pre-requisites for volume definition - accuray exchange · 2020. 1. 31. · van elmpt, r&0 2016...

Pre-requisites for volume definition

Prof Anne Laprie MD PhD

Radiation Oncologist

Laprie.anne@iuct-oncopole.fr

@anne_laprie

1

Disclosure

• Speaker Honoraria : Accuray & Varian

• An honorarium is provided by Accuray for this presentation

• The views expressed in this presentation are those of the presenters and do not necessarily reflect the views or policies of Accuray Incorporated or its subsidiaries. No official endorsement by Accuray Incorporated or any of its subsidiaries of any vendor, products or services contained in this presentation is intended or should be inferred.

Volume definition on imaging

MRI

PET

CBCT

MVCT

CT

4Inspired by Thorwarth PhiRO2019

Tumordelineation

Dose painting

Adaptive radiotherapy

Dose calculation

Motion assessment MRI

PET

CBCT

MVCT

CT

CTImpact of reconstruction for contouring

Large FOV to encompass shoulders in head&neck planification Reconstruction ↘FOV ↗ Definition

CT

MRI

In Treatment position If mask : no standard dedicated head coil

Flexible coils : lower SNR

2D or 3D MRI ?

REGISTRATION CT slices acquired in orthogonal plan2D brain: Bi-commisural→ more uncertainties3D → Voxel by voxel

DISTORSION2D : slice by slice correction

3D : whole volume correction CONTRAST

Better in 2D

MRI geometric fidelityDistorsion linked with the gradients applied

Van der Heide, ctRO 2019

MRI geometric fidelityDistorsion linked with the gradients applied

Van der Heide, ctRO 2019

MRI geometric fidelity

Van der Heide, ctRO 2019

Liney, seminars RO 2014

Choose anatomy or diagnostic ?

Integrated Body coil and flat table top

Better Signal to noise ratio but different position

Diagnostic posterior and anterior coil

Recommendations

Paulson et al, Radiother Oncol 2016

Type of tumor MRI sequences Slices Position Maxdistorsion

Brain T1 gado & FLAIR 3D No consensus 1 mm SBRT2 mm

Head and Neck

Axial T1 gado Fat-Sat

1 mm Treatmentposition

2 mm

Prostate Axial & sag T2 1 mm No consensus 2 mm

Cervix Axial & sag T2 1 mm No consensus 2 mm

MRI

Van der Heide, ctRO 2019

Interest of MRI : seeing structures that you don’t see on CT

More difficult to performRegistration

MRI only workflow ?

PET in treatment for Hodgkin’s diseaseirradiation of involved sites (after response to chemo)

15Metwally et al, IJROBP 2009

Without diagnostic PET coregistration

PET in treatment for Hodgkin’s diseaseirradiation of involved sites (after response to chemo)

16Metwally et al, IJROBP 2009

Without diagnostic PET coregistration

coregistrationWith « in treatmentposition » diagnostic PET

PET in treatment for Hodgkin’s diseaseirradiation of involved sites (after response to chemo)

17Metwally et al, IJROBP 2009

Without diagnostic PET coregistration

coregistrationWith « in treatmentposition » diagnostic PET20 patients

5 experienced radiation oncologists

Significant Diminution of interobserver variations

Significant modification of CTV volumes size

Standard Rigid Registration

• Linked series

• Variable quality of tools

• Checking and modifying the registration

– PET

– rotation : around the cross

Elastic registration

AT PLANNING

• Organ delineation using atlas-based segmentation,

• Deformation-based planning target volume definition,

• Depends on tumor site

• Recent use on most TPS

Rigaud et al, acta oncologica 2019 Esteyrie et al, CTRO 2019

IGRT

• Contour propagation

• Dose calculation on per-treatment imaging.

• Accumulated dose from fraction to fraction in external beam RT both for dose reporting and adaptive RT

Delineation

• Optimal software use – Segmentation tools

– Interpolation tools

Aselmaa et al, J Biomed Inform. 2017

Functional and Metabolic Imaging

• Diffusion MRI

• Perfusion MRI

• MR Spectroscopic imaging

• Geometric and quantification robustness =challenge

• Value for

– esophageal tumors

– pancreatic cancer

– glioblastoma

– High risk regions in Cervical cancer,

– Differentiation of tumor vs non-tumor in prostate

22Liebfarth et al, ctRO 2019

Diffusion MRI

Diffusion MRI

• FLAME phase III randomized trial• Prostate 77 Gy• Tumor 95B Gy • T2 + DCE MRI + DWMRI

23Van Schie et al, R&0 2018

3D MR spectroscopicimaging

• SPECTRO GLIO trial

• Phase III randomized

• 180 Newly diagnosed GBM

• Stupp vs 72 Gy SIB guided by MR spectroscopy

• Clinical data upcoming

• Radiomics study ongoing

Laprie et al, IJROBP 2008, Khalifa et al, Eur J Radiol 2016, Laprie et al, BMC cancer 2019; Tensaouti et al, ESTRO 2019 & 2020

High field MRI ?

• Signal on noise ratio ↗↗↗

• But inhomogeneity ↗↗↗

• better small Field of view FOV →neurooncology

• Sodium and oxygen 17 imaging,

• P31 and C13 Spectroscopy

Knowles et al ctRO 2019Knowles et al, CTRO 2019

DUAL ENERGY CT or DECT

26Van Elmpt, R&0 2016

Metal Artefact Reduction

• MVCT • CT MAR sequences• Dual-Energy CT

Kovacs et al, R&0 2018

• DUAL CT vs. MAR • Both improve

delineation• optimal reconstruction

technique depends on the type of metalimplant

Inspired by Thorwarth PhiRO2019

Tumordelineation

Dose painting

Adaptive radiotherapy

Dose calculation

Motion assessment MRI

PET

CBCT

MVCT

CT

Pre-requisites for volume definition

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Prof Anne Laprie MD PhD

Radiation Oncologist

Laprie.anne@iuct-oncopole.fr

@anne_laprie