title: Image quality & dosimetric property of an investigational imaging beam line MV-CBCT.
abstract: To measure and compare the contrast to noise ratio (CNR) as a function of dose for the CBCTs produced by the mega-voltage (MV) imaging beam line (IBL) and the treatment beam line (TBL), and to compare the dose to target and various critical structures of pediatric patients for the IBL CBCT versus standard TBL orthogonal port films. Two Siemens Oncor linear accelerators were modified at our institution such that the MV-CBCT would operate under an investigational IBL rather than the standard 6MV TBL. Prior to the modification, several CBCTs of an electron density phantom were acquired with the TBL at various dose values. After the modification, another set of CBCTs of the electron density phantom were acquired for various doses using the IBL. The Contrast to Noise Ratio (CNR) for each tissue equivalent insert was calculated. In addition, a dosimetric study of pediatric patients was conducted comparing the 1 cGy IBL CBCT and conventional TBL orthogonal pair port films. The CNR for eight tissue equivalent inserts at five different dose settings for each type of CBCT was measured. The CNR of the muscle insert was 0.8 for a 5 cGy TBL CBCT, 1.1 for a 1.5 cGy IBL CBCT and 2.8 for a conventional CT. The CNR of the trabecular bone insert was 2.9 for a 5 cGy TBL CBCT, 5.5 for a 1.5 cGy IBL CBCT and 14.8 for a conventional CT. The IBL CBCT delivered approximately one-fourth the dose to the target and critical structures of the patients as compared to the TBL orthogonal pair port films. The IBL CBCT improves image quality while simultaneously reducing the dose to the patient as compared to the TBL CBCT. A 1 cGy IBL CBCT, which is used for boney anatomy localization, delivers one-fourth the dose as compared to conventional ortho-pair films.
authors.affiliation: Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Beltran
authors.affiliation: Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, USA.
authors.forename: Renin
authors.initials: R
authors.lastname: Lukose
authors.affiliation: Siemens Medical USA, Concord, CA, USA.
authors.forename: Bijumon
authors.initials: B
authors.lastname: Gangadharan
authors.affiliation: Siemens Medical USA, Concord, CA, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Bani-Hashemi
authors.affiliation: Department of Radiation Oncology, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Faddegon
mesh_terms: D054893:Cone-Beam Computed Tomography / Q000379:methods*; D006801:Humans; D010315:Particle Accelerators; D019047:Phantoms, Imaging
references.citation: Med Phys. 2007 May;34(5):1819-27
references.pmid: 17555263
references.citation: Med Phys. 2008 Feb;35(2):480-6
references.pmid: 18383668
references.citation: Med Phys. 2007 Feb;34(2):499-506
references.pmid: 17388167
references.citation: J Pediatr Hematol Oncol. 2005 Aug;27(8):444-8
references.pmid: 16096529
references.citation: Int J Radiat Oncol Biol Phys. 2007 Mar 1;67(3):942-53
references.pmid: 17293243
references.citation: Int J Radiat Oncol Biol Phys. 2006 Oct 1;66(2):323-6
references.pmid: 16965986
references.citation: Med Phys. 2006 Jun;33(6):1573-82
references.pmid: 16872065
references.citation: Med Phys. 2004 Apr;31(4):849-59
references.pmid: 15125003
references.citation: Int J Radiat Oncol Biol Phys. 2007 Jun 1;68(2):555-61
references.pmid: 17398021
references.citation: Int J Radiat Oncol Biol Phys. 1999 Oct 1;45(3):773-89
references.pmid: 10524434
references.citation: Int J Radiat Oncol Biol Phys. 2002 Mar 1;52(3):599-605
references.pmid: 11849779
references.citation: Int J Radiat Oncol Biol Phys. 2007 May 1;68(1):243-52
references.pmid: 17331671
references.citation: Int J Radiat Oncol Biol Phys. 2007 Mar 15;67(4):1229-37
references.pmid: 17336223
references.citation: Int J Radiat Oncol Biol Phys. 2005 Jul 15;62(4):1239-46
references.pmid: 15913917
references.citation: Int J Radiat Oncol Biol Phys. 2005 Feb 1;61(2):552-60
references.pmid: 15736320
references.citation: Lung Cancer. 2007 Apr;56(1):77-88
references.pmid: 17169461
references.citation: Int J Radiat Oncol Biol Phys. 2005 Nov 15;63(4):975-84
references.pmid: 16253772
references.citation: Phys Med Biol. 2007 Mar 21;52(6):1595-615
references.pmid: 17327651
references.citation: AJR Am J Roentgenol. 2001 Feb;176(2):289-96
references.pmid: 11159059
references.citation: J Appl Clin Med Phys. 2006 Mar 27;8(1):10-20
references.pmid: 17592447
references.citation: Med Phys. 2008 Dec;35(12):5777-86
references.pmid: 19175135
references.citation: Int J Radiat Oncol Biol Phys. 2007 Jun 1;68(2):547-54
references.pmid: 17418964