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Title: Dosimetric evaluation of simultaneous integrated boost during stereotactic body radiation therapy for pancreatic cancer

Stereotactic body radiation therapy (SBRT) provides a promising way to treat locally advanced pancreatic cancer and borderline resectable pancreatic cancer. A simultaneous integrated boost (SIB) to the region of vessel abutment or encasement during SBRT has the potential to downstage otherwise likely positive surgical margins. Despite the potential benefit of using SIB-SBRT, the ability to boost is limited by the local geometry of the organs at risk (OARs), such as stomach, duodenum, and bowel (SDB), relative to tumor. In this study, we have retrospectively replanned 20 patients with 25 Gy prescribed to the planning target volume (PTV) and 33~80 Gy to the boost target volume (BTV) using an SIB technique for all patients. The number of plans and patients able to satisfy a set of clinically established constraints is analyzed. The ability to boost vessels (within the gross target volume [GTV]) is shown to correlate with the overlap volume (OLV), defined to be the overlap between the GTV + a 1(OLV1)- or 2(OLV2)-cm margin with the union of SDB. Integral dose, boost dose contrast (BDC), biologically effective BDC, tumor control probability for BTV, and normal tissue complication probabilities are used to analyze the dosimetric results. More than 65% of themore » cases can deliver a boost to 40 Gy while satisfying all OAR constraints. An OLV2 of 100 cm{sup 3} is identified as the cutoff volume: for cases with OLV2 larger than 100 cm{sup 3}, it is very unlikely the case could achieve 25 Gy to the PTV while successfully meeting all the OAR constraints.« less
Authors:
 [1] ; ;  [1] ;  [2] ;  [3] ;  [4] ; ;  [1]
  1. Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States)
  2. Department of Surgery, Cedars Sinai Medical Center, Los Angeles, CA (United States)
  3. Department of Gastrointestinal Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States)
  4. Department of Cross-Sectional Imaging Interventional Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States)
Publication Date:
OSTI Identifier:
22462424
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Dosimetry; Journal Volume: 40; Journal Issue: 1; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; ANIMAL TISSUES; EVALUATION; GEOMETRY; INTEGRAL DOSES; LIMITING VALUES; NEOPLASMS; PANCREAS; PATIENTS; PLANNING; PROBABILITY; RADIOTHERAPY; SMALL INTESTINE; SURGERY