535 / 1096
S520
ESTRO 36
_______________________________________________________________________________________________
Results
We may observe a reduction in dose at V35% and V50% in
all OAR and also a reduction in D2cm
3
occurs (Table 1).
PTV parameters increase in the case of Axxent, as
reported previously, but very few cases of vaginal
mucositis have been reported in our center as is showed
in another clinical abstract. All patients were treated
between 2015 and early 2016, enough time to develop
early problems.
Conclusion
Preliminary results are very optimistic about the adequacy
of Xoft equipment for treatment of endometrial cancer
with a clear reduction of the physical dose in organs at risk
and very few development of acute mucositis despite the
considerable increase V150 in the treatment volume.
Further studies will be necessary to take into account the
RBE in treatments with such sources.
PO-0940 3D mapping for precise definition of GTV,
CTV and their correlation in cervix cancer BT
(EMBRACE)
S. Banerjee
1
, R. Pötter
2
, C. Kirisits
2
, K. Majercakova
2
,
M.P. Schmid
2
, S.K. Shrivastava
3
, U. Mahantshetty
3
1
Medanta The Medicity, Radiation Oncology, Gurgaon,
India
2
Vienna General Hospital- Medical University of Vienna,
Departmentof Radiation Oncology, Vienna, Austria
3
Tata Memorial Hospital, Department of Radiation
Oncology, Mumbai, India
Purpose or Objective
Image Guided adaptive Brachytherapy (BT) for cervix
cancer is based on MRI and gynaecologic examination (GE)
at diagnosis (D) and at BT to define the HR CTV. For
documentation of disease at D and at BT schematic
mapping diagrams (SMD) are used indicating values for
maximum dimensions of GTV at D and at BT. For
comprehensive assessment of available volumetric
information through MRI at D and at BT an advanced
schematic 3D mapping diagram (3DMD) was developed to
provide precise reproducible topographic and quantitative
information (Fig1). This was used to evaluate the
topographic and quantitative relation between GTVD, HR
CTV and IR CTV.
Material and Methods
42 proven cervical cancer FIGO IIB-IIIB patients from
Vienna and Mumbai were selected, mean age was 52
years. All were enrolled in the EMBRACE study and
completed the planned treatment with MRI at D and at BT.
SMDs from GE with individual tumour contours and
dimensions as prescribed for EMBRACE were available.
A 3DMD in axial, coronal and sagittal orientation was used
with a scale (grid with 10 mm distance) for the precise
documentation of available volumetric information
through MRI at D and at BT. This 3DMD had been developed
by the authors to provide precise reproducible
topographic and quantitative information in one
comprehensive overview (Fig1).
Dimensions of GTV
D
, HR-CTV and IR-CTV for width,
thickness
and
maximum
height
(GEC-ESTRO
Recommendations) as assessed on MRI D/BT (SE T2
weighted sequences) was drawn at all grid levels and in all
3 dimensions as requested in the 3DMD. The cervical canal
was taken as the central axis and the external os
(surrogate for flange) as reference for the various
dimensions.
A qualitative observation was done based on the drawings
of all 42 cases on individual maps. A quantitative analysis
was done with SPSS v20. The dimensions (height, width
and thickness) and volumes were compared and correlated
(n= 42). Thereafter another quantitative analysis of the
widths of GTVD, HRCTV and IRCTV at 0, 1, 2 and 3 cm and
at NMD (Near Maximum distance from the central
tandem/central canal) was done (n=84).
Results
The dimensions of the HRCTV followed closely that of
GTVD, with some variations and exceptions. The IRCTV
volumes were closely overlapping the HRCTV volumes. In
most of the cases the HRCTV and IRCTV were
encompassing the GTVD volumes.
For the detailed quantitative results see table 1.