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Title: Use of Respiratory-Correlated Four-Dimensional Computed Tomography to Determine Acceptable Treatment Margins for Locally Advanced Pancreatic Adenocarcinoma

Purpose: Respiratory-induced excursions of locally advanced pancreatic adenocarcinoma could affect dose delivery. This study quantified tumor motion and evaluated standard treatment margins. Methods and Materials: Respiratory-correlated four-dimensional computed tomography images were obtained on 30 patients with locally advanced pancreatic adenocarcinoma; 15 of whom underwent repeat scanning before cone-down treatment. Treatment planning software was used to contour the gross tumor volume (GTV), bilateral kidneys, and biliary stent. Excursions were calculated according to the centroid of the contoured volumes. Results: The mean +- standard deviation GTV excursion in the superoinferior (SI) direction was 0.55 +- 0.23 cm; an expansion of 1.0 cm adequately accounted for the GTV motion in 97% of locally advanced pancreatic adenocarcinoma patients. Motion GTVs were generated and resulted in a 25% average volume increase compared with the static GTV. Of the 30 patients, 17 had biliary stents. The mean SI stent excursion was 0.84 +- 0.32 cm, significantly greater than the GTV motion. The xiphoid process moved an average of 0.35 +- 0.12 cm, significantly less than the GTV. The mean SI motion of the left and right kidneys was 0.65 +- 0.27 cm and 0.77 +- 0.30 cm, respectively. At repeat scanning, no significant changes were seenmore » in the mean GTV size (p = .8) or excursion (p = .3). Conclusion: These data suggest that an asymmetric expansion of 1.0, 0.7, and 0.6 cm along the respective SI, anteroposterior, and medial-lateral directions is recommended if a respiratory-correlated four-dimensional computed tomography scan is not available to evaluate the tumor motion during treatment planning. Surrogates of tumor motion, such as biliary stents or external markers, should be used with caution.« less
Authors:
 [1] ; ; ; ;  [2] ;  [2]
  1. Department of Surgery, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins University, Baltimore, MD (United States)
  2. Department of Radiation Oncology and Molecular Radiation Sciences, Sol Goldman Pancreatic Cancer Research Center, Johns Hopkins University, Baltimore, MD (United States)
Publication Date:
OSTI Identifier:
21372078
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 76; Journal Issue: 2; Other Information: DOI: 10.1016/j.ijrobp.2009.06.009; PII: S0360-3016(09)00928-6; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; CARCINOMAS; COMPUTERIZED TOMOGRAPHY; FOUR-DIMENSIONAL CALCULATIONS; MOTION; PANCREAS; PLANNING BODY; DIAGNOSTIC TECHNIQUES; DIGESTIVE SYSTEM; DISEASES; ENDOCRINE GLANDS; GLANDS; NEOPLASMS; ORGANS; TOMOGRAPHY