9 36.9 9.6 9.6 9.6 9.6 16.4 16.4 16.4 16.4 4.3 4.3 4.3 4.3 Internal Uterine Fundus Internal Uterine Fundus Os UB Os UB 14.8 14.8 3.6 3.6 24.8 24.8 4.0 4.0 Cervical Os Cervical Os + y + z

Adapting to Change Adapting to Change • Tumors are heterogeneous Tumors are heterogeneous + • Position changes Position changes – Inter Inter- -fraction, Intra fraction, Intra- -fraction fraction • Size and shape changes Size and shape changes • Biology changes Biology changes + +

Pre-Tx 8 Gy Tumour Shrinkage & Deformation • Influence of: 20 Gy 28 Gy – Tumour factors • Biology – Hypoxia – Treatment factors T t t f t • Chemo-radiation 38 Gy 48 Gy

Adaptive Image Adaptive Image Adaptive Image-Guided RT Adaptive Image-Guided RT Guided RT Guided RT • Complex dynamics of OAR & t OAR & target motion t ti • Concerns: – Margins? M i ? – Geographical miss – ↑ dose to normal tissues ↑ dose to normal tissues • What you see is not What you get • Adaptive approach is needed for treatment of intact cervix cancer intact cervix cancer

IMRT Lymph Node Plan IMRT Lymph Node Plan IMRT Lymph Node Plan IMRT Lymph Node Plan Role for image- guided guided nodal targeting using g USPIO MR

Lymph Node Margins Lymph Node Margins 2 cm radial expansion around iliac vessels Shih, 2005 Shih, 2005 Taylor, 2005 Taylor, 2005

LN Movement During RT LN Movement During RT Coverage of Unified nCTV7 105 105 Day 1 CTV Summed CTV 100 age entage Covera 95 Perce 90 85 85 0 4 8 12 16 20 Chan and Dinniwell Chan and Dinniwell 2-mm Expansions of nCTV7 4 mm PTV expansion encompasses 4 mm PTV expansion encompasses >90% of LN movement >90% of LN movement M. Milosevic, PMH-RMP IGRT, 25/1/2008

Delivered vs. Planned Dose Delivered vs. Planned Dose Image at T=0 Image at T=1 Mesh-Based Biomechanical Model • Motion • Motion Motion Motion • Deformation Deformation • Dose accumulation Dose accumulation • Adaptive re Adaptive re- p -planning planning p p g g MORFEUS MORFEUS MORFEUS MORFEUS Slide c/o Kristy Brock Slide c/o Kristy Brock

BASELINE WEEK 1 WEEK 2 WEEK 3 WEEK 4 WEEK 5 CT_0 MRI_0 MRI_1 MRI_2 MRI_3 MRI_4 MRI_5 Contours Contours Contours Contours Contours Contours Contours Contours Contours Contours Contours Contours Nominal Nominal Nominal Nominal Dose Dose Plan Plan Plan Plan Accumulated Accumulated Surface Sur Surface Sur ace ace Sur Surface Sur Surface ace ace Surface Sur Sur Surface ace ace Sur Surface Sur Surface ace ace Surface Sur Surface Sur ace ace Sur Surface Sur Surface ace ace Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Pl Pl Plans Plans Meshes Meshes Meshes Meshes Meshes Meshes Meshes Meshes Dose Dose Dose Dose Def Deformable Dose A Deformable Dose A Def Def Deformable Dose A Deformable Dose A Def rmable Dose Accumulation rmable Dose Accumulation rmable Dose Accumulation rmable Dose Accumulation ccumulation ccumulation ccumulation ccumulation Accumulated Accumulated Accumulat Accumulat d d Acc Dose Acc Dose Acc Dose Acc Dose cc Dose cc Dose cc Dose cc Dose Acc Dose Acc Dose Acc Dose Acc Dose cc Dose cc Dose cc Dose cc Dose Acc Dose Acc Dose Acc Dose Acc Dose cc Dose cc Dose cc Dose cc Dose Acc Dose Acc Dose Acc Dose Acc Dose cc Dose cc Dose cc Dose cc Dose Acc Dose Acc Dose Acc Dose Acc Dose cc Dose cc Dose cc Dose cc Dose Plans Plans Plans Plans wk1 wk1 wk1 wk1 wk2 wk2 wk2 wk2 wk3 wk3 wk3 wk3 wk4 wk4 wk4 wk4 Wk5 Wk5 Wk5 Wk5 Nominal Nominal Plan Plan Adaptive Adaptive Adaptive Adaptive Re Re- -plan plan

Initial IMRT strategy Initial IMRT strategy Initial IMRT strategy – 10 pts Initial IMRT strategy – 10 pts 10 pts 10 pts • LM (large margin) plan • SM (small margin) plan – 1-2 cm PTV margin – 0.5 cm PTV margin – Expectation – Expectation • little OAR sparing little OAR sparing • Some OAR sparing Some OAR sparing • Target always covered • Target missed

Initial IMRT strategy Initial IMRT strategy Initial IMRT strategy – 10 pts Initial IMRT strategy – 10 pts 10 pts 10 pts • Adaptive re-plan p p – Union CTV of 1 st 3 image sets (iCTV) – Expectation • More OAR sparing M OAR i • Target coverage better • Results – LM plan covered most pts – SM plan seemed adequate for more pts than expected expected – Re-plan did not spare as much OAR as hoped • WHY? WHY?

WHY? WHY? WHY? WHY? • Large CTV – tumour shrinkage did not influence treatment volume as much as expected • Organ motion – iCTV – resulted in even larger CTVs than baseline than baseline • Estimates of 3D margins too generous based on previous POI data • Influence of bladder / rectal filling – Heterogeneous despite bowel & bladder prep – Caused large displacements in CTV location in some pts Caused large displacements in CTV location in some pts • Influence of uterus position

nd Adaptive strategy 2 nd 2 Adaptive strategy – 25 pts Adaptive strategy Adaptive strategy – 25 pts 25 pts 25 pts • Use of ultra-small PTV margins (0.3cm) g ( ) • Assume perfect set-up daily (CBCT) • Separate out pts into consistent & variable Separate out pts into consistent & variable bladders • Adaptive re-plan – after 2 nd wk treatment, use p p , only imaging at that time point, no union CTV.

25pts 25pts 98% of the PTV to be covered by the 95% isodose for all plans 98% of the PTV to be covered by the 95% isodose for all plans Plan evaluation criteria: Plan evaluation criteria: 98% of GTV received 5000cGy; 98% HRCTV received ≥ 4900cGy 98% of GTV received 5000cGy; 98% HRCTV received ≥ 4900cGy Dose Accumulation with Inter Dose Accumulation with Inter Fraction Motion Applied Dose Accumulation with Inter Dose Accumulation with Inter- -Fraction Motion Applied Fraction Motion Applied Fraction Motion Applied Consistent Bladders Consistent Bladders Variable Bladders Variable Bladders Nom SM Nom SM Acc SM Acc SM Acc AM Acc AM Nom SM Nom SM Acc SM Acc SM Acc AM Acc AM GTV (D98) GTV 5024 5024 4987 4987 5008 5008 (D98) GTV GTV (D98) 5036 5036 5014 5014 5031 5031 (D98) 4783 4783 4783 4783 783 783 783 783 4780 4780 4780 4780 780 780 780 780 HRCTV (D98) HRCTV HRCTV HRCTV (D98) 4911 4911 4911 4911 (D98) (D98) 4858 4858 4858 4858 4858 4858 4858 4858 HRCTV (D98) HRCTV HRCTV (D98) HRCTV 4923 4923 4923 4923 4909 4909 4909 4909 (D98) (D98) 41 41 41 41 Rectum (V45) Rectum 52 52 50 50 Rectum Rectum (V45) 41 41 41 41 54 54 51 51 (V45) (V45) Sigmoid (V45) Sigmoid 61 61 67 67 51 51 (V45) Sigmoid Sigmoid Sigmoid Sigmoid 39 39 39 39 39 39 39 39 59 59 59 59 61 61 61 61 Bladder Bladder 4065 4065 3960 3960 3930 3930 (V45) (V45) (Mean) (Mean) Bladder Bladder 3963 3963 3963 3963 4002 4002 4103 4103 (Mean) (Mean) 0.05 compared to Nominal SM plan P < P < 0.05 P < P < 0.05 0.05