ESTRO 36 Abstract Book

S160

ESTRO 36

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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)

Symposium: Registration and fusion techniques

SP-0310 Rigid registration techniques for different

imaging modalities

N. Nesvacil

Medical University of Vienna, Department of

Radiotherapy- CCC- Christian Doppler Laboratory for

Medical Radation Research for Radiation Oncology,

Vienna, Austria

Image registration has become an important part of

treatment planning and execution in 3D image guided

external beam radiotherapy (EBRT) and brachytherapy

(BT) during the last decades. In principle, the same

algorithms for rigid or non-rigid image registration can be

applied to either type of radiotherapy. However, for their

application in brachytherapy the presence of the

brachytherapy delivery device, i.e. the applicator, plays

an essential role. This presentation will provide an

overview of rigid registration techniques in

brachytherapy, compared to external beam radiotherapy.

In gynaecological brachytherapy, where the applicator

and CTV might move in relation to the bony anatomy

during the course of a (multi-fractionated) treatment,

applicator-based rigid registration can be used to combine

images for treatment planning acquired with the same or

different modalities at different time points. One of the

most useful applications of this technique is to transfer

target contours defined on a reference image, e.g. an MRI

at the time of the first BT, to subsequent CT image

volumes for planning of further BT fractions, if MRI is not

always available for dose plan adaptation to the anatomy

of the day. Requirements and pitfalls for clinical

applications of this technique will be discussed. In order

to analyse interfraction variations for target and organs at

risk (OARs) based on image volumes acquired at different

time points, rigid image registration can provide a good

estimate of the dosimetric impact of anatomical changes

between applicator, CTV and OARs. Clinical examples will

be discussed for different treatment sites. Limitations of

the technique will be summarized and special focus will

be given to prostate and gynaecological BT treatment

planning.

Multi-modal rigid image registration for brachytherapy is

also used to improve target delineation and dose plan

optimization for a single fraction. MRI acquired before

brachytherapy can be combined with CT images for

treatment planning of prostate cancer, in order to

visualize and delineate intraprostatic lesions as boost

target volumes in HDR or LDR brachytherapy.

In the setting of gynaecological cancer brachytherapy

where only CT is available for visualization of the

applicator and surrounding organs after implantation,

rigid registration of ultrasound images obtained with

applicator in situ could be used in the future for dual

modality dose planning of a single fraction. Challenges and

solutions for the registration of ultrasound and CT images,

such as determining the applicator position in the

ultrasound image volume, will be explored to conclude

this presentation.

SP-0311 Deformable registration for dose summation

K. Tanderup

Aarhus University Hospital, Department of Oncology,

Aarhus C, Denmark

Dose summation across brachytherapy fractions and

accumulation with external beam radiotherapy (EBRT)

dose is essential for assessment of total dose to both

targets and organs at risk in treatments with fractionated

brachytherapy and in combinations with EBRT.

Brachytherapy

dose

distributions

are

highly