ESTRO 36 Abstract Book

S158

ESTRO 36 2017

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Conclusion

In sum, independently of PBS delivery scenario, the

treatment of liver tumours under free-breathing

conditions is not recommended for motions over 10mm,

even when applying large numbers of rescans. However,

re-gating (LS5+GW5) is predicted to be sufficient to

achieve acceptable 4D plan quality for all scenarios, even

though synchrotron based delivery could have a significant

added time cost in comparison to cyclotron based systems.

Symposium: Focus on ART: the clinical difficulties

SP-0307 Multi-parametri c functional PET/MR imaging

for RT individualisation

D. Thorwarth

University of Tübingen, Sectio n for Biomedical Physics-

Department of Radiation Oncology, Tübingen, Germany

Multi-parametric functional imaging using combined

positron emission tomograph y and magnetic resonance

(PET/MR) imaging may be highly beneficial for the

assessment of tumour stage, size, therapy response and

functional information before and during radiotherapy

(RT) in order to guide not only geometrical but also

biological adaptation during the course of RT treatment.

This talk will discuss a number of issues, which might

compromise the use of multi-parametric functional

imaging in a clinical setting. In order to register functional

PET/MR image data to the planning CT of an individual

patient, tailored patient positioning devices and

dedicated algorithms for PET attenuation correction with

respect to the hardware components of the positioning

aids are required. Furthermore, robust and accurate

deformable registration strategies may be required to

match PET/MR data acquired during RT to baseline

imaging data.

In addition, first results of a multi-parametric PET/MR

imaging study in head-and-neck cancer (HNC) patients will

be discussed. Here, [18F]FDG PET/CT images were

acquired in addition to functional PET/MR data consisting

of [18F]FMISO PET, anatomical T1- and T2-weighted as

well as diffusion weighted (DW) and dynamic contrast

enhanced (DCE) MR imaging. Voxel-based and regional

correlation analysis of mutual parameter pairs showed

moderate to low parameter correlations. However, on a

patient-to-patient basis large variations were observed for

most parameter correlations.

Consequently, robust and accurate workflows and image

acquisition protocols need to be identified in order to use

multi-parametric functional PET/MR imaging in the future

for adapted RT concepts in a clinical context.

SP-0308 Metabolic and functional MRI integration for

glioblastoma dose-painting trial.

A. Laprie

Institut Claudius Regaud, Toulouse Cedex 09, France

The ongoing spectro-glio trial (NCT01507506) is a phase III

multicentric randomized trial for newly diagnosed

glioblastoma.

It has included 165 patients among the 220 planned.

It compares arm A : STUPP protocol ( 60 GY + TMZ) with

arm B that includes an additional SIB targeted at MR

spectroscopic abnomalities ( CHO/NAA>2)+tumor bed at a

dose of 72Gy/2.4Gy

In this presentation we will discuss the original modalities,

the difficulties met and the solutions found for the

particularity of this trial

multicentric use of 3D MR spectroscopic imaging

developement of an innovative technique of integration of

MR spectroscopic imaging to RT-scan

centralized delineation of arm B patients - online quality

control of dosimetry in arm B patients

database developement

analysis techniques of this large prospective database of

anatomic, perfusion, diffusion and spectroscopic imaging

of glioblastoma.( follow-up every 3 months until relapse)

-preliminary imaging results

SP-0309 Plan of the day and dose-escalation for

bladder cancer (RAIDER Trial)

H. McNair

The Institute of Cancer Research and The Royal Marsden

NHS Foundation Trust, Sutton, United Kingdom

The major challenge in delivering accurate radiotherapy

to the bladder is to compensate for the daily variation in

organ size, shape and position. This change is mainly due

to differing degrees of bladder filling and can be

influenced by change in rectal volume. The plan of the day

approach has the potential to improve outcomes by

improving target coverage and decrease the dose to

bowel. However the unpredictable nature of bladder

filling and changes in organ dimensions require confident

and timely decision making for treatment delivery. This is

of particular importance when the does to the tumour bed

is escalated. This presentation will discuss the importance

of achieving a representative reference image and the

practicalities of the patient maintaining a consistent

drinking protocol. Clinical examples will be used to

illustrate common imaging problems with appropriate

decision making, in particular when not to proceed to

treatment. The importance of staff training and

maintaining competency to achieve consistent image

selection will also be discussed.

Acknowledgements: Emma Hall, Robert Huddart

and Shasita Hafeez and the RAIDER trials team.

Radiotherapy Trials Quality Assurance (RTTQA) team. We

also acknowledge funding to the NIHR Biomedical

Research Centre at The Royal Marsden and The Institute

of Cancer Research. Research at The Institute of Cancer

Research is also supported by Cancer Research UK under

Programme C33589/A19727. In addition the national trial

(RAIDER) was funded by Cancer Research UK

(CRUK/14/016)