Deep Inspiration breath-hold in gastric lymphomas.
Peter Meidahl Petersen,
Denmark
PD-0173
Abstract
Deep Inspiration breath-hold in gastric lymphomas.
Authors: Peter Meidal Petersen1, Laura Ann Rechner2, Lena Specht3
1Rigshospitalet, University of Copenhagen, Department of Oncology , Copenhagen, Denmark; 2Rigshospitalet, University of Copenhagen, Department of Oncology, Section of Radiotherapy, Copenhagen, Denmark; 3Rigshospitalet, University of Copenhagen, Department of Oncology, Copenhagen, Denmark
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Purpose or Objective
The aim of
this study was to assess the effect of the two components of assumed reduction to
the dose levels to organs at risk with deep inspiration breath-hold (DIBH)
compared with free breathing (FB): 1) the change of anatomy and 2) the
possibility of planning target volume (PTV) reduction.
Material and Methods
Radiation therapy plans were made for each of the15
patients using DIBH and FB scans. Clinical target volume (CTV) was the
stomach plus 1cm margin. The heart and surrounding organs at risk (OAR) were
contoured. We kept the variables constant separately and compared: 1) FB with 1
cm margin CTV to PTV margin in all directions vs FB with an additional 5mm
margin in cranio-caudal direction. 2) DIBH and FB with same CTV to PTV margin. Datasets were
analysed with Wilcoxon signed rank test for non-parametric paired data.
Results
Target coverage
was kept equal between FB and DIBH, while a little reduction of the estimated dose
to the heart was seen with the margin reduction and a more substantial
reduction with DIBH. Margin reduction causes a minor reduction of estimated
mean dose to the liver, duodenum, pancreas and spinal cord while the effect of DIBH
varies in between patients and between OAR’s (Table 1 and figure 1).
