title: Motion-specific internal target volumes for FDG-avid mediastinal and hilar lymph nodes.
abstract: OBJECTIVE
  To quantify the benefit of motion-specific internal target volumes for FDG-avid mediastinal and hilar lymph nodes generated using 4D-PET, vs. conventional internal target volumes generated using non-respiratory gated PET and 4D-CT scans.
  
  
  METHODS
  Five patients with FDG-avid tumors metastatic to 11 hilar or mediastinal lymph nodes were imaged with respiratory-correlated FDG-PET (4D-PET) and 4D-CT. FDG-avid nodes were contoured by a radiation oncologist in two ways. Standard-of-care volumes were contoured using conventional un-gated PET, 4D-CT, and breath-hold CT. A second, motion-specific, set of volumes were contoured using 4D-PET.Contours based on 4D-PET corresponded directly to an internal target volume (ITV(4D)), whereas contours based on un-gated PET were expanded by a series of exploratory isotropic margins (from 5 to 13 mm) based on literature recommendations on lymph node motion to form internal target volumes (ITV(3D)).
  
  
  RESULTS
  A 13 mm expansion of the un-gated PET nodal volume was needed to cover the ITV(4D) for 10 of 11 nodes studied. The ITV(3D) based on a 13 mm expansion included on average 45 cm(3) of tissue that was not included in the ITV(4D).
  
  
  CONCLUSIONS
  Motion-specific lymph-node internal target volumes generated from 4D-PET imaging could be used to improve accuracy and/or reduce normal-tissue irradiation compared to the standard-of-care un-gated PET based internal target volumes.
authors.affiliation: Department of Radiation Oncology, David Geffen School of Medicine, UCLA, Los Angeles, USA. Electronic address: jlamb@mednet.ucla.edu.
authors.forename: James M
authors.initials: JM
authors.lastname: Lamb
authors.forename: Clifford G
authors.initials: CG
authors.lastname: Robinson
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Bradley
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Low
mesh_terms: D059248:Chemoradiotherapy; D019788:Fluorodeoxyglucose F18; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008482:Mediastinum / Q000000981:diagnostic imaging*; D009038:Motion; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 4D PET/CT; Internal target volume; Lung cancer; Motion management; Treatment planning
references.citation: J Natl Cancer Inst. 1996 Sep 4;88(17):1210-5
references.pmid: 8780630
references.citation: J Nucl Med. 2006 Nov;47(11):1808-12
references.pmid: 17079814
references.citation: Med Phys. 2007 Jul;34(7):3067-76
references.pmid: 17822014
references.citation: Int J Radiat Oncol Biol Phys. 2005 Sep 1;63(1):253-60
references.pmid: 16111596
references.citation: Radiology. 2000 Jun;215 Suppl:1363-72
references.pmid: 11037552
references.citation: Radiother Oncol. 2006 Dec;81(3):264-8
references.pmid: 17113668
references.citation: Radiother Oncol. 2004 May;71(2):139-46
references.pmid: 15110446
references.citation: Int J Radiat Oncol Biol Phys. 2012 Jan 1;82(1):e99-105
references.pmid: 21377285
references.citation: Med Phys. 2009 Dec;36(12):5547-58
references.pmid: 20095267
references.citation: J Nucl Med Technol. 2011 Jun;39(2):91-9
references.pmid: 21565957
references.citation: Radiother Oncol. 2009 Apr;91(1):85-94
references.pmid: 19100641
references.citation: Int J Radiat Oncol Biol Phys. 2009 Jul 15;74(4):1092-9
references.pmid: 19095370
references.citation: Semin Radiat Oncol. 2011 Apr;21(2):88-100
references.pmid: 21356477
references.citation: Int J Radiat Oncol Biol Phys. 2012 Apr 1;82(5):1636-41
references.pmid: 21489715
references.citation: Int J Radiat Oncol Biol Phys. 2007 Dec 1;69(5):1402-8
references.pmid: 17920783
references.citation: Radiat Oncol. 2009 Jan 30;4:5
references.pmid: 19183471
references.citation: Int J Radiat Oncol Biol Phys. 2008 Nov 15;72(4):1250-8
references.pmid: 18823717
references.citation: Int J Radiat Oncol Biol Phys. 2012 Mar 15;82(4):1541-8
references.pmid: 21664070
references.citation: Int J Radiat Oncol Biol Phys. 2007 Oct 1;69(2):580-8
references.pmid: 17869671
references.citation: Med Phys. 2011 Oct;38(10):5732-7
references.pmid: 21992387
references.citation: Int J Radiat Oncol Biol Phys. 2012 May 1;83(1):459-66
references.pmid: 22197228
references.citation: J Clin Oncol. 2007 Dec 10;25(35):5557-61
references.pmid: 17984185
references.citation: J Clin Oncol. 2010 May 1;28(13):2181-90
references.pmid: 20351327
references.citation: Med Phys. 2009 May;36(5):1775-84
references.pmid: 19544796
references.citation: Phys Med Biol. 2008 Jul 7;53(13):3661-79
references.pmid: 18562782
references.citation: Eur J Nucl Med Mol Imaging. 2011 Apr;38(4):663-72
references.pmid: 21225425