title: 18F-FDG PET/CT-based gross tumor volume definition for radiotherapy in head and neck cancer: a correlation study between suitable uptake value threshold and tumor parameters.
abstract: BACKGROUND
  To define a suitable threshold setting for gross tumor volume (GTV) when using 18Fluoro-deoxyglucose positron emission tomography and computed tomogram (PET/CT) for radiotherapy planning in head and neck cancer (HNC).
  
  
  METHODS
  Fifteen HNC patients prospectively received PET/CT simulation for their radiation treatment planning. Biological target volume (BTV) was derived from PET/CT-based GTV of the primary tumor. The BTVs were defined as the isodensity volumes when adjusting different percentage of the maximal standardized uptake value (SUVmax), excluding any artifact from surrounding normal tissues. CT-based primary GTV (C-pGTV) that had been previously defined by radiation oncologists was compared with the BTV. Suitable threshold level (sTL) could be determined when BTV value and its morphology using a certain threshold level was observed to be the best fitness of the C-pGTV. Suitable standardized uptake value (sSUV) was calculated as the sTL multiplied by the SUVmax.
  
  
  RESULTS
  Our result demonstrated no single sTL or sSUV method could achieve an optimized volumetric match with the C-pGTV. The sTL was 13% to 27% (mean, 19%), whereas the sSUV was 1.64 to 3.98 (mean, 2.46). The sTL was inversely correlated with the SUVmax [sTL = -0.1004 Ln (SUVmax) + 0.4464; R2 = 0.81]. The sSUV showed a linear correlation with the SUVmax (sSUV = 0.0842 SUVmax + 1.248; R2 = 0.89). The sTL was not associated with the value of C-pGTVs.
  
  
  CONCLUSIONS
  In PET/CT-based BTV for HNC, a suitable threshold or SUV level can be established by correlating with SUVmax rather than using a fixed threshold.
authors.affiliation: Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan.
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
authors.forename: Te-Chun
authors.initials: TC
authors.lastname: Hsieh
authors.forename: Chun-Yen
authors.initials: CY
authors.lastname: Yu
authors.forename: Kuo-Yang
authors.initials: KY
authors.lastname: Yen
authors.forename: Shih-Neng
authors.initials: SN
authors.lastname: Yang
authors.forename: Yao-Ching
authors.initials: YC
authors.lastname: Wang
authors.forename: Ji-An
authors.initials: JA
authors.lastname: Liang
authors.forename: Chun-Ru
authors.initials: CR
authors.lastname: Chien
authors.forename: Shang-Wen
authors.initials: SW
authors.lastname: Chen
mesh_terms: D019788:Fluorodeoxyglucose F18; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
references.citation: J Nucl Med. 2008 Sep;49(9):1422-8
references.pmid: 18703597
references.citation: Radiother Oncol. 2004 Jun;71(3):267-73
references.pmid: 15172141
references.citation: Head Neck. 2009 Jun;31(6):709-16
references.pmid: 19260114
references.citation: Int J Radiat Oncol Biol Phys. 2004 Dec 1;60(5):1419-24
references.pmid: 15590173
references.citation: Int J Radiat Oncol Biol Phys. 2004 May 1;59(1):78-86
references.pmid: 15093902
references.citation: Int J Radiat Oncol Biol Phys. 2007 Nov 15;69(4):1282-9
references.pmid: 17967318
references.citation: J Clin Oncol. 2009 May 20;27(15):2509-15
references.pmid: 19332725
references.citation: Int J Radiat Oncol Biol Phys. 2009 May 1;74(1):9-14
references.pmid: 18930358
references.citation: J Clin Oncol. 2002 Oct 15;20(20):4199-208
references.pmid: 12377963
references.citation: Int J Radiat Oncol Biol Phys. 2004 Nov 15;60(4):1272-82
references.pmid: 15519800
references.citation: Int J Radiat Oncol Biol Phys. 2003 Nov 1;57(3):853-63
references.pmid: 14529793
references.citation: Int J Radiat Oncol Biol Phys. 2006 Jul 1;65(3):726-32
references.pmid: 16626888
references.citation: Int J Radiat Oncol Biol Phys. 2006 May 1;65(1):143-51
references.pmid: 16618577
references.citation: Int J Radiat Oncol Biol Phys. 2005 Nov 15;63(4):1016-23
references.pmid: 15979817
references.citation: Radiother Oncol. 2002 Jan;62(1):51-60
references.pmid: 11830312
references.citation: J Nucl Med. 1995 Oct;36(10):1747-57
references.pmid: 7562038
references.citation: J Nucl Med. 2006 Nov;47(11):1808-12
references.pmid: 17079814
references.citation: J Clin Oncol. 1998 Nov;16(11):3550-5
references.pmid: 9817274
references.citation: Int J Radiat Oncol Biol Phys. 2007 Sep 1;69(1):286-93
references.pmid: 17707283
references.citation: Eur J Nucl Med Mol Imaging. 2005 Dec;32(12):1392-9
references.pmid: 16133395
references.citation: Radiat Oncol. 2007 Jun 09;2:22
references.pmid: 17559684
references.citation: J Nucl Med. 2005 Aug;46(8):1342-8
references.pmid: 16085592
references.citation: Int J Radiat Oncol Biol Phys. 2005 Apr 1;61(5):1385-92
references.pmid: 15817341
references.citation: Radiother Oncol. 2000 Jun;55(3):317-24
references.pmid: 10869746
references.citation: J Nucl Med. 2009 Oct;50(10):1655-65
references.pmid: 19759099
references.citation: Int J Radiat Oncol Biol Phys. 2007 Jul 1;68(3):763-70
references.pmid: 17379435
references.citation: Eur J Nucl Med Mol Imaging. 2007 Dec;34(12):1953-62
references.pmid: 17717661
references.citation: J Clin Oncol. 2001 Jan 1;19(1):111-8
references.pmid: 11134203
references.citation: Cancer. 1997 Dec 15;80(12 Suppl):2505-9
references.pmid: 9406703
references.citation: Radiat Oncol. 2008 Sep 18;3:29
references.pmid: 18801181
references.citation: Int J Radiat Oncol Biol Phys. 2009 Mar 1;73(3):759-63
references.pmid: 18834671
references.citation: Int J Radiat Oncol Biol Phys. 2002 Feb 1;52(2):339-50
references.pmid: 11872279