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S36

ESTRO 36 2017

_______________________________________________________________________________________________

Respiratory motion is a major concern in the treatment of

lung tumors. Time resolved computed tomography (4D-CT)

is the clinical standard to determine internal target

volumes (ITVs). To overcome limitations of the 4D-CT

(radiation dose, averaging of breathing cycles) the aim of

this work is to develop a workflow for 4D-magnetic

resonance imaging (4D-MRI) based target volume

evaluation and determination.

Material and Methods

4D-MRI (real-time, 157 volumes) with a temporal

resolution of 0.5s and a spatial resolution of

3.91x3.91x10mm

3

, 4D-CT and breath-hold planning-CT

(pCT) with clinical structures of lung tumor patients were

utilized in this study. The diaphragm excursion in cranial-

caudal direction was evaluated for the retrospective

determination of the respiration phase on 4D-CT and 4D-

MRI. The established workflow is outlined in fig. 1. The

rigid registration from pCT to 4D-MRI and the

corresponding propagation of gross tumor volume (GTV)

and CT-based ITV

CT

were performed using the

Image

Processing Toolbox 9.2 (Matlab).

The non-rigid

registration and GTV propagation between the different

4D-MRI volumes was performed with the B-spline

algorithm of

plastimatch

version

1.6.3.

Fig 1: Schematic of the developed workflow: Computation

of the target volume monitoring requires p-CT, DICOM-RT

structures (GTV and ITV), 4D-CT and 4D-MRI.

Reconstruction of the breathing-curve from 4D-CT and 4D-

MRI enables a rigid registration of the p-CT to the 4D-MRI.

By rigid transformation the GTV and the CT-based ITV

CT

are transferred to the MRI. The estimation of the tumor

movement is done with a non-rigid registration of 4D-MRI

volumes and the propagation of the GTV structures.

Results

The detection of the diaphragm is robust and facilitates a

rigid registration of the p-CT to the most similar 4D-MRI

volume. Based on non-rigid transformations of the GTV in-

between the different volumes of the 4D-MRI, the

movement of the tumor is determined and tracked

(GTV

deformed

). The estimated breathing curve and two

representative MRI images are shown in fig. 2. The

algorithm highlights those voxels of the GTV

deformed

in red

which are not covered by the ITV

CT

. The ITV

CT

was too

small for 34 out of 157 MRI volumes of the shown

exemplary patient case. Maximally 7% of the GTV

deformed

were not covered by the ITV

CT

. An improved ITV

MR

can be

determined by the union of all GTV

deformed

.

Fig 2: The estimated breathing curve is shown in the upper

panel. The rigid registration form p-CT to 4D-MRI was

performed using the 4D-MRI volumes of time point C. In

the two shown MRI images the ITV

CT

and the deformed GTV

are marked for the two extreme values of the breathing

curve. For the time point B the GTV

deformed

is not covered

by the ITV

CT

.

Conclusion

The feasibility of 4D-MRI based target volume evaluation

and determination is demonstrated. The technic provides

improved determination of a 4D-MRI based ITV

MR

, which

covers the GTV motion over several breathing cycles. The

proposed technique can be used in MRI-guided

radiotherapy workflows.

OC-0073 Shoulder girdle impairment evaluation in

breast cancer patients undergoing surgery and

radiotherapy

D. Smaniotto

1

, D. Marchesano

1

, L. Boldrini

1

, V. Masiello

1

,

M. Giraffa

1

, L. Maggi

2

, E. Amabile

2

, P.E. Ferrara

2

, F.

Landi

2

, V. Valentini

1

, G. Mantini

1

1

Policlinico Universitario Agostino Gemelli- Catholic

University, Radiation Oncology Department - Gemelli

ART, Roma, Italy

2

Policlinico Universitario Agostino Gemelli- Catholic

University, Physical Medicine and Rehabilitation Unit,

Roma, Italy

Purpose or Objective

Aim of this study is to measure the incidence of pain and

functional impairment of the ipsilateral shoulder girdle in

patients who underwent surgery and radiotherapy (RT) for

breast cancer, in order to elaborate preventive

rehabilitation or treatments protocols contributing to an

increase of patient quality of life.

Material and Methods

Patients who underwent surgery and radiotherapy for

breast cancer since 2009 and currently in follow up

protocols were selected.

Exclusion criteria were the presence of moderate/severe

arthrosis history and/or rheumatologic diseases.

All the patients had complete physical and multi-

dimensional exams during joint RT and physical medicine

follow up visits.

The physical exam included the range of motion (ROM)

evaluation through goniometric measurement of flexion,

abduction, internal rotation and external rotation

movements of the shoulder girdle.

Pain trigger points were identified and global performance

status was assessed too.

The used scales were VAS (Visual Analogue Scale) for pain

and depression, DASH (Disability of the arm, shoulder and

hand) and the KI (Karnofsky Index).

Statistical analysis was realized with SPSS software v.14.

Results

111 patients were selected: 94% of them underwent

quadrantectomy while 6% had radical mastectomy. 60% of

them had SLNB, while 40% underwent lymphadenectomy.

72% of them underwent standard adjuvant RT (5040

cGy/180 cGy on the breast and 1000 cGy/200 cGy boost

and tumoral bed), while 28% had hypofractionated RT

(4005 cGy/267 cGy).

Mean ages of the groups were 57.9 and 70.1 years

respectively.

The ROM mean differences between the healthy and

surgery side in the standard treatment group were 7°56’

for shoulder flexion, 13°48’ for abduction, 1°12’ for

external rotation and 0°6’ for internal rotation.

In the hypofractionated group the observed mean values

were 8°52’, 11°8’, 0°35’ and 0°14’ respectively.

The standard RT group showed the following mean values:

VAS pain 2.0, VAS depression 3.7, DASH 12.4 and KI 91.5%.

For the hypofractionated group the following mean values

were recorded: VAS pain 2.4, VAS depression 4.8, DASH

16.8 and KI 91.2%.