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S36
ESTRO 36 2017
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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%.